Research Erik Verbruggen

Abstract

Under the current climate change scenario, unlocking the carbon (C)-sequestering potential of soils has been identified as a key mitigation strategy. In this context, grasslands constitute a large reservoir of soil C, storing ca. one-third of the global terrestrial C stocks with belowground allocation of net primary productivity reaching values up to 60%. However, different management schemes could lead to varied resource allocation and utilisation. Notably, species-enriched grasslands have been found to store more soil organic C (SOC) than their more depauperate counterparts. Nevertheless, the question remains open as to how the complete link among plant diversity, root traits and microbial communities underpins soil C sequestration. The controversy mainly stems from the alternative views posed by plant and soil scientists, focusing, respectively, on root chemical traits and soil organic matter chemical changes. IRHIS will reconcile, building on results from a biodiversity-ecosystem function experiment (LegacyNet), these two frameworks by using a trait-based approach covering root biotic, physiological, chemical and morphological traits as well as soil organic matter fractions. Our overall goal is to advance our understanding of the effects of sown forage diversity on yield and soil and root properties, and how both ecosystem compartments (above- and belowground) interact in a forage crop system under Mediterranean conditions. The general hypothesis is that sown diversity alters the quantity and quality of inputs to the belowground compartment (root biomass, exudates), which in turn results in a more active/efficient and more abundant microbial community, thus also steering microbial necromass and associated by-products. Ultimately this could result in a high C accrual and, plausibly, concomitant productivity gains.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Llovet Martin Alba

Research team(s)

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

Project type(s)

• Research Project

Abstract

Anthropogenic soil acidification alters ecosystem functioning and triggers a decline in vegetation diversity, particularly in grasslands and heathlands. A solution for ecosystem recovery may be Enhanced Silicate (rock) Weathering (ESW), which was initially developed as a climate change mitigation technique. ESW consists of fine-grinding of silicate rocks, and then applying the powder to soils. During subsequent weathering, CO2 reacts with the mineral surfaces and is captured from the atmosphere, while HCO3- and base cations (e.g. K+) are released into the soil where they counter acidification. Although this procedure may remedy two urgent but also disparate problems, rising CO2 levels and biodiversity loss, effects of ESW have barely been explored in an ecosystem restoration context. The lack of holistic and long-term empirical data has resulted in an outlook of ESW that may be too optimistic, and potentially adverse effects of ESW have been disregarded. For example, we have no knowledge of how ESW and subsequent base cation regeneration affects community assembly of plants and microbes, nor do we understand how ESW interacts with soil organic matter (SOM) or with biotic actors, or how these interactions affect the ecosystem carbon (C) balance. In this project, I will fill in key knowledge gaps by combining three complementary approaches: (i) a synthesis of existing long-term field trials on ESW, (ii) a novel field experiment, and (iii) a full-factorial mesocosm experiment.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Findeisen Sophia

Research team(s)

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

Project type(s)

• Research Project

Abstract

Biodiversity underpins ecosystem functionality and stability. It is becoming increasingly clear that soil diversity and community complexity in particular (the presence of functionally diverse, interconnected organisms) are decisive for the maintenance of multiple ecosystem processes such as plant productivity and nutrient cycling. However, due to staggering soil diversity, difficulty to manipulate, and inadequacy of prior ecological concepts when applied to soil, we lack a thorough understanding of the link between soil biodiversity, ecosystem functioning, and environmental pressures across different soil types. This project will execute for the first time a series of microcosm experiments simulating contrasting European grasslands where soil community complexity will be manipulated to examine: 1) the effect of soil complexity on plant diversity, productivity and nutrient cycling across different grassland soils and their stability under different environmental pressures (drought, biomass removal, and intensified herbivory); 2) which key soil taxa and the interactions they form might be universally responsible for enhanced ecosystem stability across soils and stressors. The findings will not only advance our knowledge about the importance of soil biodiversity for grassland functioning and stability under disturbance but also delineate the biotic network properties and keystone taxa that are at the core of these processes and should be the focus of conservation efforts.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Radujkovic Dajana

Research team(s)

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

Project type(s)

• Research Project

Abstract

Engage in research, education, and project acquisition in the field of microbial ecology. More specifically, the work focuses on extant microbes in soil such as bacteria, archaea, fungi and protists. Specific topics covered are how they interact among each other, with plants, and with various ecosystem processes such as primary productivity and greenhouse gas fluxes. Examples are interactions between plants and mycorrhizal fungi and various nutrients with microbes responsible for greenhouse gas production and consumption. Specifically, one central question is how we can make the soil more resilient to various antropogenic influences such as habitat destruction and climate change, and help in the mitigation of these pressing issues.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Verbruggen Erik

Research team(s)

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

Project type(s)

• Research Project

Abstract

PRINCESS will investigate the potential of alternative land uses on rewetted peatlands to tackle the major environmental challenges of Europe: greenhouse gas emissions, nitrogen pollution and biodiversity loss. All relevant EU policy objectives include rewetting drained peatlands as an essential ecosystem-based solution. To the date obvious synergies and trade-offs both within (e.g. between carbon dioxide and methane emissions) and between the policy objectives (e.g. between emissions, biodiversity and economic returns) remain unquantified. Such quantification is crucial for optimizing between alternative land use options for rewetted peatlands, i.e. high-intensity paludiculture, low-intensity paludiculture, and wilderness. PRINCESS will • evaluate the synergies and trade-offs between (1) restoring biodiversity and healthy ecosystems, (2) keeping global warming below 2°C, (3) clean water and (4) fair income to farmers • explore to what extent atmospheric N loads can guide decision-making on which land use option – under given circumstances – optimally contributes to the policy objectives • identify tipping points where switching from one land use option to another would maximise policy objectives. To achieve these objectives, PRINCESS will • focus on the peatlands which are the largest sources of GHG and affected most by nitrogen loads, i.e. temperate fens. Results, however, are relevant across drained-and-to-be-rewetted peatlands in the temperate and boreal zones. • bring together complementary skills from six peatland-rich countries, including those with little (FI, NO, PL) and strong peatland degradation and N loading (AT, BE, DE), the latter being also front-running in rewetting and paludicultures • analyse crucial processes under highly controlled conditions in the laboratory and in mesocosms, test them under more realistic conditions in the field, and model and upscale them to catchment and EU scale • use these different scales of study to maximize internal (sound interpretation of causal effects) and external (their relevance) validity • apply the most advanced techniques and methods from biogeochemistry, microbial ecology, plant ecology, socioeconomic modeling on and across scales, using measurable and quantifiable indicators. PRINCESS is organized in seven work packages (WP), one each for coordination and outreach, and five to cover each of the relevant scales. Each WP considers all three land use options but has a different focus within or between the indicators. PRINCESS will provide vital scientific information for agricultural land use policies for peatlands in the EU by evaluating which land use option after rewetting complies best - under high nitrogen loads - with key policy objectives such as healthy ecosystems, climate change mitigation and adaptation, clean water, fair income to farmers, or, taken together, a greener and more sustainable Europe.

Researcher(s)

• Promoter: Verbruggen Erik

Research team(s)

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

Project type(s)

• Research Project

Abstract

Microorganisms have been exploited from the earliest times for baking, brewing, and food preservation. More recently, the enormous versatility in biochemical and physiological properties of microbes has been exploited to create new chemicals and nanomaterials, and has led to bio-electrical systems employed for clean energy and waste management. Moreover, it has become clear that humans, animals and plants are greatly influenced by their microbiome, leading to new medical treatments and agricultural applications. Recent progress in molecular biology and genetic engineering provide a window of opportunity for developing new microbiology-based technology. Just as advances in physics and engineering transformed life in the 20th century, rapid progress in (micro)biology is poised to change the world in the decades to come. The Excellence Centre "Microbial Systems Technology" (MST) will assemble and consolidate the expertise in microbial ecology and technology at UAntwerpen, embracing state-of-the-art technologies and interdisciplinary systems biology approaches to better understand microbes and their environment and foster the development of transformational technologies and applications. MST connects recently established research lines across UAntwerpen in the fields of microbial ecology, medical microbial ecology, plant physiology, biomaterials and nanotechnology with essential expertise in Next Generation Sequencing and Bioinformatics. By joining forces, new and exciting developments can be more quickly integrated into research activities, thus catalyzing the development of novel microbial products and processes, including functional food, feed and fertilizers, probiotics, and novel biosensors and bio-electronics applications. This way, MST aims for an essential contribution to the sustainable improvement of human health and the environment.

Researcher(s)

• Promoter: Meysman Filip
• Co-promoter: Beemster Gerrit
• Co-promoter: Laukens Kris
• Co-promoter: Lebeer Sarah
• Co-promoter: Verbruggen Erik
• Co-promoter: Vlaeminck Siegfried

Research team(s)

• Geobiology

Project type(s)

• Research Project

Abstract

The anthropogenic increase of greenhouse gas (GHG) emissions into the atmosphere is promoting and accelerating climate warming. Among anthropogenic activities contributing to GHG emissions, agricultural soils emit ~12% of the global emission. The high amounts of nitrogen (N) added as fertilizer enhance soil N cycling and N2O emissions (representing >60% of global N2O emissions), and soil respiration (~20% of global CO2 emissions). Arable lands cover ~11% of the terrestrial surface, the modification of traditional agricultural practices is a key opportunity to reduce GHG emissions without compromising food and soil security. Recent studies have proposed agricultural management practices (e.g. biochar or silicate applications) to mitigate GHG emission, by enhancing soil organic C sequestration and promoting complete denitrification while maintaining crop productivity. Yet, there are still many uncertainties regarding the magnitude and variability of soil GHG emissions using these practices, reaching contradictory results concerning the potential role of agricultural soils as sinks or sources of C and N to the atmosphere. Moreover, little is known about how these practices can affect the soil microbial community responsible for GHG formation, and modifying the role of the soil sink/source behavior. The main goal of the project "Towards a minimization of the agricultural greenhouse gas emissions while ensuring crop production" (Acronym MAGIC) is to search for the practice where GHG emissions comprise the lowest global warming potential without compromising crop yields. Moreover, MAGIC aims to use concrete demolition, an artificial silicate, and thus, enhance material re-use and circular economy. To achieve this objective, a crop mesocosm field experiment will be set up applying different agricultural management treatments. Responses on GHG emissions, soil N transformation and soil microbial communities will be followed over a year. Overall, this project will generate valuable scientific results that will be of interest for national, European and global strategic actions in agricultural systems.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Poblador Ibanez Silvia

Research team(s)

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

Project type(s)

• Research Project

Abstract

Food security challenges mean that we need to increase global crop production in order to feed the world's growing population, under conditions of global change. Focusing on belowground plant traits, and especially root exudation, has strong promise in this regard. Exudation is the release of a vast array of compounds into the soil, and root exudates are involved in a wide range of biotic and abiotic interactions. This project aims to extend our understanding of the importance of root processes, especially exudation, through a focus on wild relatives of modern crops. Wild relatives provide a large potential source of information and genetic material and have already been identified as having desirable traits. Recent work has indicated that differences exist between root exudates of wild and crop species, providing evidence that it is worthwhile to focus on these root traits in crop wild relatives. The overall objective is to study the differences between crops and their wild relatives in terms of root exudation and the rhizosphere microbial community. This will allow us to identify belowground plant traits that could improve crop yield amount and stability and quantify the impact of agriculture on soil microbial diversity. My specific objectives are: 1)To discover if there are consistent differences between root exudate quantity and composition in crops and wild relatives and how this is related to plant species phylogeny; 2) To understand the interaction between domestication and drought on root exudation; 3) To understand how rhizosphere microbial diversity differs between crops and their wild relatives and between agricultural and non-agricultural soils. The results will have implications for plant breeders, farmers, and policymakers.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Preece Catherine

Research team(s)

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

Project type(s)

• Research Project

Abstract

The central question in this study is whether the development of the microbial community in species-poor grasslands in nature reserve "de Liereman" can be controlled by the introduction of sod cut material collected in species-rich and well-developed reference grasslands ("soil inoculation"). We use state-of-the-art molecular techniques such as metabarcoding and qPCR.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Emsens Willem-Jan
• Co-promoter: Verbruggen Erik

Research team(s)

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

Recent climate change research reveals a novel and significant trend: weather patterns at mid-latitudes, such as in temperate western Europe, are getting more persistent. With respect to rainfall, this means longer droughts, but also longer periods with excessive rain. No comprehensive study has hitherto investigated the ecological consequences of such regime shifts. Can ecosystems adapt, or will the alternation between drought stress and soil water saturation exhaust them? Will this select for communities with novel trait combinations and more volatile species dynamics? And will these novel systems still be robust in the face of further changes in the environment? This study explores the potential impact of the ongoing shift in the frequency of dry/wet cycles at multiple, connected levels of biological organization. It does so in a new, large-scale set-up at UAntwerp built in the framework of the developing European infrastructure for ecosystem research 'AnaEE'. The design simulates changes in rainfall and associated temperature changes in the open air, using a gradient with eight precipitation regimes so that non-linearity and tipping points can be discerned with great precision. The project scope ranges from plants to soil biota such as bacteria and fungi, and from metabolism and genetic regulation assessed with bioinformatics to ecosystem processes. This multi-scale approach explicitly acknowledges the interwoven nature of ecosystems, with knowledge of molecular and cellular changes being instrumental to mechanistically explain the whole-system-scale effects on productivity, greenhouse gas fluxes and biodiversity dynamics. Different experiments are planned each year: (i) year 1 features a gradient in alternating dry/wet cycles, from 1 to 60 days, across a full growing season; (ii) year 2 focuses on legacy effects and the importance of changes of soil communities; (iii) year 3 matches precipitation regimes to corresponding temperature regimes to study the impact of drought-associated warming (an important natural feedback that can greatly increase plant stress). A series of connected, hypothesis-driven measurements is carried out, which will be integrated using structural equation modelling (path analysis) and ecosystem modelling. The project team has successfully collaborated in the past, and the complementary expertise brought together here should yield both significantly increased understanding of key processes as well as new avenues to climate change impact mitigation.

Researcher(s)

• Promoter: Nijs Ivan
• Co-promoter: Asard Han
• Co-promoter: Beemster Gerrit
• Co-promoter: Laukens Kris
• Co-promoter: Verbruggen Erik

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 two-thirds of global plant diversity, and are often referred to as hyperdiverse in terms of tree species richness. 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 and diversity. In this project we will test in Forests in French Guyana the effect of neighbouring trees on seedling success through mutualists and antagonists. While it is known that plants can connect to a "common mycorrhizal network", whether this occurs in the field and whether this affects seedling success through increasing access to nutrients, carbon, and reduces vulnerability to antagonists is unknown. Moreover, whether this connection is dependent on whether the adult tree is of the same species is also unknown, but may be an important driver of forest species composition through determining seedling success. Here we will manipulate connection to a common mycorrhizal mycelium and determine the effects on seedling growth depending on adult matching (same – other), as well as the effects on microbes colonizing seedling roots. This experiment will greatly increase our understanding of the importance of mycorrhiza for seedling performance. This knowledge will allow better understanding of the importance of how plant-fungal relationships may contribute to the ecology and biodiversity of rainforests.

Researcher(s)

• Promoter: Verbruggen Erik

Research team(s)

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

Project type(s)

• Research Project

Abstract

Belowground biodiversity is formed by fungi, bacteria, archaea, animals and plants that altogether affect soil functioning, particularly by controlling rates of production and decomposition of organic matter. Peat soils, being the most concentrated stores of soil carbon, are formed by a long-term net exceedance of production over decomposition. The REPEAT project addresses the mechanisms contributing to peat formation in fen peatlands in order to improve restoration prospects of these threatened ecosystems that provide vital ecosystem services for mitigation of climate change, regional hydrology, nutrient retention and biodiversity conservation (Bonn et al. 2016) . In Europe most fen peatlands have been severely degraded by land use. Drainage has turned the peatlands from carbon sinks into significant sources of greenhouse gases (GHG) and has made Central Europe – after Indonesia - the second largest hot-spot of peat GHG emissions worldwide (Joosten 2009). Peat formation is a precondition to re-install the vital ecosystem services provided by the fen ecosystem. However, re-establishment of high groundwater tables alone is often not sufficient to restore peat formation (Grootjans et al. 2012). In spite of decades of trials, processes that control peat accumulation (including their rates, pathways and drivers) remain unknown. Previous research on peatland carbon cycling has focused almost exclusively on rainwater-fed bogs with upward growing peatmoss (Sphagnum) as the prevailing mode of peat formation. In contrast, in groundwater-fed fens roots and rhizomes of sedges and grasses grow into the older peat matrix to form 'displacement peat'. Therefore, peat formation models developed for bogs (Clymo et al. 1998, Frolking et al. 2001) do not fully apply to fens. REPEAT aims to clarify the mechanisms of peat formation in fens by linking biogeochemical processes to soil community structure and biodiversity, as well as to plant belowground litter quality, with special focus on the prospects of restoring peat formation mechanisms. Paludiculture (biomass harvest) will receive special attention because it has recently been recognized as an key management approach that allows sustainable use of wet and rewetted peatlands.

Researcher(s)

• Promoter: van Diggelen Ruurd
• Co-promoter: Verbruggen Erik

Research team(s)

Project website

Project type(s)

• Research Project

Abstract

Tropical rainforests are the most diverse and productive ecosystems on Earth. These system account for two-thirds of global plant diversity, and are often referred to as hyperdiverse in terms of tree species richness. Typically, any random draw of 300 adult individuals will represent over 100 different species. Understanding the ecological processes underlying this diversity will be essential for predicting biodiversity consequences of global change factors currently challenging tropical rainforests such as increased intensity of drought and changing nutrient balances. 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 plant interactions. Forests in French Guyana are unique in being among the most pristine and well-studied lowland tropical rain-forests on Earth. In this project we will use a variety of approaches to better understand the effect of drought and nutrients (Nitrogen and Phosphorus) on root colonizing microbes including mycorrhizal fungi, pathogens and bacteria. This will be done through combinations of small scale precipitation experiments and fertilization trials, as well as with a larger separate fertilization trial. Also, we will test the effect of neighbouring seedlings on these microbial communities on seedling inventories that have been carried out for over 10 years to test for statistical between seedling success and effects on conspecific neighbours through mutualists and antagonists. In parallel the project proposes to conduct experiments to assess the effect of mycorrhizas 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 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: Verbruggen Erik
• Fellow: Ramirez Rojas Irene

Research team(s)

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

Project type(s)

• Research Project

Abstract

The resources from this start-up grant will be allocated towards various research projects in the general field of microbial ecology. These include research into effects of mycorrhizal fungi on soil C cycling, effects of mycorrhiza on plant-plant interactions, and impact of mycorrhizal fungi and drought on soil food web community structure.

Researcher(s)

• Promoter: Verbruggen Erik
• Fellow: Verbruggen Erik

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