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Studying the population biology and monitoring the population status of Dunlin. The population under study ilives in a coatal tundra area in Northern Norway.
In contrast to many other marine regions, chemical interactions between organisms in Arctic waters are little understood. This project investigates natural products and chemical interactions in the sponge genus Haliclona in temperate and polar waters. Several new secondary metabolites isolated from Haliclona show feeding deterrence and activity against bacteria and fungi, but the compound composition varies with habitat and year. That raises the question whether sponges of the genus Haliclona as a model are able to adapt to changing environmental factors such as water temperature and colonization by bacteria by varying their secondary metabolite composition.
The effects of stratospheric ozone depletion and of global warming on the marine biosphere are still underexplored, especially in the Arctic. Seaweeds are very important primary producers but are strongly susceptible to enhanced UV radiation and elevated temperatures, especially their spores. The UV susceptibility of spores has previously been invoked to determine the depth distribution of seaweeds. Therefore, we will investigate the effect of different radiation and temperature conditions on the ultra-structure, physiology and biochemistry of spores from various brown and green algae growing in different water depths. Moreover, we will study competition between zoospores of various species of brown macroalgae in order to get an insight about biotic factors structuring seaweed communities and also to explain more clearly the present seaweed zonation pattern.
Plankton of shallow polar freshwater water bodies is exposed to increasing levels of ultraviolet radiation (UVR) due to the limited water depth. Daphnia (Crustacea, waterflea) and algae are common representatives of the food chain in these water bodies. Daphnia almost exclusively use lipids for energy storage, which they obtain from their food (mainly algae). Therefore, Daphnia and algae are closely linked to each other. Preliminary experiments on the UV-induced damage in phyto- and zooplankton point to lipids as one of the key players. With this application we want to identify how algae specific lipids and fatty acids (FA) are modified by UVR. The factors modifying UV-doses to the animals and their food are depth of the waterbody and DOC (absorbs UV). A pondsurvey shall provide a wide spectrum on ponds which vary in DOC and depth. Lipid analysis of Daphnia and their food of these ponds as well as physical parameters of the pond waters shall identify correlations between UV-exposure and specific fatty acids. This shall enable us to estimate the effect of solar UVR on the freshwater plankton community in polar ponds.
The aim is to study the diversity and function of marine bacteria closely associated with marine sponges. The special character of life strategy of the community (symbiosis – commensalism), with special emphasis to the identity and the recruitment of bacteria during live cycle of the sponges will be described.
Since nearly all microalgae are associated with bacteria and some harbor intracellular bacteria, it is most likely that these bacteria are involved in the development or termination of natural occurring plankton assemblages. The diversity and development of associated bacteria in microalgae cultures and during phytoplankton succession will be described by molecular analysis of the bacterial community structure and by phylogenetic analysis of involved microorganisms.
Little is known about the consistency or phylogenetic affiliation of accociated intra- or extracellular bacterial populations in Echinodermata. Because certain taxa harbour bacteria and other not, these associations are presumably originated by coevolution and not by ecological circumstances. The intestine of echinodermata is populated by huge amounts of bacteria. Due to the different feeding strategy of echinoderms it is controversly discussed whether these bacteria are passively taken up or if they are permanently present. Hence it will be possible to elucidate if vertical transmission occurs or bacteria are recruted. With the knowledge of phylogenetic affiliations of microbial symbionts and their distribution (or localization) in different hosts, the physiological/biochemical status of the association will be investigated. The main emphasis will be the characterization of the in situ situation by adequate histological techniques (crysectioning) and “passive” (FT-IR) or “active” chemical imaging (confocal imaging, using fluorescent enzyme substrates or physiological dyes). The main experimental work in this WP bases on the creation of 16S-rDNA sequence libraries of echinoderrm associated bacteria (SCB & intestinal). Signature sequences will be analyzed and specific gene probes will be designed and applied.
Cellphysiological investigations of the effects of marine secondary metabolites on isolated (sensory) cells
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.
Marine invertebrates have highly active digestive enzymes which can exhibit extraordinary catalytical properties with respect to specificity, turnover performance and thermal stabilty. Highly specific bio-active substances are important for various biotechnological applications. The project is aimed to investigate the catalytic properties of digestive enzymes in marine invertebrates from a wide geographical and thus ecological range. Target species will be preferably crustaceans and echinoderms.
Detection of UV-B induced DNA damage on zoospores of brown algae
Description of parameters of the population dynamics of polar bivalve communities, first year: growth and reproductive cycle of the dominant Greenland cockles (Serripes groenlandicus)
The aim of this project is to investigate natural products from polar macroalgae. As arctic waters represent an extreme habitat, formation of secondary metabolites is limited - besides other factors - by light conditions. Therefore, the influence of light, particularly different photon fluence rates and UV radiation, on secondary metabolism and on regulation of associated genes will be studied.
The goal is to understand, how bacteria in Arctic sediments are adapted to low temperature and how (climatic) changes of temperature may affect the rate and pathways of carbon cycling and the balance of mineral cycles. The diversity and physiology of bacterial populations of fjord sediments on West-Spitzbergen will be studied by a combination of molecular (16S rRNA sequence analyses and in situ hybridization) and microbiological (isolation and physiology of pure cultures) approaches. The metabolic activity of these bacteria in the sea floor and the temperature regulation of the dominant mineralization processes will be analysed by experimentel techniques during the research period in Ny Ålesund. The focus will be on the enzymatic cleavage of polymeric carbohydrates, the anaerobic respiration through sulfate reduction, the reduction of iron and mangenese oxides, and the turnover of volatile fatty acids and hydrogen. Subsequently, psychrophilic bacteria are isolated from the anoxic sediments and studied in pure culture. The bacterial populations in the sediment are studied by molecular methods to analyze their diversity and metabolic activity.
Observation how UV-radiation affects recruitment on hard substrate in the upper sublitoral zone.
The objective of the planned work with arctic higher plants is to study the range of adaptation of photosynthetic metabolism, of antioxidative and sun screen compounds in a cold and reduced UV-B climate in comparison of data already raised from high alpine plants, which live partially under stronger cold and under different light regimes, especially higher UV-B. Further, the ultrastructure of leaf cells will be studied to clear, whether adaptations found in some high alpine plants occur similarly in arctic plants, and to connect such cytological results with metabolic functions. An additional comparison will be made with snow algae from Svalbard compared to those harvested on high alpine snow fields. It is the advantage of the planned work, that a number of investigations ranging from ultrastructural studies over different aspects of photosynthesis to assays of UV-B sensitive compounds and antioxidants will be conducted mostly with measurements and sample collection in the field during the same experimental day at one place. Therefore we expect a good connection of the data raised, back to the plant system and expect a much broader description of vitality and adaptation under the current conditions.
The polar pteropod Clione limacina is characterised by high quantities of lipids with ether components (1-O-alkyldiacylglycerol=DAGE) in combination with odd-chain fatty acids. It is unknown why Clione and probably other pteropods have specialised in this manner. Furthermore the precursor of the biosynthesis of these compounds is still unknown. Therefore samples of Clione limacina and its only prey Limacina helicina will be collected by using plankton nets from small boats. The species will be kept in aquaria and feeding experiments with both species and food of different composition and nutritional value are planed.
Benthic macroalgae communities of the arctic ocean provide habitat, protection, nursery and nutrition to a large number of invertebrates. In contrast to temperate and tropical regions the basic ecological interactions between zoo- and phytobenthos of the Arctic are little understood. Therefore this project for the first time investigates biological and chemical interactions between invertebrates and macroalgae on Spitsbergen/Svalbard (Koldewey Station) with special emphasis on defense mechanisms against grazing pressure. Initial diving-investigations will map the invertebrate fauna which is associated with the macroalgae; the following feeding-experiments with herbivorous animals aim to selectively identify generalists, generalists with preference or specialists. Additional bioassays serve to reveal structural and/or chemical properties of those plants, which affect a specific impact on the grazing of herbivores. Our investigations on the chemical protection of the algae against grazing focus on the basic mechanisms and the chemical structure of potent secondary metabolites carried out in cooperation with natural product chemists.
Succession of communities and individual growth of benthic invertebrates are more or less unknown in polar waters, but nevertheless are the basic parameters of understanding the benthic sub-ecosystem, delivering data for modelling and prediction of the system´s development. Three localities, two in the Antarctic and one in the Arctic, the Kongsfjord in Spitsbergen, have been choosen as investigation localities. Hard and soft substrates, which will be sampled in regular intervalls during the duration of the project, will be deployed at different depths. The analysis includes species composition, species growth and, with respect to soft substrates, sediment parameters.
Photoinhibition of photosynthesis by UV radiation, the formation of UV-screening pigments, DNA damage by UV radiation as well as DNA repair mechanisms will be determined in marine macroalgae of the Kongsfjord. Moreover, algae from different water depths will be transplanted by divers into areas with opposite light climate or covered by UV-screening filters and their physiological reactions tested. Additionally, the susceptability of the unicellular algal spores to UV-radiation will be tested. The results will allow insights into the effect of UV and photosynthetically active radiation on the zonation of macrocalgae and on the structure of phytobenthic communities. The data will be used to model the effects of increased of UV-radiation due to stratospheric ozone depletion on the Kongsfjord phytobenthic communities.