Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2017
Erindi/veggspjald / Talk/poster E3
Höfundar / Authors: Teresa Silva (1,2), Astthor Gislason (1), Guðrún Marteinsdóttir (2) and Ólafur S. Ástþórsson (1)
Starfsvettvangur / Affiliations: 1. Marine and Freshwater Research Institute, 2. University of Iceland
Kynnir / Presenter: Teresa Silva
The North Atlantic is one of the most productive marine ecosystems on the globe. Several long-term changes or shifts in phytoplankton, zooplankton, and fishes in the North Atlantic have been suggested to be influenced by climate change. Climate-induced changes in krill stocks may affect fish that feed on them. Given their important ecological niche, as conveyors of mass and energy between phytoplankton and higher trophic levels such as pelagic fishes, whales and seabirds, it is important to study how climate may affect the krill stocks. Using data on krill abundance from the waters in the North Atlantic collected by the Continuous Plankton Recorder (CPR) survey from 1958 to 2007, we investigate the impacts of climate change on krill abundance in the North Atlantic. Sea surface temperature, sea surface salinity, NAO, surface chlorophyll a concentrations and timing of the spring bloom were used as explanatory variables. In the CPR areas investigated, we observed phytoplankton biomass was increasing since the mid-2000s while a gradual delay of the onset of the phytoplankton bloom also was found. Further, the abundance of krill was found to be decreasing since the 1980s. Between 2000-2010 the North Atlantic subpolar gyre has weakened which has led to an increase of saline and warm water south of Iceland. We hypothesize that a weakened temporal synchrony between the development of young krill and phytoplankton bloom influenced by recent climate warming may have led to the observed decrease in krill populations.