|What is the relationship between phytobenthic algal blooms and the macrobenthic community in the mesohaline region of the Westerschelde Estuary over the course of a year?|
Suvacarov, S. (2021). What is the relationship between phytobenthic algal blooms and the macrobenthic community in the mesohaline region of the Westerschelde Estuary over the course of a year? BSc Thesis. NIOZ Royal Netherlands Institute for Sea Research: Yerseke. 19 pp.
Understanding the relationship between macrobenthic communities and phytobenthic algal blooms are of great relevance due to their linking of primary production to higher trophic levels. In the Westerschelde Estuary in particular, few up to date studies have researched the seasonal progression of the mesohaline macrobenthic community in relation to phytobenthic algal blooms. This study sampled two replicate sediment cores on a bimonthly basis from the mudflat in Groot Buitenschoor, a nature reserve in the brackish region of the estuary and determined the taxa present. Monthly headcounts per m² were compared to the Chlorophyll a concentration of the upper 3.5cm of the benthic sediment. The results indicate an overall low diversity in the macrobenthic community. Three dominant macrofauna were identified: Corophium Volutator, Nereis Diversicolor and Oligochaeta. There is a clear negative correlation between the dominant species C. volutator and Chla concentration, most likely as a result of grazing and sediment resuspension. Interspecific competition between the dominant species C. volutator with both N. diversicolor and Oligochaeta, may help to explain their relatively small headcount per m² in comparison to that of C. volutator. The seasonal progression of C. volutator and its influence on the phytobenthos over the course of the year is best explained by the reproductive cycle of the species. The data suggest that C. volutator has the strongest biotic influence on Chla concentration of the phytobenthos at Groot Buitenschoor. It is crucial that more research is focused on the mesohaline benthic community of the Westerschelde Estuary as they play a key role in the functioning of the ecosystem as a whole