Description: Das Projekt "Effect of nutrient ratios on harmful phytoplankton and their toxin production" wird vom Umweltbundesamt gefördert und von Universität Jena, Institut für Ernährungswissenschaften durchgeführt. General Information: The goals of the NUTOX project are: (1) to clarify if the present dominance of non-siliceous harmful algal species is due to the high NP to Si-ratios found in European coastal waters (2) to understand how the ratios between N and P affect toxin production in some of the most harmful phytoplankton species found in European waters. Occurrence of toxic blooms in coastal waters is related to a biotic and biotic factors that controls the structure and the growth of the phytoplankton community. One of the major a biotic factors controlling phytoplankton growth is nutrient availability with respect to concentrations and ratios. Thus, to assess the capability of potentially toxic species to bloom in coastal waters, attention will be focused on factors leading to (i) their dominance in the phytoplankton communities, and (ii) to their toxin production. Nutrient ratios influence not only algal succession in natural communities but also the production of toxin by certain phytoplankton species. However, the influence depends on which type of nutrient is limit ant or deficient relative to others for the algal need. In most European marine waters the ratios between nitrogen (N) and phosphorus (P) in relation to silica (Si) have increased due to the high input from N and P from human activities. At the same time toxic algal blooms of non-silica requiring species, such as prymnesiophytes, dinoflagellates and blue-green algae have increased. We will investigate if there is a connection between high NP:Si-ratios and selection towards toxic species by exposing the natural phytoplankton communities contained in mesocosms to a gradient of N:P:Si ratios (in the inflowing medium). In this way we will be able to see if a specific toxic species will out compete the diatoms. In these experiments we will use a combination of new standardized and advanced methods. In an attempt to couple the nutrient cell status to toxicity, the cell toxin content will be determined by HPLC after cell-sorting a few thousands of the desired cells with the help of a flow cytometer. This will be the first time that the nuclear microprobe will be used for the study of the elemental composition of a single phytoplankton cell growing among thousands of other species in nature. These 2 experimental approaches have never been applied yet in phytoplankton ecology in order to get information on the connection between intracellular nutrient composition and toxin production in toxic phytoplankton species occurring in nature. The regulation of toxin production is not only due to genetical inheritance but also due to the cellular chemical composition (the latter being regulated by the medium the algae is growing in). The effect of N:P ratios on the cellular chemical composition and toxin production will be compared in different toxic species... Prime Contractor: University of Kalmar, Aquatic Ecology Department, Institutionen för Naturvetenskap; Kalmar; Sweden.
Types:
SupportProgram
Origin: /Bund/UBA/UFORDAT
Tags: Algenblüte ? Ameise ? Jena ? Kalmare ? Kultursubstrat ? Phosphorgehalt ? Gewässerökologie ? Nährstoffgehalt ? Physiologische Wirkung ? Populationsökologie ? Schadstoffgehalt ? Siliziumdioxid ? Stickstoffgehalt ? Zellphysiologie ? Pflanzensamen ? Nährstoff ? Ökologie ? Phosphor ? Cyanobakterien ? Phytoplankton ? Diatomeen ? Schadstoffwirkung ? Silizium ? Stickstoff ? Biologische Wirkung ? Zytologie ? Schweden ? Zytotoxizität ? Chemische Zusammensetzung ? Flüssigkeitschromatografie ? Toxin ? Verfahrenskombination ? Biologische Konkurrenz ? Küstengewässer ? Biotischer Faktor ? Schadstoffanalyse ? Studie ? Toxische Substanz ? Toxizität ? Wasserinhaltsstoff ? Wirkungsanalyse ? Zelle ? Kausalzusammenhang ? Algen ? Ernährungswissenschaft ? Nährstoffmangel ? Nährstoffaufnahme ? Nährstoffverfügbarkeit ? Schadstoffbildung ? Wassermikroorganismen ? flow-cytometer ?
Region: Thuringia
Bounding box: 11° .. 11° x 50.91667° .. 50.91667°
License: cc-by-nc-nd/4.0
Language: Deutsch
Time ranges: 1997-10-01 - 2000-09-30
Accessed 1 times.