Research Tom Cox

Abstract

Microphytobenthos (MPB), the algae that inhabit the intertidal mudflats, are important for the functioning of estuarine ecosystems. Their high primary production is critical, producing oxygen and sustaining the highly biodiverse estuarine food web. MPB community also excrete sticky substances that decrease sediment resuspension in the water column and increase the light climate needed for primary production. Unfortunately, these mudflats are under thread of increased hydrodynamic stress due to, amongst others, increased tidal amplitude by sea level rise and management such as channel deepening. In the Scheldt estuary there has been a strong increase in turbidity of the water column, negatively affecting the primary production. Legislations enforce the maintenance of a healthy ecosystem and therefore we need good understanding of the role of biological components, such as MPB, in estuarine ecosystem functioning. The MPB community in estuaries varies over the salinity gradient, and of some algal groups their effect on ecosystem functioning remains hardly studied. Furthermore, the importance of small-scale variation in benthic primary production (BPP) on ecosystem scale needs to be identified. Therefore, this project will tackle the central knowledge gaps: 1) quantify the benthic primary production, 2) relate this sediment stabilization potential and 3) implement these functions in a calculation tool for ecosystem functioning.

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Cox Tom
• Fellow: Bas Dorian

Research team(s)

• Ecosphere

Project type(s)

• Research Project

Abstract

The Scheldt estuary is significantly changing due to both climate change and human interventions, like fairway deepening, harbor expansion, etc. Recent monitoring results show a strong increase in turbidity and therefore the fear the system will evolve into a hyper turbid system arises. Since light availability is essential for algae growth, the foundation of the food chain, the evolution to a hyper turbid system can have a drastic impact on all life in the estuary. This worrying increase in turbidity in combination with strong (European) legislation regarding the (ecological) functioning of the Scheldt estuary results in an urgent and strong demand for insight and tools to understand and predict the impact of climate change and (future) human interventions on turbidity and algae growth. Feedback processes between turbidity and algae need explicitly to be taken into account. Therefore the proposal's aim is to study: 1. The impact of turbidity and sediment transport on algae growth 2. Conversely, the impact of algae growth on turbidity and sediment transport. I hypothesize that a sticky substance produced by algae can cause the sediment to flocculate which might have a significant impact on turbidity patterns This proposal will finally result in: 1. Further development of a recent technique to estimate in situ algae growth towards a cost efficient real time monitoring tool 2. A state of the art estuarine model coupling sediment transport and hydrodynamics with algae growth

Researcher(s)

• Promoter: Meire Patrick
• Co-promoter: Cox Tom
• Fellow: Horemans Dante

Research team(s)

Project type(s)

• Research Project