Research Tom Maris

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

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

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

This study project includes research into the effects of human interventions in the Sea Scheldt on the environment. More specifically, the effects of the Sigma plan, dredging activities and port expansion in the Zeeschelde are monitored.

Researcher(s)

• Promoter: Maris Tom
• Promoter: Meire Patrick

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Conservation of ecosystem functioning in estuaries is vital for ecological and social sustainability as they connect the marine and terrestrial environments and are one of the most productive habitats on earth. Primary production by phytoplankton is the base to the food web and thus is an extremely important function. In hyper-turbid light-limited estuaries, it is mainly influenced by light, resident time and temperature. Waterway maintenance (dredging) has the potential to negatively affect primary production by increasing turbidity, thus reducing light-climate. Scientific understanding and good monitoring are necessary for science-based adaptive-management. Knowledge of short-term fluctuation's effects on primary production is lacking, due to traditional water-quality monitoring missing these events with periodic monthly sampling frequencies. To minimize their impact on primary production, an understanding of short-term dynamics is necessary for waterway managers to regulate the locations and timings of their interventions. I will for the first time combine the use of high-frequency continuous sampled, periodic long-term sampled and satellite remote-sensed water quality data to understand the short-term dynamics between primary production, turbidity, flow and temperature in the Scheldt Estuary. This will be used to develop best management practices for mitigation of negative effects on primary production from waterway maintenance.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Maris Tom
• Fellow: Gelsomini Pali Felice

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

In principle, it is possible to determine SPM based on satellite images for a large part of the Scheldt estuary. Nevertheless, a number of challenges need to be tackled in the Zeeschelde and Boven-Zeeschelde in particular. There, the river is only 1 or a few pixels wide in places (Sentinel 2 spatial resolution: 10m-20m). Furthermore, the tidal action continuously ensures resuspension and settling. The SPM concentration at the surface therefore exhibits strong temporal variability, which complicates the interpretation of a snapshot based on satellite image. Drones offer a possible solution to both problems, but have their own difficulties (flight planning, weather conditions). In this study, methods are developed to determine SPM in the estuary from satellite and drone images, using continuous data for calibration.

Researcher(s)

• Promoter: Maris Tom

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Deltares has been commissioned by the Ministry of Infrastructure and Water Management to carry out work for the project "KPP 2018 - WN01 Scheldt estuary" with project number 11202233. Deltares wants to engage a third party to support the main project: Expert support for the discipline Water quality and ecology in general. The expert support includes attending and actively supporting team and workgroup sessions. The support can include the following aspects: giving presentations at a work session, leading workshop sessions about water quality, revision of texts or feedback on specific questions as a result of a work session.

Researcher(s)

• Promoter: Maris Tom

Research team(s)

Project type(s)

• Research Project

Abstract

The Schelde estuary, characterised as a turbid, polluted and very eutrofic system, has nowadays reached a turning point in the restoration of its water quality. During the past century, human activities have reduced the intertidal areas, essential in the estuarine ecosystem for nutrient cycling and the self-cleaning capacity. Today, in combination with a master plan to protect the population from storm surges, an opportunity rises to recreate areas with a tidal influence. One specific option of combining safety and ecology is the creation of controlled inundation areas (CIA) under influence of a controlled reduced tide (CRT). These specific areas will differ in many ways from fully tidal areas. However, these areas can fulfil important ecological functions. The ecological development of a CRT will be investigated in the 10 ha big study area Lippenbroek. This former polder area will be turned into a small CIA-CRT to test this new concept.

Researcher(s)

• Promoter: Meire Patrick
• Fellow: Maris Tom

Research team(s)

Project type(s)

• Research Project