Seasonal changes in the trophic structure of the Barents Sea ecosystem
Friday seminar by Per Fauchald
Seasonal ice-cover of polar oceans has large consequences for the seasonal dynamics of these ecosystems. The spatial distribution of pelagic top predators and prey in the Barents Sea was investigated in early autumn when the ice-cover is at a minimum, and in late winter, when the ice-cover is at a maximum. The trophic structure in summer is complex with high diversity and complex spatial interactions between predators and prey. Competing species are segregated in spatial niches, resulting in a spatially structured, stable and predictable system. The trophic structure in winter is simpler with lower diversity and simpler interactions between predators and prey. The spatial niches have largely dispersed, resulting in a spatially elusive and unpredictable system. I suggest that seasonal changes in the functional diversity of predators and prey have profound effects on the spatial organization of the ecosystem.