Das Projekt "Verhalten von Cs und Sr in natuerlichen Oekosystemen und potenzielle Strahlungsexposition bei ihrer extensiven Nutzung" wird vom Umweltbundesamt gefördert und von Bundesamt für Strahlenschutz durchgeführt. Objective: The Chernobyl accident led to an enormous amount of measurements of 134Cs and 137Cs activities in, for example, wild berries and mushrooms. These data, which vary widely, are helpful for evaluating actual radiation exposure to man, but they are of no help in understanding the behaviour of radionuclides in forest ecosystems. The project Cycling of Radiocaesium and Strontium in Natural Ecosystems, investigates the fate of radiocaesium and strontium 90 in natural ecosystems in Belgium, Germany, Sweden and Italy, in order to improve the knowledge of the cycling mechanisms and the understanding of their short and long term behaviour. General Information: Seven laboratories from Belgium, Italy, Sweden and Germany are involved in this research project. The investigations take place in different forests sites in their countries. For joint investigations, boreal forests in Sweden and beech forests in the Italian Alps have been chosen. The experimental strategy is focusing on the fate of radiocaesium and strontium 90 after their deposition in forest ecosystems. One major point is the uptake of caesium and strontium from soil to plants. Until now it is not completely understood why the uptake rates of caesium in natural ecosystems are significantly higher than on agriculturally used areas. Natural ecosystems are characterized by undisturbed soils with organic and mineral horizons. In a first step, the distribution of radiocaesium and strontium 90 within the different layers are measured. To improve the knowledge of the plant availability, soil parameters like nutrient concentration, exchange capacity, kd values, etc. are determined. Additionally, plant parameters such as mycelium and rooting depths, potassium and calcium distribution within the plants are analyzed. The importance of various parameters on the transfer of caesium and strontium will be analyzed by statistical methods. The plant and herbivore interactions are analyzed by a special programme on moose. Moose meat contributes to about 5 per cent to 10 per cent of the average meat consumption in Sweden and is therefore of radiological interest. To obtain the radionuclide intake rate, the migration of single moose is observed during the year as well as their seasonal consumption habits. Later they are shot and caesium 134 and 137 activities in meat are measured. The correlation of radiocaesium and potassium intake rates will be tested. For long term considerations, the loss of radionuclides from the ecosystems by migration and runoff is analyzed. Further studies are concerned with the distribution of caesium and strontium within the ecosystems, the antagonisms of caesium and potassium as well as strontium and calcium, etc. ... Prime Contractor: Bundesamt für Strahlenschutz, Fachbereich Strahlenschutz, Institut für Strahlenhygiene; Oberschleißheim; Germany.
Das Projekt "Überwinterungsstrategien polarer Copepoden: Physiologische Kontrollmechanismen und Auftriebsregulation durch Ammonium" wird vom Umweltbundesamt gefördert und von Universität Bremen, Fachbereich 2 Biologie,Chemie, Marine Zoologie durchgeführt. Ontogenetic seasonal migration associated with a diapause is known as an adaptation to escape temporally from an unfavourable environment in several calanoid copepod species in Polar Seas. Diapausing copepods reside for several months in greater depths where they are presumably neutrally buoyant. Ammonium buoyancy as been observed in several marine invertebrates has never been studied in diapausing copepods. Dependent on the pH, ammonia exists in solutions as both NH3 and NH4 +). Due to the toxicity and the higher diffusibility of NH3 a low haemolymph pH is required to favour the formation of ammonium (NH4 +). The trigger (onset, duration, termination) of diapause is yet unknown. In a recent study we detected ammonium values as high as 500 mmol L-1 in the haemolymph of the diapausing Antarctic copepods Calanoides acutus and Rhincalanus gigas, as well as in the diapausing calanoid copepods Calanoides carinatus and Eucalanus sp. in the Benguela Current upwelling system, indicating ammonia buoyancy in these species. In diapausing copepods metabolic depression is evident by reduced metabolic rate and reduced swim activity. We hypothesize that a low extracellular pH in the haemolymph of diapausing copepods necessary to form NH4 + and to prevent it from diffusive loss could play a fundamental role in the regulation of metabolic depression and thus in the control of diapause. This would lead to a seasonality of ammonia buoyancy with high ammonium and low pHe during diapause and high pHe and low ammonium in the active periods.
Das Projekt "Populationsgenomik baltischer Schweinswale - Individuenspezifische genetische Populationszuordnung baltischer Schweinswale mittels hochauflösender Single Nucleotide Polymorphisms (SNPs)-Technologie" wird vom Umweltbundesamt gefördert und von Universität Potsdam, Mathematisch-Naturwissenschaftliche Fakultät, Institut für Biochemie und Biologie, Professur für Evolutionsbiologie , Spezielle Zoologie durchgeführt. Ziel dieses Projekts ist es, einen repräsentativen Datensatz von baltischen Schweinswalen individuenspezifisch genetisch zu typisieren, um - die Existenz einer separaten Schweinswalpopulation in der inneren Ostsee zu überprüfen. - Das Vorkommen dieser Population regional und saisonal zu bestimmen und - Individuen dieser Population gegen saisonal migrierende Individuen anderer Populationen abzugrenzen. Mittels RAD-tag genotyping by sequencing sollen SNPs in einigen hundert Individuen untersucht werden (je mindestens 100 aus innerer Ostsee, Beltsee/Kattegat und Nordsee/Skagerak). Falls möglich, werden Proben aus der Fortpflanzungszeit bevorzugt berücksichtigt. Weitere Individuen werden anteilig für Außengruppenvergleiche (Proben aus Island, Spanien liegen vor) sowie zur weiteren Verstärkung des Ostsee-Datensatzes verwendet (z.B. Berücksichtigung zusätzlicher Proben außerhalb der Fortpflanzungszeit zum Erkennen von migrierenden Individuen). Auf der Basis dieser SNP-Typisierung werden individuenspezifische genetische Profile erstellt. Diese werden genutzt, um Populationen zu identifizieren und die Individuen diesen Populationen zuzuordnen. Hierdurch werden folgende Fragen beantwortet werden: - Wieviele (Sub-)Populationen gibt es im Bereich Ostsee/Skagerak/Nordsee? - Wo (Zuordnung möglichst zu 50x50km ICES Quadranten) und wann (saisonale Zuordnung) sind diese Populationen anzutreffen? - Welches Ausmaß hat saisonale Migration? Inwieweit führt sie zu genetischem Austausch? Betrifft sie beide Geschlechter in gleicher Weise oder migrieren Männchen stärker?