Calanoid copepodes: major players in ecosystem processes
Calanoid copepods are distributed world-wide and may contribute up to 80% of the zooplankton biomass in polar areas. Sir Alisdair Hardy, a famous biological oceanographer from the UK, has estimated “…that the copepods are the most numerous metazoan animals in the world, even outnumbering the insects, which have more species but fewer individuals,…”.
In marine food webs, calanoid copepods are a major link between primary production and higher trophic levels. Large copepod developmental stages (copepodites) and adults are consumed by fishes, invertebrate predators and even whales. Fish larvae, however, once their yolk sac is depleted, feed on copepod eggs and nauplii, the young developmental stages.
As consumers of phyto- and microzooplankton, copepods may have a strong impact on the phytoplankton community and on the microbial loop in the upper water layers. Copepods also contribute to biogeochemical cycles by producing faecal pellets, which sink to deeper waters.
Calanus finmarchicus: Eggs, nauplii and an adult female.
The main distribution area of C. finmarchicus is the North Atlantic with its adjacent seas. With the North Atlantic current, this species is transported to the Arctic. Associated with global warming, the inflow of Atlantic water into the Arctic increases, and this may lead to a shift in the dominant species: C. glacialis, a sibling species endemic to the Arctic may be replaced by C. finmarchicus and this may have severe consequences for the Arctic food web.
Research Topics:
- Feeding biology and trophic interactions of key species: „Who feeds who“ is one of the major factors structuring communities. We focus on the feeding strategies of the dominating zooplankton species and their interactions with other important components of the pelagic food web, especially algal and micro-zooplankton.
- Adaptation to changing environmental conditions: Life history traits of zooplankton organisms are dependent on environmental conditions and thus strongly effected by climate change. As a result regime shifts are expected. We study the physiological response of dominant species to i.e. rising temperature, shifts in food regimes and elevated CO2 for understanding colonisation and expatriation processes
Ongoing Projects:
BioAcid (Biological Impact of Ocean Acidification
Cooperation: Dr. F.J. Sartoris (AWI)
HGF-University Young Investigator Group:
Trophic Interactions in Pelagic Ecosystems: The role of zooplankton
Cooperation: Prof. Dr. W. Hagen, Dr. H. Auel (University Bremen), Dr. M. Graeve (AWI), Dr. J. Soreide (UNIS, Svalbard)