Research Ivan Janssens

Abstract

CARBIZON provides a new technology for soil engineering. It is our ambition to achieve 'negative erosion with CO2 removal': rebuilding soils based on natural soil regeneration technology, combined with CO2 sequestration. To achieve this, CARBIZON combines three nature-based carbon dioxide removal methods (CDRs) to rapidly restore fertile topsoil. The technology provides a drastic solution to the longstanding issue of soil degradation in the Global South. With CARBIZON, we aim to reverse the effects of soil degradation and create healthy, fertile soils that can re-support sustainable agriculture, while also taking up massive amounts of carbon from the atmosphere. The issue of soil degradation is a major concern in the Global South, affecting millions of individuals who depend on agriculture for their livelihoods. Key value of CARBIZON technology lies in its potential beyond carbon sequestration. The CARBIZON approach improves soil water retention (rendering irrigation more efficient), it provides a natural source of essential micro- and macro-nutrients, fostering healthy crop growth, and creates a stable soil matrix that fosters soil health and prevents renewed erosion. Our approach ensures that the soil is not only climate-proof, but also resource-smart, making it suitable for sustainable agriculture in the long run. We envision that CARBIZON will deliver the crucial foundation to initiate the development of a carbon-as-a-service business model in soil restoration, providing landowners and governments with the innovation potential to restore degraded soils. Our approach puts a sustainable business model into future-proofing soils in the Global South, largely financed by the carbon market through the sales of the carbon credits obtained by CO2 sequestration.

Researcher(s)

• Promoter: Vicca Sara
• Co-promoter: Janssens Ivan
• Co-promoter: Struyf Eric

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Ecosystems sustain society by providing natural resources and socio-economic services. Understanding their functioning is thus vital for accurate projections of, among others, global climate and food production and prerequisite to drawing up policies for sustainable management of the planet. This proposal therefore aims at creating the scientific breakthroughs needed to make major advances in understanding of several critical processes that determine the functioning of ecosystems and their interactions with ongoing changes in climate and in resource availabilities. The overarching, long-term goal is to understand ecosystem functioning sufficiently well so that we can, in collaboration with modelling groups, confidently project how ecosystem functioning and services will change in the near and distant future. To pursue this goal, the following four research lines will be prioritized when allocating the Methusalem funding: 1. Obtaining a quantitative understanding of plant carbon allocation to growth, energy production (respiration), and nutrient acquisition (fine roots, root exudation, root symbionts). 2. Improving insight in, and measurements of, biomass production. 3. Better understanding soil carbon dynamics and sequestration. 4. Understanding spatial and temporal variation in carbon and greenhouse gas balances at ecosystem to regional scale and attribution to drivers. In each of these research lines, we aim to understand the mechanisms underlying the global and local spatial variation as well as those underlying the long-term trends and short-term temporal patterns. Focus is on how Global Changes (climate change including extreme events, increasing atmospheric CO2 concentration, nitrogen deposition, etc.) are affecting ecosystem processes and functioning. Many projects will be conducted with the research group of the Methusalem Chair at the University of Hasselt as prioritized partners.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Campioli Matteo
• Co-promoter: Matthysen Erik
• Co-promoter: Nijs Ivan
• Co-promoter: Schoelynck Jonas
• Co-promoter: Temmerman Stijn
• Co-promoter: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Safe and scalable negative emission technologies (NETs), which actively remove CO2 from the atmosphere and provide long-term carbon sequestration, are needed to complement conventional climate change mitigation measures. There are low-tech and less expensive NETs that can provide additional benefits to society. One such NET is 'enhanced weathering' of silicate minerals (EW). EW is particularly promising as a NET because it can be associated with multiple societal and environmental benefits, as well as avoiding competition for land with food production. Greater crop yields, restoration of stocks of basic cations (e.g. Mg, Ca) and micronutrients (e.g. Zn, Se), less loss of N2O (a potent greenhouse gas) and NO3, higher pH. EW is not the only NET that can be applied in agriculture and provide additional benefits. The addition of organic matter (Soil Carbon Sequestration; SCS) and of biochar (BC) to soils is also being investigated. Research is needed to quantify impacts on climate change mitigation and adaptation, and the other environmental and societal benefits. The true potential of agro-NETs depends on the combination of net greenhouse gas emission reductions, agricultural benefits, positive side effects on the environment, societal barriers and economic feasibility. The most climate effective, environmentally friendly and cost-efficient options must be identified to enable rapid adoption by farmers and society. C-Farms will therefore not only assess climatic, technical and economic aspects, but also engage with farmers and industry to proactively address key opportunities and challenges in a co-creative process. Stakeholder engagement will culminate in a major joint pilot study. This will pave the way for policy measures (e.g. carbon pricing) to encourage this application.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Tropical forests play a crucial role in the global carbon (C) cycle, and the African continent holds the second largest continuous block of tropical forest worldwide. Through a persistent research bias, our current understanding of ecosystem-atmosphere C exchange is mainly based on the Neotropics, while the Congo basin remains a blind spot. However, recent efforts have uncovered that these forests stand out by their ecological, climatological and biogeochemical differences with their Neotropical counterpart. Especially the much drier, bimodal rainfall distribution raises questions on the seasonal C dynamics in these forests. As such, this proposal aims to deliver an in-depth characterization of the annual and seasonal C exchange of a central African forest, using combination of new eddy covariance infrastructure and intensive C monitoring at a research site in the heart of the Congo basin. Moreover, the proposal wants to uncover the ecological basis for seasonal changes in C exchange, by valorising an extensive, historic species-specific phenology dataset. This dataset will help us to tackle the question: can we predict present-day gross primary productivity from species-specific drought avoidance strategies? Finally, the mechanistic -biogeochemical - understanding, along with the underlying ecological knowledge, will be used to look beyond the research site-level, and assess the basin-wide seasonality in C exchange in the Congo basin.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Bauters Marijn

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The European Green Deal relies on healthy forests to remove carbon (C) from the atmosphere, stabilize the water cycle and provide sufficient biomass for the future bioeconomy. The Flanders Forest Living lab realizes a specific breakthrough in the assessment of these crucial ecosystem functions, at spatial scales ranging from the individual tree to the entire forest. The Living Lab is situated in an ICOS flux-tower observatory, that currently already provides a permanent assessment of ecosystem scale CO2-fluxes, evapotranspiration and respiration. To date however, no technique is available to study the function of individual trees, at daily resolution, across a forest. achieving this is the groundbreaking objective of this new infrastructure. Its specific equipment allows for crucial realistic simulation of the water-, energy- and carbon fluxes by advanced vegetation models at spatial scales matching those of satellite imagery products, thereby creating new possibilities for applications such as automated precision forestry management, fire prevention and worldwide carbon budget quantifications. The new infrastructure involves an UAV and a set of linked validation sensors. Observations are steered by artificial intelligence, in order to be able to adapt the flight pattern to the fluctuating source area of the flux-tower, and in order to proactively adapt to specific weather patterns and potentially interesting ground-sensor observations.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Campioli Matteo
• Co-promoter: Gielen Bert
• Co-promoter: Latré Steven
• Co-promoter: Nijs Ivan
• Co-promoter: Roland Marilyn
• Co-promoter: Scheunders Paul
• Co-promoter: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The "Pilot Application in Urban Landscapes - Towards integrated city observatories for greenhouse gases" (PAUL) project supports the European Green Deal by creating capabilities to observe and verify greenhouse gas emissions from densely populated urban areas across Europe. Cities are recognized as important anthropogenic greenhouse gas emission hotspots and therefore play a significant role in any emission reduction efforts. The PAUL project aims to increase our understanding of specific needs of greenhouse gas emission assessment in urban environments; it compares available and novel observational approaches and implements an integrated concept for a city observatory, providing unique data sets that feed diverse modelling approaches, scientific studies and will be the base of services towards the city administrations. A specifically innovative approach is the co-design of services, models and observations between city administrators and scientists from multiple disciplines including social and governmental sciences.The PAUL co-design approach will explore the needs of the cities and combine these with the scientific outcomes. This allows to introduce smart services to the cities, supporting evidence-based decisions on climate action and strategic investments. Overarching goals of PAUL are to: 1) implement elements of a pilot city observatory in a large (Paris), a medium (Munich) and a small (Zurich) European city, 2) collaborate with city stakeholders and engage citizens in co-designing services that are required for GHG monitoring in order to validate the implementation of Paris Agreement, and 3) increase our understanding of specific needs of GHG assessment in urban environments and create a service portfolio for setting up an urban greenhouse gas observatory.

Researcher(s)

• Promoter: Gielen Bert
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Conventional climate change mitigation alone will not be able to stabilise atmospheric CO2 concentrations at a level compatible with the 2°C warming limit of the Paris Agreement. Safe and scalable negative emission technologies (NETs), which actively remove CO2 from the atmosphere and ensure long-term carbon (C) sequestration, will be needed. Fast progress in NET-development is needed, if NETs are to serve as a risk-hedging mechanism for unexpected geopolitical events and for the transgression of tipping points in the Earth system. Still, no NETs are even on the verge of achieving a substantial contribution to the climate crisis in a sustainable, energy-efficient and cost-effective manner. BAM! develops 'super bio-accelerated mineral weathering' (BAM) as a radical, innovative solution to the NET challenge. While enhanced silicate weathering (ESW) was put forward as a potential NET earlier, we argue that current research focus on either 1/ ex natura carbonation or 2/ slow in natura ecosystem-based ESW, hampers the potential of the technology to provide a substantial contribution to negative emissions within the next two decades. BAM! focuses on an unparalleled reactor effort to maximize biotic weathering stimulation at low resource inputs, and implementation of an automated, rapidlearning process that allows to fast-adopt and improve on critical weathering rate breakthroughs. The direct transformational impact of BAM! lies in its ambition to develop a NET that serves as a climate risk hedging tool on the short term (within 10-20 years). BAM! builds on the natural powers that have triggered dramatic changes in the Earth's weathering environment, embedding them into a novel, reactor-based technology. The ambitious end-result is the development of an indispensable environmental remediation solution, that transforms large industrial CO2 emitters into no-net CO2 emitters.

Researcher(s)

• Promoter: Vicca Sara
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Besides rapid decarbonization of all sectors, limiting global warming to well below 2°C will also require active removal of CO2 from the atmosphere. A number of so-called negative emission technologies (NETs) have been proposed for this purpose, including several land-based solutions using natural processes. A promising but yet poorly studied land-based NET is accelerated silicate weathering (EW). When silicates weather, a slow dissolution process occurs, binding CO2 in aqueous form. This CO2 is sequestered for millennia. The idea behind EW is to speed up this natural process, by artificially increasing the weathering rate. This can be achieved by distributing finely ground silicate rock (e.g. basalt) or artificial silicates such as steel slag on soils. While the latter weathers more slowly, using waste streams has the advantage that source material is abundant and that it can be embedded in a circular economy. Thus far, research on EW has mainly been limited to laboratory experiments. Empirical research under more realistic conditions is urgently needed to determine the true climate change mitigation potential as well as the side-effects of EW. An essential step between the lab-based research and applications in the field are mesocosm experiments that allow accurate quantification of the CO2 sequestration and method development for practical C sequestration assessment in the field. In this project, a mesocosm experiment will be set up to accurately quantify CO2 sequestration by EW. Sideeffects on plant growth and plant nutrient concentrations will also be quantified. Specifically, 15 mesocosms will be filled with agricultural soil and planted with maize. Five receive only fertilizer, while the others receive also finely ground basalt (n=5) or steel slag (n=5), i.e., a natural and an artificial silicate. Weathering rates are monitored by analyzing top soil pore water samples as well as leachates for weathering products (DIC, alkalinity, Si, Mg and Ca). Weathering products can also precipitate in the soil and quantification of CO2 sequestration rates thus also requires analysis of carbonates in the soil after the experiment. Plants are harvested at the end of the experiment to quantify plant biomass (above- and belowground) and subsamples are analyzed for important plant nutrients, including N, P, K, Si, Ca, Mg.

Researcher(s)

• Promoter: Vicca Sara
• Co-promoter: Janssens Ivan
• Co-promoter: Meysman Filip

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The objective of the Copernicus Cal/Val Solution (CCVS) is to define a holistic solution for all Copernicus Sentinel missions (either operational or planned) to overcome current limitations of Calibration and Validation (Cal/Val) activities. Operational Cal/Val is required to ensure the quality of and build confidence in Copernicus data. However, these activities are currently limited by the following considerations: • The requirements and objectives need to be revisited to consider new usage of Copernicus products, inter-operability requirements, and to anticipate the needs of future Copernicus missions • Current Cal/Val activities are constrained by programmatic and budgetary requirements and do not necessarily follow scientific priorities • Cal/Val activities depend on the operational availability of high-quality Fiducial Reference Measurements (FRM) which are today mostly provided by external entities without strong commitment to the Copernicus program • Synergies within Copernicus and with other national and international programs are not systematically explored. To address these limitations CCVS will propose: • An updated specification of Cal/Val requirements for the Sentinel missions, taking into account inter-operability needs • An overview of existing Calibration and Validation sources and means • A gap analysis identifying missing elements and required developments in terms of technologies and instrumentation, Cal/Val methods, instrumented sites and dissemination service. • A comprehensive Copernicus Cal/Val Solution to organize the long-term provision of FRM for Sentinel missions • A roadmap documenting how the Cal/Val Solution can be implemented, highlighting responsibility, cost and schedule aspects. This plan will be elaborated in concertation with all stakeholders through four Working Groups gathering European Space Agencies, Copernicus Services, measurements and International partners.

Researcher(s)

• Promoter: Gielen Bert
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Autumn phenological events (e.g. leaf senescence) signal the end of vegetation activity in deciduous trees and alter their albedo, thereby exerting a strong control on various ecological processes and climate feedbacks. Predicting their timing with high accuracy is a prerequisite for better understanding the climate-ecosystem interactions. Modeling autumn phenology at larger spatial and temporal scales remains challenging, because the processes behind autumn phenological events are not well understood. Previous experimental studies have not resulted in a strong consensus on the relationship between environmental cues and leaf senescence. Most of current phenological models regarded temperature and/or photoperiod sum as the primary predictors, but have neglected the impact of other, recently discovered cues, such as nutrient limitation and drought extremes. In this project, the applicant seeks to: i) set up a database covering the records extracted from phenological observation networks as well as metrics derived from eddy covariance and remote sensing-based measurement. ii) evaluate current models at multiple spatial scales. iii) develop a new mechanistic/semimechanistic model that considers recently discovered environmental cues and allows improved model structures. The applicant will also couple this newly developed phenology model with a state-of-the art dynamic global vegetation model to improve its predictive capacity of ecosystem carbon balances.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Campioli Matteo
• Fellow: Liu Qiang

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Fens are nutrient-poor wetlands characterized by active accumulation of organic plant matter (peat). This process requires waterlogged conditions and low microbial activity. Fens are important global sinks for atmospheric carbon dioxide (CO2), an important greenhouse gas (GHG). Unfortunately very few undisturbed fens remain, and most fens have been drained by human activity. Drainage triggers a myriad of cascading effects on fen biogeochemistry, vegetation and microbiology, and turns fens into sources of CO2. To make matters worse, fens are also increasingly threatened by nitrogen (N) enrichment. This may hamper peat formation, and could increase emissions of other potent GHGs such as methane (CH4) and nitrous oxide (N2O). The idea that degraded fens can quickly be restored by raising water levels seems naïve: recent observations suggest that rewetted fens often become nutrient-rich marshes. The effect of the drainage-rewetting cycle on GHG emissions is largely unknown, but might be dramatic. In this project, I will disentangle the interactive effects of fen hydrology and nitrogen enrichment on GHG emission. Moreover, I will investigate the influence of shifts in plant- and microbial community composition on altered GHG emissions. We hypothesize that drainage and N enrichment turn fens from sinks into sources of GHGs, and that this is partly due to shifts in plant- and microbial community composition. This change may be irreversible within human time-scales.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Janssens Ivan
• Fellow: Emsens Willem-Jan

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

Autumn phenological events (e.g. leaf senescence) signal the end of vegetation activity in deciduous trees and alter their albedo, thereby exerting a strong control on various ecological processes and climate feedbacks. Predicting their timing with high accuracy is a prerequisite for better understanding the climate-ecosystem interactions. Modeling autumn phenology at larger spatial and temporal scales remains challenging, because the processes behind autumn phenological events are not well understood. Previous experimental studies have not resulted in a strong consensus on the relationship between environmental cues and leaf senescence. Most of current phenological models regarded temperature and/or photoperiod sum as the primary predictors, but have neglected the impact of other, recently discovered cues, such as nutrient limitation and drought extremes. In this project, the applicant seeks to: i) set up a database covering the records extracted from phenological observation networks as well as metrics derived from eddy covariance and remote sensing-based measurement. ii) evaluate current models at multiple spatial scales. iii) develop a new mechanistic/semi-mechanistic model that considers recently discovered environmental cues and allows improved model structures. The applicant will also couple this newly developed phenology model with a state-of-the art dynamic global vegetation model to improve its predictive capacity of ecosystem carbon balances.

Researcher(s)

• Promoter: Campioli Matteo
• Co-promoter: Janssens Ivan
• Fellow: Liu Qiang

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The assessment of carbon cycle in the Earth-climate system is one the highest challenge in science nowadays. It still remains some key knowledge gaps and uncertainties concerning the budgets of greenhouse gases (GHGs) at ecosystem scale and the key role of microbial communities. Karst ecosystems cover up to 25 % of the land surface and they are acting as rapid CH4 sink and as alternately CO2 source or sink. Pioneer results point to microbial action must be playing a crucial role in CO2 and CH4 uptake, fixation or production and maybe determining the strong variations of these major GHGs in karst ecosystems. MIFLUKE will elucidate, for the first time, the role of karst microbiota in the main GHGs -CO2 and CH4- content and fluxes in underground vadose atmospheres, as a key challenge to clarify the accurate effective contribution of karst ecosystems to the global carbon cycle. By applying an innovative and multidisciplinary combination of a broad suite of advanced tools and cutting-edge technologies from very different research areas -GHGs flux monitoring, isotopic geochemical tracing, biogeochemistry, metagenomics, etc.- a biogeochemical model of microbial processes will be developed. This project will combine the expertise of a multidisciplinary group of leading researchers on ecosystem functioning, GHGs and biogeochemistry modelling, with the extraordinary resources including analytical facilities and training support in PLECO (Univ. Antwerp, Belgium).

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Cuezva Robleno Soledad

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Climate change will affect Arctic ecosystems more than any other ecosystem worldwide, with temperature increases expected up to 4-6°C. While this is threatening the integrity and biodiversity of the ecosystems in itself, the larger ecosystem feedbacks triggered by this change are even more worrisome. During millions of years, atmospheric carbon has been stored in the Arctic soils. With warming, the carbon can rapidly escape the soils in the form of CO2 and (even worse) the strong greenhouse agent CH4. Despite decades of research, scientists still struggle to unveil the scale of this carbon exchange, and especially how it will interact with climate change. An overarching question remains: how much carbon will potentially escape the Arctic in the future climate, and how will this affect climate change? FutureArctic embeds this research challenge directly in an inter-sectoral training initiative for early stage researchers, that aims to form "ecosystem-of-things" scientists and engineers at the ForHot site. The FORHOT site in Iceland offers a geothermally controlled soil temperature warming gradient, to study how Arctic ecosystem processes are affected by temperature increases as expected through climate change. FutureArctic aims to pave the way for generalized permanently connected data acquisition systems for key environmental variables and processes. We will initiate a new machine-learning approach to analyse large high-throughput environmental data-streams, through installing a pioneer "ecosystem-of-things" at the ForHot site. FutureArctic will thus channel, building on a timely project in the ForHot area, an important evolution to machineassisted environmental fundamental research. This is achieved through the dedicated training of researchers with profiles at the inter-sectoral edge of computer science, artificial intelligence, environmental science (both experimental and modelling), scoial sciences and sensor engineering and communication.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Verbruggen Erik

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

ICOS monitors the global cycle of carbon and of greenhouse gases across the European continent. It provides an infrastructure for researchers and climate modellers as well as processed data and a complete map of the European greenhouse gas balance for policy makers and the general public. The high quality data and products are of crucial importance for the rapid evaluation of the impact of climate change mitigation policies in Europe and the validation of the general circulation models used for the IPCC reports. Because no similar facilities exist within Europe ICOS is the flagship environmental research infrastructure of Europe with regard to the Kyoto protocol, COP21 and to the global carbon issue. As greenhouse gases surpass the borders of countries or regions, a pan-European infrastructure and approach are the only feasible ones. Since greenhouse gas concentrations keep on increasing and mitigation efforts are being increasingly implemented, there is a sense of urgency for a continuous carbon observation infrastructure. In addition to the clear value for policy makers, the high-quality ICOS data are also extremely valuable for advancing science in several fields. Because of the unique synergy of atmospheric, terrestrial, and oceanic observatories, the projected lifespan of 20 years and the extensive geographical coverage of the infrastructure ICOS provides unique data on greenhouse gases in Europe. As such the infrastructure will leverage top of the world research and will attract large project consortia to access the observation stations. ICOS also provides the potential to bring new H2020 projects (ear-marked for infrastructure research) or new ERC grants to Flanders and Belgium. ICOS contributes to the international Observing Strategy for measuring carbon fluxes and their underlying processes globally, formulated by the Integrated Global Carbon Observation Strategy (IGCO-P; www.fao.org/gtos/igos) and taken further towards implementation by GEO.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Ceulemans Reinhart

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

By affecting the uptake of carbon and the transpiration of water by forests, tree phenology also influences local weather and long-term climate change. Studying spring phenology of temperate trees is thus more than just a biologist's hobby. Despite a wealth of observations of the date that leaves appear in spring, this process is still not fully understood. Leaf out can occur at very different moments in spring, despite similar spring weather. Part of the reason is that spring leaf out is only the end point of an entire winter of bud responses to cold temperatures, to warm temperatures, and to changes in day length. To fully understand the climatic controls over spring phenology, and thus to be able to produce models that can accurately predict future changes in spring phenology, insight is needed into what happens during the long winter, when buds are apparently asleep. This project focuses on just that: what happens during the bud's resting phase that makes them more or less responsive to warmer spring temperatures. We will conduct two large experiments in which temperature and day length will be altered, and throughout the entire winter season monitor changes in gene expression, in metabolite concentrations, and in depth of dormancy. The ultimate aim is to advance insight in spring phenology, but also to identify genes or metabolites that could give information on the state of dormancy during winter, and thereby on the bud's sensitivity to spring warming. -

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Abd Elgawad Hamada
• Co-promoter: Asard Han
• Co-promoter: Campioli Matteo

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This funding was obtained to prepare the EU project with the following abstract: C-Attract will deploy an innovative combination of experimental research and modelling to develop realistic climate security scenarios involving rapid and large-scale deployment of NETs. In a unique set of targeted field experiments, we will address crucial knowledge gaps concerning nature-based NETs. In these experiments, specific focus is on a promising NET, enhanced weathering, for which the lack of real-world applications hampers our ability to assess its effectiveness. Yet unexplored combinations of nature-based NETs will also be experimentally tested . We will not only investigate how current management practices on land and in the coastal zone can be adapted to deliver nature-based C sequestration, but also how to maximize co-benefits to ecosystems and society. We will provide a comprehensive assessment of the impact of NETs on sustainable development goals, including food security, biodiversity and ocean acidification. Life cycle analysis, Earth system models and integrated assessment models are combined in a novel fit-to-purpose cluster to comprehensively assess the impact of NETs for Europe in a global context. We will thereby augment the existing IPCC scenarios through a novel climate security focus by taking into account Earth system tipping points in a 500-year timeframe. Citizen science campaigns designed around our field experiments will elucidate public acceptance issues and policies to address them. Within the continuation of our long-lasting engagement with the NETs community, we will coproduce viable transformational pathways of NETs, and focus on potential inclusion of NETs in the circular bio-economy. This will guide the coproduction of realistic roadmaps for rapid and large-scale deployment of NETs. We will initiate a helix for nature-based NETs to spark investors, promote actor engagement and ensure sustainable impact beyond C-Attract.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Tropical forests are among the most diverse ecosystems in the world and account for more than one third of global primary productivity. Tropical rainforests thus play a key role in the global carbon (C) balance. Most tropical forests are phosphorus (P) rather than nitrogen (N) limited, in contrast to the much better studied temperate and boreal forests. The effects of soil fertility on C cycling in tropical rainforests is, however, still poorly understood. The aim of this study is twofold: I want to improve our understanding of photosynthesis of tropical forests and how this changes along gradients of soil N and P availability. Further, I will investigate how plant C allocation varies along these gradients. Ecosystem C allocation is very important because it determines the residence time of C in the ecosystem and thereby the CO2 removal from the atmosphere. Both processes will be studied in the lowland tropical rainforests of French Guiana. The rainforests I will study are virtually undisturbed and cover a large gradient in soil fertility, which will be even enlarged by a fertiliser addition experiment. Therefore, these forests are ideally suited to study effects of nutrient imbalances on the functioning of tropical rainforests.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Vicca Sara
• Fellow: Verryckt Lore

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Climate change, biodiversity loss and changes in the availability of nutrients are three of the most important components of global change that are affecting life on Earth. However, despite strong efforts from the scientific community, it is not yet clear how these three components interact with each other in altering the function of ecosystems and the carbon they exchange with the atmosphere. This proposal aims to understand how biodiversity and nutrient availability interact with climate variability to determine ecosystem productivity and stability at different spatial and temporal scales, ranging from local to global and from annual to decadal scales. To achieve this main goal we will gather satellite images and global databases of ecosystem carbon flux exchange, measured in situ, to test the hypotheses that i) more diverse and nutrient-rich ecosystems are less sensitive to weather conditions and, hence, their productivity is more stable, ii) that more diverse ecosystems sequester more carbon only when nutrient availability is high, and iii) that biodiversity loss and increasing climate variability are increasing variability in ecosystem productivity, especially in nutrient-poor ones. This novel, integrative approach will help us increase our understanding of the role of climate change, biodiversity and nutrient availability in the carbon cycle of terrestrial ecosystems, which is key information for improving predictions about how the biosphere will respond in the future.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Fernandez-Martinez Marcos

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

RainForest-GHG aims to quantify ecosystem sinks and emissions of three major greenhouse gases (GHGs), i.e. carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O), in a tropical rainforest, and examine the contributions of the soil and the woody tissues to the ecosystem-scale GHG fluxes. RainForest-GHG further aims to determine the main environmental drivers responsible for the temporal and spatial variations of these GHG fluxes.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Brechet Laetitia

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Photosynthesis is the largest flux in the global carbon cycle and therefore of utmost importance for climate change and agricultural research. Radiometric sensors mounted on satellites and airplanes are the only technology providing spatially explicit information about vegetation activity and health at regional to global scale. In particular, the recent availability of remotely sensed sun-induced fluorescence (F), which is directly coupled to the photosynthetic process, opens new perspectives in estimating plant photosynthesis at larger scales. Considering the recently selected satellite Fluorescence Explorer (FLEX) mission by the European Space Agency (ESA) that will launch in 2022, new methods have to be developed to optimally use the F signal for an improved global estimation of photosynthesis. "ReSPEc" aims to develop new algorithms to improve the estimation of plant photosynthesis at ecosystem to regional scale (gross primary production; GPP) by assessing the photosynthetic energy balance of the light reactions from remote sensing platforms. To achieve this goal an open-field manipulation experiment will be setup to develop and test a semi-mechanistic model that links novel and established optical signals with gas-exchange measurements to assess the photosynthetic energy balance on leaf and plant scale. The semi-mechanistic model will then be applied to a pre-existing datasets of airborne measured F and vegetation reflectance to estimate GPP on ecosystem scale. Results will be compared and validated with eddy-covariance-based estimates of GPP. The outcome of this project will contribute to a better understanding of the photosynthetic energy balance on leaf-, plant- and ecosystem scale, which in turn allows an improved estimation of GPP. By ensuring that all necessary parameters will be measurable by the FLEX satellite mission, this project will take a first step towards a new global estimation of the photosynthetic energy balance.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Wieneke Sebastian

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The bud set of indigenous trees in spring is an annually recurring natural highlight. But did you also notice that the start of the appearance of the leaves differs from year to year? And have you ever wondered why? The fact is that even scientists are not quite sure why trees bud one year earlier than the other. We do know different steering factors, such as day length, temperature, availability of nutrients ... But how this really works is still an unanswered question. That is why scientists and citizens have to work together. We need study data from a lot of trees to know if the trees bud differently than they used to. Every morning and evening a small experiment must be performed on all those trees and always at the same time. Problem: there are simply too few scientists to do that. This is why hundreds of citizens in Flanders study the bud set of trees, and look in detail at the effect of day length, winter temperature and spring temperature on the appearance of the leaves. They do this in close collaboration with the University of Antwerp and ReaGent. Citizens and scientists join forces and together they take a crucial scientific step forward: are our trees armed for a warmer world?

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

EcoCities will carry out an integrated and comparative analysis of different types of green walls (GW) and green roofs (GD). In essence, the research will be carried out: - an in-depth determination of the contribution of different (growth substrate, plant species) types of GD and GW to the most important ecosystem services (ED) in an urban context. - an integrated evaluation of the ED provided.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Climate change, biodiversity loss and changes in the availability of nutrients are three of the most important components of global change that are affecting life on Earth. However, despite strong efforts from the scientific community, it is not yet clear how these three components interact with each other in altering the function of ecosystems and the carbon they exchange with the atmosphere. This proposal aims to understand how biodiversity and nutrient availability interact with climate variability to determine ecosystem productivity and stability at different spatial and temporal scales, ranging from local to global and from annual to decadal scales. To achieve this main goal we will gather satellite images and global databases of in situ measured ecosystem carbon flux exchange to i) test the hypothesis that more diverse and nutrient-rich ecosystems are less sensitive to weather conditions and investigate how this affects their ability to absorb CO2, and ii) to test the hypotheses that the increasing climate variability and biodiversity loss are decreasing ecosystem stability at the global scale, and that nutrient availability lessens this detrimental effect. This novel, integrative approach will help us increase our understanding of the role of climate change, biodiversity and nutrient availability in the carbon cycle of terrestrial ecosystems, which is key information for improving predictions about how the biosphere will respond in the future.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Fernandez-Martinez Marcos

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

-ForestFlow will: - Quantify dissolved organic carbon export from deciduous and coniferous forest, and hereby close ecosystem carbon balances in two Belgian ICOS-sites - Quantify the seasonality in dissolved vs. gaseous carbon export from forests: tree phenology and rain regime are hypothesized to be the main control factors - Investigate whether shifts in gaseous vs. dissolved carbon export occur during rain events and persistent drought - Model future alterations in the forest carbon balance, by implementing the results in coupled climate, hydrological and forest ecosystem biogeochemical models.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Soils contain over three times as much carbon as the atmosphere in soil organic matter, and have the potential to slow down or accelerate climate change through altered rates of plant growth and soil organic matter decomposition. Cold, northern ecosystems in particular, store vast amounts of carbon in the soil, but these stocks are vulnerable to increased carbon losses due to warming temperatures and changes in the availability of limiting nutrients such as nitrogen. In addition to the direct effects of warming and increasing nitrogen availability on organic matter decay by microbes, plants also play a major role by changing the way in which they use their photosynthates. By allocating more or less carbon belowground to roots, symbionts, or exudation, plants can alter soil carbon input rates and pathways, and thereby change the way soil organic matter responds to warming and nitrogen enrichment. Our research will examine how warming and nitrogen availability impact on carbon dynamics of plants and soil microbes in order to improve our understanding of plant-soil carbon cycling under future global change scenarios. In order to do this we will carry out experiments in a subarctic grassland of Iceland, tracking carbon flows from plant photosynthesis into the soil and back to the atmosphere and input this data into mathematical models to help better predict ecosystem carbon cycling feedbacks to global warming.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Soong Jennifer
• Co-promoter: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Readiness of ICOS for Necessities of integrated Global Observations (RINGO) is a H2020 EU project that serves to further developed and support the ICOS research infrastructure. Within this project the University of Antwerp has a task that aims to investigate the ability to apply terrestrial light Detection and Ranging (LiDAR) measurements to estimate above ground biomass at forest ecosystems. Aboveground biomass is crucial component of the carbon balance of forest ecosystems however it is very difficult to accurately estimate. LiDAR is a new and promising technique that offers the possibility to obtain highly accurate estimates of tree volumes. Within this project we will select several test sites in Belgium with different tree species which will be scanned and at each site several trees will be destructively harvested to validate estimated volume. In a second stage several ICOS sites in Belgium and neighbouring countries will be visited to perform LiDAR scans in order to estimate Aboveground biomass accurately. The outcome of this project will be a protocol to perform LiDAR measurements at the ICOS ecosystem station.

Researcher(s)

• Promoter: Gielen Bert
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project website

Project type(s)

• Research Project

Abstract

There is an increasing awareness that climate variability will increase in frequency and severity during the coming decades, triggering amplified responses in the cycling of carbon in terrestrial ecosystems and its feedback to the climate system. While recent studies have shown the strong concurrent impact of climate extremes on the terrestrial carbon cycle, mainly for drought and heatwaves, there is still an important knowledge gap on the impacts of legacy effects in particular for ecosystems that slowly recover from climate-extreme induced disturbances such as forests. In the proposed project we aim to understand how legacy effects of drought will impact the carbon cycle of forests across biomes and spatial levels using an integrated approach. In order to address this aim we will (1) analyse how legacy effects of drought on the carbon cycle of forests are coupled to concurrent effects by integrating tree-ring and ecosystem level CO2 and H2O flux measurements, (2) validate remote sensing observations of legacy effects of drought at the landscape scale using ground-level observations for selected sites and (3) constrain site-level model simulations of the impact of drought on the forest carbon cycle, which currently do not account for legacy effects. This novel approach will strongly improve our understanding of drought legacies in the carbon cycle of forests across the globe, which is crucial for optimizing future projections of the global carbon budget.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Bloemen Jasper

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

By providing food, animal-feed, fibre and energy, biomass production is possibly the most important ecosystem service made to society. While global products of biomass production from Remote Sensing (MOD17) and Land Surface models do capture the global patterns as described by in-situ observations, they still fail to capture the existing huge variability within biomes. The ECOPROPHET project aims to improve this situation 1) by testing to what degree the multitude of new Earth Observation data (e.g. from Sentinel 2, Proba-V) are able to be exploited as better proxies of ecosystem functional phenology (photosynthetic activity) and can be used to improve the phenology modules of Land Surface models, 2) by exploring the potential of these new remote sensing data to produce a new gross primary productivity (GPP) product, 3) by developing an entirely new algorithm to convert remote sensing-based GPP products to biomass production, and 4) by using a large database of quality-controlled in situ measurements of biomass production, all accompanied by a standardized uncertainty estimate, and the FLUXNET 2015 and ICOS databases (for in situ GPP estimates and functional phenology data) to assess whether our efforts did in fact reduce the currently large unexplained variation in ecosystem gross primary productivity and biomass production. A major focus of this project is on functional phenology as a key determinant of ecosystem carbon, water and energy balances. Current phenological observations are all based on differences in the Normalized Difference Vegetation Index (NDVI), which is a good proxy for canopy leaf area and light absorption, but is not an ideal proxy for canopy photosynthesis, especially during drought periods and during autumn when greenness and photosynthesis become uncoupled. We propose to use novel remote sensing-based indicators, more closely related to photosynthetic processes than to greenness, to parameterize phenology modules of Land Surface models and thereby improve their estimates for present time and projections under future climate. The novel developed indicator will be used to produce a new generation remote sensing-based GPP and NPP product.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Balzarolo Manuela

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Gross primary production (GPP) is the basis for life on Earth. Terrestrial net primary production (NPP) is the remainder after plant (autotrophic) respiration (RA) has returned approximately half of the terrestrial GPP to the atmosphere, in the process of carrying out essential functions (metabolism and growth). Most of the NPP is used to construct plant tissues, although there are some losses via the emission of volatile organic compounds (VOCs) to the atmosphere and the exudation of labile organic compounds to the rhizosphere. The objective of the TerrA-P project is to define, implement and validate a model to derive information on primary production by vegetation based on data from MERIS and Sentinel-3. The project combines the expertise from three domains: the ecophysiology of plants as expressed in the productivity model, the EO data sets that can be used as input for this model, and the in-situ data that allow validation of the model outcome using EO-input data. The P-model developed by Imperial College London (Wang, H., I.C. Prentice, et al. (2016); http://dx.doi.org/10.1101/040246) will be used as a basis for the estimation of GPP. This model starts from first principles, has a firm basis in theory and provides the optimum combination of parsimony, theoretical foundation, and empirical support. It is based on the standard (Farquhar, von Caemmerer and Berry) photosynthesis model while also accounting for acclimation processes that lead to a proportional relationship between GPP and light absorbed, the constant or proportionality varying as a function of environmental variables (temperature, vapour pressure deficit, atmospheric pressure and CO2). The model has been tested using eddy covariance GPP data derived from flux sites worldwide. This model will be further elaborated to use EO data (fAPAR) derived from Sentinel-3, to include estimated uncertainties at the pixel level, to comply with the current user requirements of such products, and to provide estimates of above-ground biomass production (ABP) as well as GPP. The model will be validated using data from many flux measurement sites worldwide, and will be benchmarked against other comparable products.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Chemical fossils are molecular components that carry information on the environment in which they were produced, sometimes millions of years ago. The distribution of a group of 15 membrane lipids in soils, for instance, depends on the temperature and pH of the soils in which these organisms are living. They are conserved in several types of geological archives (marine sediments, lake sediments, soils) and their distribution has been used to reconstruct changes in the temperature of the past. However, even the most recent temperature calibration is not accurate enough to reconstruct absolute temperatures. In this research project we aim to improve this thermometer of the past, with geochemical and microbiological research. Firstly, the branched tetraethers that are currently used in the existing climate proxies will be measured in soils, together with their precursor compounds, their building blocks. These components will be measured in a set of Icelandic soils that are warmed by thermal water, and thus show a gradient in temperature. As these soils have been studied extensively in the framework of the Forhot project (www.forhot.is), the lipid distribution can be linked directly to the in-situ measured temperature. Following up on this, the patterns that are recognized on a local scale will be tested on a larger spatial scale. For this purpose, soil that have been studied in the framework of the EU ICOS project (www.icos-ri.eu) will be used, as they cover the different European ecosystems and soil types. Previous studies have indicated that Acidobacteria are probably the source organisms of the branched tetraether lipids, but only 1 of the 15 compounds that are frequently encountered in soils, has been recovered from an Acidobacterial culture. To shed light on the abundance and variability of the source organisms in soils, the bacterial diversity along the local temperature gradient (Forhot soils) will be analyzed with Illumina MiSeq technology. This diversity and its dependence on soil temperature will also be studied on a larger spatial scale (ICOS soils). This research will allow to gain a better insight in the environmental factors that influence the bacterial source organisms. This understanding will improve the accuracy and interpretation of the thermometer for the temperature in the past.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: De Jonge Cindy

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Tropical forests are among the most diverse ecosystems in the world and account for more than one third of global primary productivity. Tropical rainforests thus play a key role in the global carbon (C) balance. Most tropical forests are phosphorus (P) rather than nitrogen (N) limited, in contrast to the much better studied temperate and boreal forests. The effects of soil fertility on C cycling in tropical rainforests is, however, still poorly understood. The aim of this study is twofold: I want to improve our understanding of photosynthesis of tropical forests and how this changes along gradients of soil N and P availability. Further, I will investigate how plant C allocation varies along these gradients. Ecosystem C allocation is very important because it determines the residence time of C in the ecosystem and thereby the CO2 removal from the atmosphere. Both processes will be studied in the lowland tropical rainforests of French Guiana. The rainforests I will study are virtually undisturbed and cover a large gradient in soil fertility, which will be even enlarged by a fertiliser addition experiment. Therefore, these forests are ideally suited to study effects of nutrient imbalances on the functioning of tropical rainforests.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Vicca Sara
• Fellow: Verryckt Lore

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Ecosystems sustain society by providing natural resources and socio-economic services. Understanding their functioning is thus vital for accurate projections of, among others, global climate and food production and prerequisite to drawing up policies for sustainable management of the planet. This proposal therefore aims at creating the scientific breakthroughs needed to make major advances in understanding of several critical processes that determine the functioning of ecosystems and their interactions with ongoing changes in climate and in resource availabilities. The overarching, long-term goal is to understand ecosystem functioning sufficiently well so that we can, in collaboration with modelling groups, confidently project how ecosystem functioning and services will change in the near and distant future. To pursue this goal, the following four research lines will be prioritized when allocating the Methusalem funding: 1. Obtaining a quantitative understanding of plant carbon allocation to growth, energy production (respiration), and nutrient acquisition (fine roots, root exudation, root symbionts). 2. Improving insight in, and measurements of, biomass production. 3. Better understanding soil carbon dynamics and sequestration. 4. Understanding spatial and temporal variation in carbon and greenhouse gas balances at ecosystem to regional scale and attribution to drivers. In each of these research lines, we aim to understand the mechanisms underlying the global and local spatial variation as well as those underlying the long-term trends and short-term temporal patterns. Focus is on how Global Changes (climate change including extreme events, increasing atmospheric CO2 concentration, nitrogen deposition, etc.) are affecting ecosystem processes and functioning. Many projects will be conducted with the research group of the Methusalem Chair at the University of Hasselt as prioritized partners.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Matthysen Erik
• Co-promoter: Meire Patrick
• Co-promoter: Nijs Ivan
• Co-promoter: Temmerman Stijn

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The terrestrial biosphere mitigates climate change through carbon sequestration into plant biomass and soil. The way in which plants use the carbon assimilated during photosynthesis, ultimately determines the carbon sink strength of the ecosystem. However, the mechanisms driving variation in carbon allocation are still poorly understood. Previous research has reported large variation in the fraction of photosynthates used for autotrophic respiration, but the underlying mechanisms are still uncertain. Evidence is growing, however, that nutrient availability plays a key role. The main aim of the research proposal is to determine the impact of soil nutrition on the fraction of photosynthates used in autotrophic plant respiration. This will be studied via both chamber and leaf scale measurements in an experimental setup where GPP is measured and also NPP is being assessed completely. Given that observations in a mesocosm experiment require testing in more realistic conditions, I will also study autotrophic respiration in an ongoing nutrient manipulation field experiment. Further, I will study whether the process of nutrient retranslocation and light-induced inhibition of plant respiration depend strongly enough on nutrient availability such that they can explain additional variation in the autotrophic respiratory cost. If successful, this project will provide important benchmarking datasets to the modelling community that will allow further testing of the observed mechanisms.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Verlinden Melanie

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The biomass production (BP) of terrestrial ecosystems is a fundamental ecological process and a key ecosystem service. In fact, BP represents the supply of food, fibers and wood to our society and the carbon (C) accumulated annually on the Earth's land, which is a crucial determinant of the global C cycle and climate. Biomass production has been widely investigated and BP estimates are available from 'direct' (field-level) measurements at hundreds of experimental sites worldwide. However, global analyses of BP dynamics are limited or largely based on 'indirect' BP estimates from remote sensing, which have high resolution but low accuracy. Here, I aim to fill the critical knowledge gaps on global BP dynamics (1) by providing robust BP estimates for all major terrestrial ecosystem types (e.g. forests, grasslands, croplands, wetlands, tundra, deserts) and for the entire Earth's land, and (2) by elucidating which are the key global drivers of BP (e.g. plant traits, climate, site fertility, soil water content or management activities). In addition, the study will compare the performance of direct and indirect methods to assess global BP dynamics and clarify features and weaknesses of both approaches. These tasks will be accomplished by using a new, unique, database of direct BP estimates, that I recently compiled, and remote sensing BP estimates from MODIS.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Campioli Matteo

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Nutrients are key determinants of plant growth and are important influencing factors of terrestrial carbon cycling and its response to climate change. Although nutrients were long overlooked in carbon cycle studies, nowadays, an increasing number of empirical studies aim to unravel the mediating role of nutrient availability in terrestrial carbon cycling. However, despite the great potential of the increasing number of experimental and observational datasets, in-depth synthesis work to identify overarching patterns is currently hampered by difficulties comparing the nutrient status of different sites. The aim of this project is therefore to develop a standardized metric of nutrient availability that opens the door for in-depth analyses of the influence of nutrient availability on terrestrial carbon cycling and other important ecosystem functions. To this end, I will evaluate two existing metrics that include several important soil factors, but were never validated and, importantly, do not explicitly account for nitrogen (N) and phosphorous (P) availability. I will therefore test the applicability of both metrics, and especially how N and P availability should be considered. For this evaluation, I will use data from (1) European soil and plant surveys (ICP forests database), (2) three natural fertility gradients in different biomes, and (3) five nutrient addition experiments. Finally, I aim to develop one final standardized metric that can be widely applied.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Chemical fossils are molecular components that carry information on the environment in which they were produced, sometimes millions of years ago. The distribution of a group of 15 membrane lipids in soils, for instance, depends on the temperature and pH of the soils in which these organisms are living. They are conserved in several types of geological archives (marine sediments, lake sediments, soils) and their distribution has been used to reconstruct changes in the temperature of the past. However, even the most recent temperature calibration is not accurate enough to reconstruct absolute temperatures. In this research project we aim to improve this thermometer of the past, with geochemical and microbiological research. Firstly, the branched tetraethers that are currently used in the existing climate proxies will be measured in soils, together with their precursor compounds, their building blocks. These components will be measured in a set of Icelandic soils that are warmed by thermal water, and thus show a gradient in temperature. As these soils have been studied extensively in the framework of the Forhot project (www.forhot.is), the lipid distribution can be linked directly to the in-situ measured temperature. Following up on this, the patterns that are recognized on a local scale will be tested on a larger spatial scale. For this purpose, soil that have been studied in the framework of the EU ICOS project (www.icos-ri.eu) will be used, as they cover the different European ecosystems and soil types. Previous studies have indicated that Acidobacteria are probably the source organisms of the branched tetraether lipids, but only 1 of the 15 compounds that are frequently encountered in soils, has been recovered from an Acidobacterial culture. To shed light on the abundance and variability of the source organisms in soils, the bacterial diversity along the local temperature gradient (Forhot soils) will be analyzed with Illumina MiSeq technology. This diversity and its dependence on soil temperature will also be studied on a larger spatial scale (ICOS soils). This research will allow to gain a better insight in the environmental factors that influence the bacterial source organisms. This understanding will improve the accuracy and interpretation of the thermometer for the temperature in the past.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: De Jonge Cindy

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Tropical rainforests are the most diverse and productive ecosystems on Earth. These system account for one third of carbon assimilation on land, and harbor two-thirds of global plant diversity. Understanding the ecological processes underlying these vital properties will be essential for addressing the twin challenges of biodiversity loss and man-made climate change. Mycorrhizal fungi act as a major conduit of carbon into soil, and affect competition between trees through connecting them belowground. This plant-fungal interaction is one of the most abundant symbioses on earth and is tightly linked to plant nutrient limitation. Ecosystems are increasingly enriched with CO2 and nitrogen and subject to climate change, which could alter abundance and functional properties of mycorrhizas in yet unknown ways. This in turn could have large consequences for the soil carbon economy and plant interactions. Forests in French Guyana represent are unique in being among the most pristine and well-studied lowland tropical rain-forests on Earth. Major gradients of one of the most important drivers of mycorrhizas, soil phosphate availability, have already been identified within and among established research sites. This offers a unique opportunity to unveil the interplay between soil nutrients, mycorrhizal fungi, and soil carbon stocks. Here I propose to accomplish this through measuring abundance of mycorrhizal fungi through biomarkers (membrane lipids) that broadly distinguish mycorrhizal type, accompanied by next generation sequencing of DNA markers to reveal shifts in community composition. Moreover, I will conduct experiments to assess the effect of mycorrhizas on litter decomposition and on adult-seedling interactions, which may have a major influence on tree biodiversity. Together, these experiments will greatly increase our understanding of the importance of this plant-fungal symbiosis for soil carbon sequestration and seedling performance. This knowledge will allow better prediction of the interdependence of soil fertility, plant-fungal relationships, and their combined effect on plant diversity and soil carbon levels.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Verbruggen Erik

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Spring vegetation phenology determines the onset of the growing season. Changes in spring vegetation phenology alter the length of the growing season and thereby affect ecosystem productivity and regional and global carbon and energy balances. Satellite-derived vegetation indices have long been used as proxies for representing the status of terrestrial vegetation. However, the modeling of such large scale vegetation phenology dynamics is still a big challenge because the underlying mechanisms of vegetation phenology process are still unclear. To date, the performance of vegetation phenology models at global scale is rarely examined. Within this project, global-scale vegetation phenology models will be developed based on specieslevel models. Bayesian model comparisons will subsequently be conducted to select the most parsimonious vegetation phenology model for global carbon cycle models. In addition, remote sensing-based phenological dates will be compared to ground observations at species level to answer whether the satellite images capture the phenology dynamics observed in situ. This project also aims to explore the recent controversial debate on the amplitude of the advancement of spring phenology since the 1980s. The present study will make a step forward in the study of vegetation phenology and will have important implications for the ecological modeling community by suggesting the most optimal phenology model.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Fu Yongshuo

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Matthysen Erik
• Co-promoter: Meire Patrick
• Co-promoter: Nijs Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project aims at understanding how structure and function of Icelandic ecosystems are affected by global change. Global climate change is predicted to continue in the 21st century and will be most pronounced at higher latitudes. This will undeniably entail changes in ecosystem processes as nutrient dynamics and plant and microbial community compositions.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Leblans Niki

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

P is an earthbound and finite element and the prospect of constrained access to mineable P resources has already triggered geopolitical disputes. In contrast to P, availabilities of carbon (C) and nitrogen (N) to ecosystems are rapidly increasing in most areas of the globe. The resulting imminent change in the stoichiometry of available elements will have no equivalent in the Earth's history and will bear profound, yet, unknown consequences for life, the Earth System and human society. The ongoing shifts in C:N:P balances in ecosystems will necessarily affect the structure, function and diversity of the Earth system. P-market crises might put pressure on the global food system and create environmental ripple effects ranging from expansion of agricultural land to P-price-induced changes in land management exacerbating the stoichiometric resource imbalance. Yet, the impacts of this unprecedented human disturbance of elemental stoichiometry remain a research enigma. The IMBALANCE-P-team, that gathers four leading researchers in the fields of ecosystem diversity and ecology, biogeochemistry, Earth System modelling, and global agricultural and resource economics, is formidably positioned to address this Earth System management challenge by providing improved understanding and quantitative foresight needed to formulate a range of policy options that will contain the risks and mitigate the consequences of stoichiometric imbalances. IMBALANCE-P will integrate some of Europe's leading integrated assessment and Earth system models, calibrated using ecosystem nutrient limitation data obtained from field experiments. The project will establish an international process of science-based P-diplomacy.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project will study ecosystem structure (plant and microbial community composition; carbon stocks) and function (productivity, biogeochemistry) along a natural temperature gradient on Iceland to answer critical research questions about the effect of warming on ecosystems. We will address 1) the nonlinearities of the ecosystem responses to warming; 2) the transient nature of ecosystem changes after 5 years of temperature change; and 3) the hypothesis that warming effects are mainly induced by accelerated nutrient cycling.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project will improve our understanding of the nature of this contribution by characterizing the seasonality of soil microbial communities, and linking it to high-resolution ecosystem monitoring data in a variety of ecosystems across Europe. We will investigate whether seasonal patterns in below-ground communities are associated with the annual cycles of vegetation (bud burst, peak photosynthesis, leaf fall), and whether they can be linked to seasonal patterns in ecosystem functions. As well as providing much needed data about the nature and drivers of temporal dynamics of soil microbes, the research will help to lay the foundation for the next generation of models used to understand and forecast global carbon dynamics and climate change.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Weedon James

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

We hypothesize that Si-fertilization of croplands with easily weathered silicates increases uptake of atmospheric CO2, providing a new ecosystem service to croplands, while at the same time improving cropland yield. To study this hypothesis, we will couple experimental setups to modeling efforts, to shed new light on the by far understudied Si-C interactions in soils.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Janssens Ivan
• Co-promoter: Struyf Eric

Research team(s)

Project type(s)

• Research Project

Abstract

The biomass production efficiency (BPE) is the fraction of carbon assimilated through photosynthesis that is used to produce plant biomass. BPE is particularly relevant to evaluate the feedback of terrestrial ecosystems to the greenhouse effect. This study will provide BPE estimates for major world's biomes (e.g. grasslands, forests, croplands, wetlands), reveal the environmental drivers of BPE, and explore the relationship between BPE and ecosystem carbon sequestration. In particular, we hypothesize that BPE is positively related to soil fertility and that such relationship holds across biomes. Plant communities are more productive in richer soils because less non-structural carbohydrates are needed belowground (for roots symbionts and root exudates) to facilitate nutrient acquisition. Thus, the better the nutrient status, the larger is the carbon available for biomass production and sequestration in the ecosystem. We will test these hypotheses with a new global biome database with hundreds of experimental sites worldwide and a mesocosm experiment focused on typical temperate biomes (e.g. grasslands).

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Campioli Matteo

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project aims at understanding how structure and function of Icelandic ecosystems are affected by global change. Global climate change is predicted to continue in the 21st century and will be most pronounced at higher latitudes. This will undeniably entail changes in ecosystem processes as nutrient dynamics and plant and microbial community compositions.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Leblans Niki

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

At present 81% of global energy production comes from fossil fuels, that are finite and emit CO2 into the atmosphere. For these reasons, alternative energy sources are sought for. Bioenergy, in particular Short Rotation Coppice (SRC) culture, is a promising alternative for the generation of electricity. SRCs can be defined as carefully tended, high-density plantations of fast-growing trees, in this project poplar, which are cut back every 2-5 years. The harvest is then burned or gasified to generate electricity. The CO2 that is emitted by this process was withdrawn from the atmosphere when the crop was growing; so theoretically there is no new carbon added to the atmosphere. However, SRC management (transport, harvest, fertilizers, irrigation), produces certain amounts of CO2 and other greenhouse gases. Moreover, SRC consumes much water, which may be needed for surrounding regions. This project will use a computer model to predict biomass production, greenhouse gas balance and water use of SRC plantations, for different management types in different regions. The overall objective is to determine, for each region, the optimal management that maximizes wood growth for energy production, while minimizing the greenhouse gas emissions and water use.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: De Groote Toon

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This is a fundamental research project financed by the Research Foundation - Flanders (FWO). The project was subsidized after selection by the FWO-expert panel.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The main objectives of ICOS are: (1) to establish an integrated long-term global carbon and GHG observation infrastructure; (2) to determine regional carbon and GHG fluxes from observations and attribute these to processes; (3) to provide regional GHG budgets for policy support; (4) to provide access and services for data and data products

Researcher(s)

• Promoter: Ceulemans Reinhart
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project website

Project type(s)

• Research Project

Abstract

The aim of this project is to achieve an improved knowledge of the response of the terrestrial carbon cycle to climate variability and extremes. Specifically, effects of extreme weather events on plant growth and its underlying processes, crop yields and harvestable products, soil processes such as microbial respiration and water retention, soil carbon stocks and ecosystem carbon sequestration will be studied over a wide range of ecosystems.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The MOMEVIP partners will integrate competences in ecology, physiology, biochemistry, molecular biology, functional genomics and bioinformatics to improve knowledge about the molecular and metabolic bases of VIP biosynthesis, and the functions of VIP (isoprene, monoterpenes and sesquiterpenes, collectively) in plant protection, per se and when interacting with other defensive pathways.

Researcher(s)

• Promoter: Asard Han
• Co-promoter: Beemster Gerrit
• Co-promoter: Janssens Ivan
• Co-promoter: Nijs Ivan

Research team(s)

• Integrated Molecular Plant Physiology Research (IMPRES)

Project type(s)

• Research Project

Abstract

At present 81% of global energy production comes from fossil fuels, that are finite and emit CO2 into the atmosphere. For these reasons, alternative energy sources are sought for. Bioenergy, in particular Short Rotation Coppice (SRC) culture, is a promising alternative for the generation of electricity. SRCs can be defined as carefully tended, high-density plantations of fast-growing trees, in this project poplar, which are cut back every 2-5 years. The harvest is then burned or gasified to generate electricity. The CO2 that is emitted by this process was withdrawn from the atmosphere when the crop was growing; so theoretically there is no new carbon added to the atmosphere. However, SRC management (transport, harvest, fertilizers, irrigation), produces certain amounts of CO2 and other greenhouse gases. Moreover, SRC consumes much water, which may be needed for surrounding regions. This project will use a computer model to predict biomass production, greenhouse gas balance and water use of SRC plantations, for different management types in different regions. The overall objective is to determine, for each region, the optimal management that maximizes wood growth for energy production, while minimizing the greenhouse gas emissions and water use.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: De Groote Toon

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project represents a formal research agreement between UA and on the other hand the Flemish Public Service. UA provides the Flemish Public Service research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Ceulemans Reinhart
• Co-promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project website

Project type(s)

• Research Project

Abstract

The overall goal of DOFOCO is to quantify and understand the role of forest management in mitigating climate change. Specifically, we want to challenge the current focus on the carbon cycle and replace it with a total climate impact approach. Hence, the whole forest management spectrum ranging from short rotation coppice to old-growth forests will be analyzed for its effects on the water, energy and carbon cycles. Climate response of forest will be quantified by means of albedo, evapotranspiration, greenhouse gas sources and sinks and their resulting climate feedback mechanisms. DOFOCO will deliver the first quantitative insights into how forest management strategies can be linked to climate change mitigation. These results will be used to lay the foundations for a portfolio of management strategies which sustain wood production while minimizing climate change impacts.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Luyssaert Sebastiaan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The GHG-Europe project aims to improve our understanding and capacity for predicting the European terrestrial carbon and greenhouse gas (GHG) budget by applying a systematic, comprehensive and integrative approach. GHG-Europe quantifies the annual to decadal variability of the carbon and GHG budgets of terrestrial ecosystems in EU27 plus Switzerland and in six data-rich European regions via data-model integration, diagnostic and predictive modelling.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project represents a research agreement between the UA and on the onther hand IWT. UA provides IWT research results mentioned in the title of the project under the conditions as stipulated in this contract.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Roland Marilyn

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The aim of this project is to achieve an improved knowledge of the terrestrial carbon cycle in response to climate variability and extremes, to represent and apply this knowledge over Europe with predictive terrestrial carbon cycle modelling, to interpret the model predictions in terms of vulnerability of the terrestrial - in particular soil - carbon pools and give according advice to EU climate and soil protection policies.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Existing soil carbon models are primarily empirical. Hence, these empirical models cannot be applied to simulate soil carbon changes under future atmospheric conditions that never occured during the observation phase. In this project, we will aim do develop a generic mechanistic module that describes soil carbon cycling by recognized and acknowledged mechanisms and a common set of first principles, which will be applicable globally, as well as under future atmospheric conditions.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This is a fundamental research project financed by the Research Foundation - Flanders (FWO). The project was subsidized after selection by the FWO-expert panel.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Increasing temperature and water level drawdown are two important factors of global change. Both factors are of high importance with regard to the carbon and greenhouse gas balance of peatlands. This project is set up to determine how temperature and groundwater level influence these balances. Furthermore, we give special attention to the underlying processes of methane and nitrous oxide emissions and how these are influenced by temperature and groundwater level. At the University of Antwerp, an experimental platform was established at which nine greenhouses each contain four mesocosms filled with fen peat. In these mesocosms, the groundwater level is regulated. From April till November, the groundwater level is set at 5, 10, 17 or 24 cm below the surface. During the other six months of the year, water levels are raised with 10 cm (except the highest level, which is only raised with 5 cm). In each greenhouse, temperature is regulated. Three greenhouses remain unheated, whereas the others are either heated by 3 °C or by 6 °C. At regular time intervals, we measure CO2, CH4 and N2O emissions with a dynamic closed chamber. Furthermore, we determine all components of the carbon balance (DOC, POC, VOC and DIC), some components of the nitrogen balance (NO3-, NH4+, DON and DIN) and several important parameters such as O2 concentration, temperature and soil water content. In addition, we also determine concentrations of CO2, CH4 and N2O at different depths in the soil in order to obtain more information about underlying processes. Besides this mesocosm experiment, some small experiments are performed in which the underlying processes of production and oxidation of CH4 and the formation of N2O are studied in more detail and in which some experimental procedures are tested. Furthermore, we also determine the fractionation factors (for 13C) of the two main pathways for CH4 production and of the oxidation of CH4.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Global temperatures and atmospheric CO² concentrations are expected to increase, and so is the frequency and intensity of climate extremes. The main aim of this project is therefore to test whether plants raised under warmer conditions and/or elevated atmospheric CO² concentrations are more tolerant to current and future heat stress than plants grown under current conditions. For this, we will grow wild-type Arabidopsis thaliana (Heynh.) plants throughout their entire life cycle under either current climate conditions or a variety of future climate scenarios, and expose these plants to one or several, two-day heat pulses of different intensity.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Asard Han
• Co-promoter: Nijs Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Specific objectives: 1. Couple a biological and a geochemical model. 2. Collect the missing model parameters and apply the newly produced biogeochemical model at two study sites in contrasting climates. 3. Validate the model outputs with the measured CO2 fluxes and their 13C/12C ratio's. 4. Interpret the primary biological and geological flxes in relation to their dominant drivers. 5. One of the two study sites is located on top of tha Altamira cave, world famous for its Palaeolithic cave paintings. Using the biogeochemical model, we will determine the risk for damage of the paintings under conditions of climate change of alternative cave management.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Van Grieken Rene

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Roland Marilyn

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

This project represents a research contract awarded by the University of Antwerp. The supervisor provides the Antwerp University research mentioned in the title of the project under the conditions stipulated by the university.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

One of the most important ecosystem processes is decomposition. Decomposition plays a key role in the nutrient cycle, and is one of the main factors limiting plant growth. In addition it can substantially influence species composition. Goose numbers have increased dramatically over the past 50 years mainly due to land use changes and a reduced hunting pressure in their wintering grounds. To understand fully the consequences of these changes, studies on ecosystems processes on both the wintering grounds in temperate regions and the breeding grounds in the high arctic are indispensable. In this project we will investigate how geese influence decomposition processes and related processes: besides decomposition the nitrogen and carbon cycle, the microbial communities and the availability of nutrients for plants will be studied .

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Beyens Louis
• Co-promoter: Janssens Ivan
• Fellow: Fivez Lise

Research team(s)

Project type(s)

• Research Project

Abstract

The central research question of this project is whether the resistance of species-rich plant communities to different stress factors will change in a future climate. To this end we will grow grassland mesocosms in sunlit controlled chambers under either the present or future climate conditions, and expose them to a wide range of stressors: tropospheric ozone, drought, nitrogen deficiency, nitrogen saturation (eutrophication), and heavy metals (cadmium). Stressors will be applied separately to assess dose-response relations, but also in combination to examine their interactive impact. By combining expertise from ecology, plant physiology, and biochemistry, we will evaluate the responses to stress in a future climate across a wide range of biological complexity, from cell to ecosystem.

Researcher(s)

• Promoter: Ceulemans Reinhart
• Co-promoter: Asard Han
• Co-promoter: Janssens Ivan
• Co-promoter: Nijs Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project website

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Increasing temperature and water level drawdown are two important factors of global change. Both factors are of high importance with regard to the carbon and greenhouse gas balance of peatlands. This project is set up to determine how temperature and groundwater level influence these balances. Furthermore, we give special attention to the underlying processes of methane and nitrous oxide emissions and how these are influenced by temperature and groundwater level. At the University of Antwerp, an experimental platform was established at which nine greenhouses each contain four mesocosms filled with fen peat. In these mesocosms, the groundwater level is regulated. From April till November, the groundwater level is set at 5, 10, 17 or 24 cm below the surface. During the other six months of the year, water levels are raised with 10 cm (except the highest level, which is only raised with 5 cm). In each greenhouse, temperature is regulated. Three greenhouses remain unheated, whereas the others are either heated by 3 °C or by 6 °C. At regular time intervals, we measure CO2, CH4 and N2O emissions with a dynamic closed chamber. Furthermore, we determine all components of the carbon balance (DOC, POC, VOC and DIC), some components of the nitrogen balance (NO3-, NH4+, DON and DIN) and several important parameters such as O2 concentration, temperature and soil water content. In addition, we also determine concentrations of CO2, CH4 and N2O at different depths in the soil in order to obtain more information about underlying processes. Besides this mesocosm experiment, some small experiments are performed in which the underlying processes of production and oxidation of CH4 and the formation of N2O are studied in more detail and in which some experimental procedures are tested. Furthermore, we also determine the fractionation factors (for 13C) of the two main pathways for CH4 production and of the oxidation of CH4.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Vicca Sara

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The relationship will be studied between reactive volatile organic compounds, which are emitted by the vegetation or anthropogenic sources and are photo-oxidized in the atmosphere, and organic aerosol formation. In addition, the contribution of bioaerosols to the organic aerosol load will be assessed. The experiments will be conducted in plant growth chambers and a mixed pine-oak forest.

Researcher(s)

• Promoter: Claeys-Maenhaut Magda
• Co-promoter: Janssens Ivan

Research team(s)

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Janssens Ivan
• Fellow: Opdekamp Wout

Research team(s)

Project type(s)

• Research Project

Abstract

The main objectives of this proposal are: 1) to assess the global warming potential of wetlands in the upper basin of the Biebrza river; 2) to determine the potential effects of woody encroachment, desiccation and eutrophication on plant diversity and on the warming potential; 3) to simulate future changes and predict the efficiency of protective measures.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Janssens Ivan

Research team(s)

Project type(s)

• Research Project

Abstract

In this project, we intend to study the importance of VOC emissions both in the total carbon budget of terrestrial ecosystems (objective 1) and the importance of specific VOC's in the formation of secondary organic aerosols (objective 2). Objective 1 will be realized by incorporating an existing mechanistic VOC model into a mechanistic SVAT model and by direct VOC-flux measurements using PTR-MS and either chambers of disjunct eddy covariance. Objective 2 will be achieved by chemical characterization of the organic aerosols and its comparison with the spectrum of the emitted VOC's.

Researcher(s)

• Promoter: Janssens Ivan
• Co-promoter: Claeys-Maenhaut Magda

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Gielen Bert

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Beyens Louis
• Co-promoter: Janssens Ivan
• Fellow: Fivez Lise

Research team(s)

Project type(s)

• Research Project

Abstract

Global change-induced losses of soil C could significantly enhance atmospheric CO2 concentrations and, thus, exacerbate global warming. We propose to experimentally test the individual and interactive effects of increased temperature, altered precipitation pattern, and altered ground water level on C inputs and C losses in a wetland soil. Parameterisation of the Century model will allow predictions of C cycling in wetland soils in future climate.

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Gobal change-induced losses of soil C could significantly enhance atmospheric CO2 concentrations and, thus exacerbate global warming. We propose to experimentally test the individual and interactive effects of increased temperature, altered precipitation pattern, and altered ground water level on C inputs and C losses in a wetland soil. Parameterisation of the Century model will allow predictions of C cycling in wetland soils in future climate.

Researcher(s)

• Promoter: Janssens Ivan
• Fellow: Konopka Bohdan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

The possibility of a causal relationship between the parallel increases in atmospheric CO2 concentrations and in global temperature has pinpointed the urgent need of a thorough understanding of the global carbon (C) cycle. If we are to optimise general circulation models and make realistic climate projections, deeper insight is needed in the climate-dependency of processes such as primary productivity of ecosystems or turnover of soil organic matter. Although still far from being perfect, our understanding of the global C cycle has improved considerably over the past decades. The integration of atmospheric, terrestrial and oceanic modelling and experimental studies has significantly decreased uncertainties and has allowed separation of terrestrial and oceanic carbon sinks. Nonetheless, considerable uncertainty remains regarding the continental distribution of the Northern-Hemispheric C sink. Over very long time periods, C sequestration in terrestrial ecosystems depends primarily on the occurrence of catastrophic events, such as fires, pest outbreaks, hurricanes or floodings. At shorter time scales, the net exchange of C between terrestrial ecosystems and the atmosphere is determined by the difference between photosynthetic C uptake and its release through autotrophic and heterotrophic respiration, and is typically one order of magnitude smaller than these nearly-offsetting terms. Both photosynthesis and respiration are strongly climate-dependent (although the parameters exerting dominant control differ). Because of the large interannual variability in climate, also the interannual variability in the net exchange of C between ecosystems and the atmosphere is very large. At this moment, our understanding of the climate-dependency of the net C exchange is still limited. Temperature-response functions, for example, vary among seasons, as well as among years. Unless we understand which factors determine this seasonal and interannual variability, we cannot further reduce the uncertainty surrounding future climate projections. If we cannot accurately predict how climate change will affect the balance between uptake and release of C from terrestrial ecosystems and oceans, we cannot determine whether natural ecosystems will mitigate or exacerbate global warming. Thus, there is an urgent need of studies that relate net C exchange to climate at both short (heat waves, drought spells, etc) and longer periods (El Nino-Southern Oscillation, North Atlantic Oscillation), but also for a variety of different climatic regions (boreal, maritime-temperate, continental-temperate, mediterranean). In this project, we will focus on three main objectives that differ in both the spatial resolution as in the carbon-cycle components being studied. The first objective of this research proposal is to quantitatively estimate the net biospheric C sink of the entire European continent. This will be done using a dual approach, namely up-scaling of C inventories and validation of these results with estimates obtained independently with inverse atmospheric tracer-transport models. The second objective of this research proposal is to study in great detail the relationship between the temporal variability in climate and in net C exchange between terrestrial ecosystems and the atmosphere. For this study we will analyse measured fluxes obtained with the 'eddy covariance" technique in a selection of ecosystems from different climatic regions at both short and long time scales. The third objective of this research proposal goes one step further: we will try to deconvolute the net C exchange into the component fluxes (photosynthetic uptake, above-ground respiration, soil C efflux, heterotrophic respiration) and study their climate-dependency. This "case" study is restricted to one ecosystem (a mixed coniferous/deciduous forest at Brasschaat, Belgium), where our research group has been studying in great detail the balances of C, nutrients and water since

Researcher(s)

• Promoter: Ceulemans Reinhart
• Fellow: Janssens Ivan

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

Soil organic matter (SOM) constitutes an important carbon (C) pool that exchanges C with the atmosphere. The sequestration of SOM can only be assessed by means of complicated biogeochemical models that are very difficult to parameterize. The requested funding will be used to perform measurements of 13C, 14C and 18O, which can be used to estimate the turnover of different SOM pools and to separate heterotrophic from autotrophic respiration. The main objectives are: 1) to estimate how fast do different SOM pools turn over in the Scots pine forest 'De Inslag' at Brasschaat? 2) to assess how climate affects the turnover of different SOM pools and what changes in SOM sequestration are expected under the IPCC climate scenarios?

Researcher(s)

• Promoter: Janssens Ivan

Research team(s)

• Plant and Ecosystems (PLECO) - Ecology in a time of change

Project type(s)

• Research Project

Abstract

Soil organic matter (SOM) represents an important carbon (C) store, which exchanges C with the atmosphere. Carbon sequestration in forest soils is an important sink for atmospheric C. Thus, storage of C in forest soils has been put forward as a strategy to mitigate the rise of the atmosferic CO2 concentration. During this fellowship we will try to determine the C sequestration in a number of terrestrial ecosystems. In addition we will implement a number of future scenarios for climate, atmosferic CO2 concentrations and nitrogen deposition to simulate potential changes in carbon sequestration. The specific goals of this fellowship are: 1° To investigate how climate influences the turnover of SOM, and how changes in climate could affect soil C sequestration. 2° To pinpoint the critical physiological parameters that determine the quantity of C that is sequestered by the ecosystem. 3° To determine the relative contribution of roots and heterotrophs to soil respiration, and to investigate whether the future climate changes are likely to change these. 4° To investigate how important the links with the biogeochemical cycles of water and nutrients are, and to assess the influence of nitrogen deposition. 5° To study the role of soil texture in SOM storage. 6° To estimate the amount of C which leaches out of the ecosystem. To achieve these goals we will use the Soil-Vegetation-Atmosphere model SECRETS, developed at the University of Antwerp in the Biology department. Experiments will emphasize on the use of stable isotopes of C, N, H and O.

Researcher(s)

• Promoter: Ceulemans Reinhart
• Fellow: Janssens Ivan

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

This project aims to increase our knowledge and improve the data sets on the soil respiratory activities of several forest ecosystems in the temperate zone through a detailed study and quantification of soil CO2 evolution rates. Both diurnal as well as seasonal cycles will be examined from different forest types, as mixed forest stands, oak-beech forests, coniferous forest vegetations and intensive poplar plantations. Special emphasis will be on the selection of the various experimental sites, with regard to dimension, location, distribution, etc...

Researcher(s)

• Promoter: Ceulemans Reinhart
• Fellow: Janssens Ivan

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

This project aims to increase our knowledge and improve the data sets on the soil respiratory activities of several forest ecosystems in the temperate zone through a detailed study and quantification of soil CO2 evolution rates. Both diurnal as well as seasonal cycles will be examined from different forest types, as mixed forest stands, oak-beech forests, coniferous forest vegetations and intensive poplar plantations. Special emphasis will be on the selection of the various experimental sites, with regard to dimension, location, distribution, etc...

Researcher(s)

• Promoter: Ceulemans Reinhart
• Fellow: Janssens Ivan

Research team(s)

Project website

Project type(s)

• Research Project