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1

Phytoplankton based biomonitoring on Hungarian Upper-Tisa

100%
Imre A.
Oceanological and Hydrobiological Studies
|
2004
|
tom 33
|
nr 2
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
Content available

Influence of bacterial activities on nitrogen uptake rates determined by the application of antibiotics

100%
Tungaraza C., Brion N., Rousseau V., Baeyens W., Goeyens L.
Oceanologia
|
2003
|
tom 45
|
nr 3
The influence of bacterial activities on inorganic nutrients has always affected total phytoplankton uptake rates owing to the absence of a reliable method that can exclude these effects. The use of natural samples to determine the contribution of bacterial activities has been based on the size fractionation method which, unfortunately, is encumbered with uncertainties, especially because of the size overlap between bacteria and phytoplankton communities. In this paper, the results are reported of an estimation of bacterial activities by the use of inhibitors (antibiotics). It was shown that the contribution of bacterial activities to the uptake of nitrogenous nutrients was highest for ammonium (79%), followed by nitrate (72%) and urea (62%). In a second set of experiments the concentration of ammonium was raised by 5 μM. This was done to avoid nutrient limitation resulting from the absence of recycled nutrients following the addition of antibiotics and the maximum contribution of bacterial activity to the uptake rate of ammonium increased to 87%. It can be concluded that the use of inhibitors is a good method, a reliable alternative to the fractionation method. However, it is important to note that inhibitors can affect both phytoplankton growth and the nutrient recycling process. Our results indicate that the application of antibiotics had measurable effects not only on the target bacteria but also on the uptake behaviour of phytoplankton. Our observations were therefore limited to the period when there was no effect on the phytoplankton, as was demonstrated by a carbon protein incorporation experiment.
3
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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Spatiotemporal variation of alkaline phosphatase activity in coastal waters off Trivandrum

84%
Shivaramu M. S., Randive A. K., Kumari R., Gauns M., Ponnapakkam L. A.
Oceanologia
|
2019
|
tom 61
|
nr 1
4

Biodegradation of engine oil in soil

84%
Sztompka E.
Acta Microbiologica Polonica
|
1999
|
tom 48
|
nr 2
5

Inorganic phosphorus and nitrogen modify composition and diversity of microbial communities in water of mesotrophic lake

67%
Chrost R. J., Adamczewski T., Kalinowska K., Skowronska A.
Polish Journal of Microbiology
|
2009
|
tom 58
|
nr 1
77-90
The effects of inorganic nutrients (N, P) enrichment of mesotrophic lake water on changes in bacterial and protistan (heterotrophic nanoflagellates and ciliates) communities compositions were studied in the mesocosm experiment. Phosphorus (PO₄³⁻) and nitrogen (NH₄⁺) alone and in combination were added to three types of experimental mesocosms. Mesocosms results suggested that simultaneous addition of P and N stimulated phytoplankton growth and production rates of bacterial biomass its turnover rate. Strong positive correlations between chlorophyll a and bacterial secondary production rates suggested that bacteria were mainly controlled by organic substrates released in course of phytoplankton photosynthesis. Both nutrients increased distinctly protistan biomass and resulted in the shift in ciliate community composition from algivorous to large omnivorous species. The response of bacterial numbers and biomass to nutrients addition was less evident. However, intensive grazing caused their dynamic changes. Fluorescence in situ hybridization (FISH) revealed only small changes in bacterial taxonomic composition. There was an apparent shift in dominance from Cytophaga-Flavobacterium to the Alphaproteobacteria group in the mesocosm with simultaneous addition of P and N, which positively related to increased abundance of bacterivorous protists. Experiment demonstrated that inorganic N and P nutrients directly influenced the bottom-down control of microbial communities, which had a crucial effect on morphological diversity of bacteria.
6

Potamozooplankton communities in three different outlets from mesotrophic lakes located in lake-river system

67%
Czerniawski R., Domagala J.
Oceanological and Hydrobiological Studies
|
2012
|
tom 41
|
nr 1
7
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The Baltic Sea - an example of how to protect marine coastal ecosystems

67%
Nehring D.
Oceanologia
|
2001
|
tom 43
|
nr 1
The Baltic Sea covers an area of 415 000 km2. A typical brackish sea, it is very sensitive to anthropogenic activities. Inorganic nutrients, trace metals, chlorinated hydrocarbons and crude oil products are contaminants studied in the Baltic Monitoring Programme of HELCOM. The data collected by the riparian countries forms the basis for the periodic assessments of the state of the marine environment of the Baltic Sea Area produced by HELCOM every five years. Since 1992 marine nature conservation has been part of the HELCOM convention. According to the third status report issued in 1996, it was the first time that HELCOM could strike a positive balance with regard to the decreasing environmental load. This is also reflected in lower concentrations of harmful substances in fish, marine mammals and seabirds in the Baltic Sea Area. The reasons for this progress are the protective actions initiated by HELCOM and the economic collapse in some of the former East Bloc countries, the latter resulting in an abrupt fall in industrial and agricultural production. Although the restoration of the Baltic ecosystem has only just begun, the protective measures introduced to achieve this aim can serve as an example of how to solve similar problems in other semi-enclosed basins and shelf seas.
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