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Displaying: 241 - 260 of 386 Next
241. The Effects of Turbidity on Marine Fishes

(a) To assemble and further develop an integrative methodology for in situ evaluation of the effects of turbidity and hypoxia on fish physiological and/or behavioural performance. (b) To determine experimentally the threshold values beyond which oxygen and turbidity levels are liable to alter fish physiological and/or behavioural performance. (c) To integrate the results obtained in a conceptual and predictive model. Main expected achievements: [1] establishment of a link between laboratory studies, studies in mesocosms and field studies, using the most advanced techniques for monitoring behaviour in various environmental conditions. [2] an understanding of the impact of water turbidity and oxygenation on three major components of the behavioural repertoire of fish: habitat selection, predator-prey interactions and schooling-aggregation. [3] Predictive ability for the effect of the environmental variables studied on ecologically relevant behaviour.

Shelf seas Biological effects Fish Environmental management Local pollution Food webs
242. Bacterial diversity in marine sponges

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.

Shelf seas Biological effects Biodiversity Ecosystems
243. Bacterial populations in the pelagic foodweb

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.

Shelf seas Biological effects Biodiversity
244. Bacterial diversity in echinodermata

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.

Shelf seas Biological effects Biodiversity Ecosystems
245. Investigations on the diversity and role of microphytobenthos in marine and freshwater food webs.

The main research goal of this project is focused on trophic interactions within microbenthic communities in aquatic systems. Grazer-microalgae interactions are investigated by conducting field and laboratory experiments in order to get a closer idea of the microphytobenthos community structure itself. Especially the role of morphological and physiological adaptations of microalgae in the presence of specific meio- and macrofaunal predators are of great interest. In addition to that we have devised a new benthic sensor for the quantitative and qualitative assessment in situ of diverse populations of microphytobenthos with high spatial and temporal resolution, enabling rapid evaluation of the community structure and distribution.

microphytobenthos Food webs Sediments chlorophyll fluorescence marine and freshwater sediments Ecosystems benthic algae
246. Helgoland Foodweb Project

To study the organisms involved in phytoplankton succession and the Key factors involved. This includes Bacteria-Algae, Algae-zooplankton and Zooplankton-Fish interactions. Aspects such as algal-grazer defence mechanisms and digestability of alage are core topics.

Biology Environmental management Biodiversity Ecosystems
247. Chemoreception of marine secondary metabolites

Cellphysiological investigations of the effects of marine secondary metabolites on isolated (sensory) cells

Biological effects Biology
248. Effects of UV-B radiation on Microbial communities in Kongsfjorden

Effects of UV-B radiation on microbial communities in Kongsfjorden in relation to metal and dissolved organic matter availabillity.

Biological effects Ozone Biology UV radiation Heavy metals Environmental management Exposure Arctic Model ecosystem Ecosystems
249. Ecological and Physiological Investigations about the Impact of UV Radiation (UVR) on the Succession of Benthic Primary Producers in Antarctica

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.

Biological effects Biology UV radiation Environmental management Climate change Biodiversity Arctic Ecosystems Seaweeds
250. Strategies of enzymatic food utilization in marine invertebrates

Marine invertebrates show a large variety of feeding strategies. These comprise mechanisms for catching prey, the uptake of food and the utilisation of various food sources. Morphological and anatomical adaptations allow for the capture and the ingestion of the food. However, the organism's physiological properties are the key for the efficient digestion, the nutrient uptake and the assimilation of food. In response to environmental factors marine organisms have developed highly specialised biochemical adaptations which are particularly reflected by the immeasurable diversity of digestive enzymes. The detailed function of digestive enzymes in marine invertebrates and, particularly, their synergistic interplay is still poorly understood.The overall aim is to investigate the mechanisms of enzymatic food utilisation and enzyme induction in different taxa of marine invertebrates in response to environmental factors.

Shelf seas Biology Food webs
251. RADNOR - Radioactive dose assessment improvements for the Nordic marine environment: Transport and environmental impact of technetium 99 (99Tc) in marine ecosystems

Radioactivity in the Arctic environment is a central topic within environmental pollution issues. Increased discharges of technetium-99 (99Tc) from the nuclear fuel reprocessing plant Sellafield to the Irish Sea has caused public concerns in Norway. This project (acronym “RADNOR”) includes model and monitoring assessments and improvements, assessment of current and novel abiotic and biotic dose parameters and dose calculations and use of realistic climatic background scenarios in order to assess corresponding consequences for transport of radioactive pollutants. RADNOR consists of three main components: part 1, the determination of levels and time series of 99Tc in benthic and pelagic food webs; part 2, containing working packages on improvements to the understanding of site-specific and time-dependent sediment-water interactions (KD), kinetics of accumulation (CF) and body distribution in marine organisms, including contaminated products for the alginate industry and part 3, dealing with model hindcasts and observations for spreading of 99Tc from the Sellafield nuclear reprocessing plant during the 1990s and improvement of the NRPA dose assessment box model. From the model outputs, doses to man and environment will be calculated resulting in a valuable database for use within environmental management and for decision makers.

distribution coefficients (KD) RADNOR Long-range transport Spatial trends Contaminant transport concentration factors (CF) Radionuclides Modelling Oceanography Arctic Food webs Sediments Temporal trends Human intake Technetium 99
252. Detection of UV-B induced DNA damage

Detection of UV-B induced DNA damage on zoospores of brown algae

Biological effects Biology UV radiation CPD Temporal trends Ecosystems
253. Helgoland Foodweb Project

The aim of this project is to investigate and understand those factors that play a role in the seasonal dynamics of different functional groups in the pelagic zone of coastal seas. We investigate the interactions between bacteria, phytoplankton, zooplankton and juvenile fish in order to assess the importance of biological interactions in the seasonal succession.

Biology Fish Plankton Bacteria Food webs Ecosystems
254. Dynamics of benthic bivalve communities in polar environments

Description of parameters of the population dynamics of polar bivalve communities, first year: growth and reproductive cycle of the dominant Greenland cockles (Serripes groenlandicus)

Biological effects population dynamics Biodiversity Arctic
255. Macroalgal secondary metabolites from Arctic waters

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.

polar macroalgae Biological effects UV radiation Ecosystems
256. Adaptation of bacteria in marine sediments to Arctic temperatures

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.

Biological effects microbial life Sediments
257. Optical properties, structure, and thickness of sea ice in Kongsfjorden

Study of the energy exchange between atmosphere, sea ice and ocean during freezing and melting conditions; within that, measurements of solar radiation (visible and UV) and optical properties, snow and sea ice characteristics, vertical heat and salt fluxes, oceanographic parameters.

UV radiation Geophysics Climate variability Climate remote sensing Sea ice Climate change Modelling Ice Oceanography Arctic Ice cores Atmosphere Ocean currents optical properties
258. The surface energy budget and its impact on superimposed ice formation (SEBISUP)

During the spring/summer transition, sea ice and snow properties change considerably in response to warming and the eventual reversal of temperature gradients within the snow and ice. Snow melt water percolates down towards the colder snow/ice interface, where it refreezes to form superimposed ice. On sea ice this process occurs probably longer and more intensive than on land, because throughout the summer the ice and underlying seawater is always colder than the snow. In Antarctica superimposed ice may actually form layers of some decimeters in thickness. The objective of this study is to investigate the main processes and boundary conditions for superimposed ice formation, in recognition of its importance for Antarctic sea ice, and its possible importance for Arctic sea ice in case of environmental changes due to future climate change. This will be performed by means of modeling as well as by combined measurements of the temporal evolution of snow and ice properties and the energy budget.

Snow and ice properties Sea ice Climate change Modelling Ice Ice sheets Arctic Ice cores Superimposed ice formation
259. Physiological response of growth, photosynthesis and nutrient uptake of marine macrophytes in a UV- and CO2 - enriched environment

As a result of the increasing atmospheric CO2 levels and other greenhose gases due to anthropogenic activities, global and water temperature is rising. The objectives of our project might be summarized as follows: I. To measure the activity of the enzymatic systems involved in carbon, nitrogen and phosphorus uptake (carbonic anhydrase, nitrate reductase and alkaline phosphatase) in selected macroalgae. To assess the optimal concentration of inorganic nitrogen and phosphorus for growth and photosynthesis. To study the total concentration of carbon and nitrogen metabolites in the macroalgae (proteins, total carbohydrates, and lipids) in order to define the possible existence of nutrient limitation. II. To simulate the conditions of climate change, represented as CO2 enrichment and increasing UV radiation, on the activity of carbon, nitrogen and phosphorus uptake mechanisms. III. To screen the activity of the enzymatic systems previously detailed in macroalgae from the Konjsfjord, in order to know their nutritional state.

Biological effects nutrient uptake UV radiation Climate change Macroalgae eutrophycation Ecosystems
260. Transport, burial and fluxes of carbon and contaminants in Arctic lake and fjordic sediments

To distinguish between atmospheric and marine transport of contaminants to northen latitudes by comparison inventories of lake and fjordic sediments.

Contaminant transport Sediments Atmosphere