Potential future fisheries yields in shelf waters: a model study of the effects of climate change and ocean acidification

[摘要] We applied a coupled marine water column model to three sites in the NorthSea. The three sites represent different hydrodynamic regimes and are thusrepresentative of a wider area. The model consists of a hydro-biogeochemicalmodel (GOTM-ERSEM-BFM) coupled one way upwards to a size-structured modelrepresenting pelagic predators and detritivores (Blanchard et al., 2009). Thus,bottom-up pressures like changing abiotic environment (climate change,chemical cycling) will have an impact on fish biomass across the size spectrum. Here, we studied three different impacts of future conditions on fish yield: climatic impacts (medium emission scenario), abiotic ocean acidification impacts(reduced pelagic nitrification), and biotic ocean acidification impacts(reduced detritivore growth rate). The three impacts were studied separatelyand combined, and results showed that sites within different hydrodynamic regimes can respond very differently. The seasonally stratified site showed an increase in fish yields (occurring in winter and spring), with acidification effects of the same order of magnitude as climatic effects. The permanently mixed site also showed an increase in fish yield (increase in summer, decrease in winter), due to climatic effects moderated by acidification impacts. Thethird site, which is characterised by large inter-annual variability inthermal stratification duration, showed a decline in fish yields (occurringin winter) due to decline in the benthic system which forms an importantcarbon pathway at this site. All sites displayed a shift towards a morepelagic-oriented system.

[学科分类] 地球化学与岩石