Virtual Posters

The genus Calanus is regarded as a key element in arctic marine ecosystems, and may in some areas constitute up to 80% of the zooplankton biomass. Thus they represent the prime herbivores and largely influence the energy flow and functioning of the marine food webs. Their main adaptation is commonly assumed to be their capability of transforming and storing large amounts of energy in form of lipids. This energy is directly harvested from both ice algal and phytoplankton blooms, and is stored throughout the year in a large visible lipidsack inside the animal. Thus, the three co occurring species C. finmarchicus, C. glacialis and C. hyperboreus are a major source of energy for a number of important species at higher trophic levels. These three species are commonly identified based on size differences alone, due to their great morphological resemblance.
Recent molecular research, carried out at the University Centre in Svalbard (UNIS), has demonstrated that such identification most often is flawed, and that the actual species boundaries are not displayed in the size distributions alone. We studied possible changes in the morphological boundaries between C. finmarchicus and C. glacialis during the arctic spring. This was realized using both traditional morphological and new molecular methods.
Molecular analyses showed that the existing size definitions for C. finmarchicus and C. glacialis are not as accurate as previously assumed. Also, populations of C. glacialis vary much more in their size distribution for each copepodite stage and over time than previously reported, and small adult female C. glacialis were misidentified as C. finmarchicus during spring in Billefjorden using morphological methods.