Nitrogen Fixation During Blooms of Nodularia in Coastal Waters and Backwaters of the Arkona Sea (Baltic Sea) in 1974

Abstract

Nitrogen fixation was investigated by means of the acetylene reduction method during the development of a water bloom of Nodularia in coastal waters of the Baltic Sea west of the island of Hiddensee and in backwaters showing different degrees of eutrophication. Depending on plankton density, the values found varied greatly. The maximum of nitrogen fixation values found in extremely dense water blooms under special conditions (Baltic Sea, 2250 pg N2/l * h ; Kleiner Jasmunder Bodden, 374 pg Nz/l * h) are up to 10' times higher than from other parts of the Baltic Sea or from inland waters. The average nitrogenase activity determined for coastal water populations of the Baltic Sea is 2.15 pg N2/heterocyst . h and that of the inmost backwaters 0.77 pg N2/ heterocyst . h. The relationship between N2-fixation and nutrient content in water is discussed.

Phytoplankton Periodicity in a Eutrophic Coastal Water of the Baltic Sea

“…The cyanobacterial blooms in the Darss-Zingst boddens always start after a marked increase of the water temperature, normally within the range of 16-20°C. HUBEL and HUBEL (1980) thought that a minimal temperature of 17OC is required for the mass growth of Nodularia in Baltic coastal waters. Aphanizomenon Jos-aquae occurs in temperatures ranging from 16 to 26OC according to most authors but apart from the typical summer blooms the species was also recorded at temperatures below 10°C (PECHAR 1992).…”

Phytoplankton trends in the Baltic Sea

“…Cyanobacterial blooms have been reported from the open Baltic Sea already in the 19th century, but their intensity and frequency seem to increase (Finni et al, 2001). Hübel and Hübel (1980) and Melvasalo and Viljamaa (1987) observed intensive blooms in the Baltic proper since 1969, while Postel (2000) found high biomass of net plankton in the western Baltic Sea in 1972Sea in /1973Sea in , 1983Sea in and 1992. Large blooms were detected by satellite also in 1982-1984and 1991-1993(Kahru et al, 1994.…”

Identification of a Δ6 fatty acid elongase gene for arachidonic acid biosynthesis localized to the endoplasmic reticulum in the green microalga Myrmecia incisa Reisigl

“…During the rainy season, soil surface runoff can lead to increasing amounts of these compounds in water due to a lack of immediate absorption by land plants (Klausner et al, 1973;Turtola, 1998). In contrast, when aquatic plants, such as waterbloom microalgae, grow luxuriantly under favorable conditions, these compounds become limited (Hübel and Hübel, 1980;Nalewajko and Murphy, 2001). In nature, higher aquatic plants and algae usually suffer from stress induced by nitrogen starvation, and these organisms must physiologically adapt to the changing nitrogen concentrations in water to survive (Thompson, 1996;Guschina and Harwood, 2006).…”