Research Jonas Schoelynck

Abstract

The common denominator of the European Duckweed Network is duckweed or Lemnaceae. These small aquatic plants are not only the world's fastest growing flowering plants, they can produce a substantial amount of protein per hectare, considerably in excess of conventional protein crops. Furthermore, they take up nutrients, heavy metals, and nuclear contaminations from heavy polluted wastewater. These are all traits that make duckweed highly suitable to tackle European and global challenges such as food and feed production, bioremediation, or even combinations of both. Thus, duckweed can be a key part of a circular solution to the current sustainability crisis, for example by growing duckweed on pig manure waste, and subsequently using it as pig feed. The European Duckweed Network brings together key research experts from diverse fields such as agriculture, genomics, physiology, space research and nuclear science, and allows knowledge transfer on pilot and large-scale research on duckweed cultivation. Despite the differences in background, all network partners share a common aim, to develop duckweed cultivation for a more sustainable future. It is also recognized by the partners that open communication and knowledge exchange is necessary to achieve this. This way, common challenges such as optimizing harvesting techniques, improved crop protection (against algae, black water lily aphids, and pythium), and reduced plant stress (nutrient imbalances, and climatic conditions) can be systematically tackled, optimally using the multidisciplinary expertise that is present in the network.

Researcher(s)

• Promoter: De Boeck Gudrun
• Co-promoter: Groffen Thimo
• Co-promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

For more than 20 years, special attention is paid to the study of the Schelde estuary and the scientific support of necessary management actions to meet both human use as the ecological functioning of the system. To gain more insight and to support decision making in the Schelde estuary, an ecosystem model was developed at UAntwerpen. This model builds on the MOSES model that was developed in the 1990s by Karline Soetaert and Peter Herman, affiliated with the then NIOO-CEME, now NIOZ-Yerseke. At UAntwerpen, the model has been expanded and refined in various ways. In the current version, the Boven-Zeeschelde and the Rupel also belong to the model domain and boundary conditions are defined at the lock complex in Merelbeke and at the confluence of the Dijle and the Nete. Based on Tom Cox's research into primary production and its influence on oxygen dynamics in the Scheldt, the dynamics of phytoplankton became more realistic modeled. Interest in pelagic primary production (the build-up of biomass by phytoplankton) has increased in recent years. An important reason for this is the changes in dynamics of suspended material that have been observed in different estuaries in response to changes in the geometry of estuaries (deepening, channelization, depoldering, etc.). Abrupt changes (so-called critical transitions) have also been observed in the Scheldt in recent decades. In light-limited systems, the amount of sludge in suspension is one of the most important determinants of primary production. Given the many observational and theoretical indications that human interventions influence the dynamics of suspended material, in light-limited systems the influence on primary production is one of the most closely examined ecological impacts of interventions that change geometry. With climate change, further expansion of harbors and the need for new measures to protect against floodings, the estuary faces new challenges. This creates also new challenges for modelling the Schelde ecosystem, that will be tackled in this PhD. The existing model tools offer a solid foundation for further development of the model where it seems most useful. A better approach to lateral areas is an option, where ways to explicitly include the lateral systems can be implemented as a separate model box where processes can take place under changed conditions (e.g. more light availability). Processes in the soil can also be included.

Researcher(s)

• Promoter: Schoelynck Jonas
• Co-promoter: Maris Tom

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

National parks in Africa are essential to protect megafauna, associated biodiversity and landscape. Park authorities hence restrict the use of natural resources by local communities, to avoid illegal land encroachment, poaching and ecosystem degradation. Yet, the persistent poverty, and the need for natural resources for their livelihood results in conflicts 1) between local communities and park authorities, and 2) between humans and wildlife. The RUBICOM project aims to provide the basis for a knowledge driven, sustainable human-bioversity coexistence in the River Rusizi plain of Burundi, focusing on aquatic and wetland ecosystems. Community based biodiversity conservation requires a stronger focus on optimizing conservation efforts that maximize synergies between biodiversity and ecosystem functioning, and local communities being able to benefit from the ecosystem services the wetlands provide (e.g. for drinking water, fish, medicinal plants, drought resilience, flood protection). The project will focus on wetland biodiversity, and more specifically targets the hippopotamus (in short hippo) as a key or 'flagship' species for conservation. The hippo is a key species determining the ecosystem's primary production, water quality and plant biodiversity, but is also involved most directly in human-biodiversity conflicts, often leading to direct confrontations and injuries. The project aims to set a baseline for biodiversity status in the region, as well as improve understanding of people's perception on human-wildlife conflicts and potential for community-supported biodiversity conservation. This can serve as basis for developing solutions for a more community-based biodiversity management, and creation of locally embedded knowledge hubs that further strengthen these community-based biodiversity strategies, which is also key to developing future climate change adaptation strategies. Wetlands play a key role in developing a climate-resilient future for the community.

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The project aims to launch a service platform for soil and water characterization in aquatic ecosystems. The platform will provide technical services for water and soil characterization, as well as scientific support for private industry and governmental organizations. By integrating the new service platform in the existing ECOSPHERE Analytics concept, focused on aquatic ecotoxicology and risk assessment, we will develop the most versatile environmental lab in Flanders by offering a broad scope in ecosystem assessment tools, both from the ecology and ecotoxicology side. The project will align with the ISO 17025:2017 standard and integrate with the different platform components (soil and water characterization, ecotoxicology, chemical analysis, risk assessment and water treatment) to offer a unique selling proposition in the field of ecosystem monitoring, risk assessment, prevention, and remediation. Our customers will be diverse, ranging from academia, government and legislators to industrial stakeholders.

Researcher(s)

• Promoter: De Boeck Gudrun
• Co-promoter: Maris Tom
• Co-promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project website

Project type(s)

• Research Project

Abstract

The Chinese mitten crab is listed by the International Union for Conservation of Nature (IUCN) as one of the "World's 100 Worst Invasive Alien Species". Eight institutions from four countries (FR, BE, DE, SE) joined forces to find a strategy on a European level for a lasting and efficient reduction of this invasive species. Juvenile crabs migrate up almost all coastal river systems in Western Europe where they spend part of their adult life before their migration back towards the North Sea for reproduction. Therefore, the mitten crabs can be caught at two different life stages and be removed in large quantities from the river systems at suitable locations using an innovative trap concept. This will significantly reduce the negative ecological impact of the mitten crabs in the river systems. The University of Antwerp and the Flanders Environment Agency, have collaboratively developed a trap concept and successfully tested it in the "Kleine Nete River" close to Antwerp. Now, we will set up 5 new traps in Belgium and 5 traps in Germany to test the concept under different conditions and in different river sizes. We will also use common crab traps in different locations in Sweden and Northern France to identify spots of migration and/or migration patterns. Overall, these traps will reveal the most suitable modifications and locations in terms of total catch and lowest maintenance costs. Over the course of five years, we will monitor the effect of the traps/crab reduction on the river ecosystems and develop concepts for a sensible use of the crab biomass. Clancy seeks to demonstrate how invasive species can successfully and efficiently be controlled at a European level. As such it is intended to help national authorities implement the EU's requirements for combating invasive species.

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project website

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

ANAEE provides Europe with a distributed and coordinated set of experimental, analytical and modelling platforms to analyse and predict in a precise manner the response of the main continental ecosystems to environmental and land use changes. ANAEE consists of highly equipped in natura and in vitro experimental platforms associated with sophisticated analytical and modelling platforms, under a European umbrella of supranational entities. At UAntwerp these platforms include both terrestrial and aquatic experimental facilities: FATI, MESOSCALE ECOTRON, en MESODROME (see anaee.be).

Researcher(s)

• Promoter: Nijs Ivan
• Co-promoter: Blust Ronny
• Co-promoter: De Boeck Gudrun
• Co-promoter: Schoelynck Jonas

Research team(s)

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

Project type(s)

• Research Project

Abstract

Tidal marshes are increasingly proposed as nature-based shoreline protection against climate change induced sea level rise and increasing storminess. In this project I address the following key knowledge gaps on the effectiveness of this nature-based climate adaptation function: how do two-way interactions between plants and waves lead to spatial self-organization of species zonation and wave attenuation, and how does this self-organization determines the resilience (i.e. persistence) of the wave attenuation function under changing climate conditions. A mesocosm experiment in the new UAntwerpen tidal flume will demonstrate the specific growth response of three dominant tidal marsh species to interactive stresses from waves, tidal inundation and sediment salinity. A novel coupled model of plant species distribution and wave transformation will be calibrated and evaluated against field data to demonstrate that the plant-wave interactions lead to spatial self-organization of both species zonation and wave attenuation rate. The model will be applied to future scenarios of changed climate conditions (i.e. sea level rise, increased wave exposure) to show the impact of the self-organization on the persistence of the wave attenuation function. As such my project will make a major advancement to the field of nature-based climate adaptation in the coastal zone.

Researcher(s)

• Promoter: Temmerman Stijn
• Co-promoter: Schoelynck Jonas
• Fellow: Schoutens Ken

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Nutrients are vital, not only for individual organisms but also for entire ecosystems. The SKALAR SAN++ Advanced System allows us to analyze a whole range of nutrients in continuous flow. It is essential for the research of the new research group ECOSPHERE on aquatic and terrestrial ecosystems, where nutrient analysis in water, plants and soil are essential, and for the research group DuEL, where nutrient analysis in wastewater streams and microbial growth media are indispensable. The equipment also delivers analysis services to other research groups and external parties.

Researcher(s)

• Promoter: De Boeck Gudrun
• Co-promoter: Bervoets Lieven
• Co-promoter: Schoelynck Jonas
• Co-promoter: Vlaeminck Siegfried

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The BiNatUr project will explore the role of biodiversity and its linkages with regulating ecosystem services (ES) in urban aquatic nature-based solutions (aquaNBS), and its overall aim is to improve the planning, building, restoration, and management of aquaNBS, supporting the transformation to climate-smart, biodiversity-friendly, and sustainable cities. BiNatUr will explicitly focus on four main research questions: • How are biodiversity and ES of aquaNBS mediated by social, ecological, and technological factors? • Does this vary among cities in different regions of Europe? • How does biodiversity influence the regulating ES provided by aquaNBS? • How can urban planning effectively design, manage, and monitor the biodiversity and regulating ES of aquaNBS?

Researcher(s)

• Promoter: Schoelynck Jonas
• Co-promoter: Staes Jan

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Large wildlife, as a sort of "wild alchemists", redistribute and mobilize nutrients across and beyond the boundaries of ecosystems, turning dung into gold & engineering landscapes in ways that keep surprising scientists. These fascinating influences of wildlife on biogeochemical cycles are studied by Zoogeochemistry, an exciting new branch of biogeochemistry research. It is anchored in the premise that animals do not necessarily eat, defecate and die in the same place. As such they can deplete, replenish and transport chemical elements that are essential for life, such as carbon and nutrients, and thereby modify resource landscapes and entire ecosystems. The influence of wildlife on shaping nutrient landscapes is only just starting to attract attention, with recent case-studies revealing intriguing new patterns and insights. We aim to create the momentum necessary to bring zoogeochemistry into mainstream ecological research, and achieve a knowledge build-up that creates energy for the emergence of a critical mass of researchers in zoogeochemistry. Our overarching vision for this network is to create a platform for collaboration that will promote coordinated, multi-site research projects that will allow for student exchange between systems and participants, cross-disciplinary knowledge exchange and joint funding application development to scale up the impact and reach of zoogeochemistry research.

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

In many valleys in Flanders, rivers have been straightened to improve drainage, rapid evacuation of rainwater and optimize land use for agriculture. Doing so, the ecology of these rivers declined and hence the delivery of important ecosystem services. With climate change, the demand for certain ecosystem services is steadily increasing. River valleys are already now often suffering periods of drought during summer, and climate change scenarios predict more problems in the future. In this project, we will investigate if and how reconnecting former meanders in the Demer valley (Flanders, Belgium) can mitigate climate change problems and restore ecosystem functioning, with focus on drought prevention, nutrient cycling and carbon sequestration. Research and monitoring of the first phase of this restoration project should give more insight in the efficiency of these measures, and result in advice to improve future projects.

Researcher(s)

• Promoter: Schoelynck Jonas
• Co-promoter: Maris Tom

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

A promising but yet poorly studied negative emission technology (NET) is accelerated silicate weathering (EW). Thus far, research on EW has mainly been limited to laboratory experiments, without soil and important biota. However, biota such as plants and soil can strongly influence mineral weathering. On the other hand, field investigations face a major challenge because weathering products and hence C sequestration are very difficult to accurately quantify. In this project mesocosm experiments will therefore be conducted to determine the influence of important biota, hence providing critical information needed to extrapolate lab-based results to the real world.

Researcher(s)

• Promoter: Vicca Sara
• Co-promoter: Schoelynck Jonas

Research team(s)

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

Project type(s)

• Research Project

Abstract

It is common knowledge that natural ecosystems are globally under threat. This is largely because of human activities. By misusing the land, polluting rivers and lakes with chemicals and agricultural fertilizers, releasing alien species from around the world, and altering climatic conditions, we are changing the world we live in. Scientific research to find ways to respond to these challenges can provide solutions to halt the deterioration, and restore the functioning of our valuable freshwater ecosystems. In my research I will endeavour to better understand how ecosystems work with the aim of discovering what we can do to relieve them from the pressures they are under. Rather than studying each pressure source independently, I intend to focus on the combination of different pressure elements working together, which is closer to the reality of the situation.

Researcher(s)

• Promoter: Schoelynck Jonas
• Fellow: Schoelynck Jonas

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The impact of invasive species on ecosystems can cause habitat alteration or even habitat loss. This could ultimately lead to fundamental effects on ecosystem functioning. This project is focused on the case of the Chinese mitten crab (CMC). This is a new species and the only freshwater crab species in Flanders. Being the largest representative of the macroinvertebrates, it probably takes a prominent role in the processing of organic matter. This could have a profound effect on nutrient cycling and water quality in general. Through bioturbation, burrowing behaviour and their destructive impact on macrophytes, the CMC potentially impacts also the stability of river ecosystems, which may lead to enhanced erodibility. By investigating these different effects, this project will give fundamental insight in the impact of freshwater crab species on aquatic habitats along the river continuum.

Researcher(s)

• Promoter: Schoelynck Jonas
• Fellow: Keirsebelik Heleen

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

In this project, our specific focus will be directed towards understanding the interaction between climate warming and two prominent stressors in freshwater habitats: eutrophication (as nitrate pollution) and low dissolved oxygen (hypoxia). Freshwater habitats often receive excessive inputs of nitrates from urban and agricultural sources, and nitrogen is considered the main limiting nutrient for primary production. Nitrate pollution is closely linked to a second stressor - hypoxia. Because of the nitrate pollution, rapid, uncontrolled growth of algal blooms is often triggered, and the unnatural density of algal blooms causes light reduction for macrophytes during the day and nightly hypoxia when photosynthesis is not occurring. In the past it has been postulated that many small fish deplete the zooplanktonic grazers such as daphnids under warm and eutrophic conditions, inducing the turbid waters with algal blooms. However, climate change does not only induce steady increases in temperature but is also causing more frequent and severe heatwaves. In this project we postulate that these heatwaves will seriously negatively affect performance and survival of the fish, which in turn will affect shifts in the aquatic food web towards more zooplankton and hence potential less severe algal blooms.

Researcher(s)

• Promoter: De Boeck Gudrun
• Co-promoter: Schoelynck Jonas
• Fellow: Akter Sabiha

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The objective of this study is to map and measure the architecture of the burrow network in a non-intrusive manner using Structure-from-Motion (SfM) photogrammetry and ground-penetrating radar (GPR).

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

In this project, the conditions for native fish to be used as biological control in restored tidal marshes is investigated. Using native fish may not only be extremely cost-effective, improving the conditions will also improve restored flooding areas as habitats for fish at the same time. Information will be collected on the current distribution and habitat preferences of nuisance species and native fish communities in three flooding areas along the Scheldt estuary. The first is a flooding area which had very recent serious outbreaks of midges. This area is connected to a second and neighboring a third flooding area, which both have a different design as the first and which have no issues with outbreaks. The collected field information will be combined with experiments that look at which factors can help fish to eat more nuisance species and to create habitat suitability models. These are models that can be used to predict the risk of nuisance species outbreaks. They will also show the conditions that are important for fish in flooding areas. These models can be used to evaluate and potentially improve any of the flooding areas in Flanders and abroad. They will be made public to policymakers and project managers and companies involved in the construction and restoration of flooding areas to be used as a tool for controlling nuisance species and improving flooding areas for fish.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Schoelynck Jonas
• Fellow: Franquet Sam

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The aim is to draw up differentiated guidelines for effective and cost-efficient small-scale management and maintenance of stream systems (stream and valley), making use of or responding to natural processes, whether or not supported by additional (small-scale) design measures. These guidelines describe the nature, scope, spread over locations, frequency, timing and execution of the named actions. The subgoals are: • Knowledge-building nature-oriented, local management measures (differentiated mowing of streams and streams and the targeted introduction of dead wood, preferably linked to shadows), which are connected with the natural processes in brooks that occur on a higher scale in the catchment area. In this way, specific natural values ​​in brook and stream valley are reinforced or restored. • Developing new knowledge by means of experiments on restoring and strengthening habitat variation and - stability through differentiated management of the stream and the banks to renew and strengthen the existing knowledge based on empirical data. • Communicating existing and new knowledge to management practice.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

The scientific understanding of the Si cycle has progressed from conceptualizing it as almost purely driven by geological processes, to a much more nuanced understanding that includes biological transformation and cycling. A recent pioneer study showed that the hippopotamus is a key factor in the savannah biogeochemical Si cycle on a regional scale. This has a potentially large impact on downstream lake ecosystem functioning, where Si availability directly affects the principal primary producers -diatoms- which dominate the base of the food web. The objective the current study is to determine the filtering capacity of Wetlands controlling the (biogenic) silica transported by rivers before it enters Lake Victoria. To meet this objective, a joint expedition to the Mara wetlands will be done, together with the Sokoine University of Agriculture (SUA), Morogoro (Tanzania). During this expedition we will take water-, sediment- and plant samples to calculate the silica stock and -flux to the Lake.

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

The Chinese mitten crab is an invasive exotic species in our freshwater ecosystems and the population seems on the rise in recent years, especially in the upstream reaches of rivers. In these upstream reaches, water plants flourish and fulfill a crucial ecological role in the ecosystem. The effect of the mitten crabs on this aquatic vegetation is poorly understood. A handful of laboratory test show that macrophytes are part of the crab diet, but not exclusively. Also some case studies in the field blame the crabs to have completely clear-cut the entire aquatic vegetation, though there was no conclusive proof for that. Our hypothesis is that mitten crabs are indeed capable of heaving a devastating effect on the aquatic vegetation, but only if this vegetation is already impaired or experiences considerable levels of (abiotic) stress. In this project we will experimentally investigate whether crabs can have a negative effect on aquatic vegetation and whether this effect is bigger when plants are stressed. The studied stresses are EDTA-pollution and light stress, both factors are linked to the earlier mentioned case studies. Combining density data from literature and knowledge on herbivory pressure by certain crab densities will allow estimating the threat these crabs potentially are for the native flora in freshwater rivers.

Researcher(s)

• Promoter: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

It is known that water plants interact with flow and can therefore significantly influence hydrological and biogeochemical processes. Numerical models are mathematical tools to integrate large amount of data to understand complex processes in river ecosystems. Yet very few of the existing models are capable of implementing aquatic vegetation and their role is mostly neglected. The current project, called FLASHMOB (FLuxes Affected by Stream Hydrophytes: Modelling Of Biogeochemistry), proposes a unique combination of a Belgian-Austrian team to combine expertise in numerical modelling with fieldwork and lab experiments. We hypothesize that the interaction between plants (in-stream vegetation) and water flow (hydrodynamic conditions) is key in determining production, downstream transport/retention and transformation of organic matter and associated nutrients. An existing model (DELWAQ) was adapted to floodplain sections of the Danube River and forms the ideal basis for integrating the role of water plants in river systems. Organic matter dynamics and aquatic primary production in the current model are coupled to dynamic surface exchange conditions. The first step is to implement the role of in-stream vegetation in a more explicit way including feedback processes through a stepwise and iterative work plan calculating the specific effects of each aspect of plant-flow interaction separately. Finally, all steps are combined and the total net effect of in-stream vegetation on water quality and –quantity of larger river sections (sub basin scale) can be quantified and used for predictions of future development of river ecosystems.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

Climate change seems inevitable over the next few decades. The RCP6.0 scenario of the IPCC predicts the atmospheric CO2 concentration to double by 2100, and the associated climatic shifts will affect many ecosystems. However freshwater ecosystems are poorly studied compared to their terrestrial counterparts, and therefore we are uncertain as to how these systems will respond to climate change. On the other hand it is well established that the predicted changes in precipitation – longer droughts and more extreme rainfall events – will affect rivers and wetlands tremendously. Aquatic plants are some of the key primary producers in these rivers, which govern (i) the aquatic food web (plant material consumed by decomposers) and (ii) biogeochemical processing (nutrient and carbon cycling). Enhanced CO2 and increased nutrient concentrations may lead to an increase in the production of these aquatic plants. Yet the more severe flood pulses are likely to affect plant survival, leading to increased plant mortality and therefore an increase in litter in the system. Climate change may also affect aquatic ecosystems by affecting plants nutrient stoichiometry. Both plant quantity and quality are key driving factors for the aquatic decomposers' food web, which would have knock-on effects for the entire food web. We hypothesize that the performance of macro-invertebrates and bacteria may change, which leads to changing decomposition rates and a direct impact on nutrient and carbon cycling.

Researcher(s)

• Promoter: Meire Patrick
• Fellow: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

Macrophyte patches as biogeochemical hotspots: impact on river water quality? 1. Problem Macrophytes play an important role in the structural biodiversity in aquatic ecosystems. Being primary producers, they are a matter of life and death for many organisms. Even on a ecosystem level, they take a central role, but the processes here involved are not yet well known. Though, a good knowledge is crucial to be able to take correct management decisions concerning the improvement of our fresh water ecosystems. On top of this, the presence of macrophytes has an even greater influence on the hydraulics. Macrophytes act as ecological engineers and have therefore a direct influence on stream velocity patterns and on sedimentation and erosion patterns. Changes in these patterns have immediate consequences on biodiversity and geomorphology. 2. Objectives I want to test the main concept of macrophytes being biogeochemical hotspots. After all, there are strong indications that the processes in the sediments underneath macrophyte patches can have greater impact on the water quality than the typically studied pelagic processes. To test this hypothesis, three questions are postulated: 1) Are macrophyte patches biogeochemical hotspots and at what quantity? 2) Which is the maximal length and width a patch can have under certain circumstances? 3) What is theoretically the maximal surface patches can have in a river stretch, given certain circumstances (and what is the total effect of these patches on the water quality, regarding question 1)? 3. Methodology Question 1) will be answered by gathering field data. The organic material from selected patches will be characterized and processes such as denitrification and silica transformation are followed up. All these data will be merged with patterns of stream velocity and sedimentation and erosion in and around the patches. Afterwards, results are analyzed with a diagenetic model and statistically tested. Question 2) will be answered by placing in situ flumes around patches in rivers. In these flumes, the patch growth limiting factors such as stream velocity and erosion-sedimentation will be quantified. Additionally, a great number of patches throughout the country will be measured to verify field flume data. Question 3) will be answered with the Delft-3D model. Data from question 1) will calibrate the model, data from question 2) will validate the model. With this model, I want to estimate the impact of macrophyte patches on the water quality of larger parts of rivers (e.g. 100-1000 m).

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Temmerman Stijn
• Fellow: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project

Abstract

Macrophyte patches as biogeochemical hotspots: impact on river water quality? 1. Problem Macrophytes play an important role in the structural biodiversity in aquatic ecosystems. Being primary producers, they are a matter of life and death for many organisms. Even on a ecosystem level, they take a central role, but the processes here involved are not yet well known. Though, a good knowledge is crucial to be able to take correct management decisions concerning the improvement of our fresh water ecosystems. On top of this, the presence of macrophytes has an even greater influence on the hydraulics. Macrophytes act as ecological engineers and have therefore a direct influence on stream velocity patterns and on sedimentation and erosion patterns. Changes in these patterns have immediate consequences on biodiversity and geomorphology. 2. Objectives I want to test the main concept of macrophytes being biogeochemical hotspots. After all, there are strong indications that the processes in the sediments underneath macrophyte patches can have greater impact on the water quality than the typically studied pelagic processes. To test this hypothesis, three questions are postulated: 1) Are macrophyte patches biogeochemical hotspots and at what quantity? 2) Which is the maximal length and width a patch can have under certain circumstances? 3) What is theoretically the maximal surface patches can have in a river stretch, given certain circumstances (and what is the total effect of these patches on the water quality, regarding question 1)? 3. Methodology Question 1) will be answered by gathering field data. The organic material from selected patches will be characterized and processes such as denitrification and silica transformation are followed up. All these data will be merged with patterns of stream velocity and sedimentation and erosion in and around the patches. Afterwards, results are analyzed with a diagenetic model and statistically tested. Question 2) will be answered by placing in situ flumes around patches in rivers. In these flumes, the patch growth limiting factors such as stream velocity and erosion-sedimentation will be quantified. Additionally, a great number of patches throughout the country will be measured to verify field flume data. Question 3) will be answered with the Delft-3D model. Data from question 1) will calibrate the model, data from question 2) will validate the model. With this model, I want to estimate the impact of macrophyte patches on the water quality of larger parts of rivers (e.g. 100-1000 m).

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Temmerman Stijn
• Fellow: Schoelynck Jonas

Research team(s)

Project type(s)

• Research Project