Five sites across the Kiel Fjord in the Baltic Sea (GEOMAR Pier: 54.330383 N 10.150683 E, Kiel Canal Entry: 54.361167 N, 10.162533 E, Falckenstein: 54.390217 N, 10.194983 E, Laboe: 54.405633 N, 10.209750 E, and Strande: 54.428267 N, 10.209267 E) were monitored biweekly from June 2013 until October 2020 (with some discontinuities in winter). At each station water samples from 2 m depth were taken (2013-2015: 240 mL per filter; 2016-2020: 500 mL per filter). The water samples were filtered over filters with different sizes (2013: Cellulose Filters with 0.2, 3 and 12 µm and 50 mm diameter; 8µm Filter with 47 mm diameter; 2014: Cellulose Filters with 3µm and 8µm and 47 and 50 mm diameter, respectively; 2015: Cellulose Filters with 8 µm and 50 mm diameter; 2016-2020: Glas Fiber Filters). Filters were dried and seston dry weight was measured. For the years 2016-2020 the filters were burned afterwards and the POM ash free dry weight was measured.
Changes in silicon to nitrogen (Si:N) ratios are known to affect phytoplankton community composition, as silicon is an essential nutrient for diatoms but not for most other phytoplankton. Less is known if and how this ratio affects biochemical composition and stoichiometry of seston. This is of importance, as changes in seston chemistry can have implications on the quality of food available for zooplankton. We applied a range of Si:N ratios and two levels of copepod grazing on a natural Baltic sea plankton community pre-filtered with 125um mesh size filter. Si:N ratios were achieved by adding silicate (at target concentrations of 10, 16, 22, 28 and 34 μmol L−1) and nitrate solutions (at target nitrogen concentration of 40 µmol L-1) to the experimental units at the start of the experiment. Copepod grazing was manipulated by adding 30 individuals of adult Eurytemora affinis copepods per liter to high copepod treatments once phytoplankton bloom has established (day 6 of the experiment). The mesocosm experiment was carried out in summer 2016 and lasted 20 days. The response of particulate carbon, nitrogen, phosphorus was followed by sampling three times per week and fatty acid samples were taken at the end of the experiment. Our data reveals that increasing Si:N ratios result in an increase of particulate carbon, phosphorus, nitrogen and total fatty acid concentrations. Carbon to nitrogen (C:N) and carbon to phosphorus (C:P) ratios increased with increasing Si:N ratios as well as the concentrations of individual essential fatty acids such as DHA and EPA per seston carbon. Enhanced copepod grazing affected C:N, C:P and DHA and ALA concentrations negatively. Consequently, this data illustrates the importance of bottom up effects such as changes in Si:N ratio and top-down controls like copepod grazing in shaping particulate nutrient and fatty acid composition of marine seston.
Changes in silicon to nitrogen (Si:N) ratios are known to affect phytoplankton community composition, as silicon is an essential nutrient for diatoms but not for most other phytoplankton. Less is known if and how this ratio affects biochemical composition and stoichiometry of seston. This is of importance, as changes in seston chemistry can have implications on the quality of food available for zooplankton. We applied a range of Si:N ratios and two levels of copepod grazing on a natural Baltic sea plankton community pre-filtered with 125um mesh size filter. Si:N ratios were achieved by adding silicate (at target concentrations of 10, 16, 22, 28 and 34 μmol L−1) and nitrate solutions (at target nitrogen concentration of 40 µmol L-1) to the experimental units at the start of the experiment. Copepod grazing was manipulated by adding 30 individuals of adult Eurytemora affinis copepods per liter to high copepod treatments once phytoplankton bloom has established (day 6 of the experiment). The mesocosm experiment was carried out in summer 2016 and lasted 20 days. The response of particulate carbon, nitrogen, phosphorus was followed by sampling three times per week and fatty acid samples were taken at the end of the experiment. Our data reveals that increasing Si:N ratios result in an increase of particulate carbon, phosphorus, nitrogen and total fatty acid concentrations. Carbon to nitrogen (C:N) and carbon to phosphorus (C:P) ratios increased with increasing Si:N ratios as well as the concentrations of individual essential fatty acids such as DHA and EPA per seston carbon. Enhanced copepod grazing affected C:N, C:P and DHA and ALA concentrations negatively. Consequently, this data illustrates the importance of bottom up effects such as changes in Si:N ratio and top-down controls like copepod grazing in shaping particulate nutrient and fatty acid composition of marine seston.
Growth rates of entire coral colonies in the Gulf of Aqaba are species-specific and depend upon the water depth level. Water depth is an environmental factor comprising several subfactors, such as: gradients in radiation, temperature, salinity and pressure. Incorporating water movement, substrate properties substrate inclination and the availability of POM. Each of the above listed subfactors can potentially influence the carbonate production. In our field studies we are particularly interested in energy deliviering processes involved in calcification. In zooxanthellate, hermatypic coral species growth and carbonate production depends on metabolic energy, which may originate from all of the four nutritional pathways mentioned above. We tried to quantify the availability of POM and irradiance with carbonate production in bathymetric dependence and in an annual cycle. Species-specific differences in colonial carbonate production exist the whole year round independent of growing depths and exhibit a maximum during the summer months. The absolute increment of carbonate decreases in all species as a function of depth. At different depth levels studied (2, 10, 20, 40 m) the carbonate production of the different species apprears similar when realted to the surface of the skeletogenic tissue. The annual availability of POM (we determined the amount of organic carbon in the sediment and the seston) does not correlate with carbonate production. The annual skeletal mass increment corrlates best with seasonal changes of irradiance, a fact which supports the importance of the zooxanthellae in calcification.
In diesem Projekt wurden die Auswirkungen der radioaktiven Ableitungen einer kerntechnischen Anlage auf ein Gewaessersystem (Donau) untersucht. Kernkraftwerke liegen in der Regel an Flusslaeufen, da auf Flusswasser als Kuehlmittel meist nicht verzichtet wird. Geringe Mengen radioaktiver Substanzen gelangen ueber das Kuehlwasser und auf dem Umweg ueber die Abluft in das Flusswasser. Je nachdem in welcher chemischen Form diese Substanzen vorliegen, koennen sie sich an andere Wasserinhaltsstoffe anlagern oder in Naehrstoffketten eingebaut werden, womit Strahlenwirkungen auf bestimmte Bevoelkerungsgruppen denkbar werden. Als Untersuchungsprojekte dienen Oberflaechenwaesser, Regenwaesser, Sedimente, Sestonproben, Fische und Wasserpflanzen. Sie werden mit Hilfe der Gammaspektrometrie, der Rest-Beta-Bestimmung und der Strontiumbestimmung analysiert. Bei allen Waessern erfolgt zusaetzlich eine Tritiumbestimmung. Neben den radioaktiven Konzentrationserfassungen werden die Anreicherungsvorgaenge radioaktiver Stoffe in oben genannten Materialien (Sedimente, Fische, Seston) dargestellt, ebenso ein Vergleich von radioaktiven und stabilen Isotopen. Weitere Untersuchungen sind mit den Kohlenstoff -14- und den Tritiumverhaeltnissen in den bayerischen Oberflaechenwaessern zu nennen.
Simultaneous triple stable isotope analysis of carbon, nitrogen and sulphur was employed to study the temporal variation in the food web of a subtidal eelgrass (Zostera marina) bed in the western Baltic Sea. Samples of three potential food sources: eelgrass, epiphytes and seston, as well as consumer species were collected biweekly from March through September 2011. Temporal variation of stable isotope signatures was observed in primary producers and consumer species. However, variation within a species, particularly omnivores, often exceeded variation over time. The high degree of omnivory among the generalist feeders in this eelgrass community allows for generalist feeders to flexibly switch food sources, thus enhancing food web stability. As coastal systems are subject to seasonal changes, as well as alterations related to human disturbance and climate, these food webs may retain a certain resilience due to their plentiful omnivores.
Peildaten mit Einstrahlecholot von FB SESTON aufgenommen. Beschickung auf NHN
In den Jahren 1973 bis 1978 erfolgten umfangreiche mikrobiologische-ökologische Untersuchungen in der Elbe und in einigen kleineren Flüssen Schleswig-Holsteins sowie im Nordostseekanal. In diesem Zusammenhang wurden verschiedene bateriologische und eine Reihe von hydrographisch-chemischen Parametern bestimmt. Die Daten geben Auskunft über den bakteriologischen Zustand der Gewässer in Abhängigkeit von Schwankungen der wichtigsten hydrographischen Faktoren insbsosondere der Temperatur und Wasserführung. Weiter ermöglichen sie Aussagen über die Abwasserbelastung der untersuchten Flüsse.
This data volume presents a series of planktological observations carried out over a 19-year-period in Kiel Bight in the Western Baltic Sea. Three fixed stations were visited at monthly intervals, and the planktion standing stock was investigated in relation to depth and environmental factors, employing a standard observation programme. This consisted in the measurements of temperature, salinity, density, oxygen, phosphorus, seston, protein and chlorophyll a. Additional measurements comprised in the caloric content of seston, particulate organic carbon and nitrogen, as well as dry weight and organic matter of plankton, sampled by vertical hauls of three plankton nets of different mesh size.
Ziele: Indonesien hat die weltweit artenreichsten Korallenriffe und Seegraswiesen. Durch die hohe Bevölkerungsdichte entlang der Küsten, die traditionell enge Verflechtung der Bevölkerung dieses 17.000 Inseln umfassenden Landes mit dem Meer und der damit einhergehende starke Nutzung der Meeresressourcen sind Seegraswiesen und Korallenriffe starken Veränderungen ausgesetzt. Im Rahmen des Verbundprojektes an dem deutsche und indonesische Wissenschaftler zusammenarbeiten soll die Funktion von tropischen riffgebundenen Küstenökosystemen an Hand eines Modellgebietes charakterisiert und der Stoff- und Organismenaustausch zwischen Korallenriff und Seegraswiese quantifiziert werden. Durch gezielte Feld-Experimente werden künstliche Störungen erzeugt, die den anthropogenen und natürlichen Stressoren im Gebiet entsprechen. Anhand dieser Experimente soll erfasst werden, wie das Ökosystem als Ganzes auf eine spezifische Störung reagiert und wie sich dadurch der Austausch von gelösten und partikulären Stoffen sowie von Organismen zwischen Korallenriff und benachbarten Seegraswiesen verändert.
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