Jim de Fouw


I am a PhD at Groningen University based at The Royal Netherlands Institute for Sea Research (NIOZ) at Texel and in my last year. My research is mainly conducted in Banc d’Arguin (Mauritania) in a large intertidal seagrass dominated ecosystem where I focus on a recently discovered three-stage mutualism between the seagrass Zostera noltii and Loripes lucinalis (a lucinid bivalve with sulphide-oxidizing bacteria). Seagrasses facilitate their own growing conditions by increasing water clarity through accumulation and stabilization of sediments. The accumulation of organic matter stimulates decomposition controlled by sulphate-reducing bacteria that produce sulphide, being highly toxic to seagrasses and all other live. Here the mutualism starts to play an important role. Seagrasses engage in a mutualistic interaction with lucinid bivalves and their sulphide-oxidizing, gill-inhabiting bacteria to reduce sulphide stress. In turn, the bivalves and their endosymbionts not only profit from sulphide that is indirectly provided by seagrasses due to organic matter trapping, but also from oxygen released by seagrass roots. A potential disruption of the mutualism is desiccation stress, leading to breakdown of the mutualistic interaction. In addition to stress, predation (by Red knots Calidris canutus) on the detoxifying lucinid bivalve may push the system to another state.

During the course I would like to gain more insight in how positive feedback mechanisms between seagrasses and lucinids behave under different ecosystem states and whether these feedbacks may lead from a stable to an unstable state, a situation which occures in our study system. Looking forward to see all of you and have inspiring and great week!