Abstract
Salinity is a decisive factor for the distribution of animals in the marine environment but the knowledge is still limited on how salinity affects the most numerous metazoans of the Sea, the copepods. Copepods are key organisms in pelagic food webs, constituting a crucial link between primary producers and higher trophic levels, and many commercially important fish species rely on copepods as food. Previous studies in coastal ecosystems showed that salinity is important for the species composition and dynamics of copepod communities. However, for the majority of species experimental evidence on how salinity affects growth and fitness as well as copepod functional biology is non-existing and badly needed. In the present project laboratory experiments will be conducted with four of the most abundant and ecologically significant species in the Baltic Sea - North Sea corridor. The following questions will be addressed: 1) How does salinity affect the survival, gross growth efficiency and reproductive success? 2) Does salinity affect the role of copepods as grazers on phytoplankton? 3) Do copepods exhibit any behavioural responses to salinity? Methods will include traditional bottle incubation experiments as well as the use of highly advanced video-equipment for 3-dimensional filming of live copepods. The results will increase our knowledge on the dynamics of copepod communities and facilitate the prediction of fish production in a future with changing climatic conditions.
Sweden