Arctic Seas: projects/activities

The succession of macro- and microalgal communities in the Antarctic will be investigated in field experiments under various UV radiation (UVR) conditions and in the absence or presence of grazers. The observed differences in the succession process will be correlated to physiological traits of single species, especially in spores and germlings, which are the most vulnerable stages in their life histories. Photosynthetic activity of the different developmental stages will be measured routinely. Additionally we plan the determination of pigment composition, C:N ratios, content of UV protective pigments and of possible DNA damage. The experiments will start in spring, concomitant to the time of highest UVBR, due to the seasonal depletion of the ozone layer in the Antarctic region. Supplemental laboratory experiments will be conducted to determine the effects of UVR on spores and germlings of individual species. In addition to the above analyses, we plan to examine of UVR induced damage of cell fine structure and of the cytoskeleton. The results of both the field and laboratory experiments will allow us to predict the consequences of enhanced UVR for the diversity and stability of the algal community.

Due to its high energy, UV radiation can induce severe damage at the molecular and cellular level. On the molecular level proteins and lipids, as well as nucleic acids are particularly affected. Conformation changes of certain proteins involved in photosynthesis, such as the reaction center protein (D1) of photosystem II or the CO2 fixing enzyme in the Calvin cycle (RuBisCo) lead to an inhibition of photosynthesis, and consequently to a decrease in biomass production. This might shift certain algal species into deeper waters, not reached by UV radiation. The aim of the studies is to demonstrate how strong an increase of UV radiation due to stratospheric ozone depletion will influence the depth distribution and biomass production of macroalgae, and which molecules and processes are most severely affected. Moreover, it will be studied, which stage in the life cycle of the individual species is most sensitive to UV radiation as it will be this particular stage, which in the end determines the upper distribution limit of a certain species on the shore.

The Submarine Operational And Research Environmental Database (SOARED)is comprised of a fixed relational environmental database using unclassified data collected during the Science Ice Exercises (SCICEX) during the past several years. It also includes publicly accessible gridded historical sound velocity, temperature and salinity data from 1900 from the US National Oceanographic Data Center. This project is a demonstration system to show ways to retrieve and analyze sound velocity, temperature and salinity profiles, bathymetry and ice thickness data using a mouse-driven GIS-based query.

Biological materials obtained in the central Arctic Ocean at the FSU “North Pole stations” in 1975-1981 have shown that the multi-year ice and ice/water interface is of rich and diverse biotop inhabited by the large number of diatoms and invertebrate animals. Two main matter fluxes in the sea ice ecosystem may be distinguished: (1) the inflow of biogenous elements from water into the ice interior where they are assimilated by the microflora during photosynthesis (summer stage), and (2) the outflow – from ice to water - of the organic matter accumulated in the summer due to photosynthesis (winter stage). Accumulation of organic matter within the sea ice interior during the process of photosynthesis may be considered as an energy depot for organisms of the whole trophic network of the arctic sea ice ecosystem. Recent data from the SHEBA Ice Camp drifted within the Beaufort Gyre 1997-1998 have shown that: (1) sea ice diatoms are very scarce by species and numbers; (2) fresh water green algae are dominated by numbers and distributed within the whole sea ice thickness; (3) invertebrate animals within the sea ice interior are not indicated; (4) invertebrate animals from the ice/water interface are scarce by species and numbers; (5) concentrations of chlorophyll and nutrients in the sea ice are significantly lower of the average concentrations measured before in this region for the same period of time. Remarkable accumulation of the organic mater within the sea ice interior were not indicated.

Multi-institutional, international cooperative project to determine the possible responses of Arctic marine communities to future global climate change by comparing retrospective patterns in benthic composition and distributions to past climatic events in the Barents and Bering Seas.

Our broad area of enquiry is the role of polar regions in the global energy and water cycles, and the atmospheric, oceanic and sea ice processes that determine that role. The primary importance of our investigation is to show how these polar processes relate to global climate.