Eine statistische Auswertung von Phytoplankton- und Nährstoffwerten aus den Boddengewässern des Darß und des Zingst (südliche Ostsee) unter Anwendung des nichtparametrischen Rangkorrelationskoeffizienten nach Spearman

A statistical analysis for the waters of the Darss-Zingst inlets (Southern Baltic) using the rank correlation coefficient according to Spearman shows a significant correlation between the amount of phytoplankton and total dissolved nitrogen. In contrast, no correlation could be found between phytoplankton and total dissolved phosphorus.     

Der schmale Grat zwischen Prävention und Placebo: Nahrungsergänzungsmittel

Consumers expect vitamin and mineral supplements to protect them against diseases. In Germany the legal basis of food supplements is the national food law, therefore any advertising regarding diseases is forbidden. Since there exist no definition and no legal basis for the product group by now, there are many products with illegal advertisement and without any health effect in the market. Furthermore the differentiation from other product categories, especially drugs, is difficult. Food supplements can help to meet the needs for critical nutrients and are able to ameliorate the supply of health protecting substances. This is especially important for risk groups with higher nutrient requirements or low energy intake. The bioavailability of substances from supplements is mostly better than from food. Therefore dosages should correspond to those taken by normal food consumption. It is the pragmatic way to use food supplements in order to prevent inadequate nutrient intake especially in risk groups.     

Salzwiesen: Leben zwischen Land und Meer: Im Einfluss der Gezeiten

Terrestrial halophytic vegetation units (salt marshes) cover the alluvial mud‐flats or sandy clays between tidal mean low and mean high water levels and thus form the biological border between sea and land. The various vegetation units of this zone represent the only natural grassland of Europe outside the mountaineous range above the timberline. Their organismic components are subject to a highly dynamic regime of ecological factors due to tidal and other influences, but nevertheless build up communities of relatively high species diversity. They all exhibit remarkable ecophysiological adaptations to their habitat. Eve during the recent decades natural salt marshes have substantially been threatened by technical land reclamation projects along the coastline and now urgently need habitat protection, e.g.in the scope of the national park programs.     

Quantitative Untersuchungen zu Wechselbeziehungen zwischen Balzaktivität und Testosterontitern bei männlichen Zebrafinken

The determination of hormone titers in small plasma volumes by radioimmunoassay makes it possible to demonstrate the mutual relationship between testosterone titers and sexual behaviour. Testosterone titers were measured after courtship tests in male Zebra Finches to determine whether these levels are influenced by sexual behaviour. The results show that immediately after a courtship test there is a significant difference in hormone levels between sexually experienced and inexperienced birds. Sexual experience can also be shown to influence baseline testosterone titers in male Zebra Finches: experienced ♂♂ have a high baseline level while inexperienced ♂♂ have a low baseline level. In two other behaviour patterns, undirected song and courtship song, it could be demonstrated, that the amount of these behaviours shown is linearly correlated with the amount of testosterone in the blood plasma. Both song types have different hormonal threshold values. The comparison of testosterone titers between different treatment groups can only be made if the groups are maintained under identical conditions, since housing conditions appear to have a very marked influence on testosterone titers. The mechanism of action of testosterone in sexual behaviour is discussed.