Research Jean-Philippe Belliard

Abstract

Low-lying coastal zones host dense populations, critical infrastructure, and valuable ecosystems, yet they are highly exposed to climate induced hazards such as sea level rise and storm surges. To enhance coastal resilience, Nature-based Solutions (NbS) are increasingly promoted, particularly the creation or restoration of tidal wetlands such as salt marshes and mangroves. These ecosystems offer dual benefits: climate adaptation through shoreline protection, and climate mitigation through sequestration of atmospheric CO2 into carbon in the wetland vegetation and soil. However, the carbon sequestration potential of NbS projects remains uncertain. Several projects have failed to deliver this function, raising questions about whether, and over what timescales, newly established wetlands can effectively contribute to climate mitigation. In particular, when a tidal wetland is newly (re)created as part of a NbS project, it is not immediately functional: the wetland vegetation and carbon storage capacity may take several years to even decades to fully develop. A key challenge lies in quantifying and comparing the different components of the carbon balance. Current methods often separate the measurement of carbon stored in vegetation and soils from the fluxes exchanged with (i) the atmosphere (vertical CO₂ and CH₄ fluxes) and (ii) the adjacent estuarine waters (lateral tidal fluxes). Without integrating these components, full carbon budgets, and therefore the true climate mitigation benefit of tidal wetlands, remain poorly constrained. This project aims to develop a novel methodological framework to measure the carbon sequestration functionality of NbS by studying (re)created tidal wetlands of different ages and designs within the Schelde River basin. The methodological framework combines: (i) measurements of CO₂ and CH₄ fluxes between wetlands and the atmosphere, (ii) quantification of tidally-driven carbon fluxes in and out of wetlands, and (iii) direct measurements of the actual carbon accumulation in vegetation and soils. By integrating these approaches, we will enable more comprehensive carbon budget evaluations and provide improved estimates of the climate mitigation potential of NbS.

Researcher(s)

• Promoter: Belliard Jean-Philippe
• Co-promoter: Temmerman Stijn

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Tidal marshes are highly valuable coastal wetlands ecosystems, but at the same time they are seriously threatened by sea level rise (SLR). Marshes need sufficient supply of suspended sediment (or SPM) to build up their land and avoid being submerged by the rising seas. However, understanding the complex patterns of SPM concentration, composition, among other properties, is extremely difficult and remains largely under-explored. Because of this complexity, current models of marsh evolution only consider simplified representations of sediment supply, leading to significant uncertainties as to predicting how these tidal marshes will cope with future SLR. Our goal is to deepen our understanding on the dynamics of SPM and its properties across different spatial and temporal scales. To achieve this, we will employ a multidisciplinary approach that combines field studies with computer modelling. By collecting new data in the field, we will conduct a comprehensive characterization of SPM quantities, qualities and pathways, considering spatial variations (from the estuarine channel to the marsh interior) and temporal variations (from tidal cycles to multiple years). These findings will then be integrated into a sophisticated numerical model of tidal marsh morphological evolution, allowing us to explore how different sediment supply scenarios may affect marsh survival to SLR. Therefore, this project aims to push the boundaries of our knowledge about sediment supply to tidal marshes and, as such, improve future model assessments of marsh survival to SLR. Ultimately, this will contribute to better-informed decisions about how to protect and manage these crucial ecosystems in the future.

Researcher(s)

• Promoter: Belliard Jean-Philippe
• Fellow: Torres Monroy Julio

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

Within the framework of the FED-tWIN program for sustainable research cooperation between the federal scientific institutes and the universities, supported by the Belgian Institute for Science Policy (BELSPO), the Royal Belgian Institute of Natural Sciences (Operational Directorate Natural Environment) and the University of Antwerp (Department of Biology, ecosystem management research group) wish to develop new research for the interactions of estuarine and marine ecosystems. The project AbioGrad focuses on the interaction and feedback between biological, biogeochemical and sedimentological processes using in situ data and numerical modelling, more specifically on the behaviour of suspended particulate matter (SPM) and associated organic matter and biota. A steady supply of sediments and associated organic matter is needed for mud flats, tidal marshes and banks to cope with sea level rise and maintain their spatial extent, while it also determines the rate of carbon sequestration through precipitation in estuarine and marine sediments. Human interventions largely determine the SPM concentrations, either directly through dredging and dumping, or indirectly through influencing the hydrodynamics. SPM determines the light penetration in the water column and thus photosynthesis. Changes in SPM concentration and composition are therefore among the most important effects of human intervention on the functioning of ecosystems. A good understanding of particle dynamics, of the interaction with biogeochemistry and possibly with biota, of past changes in SPM dynamics and the existence of well adapted monitoring and observation strategies are crucial to successfully ensure further coastal and estuarine developments.

Researcher(s)

• Promoter: Temmerman Stijn
• Fellow: Belliard Jean-Philippe

Research team(s)

• Ecosphere

Project type(s)

• Research Project