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1
Content available remote Do toxic cyanobacteria blooms pose a threat to the Baltic ecosystem?
Mazur-Marzec H., Pliński M.
Oceanologia
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2009
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No. 51 (3)
293-319
EN
Cyanobacteria, otherwise known as blue-green algae, are oxygenic, photosynthetic prokaryotes. They occur naturally in many fresh, marine and brackish waters worldwide and play an important role in global carbon and nitrogen cycles. In their long history, cyanobacteria have developed structures and mechanisms that enable them to survive and proliferate under different environmental conditions. In the Baltic Sea, the mass development of cyanobacteria is compounded by a high level of eutrophication. The dominant species in the Baltic, the filamentous Aphanizomenon flos-aquae and Nodularia spumigena, can fix dissolved atmospheric N2, as a result of which they can outcompete other phytoplankton organisms. Heterocystous, filamentous cyanobacteria also make a significant contribution to the internal nutrient loading in the Baltic. The blooms of N. spumigena are of particular concern, as this cyanobacterium produces nodularin (NOD), a hepatotoxic peptide. The concentration of the toxin in the sea is regulated mainly by dilution with uncontaminated water, photolysis, sorption to sediments and microbial degradation. The transfer of the toxin in the Baltic trophic chain through zooplankton, mussels, fish and birds has been reported, but biodilution rather than bioconcentration has been observed. Cyanobacterial blooms are thought to pose a serious threat to the ecosystem. Their harmful effects are related to the occurrence of a high biomass, oxygen depletion, a reduction in biodiversity, and the production of toxic metabolites.
2
Content available remote Nodularyny i inne toksyny produkowane przez cyjanobakterie (sinice)
Mazur-Marzec H., Toruńska A.
Wiadomości Chemiczne
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2007
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[Z] 61, 3-4
247-277
EN
Cyanobacteria are photosynthetic prokaryotes that produce a wide range of secondary metabolites. Part of them is toxic or shows bioactivity in other organisms, including mammals . The main classes of cyanobacterial toxins comprise of hepatotoxins, neurotoxins, cytotoxins, dermatotoxins and lipopolysaccharides. Hepatotoxins, microcystins and nodularins are the most common cyanotoxins. Microcystins, the cyclic heptapeptides are produced by freshwater cyanobacteria of the genera Microcystis, Anabaena, Planktothrix (Oscillatoria), Nostoc, Hapalosiphon and Anabaenopsis. Nodularin (NOD-R) the cyclic pentapeptide hepatotoxin is produced by brackish water cyanobacterium Nodularia spumigena. Microcystins and nodularins are extremely toxic due to their action on type 1 and 2A protein phosphatase enzymes that play a key role in the control of cellular meta-bolism. The main groups of neurotoxins produced by cyanobacteria include anatoxin-a, anatoxin-a(s), saxitoxins and the recently identified B-N-methylamino--L-alanine (BMAA). The latter has been reported to biomagnify within the Guam ecosystem and was suggested to be a possible cause of the amyotrophic lateral sclerosis/parkinsonism-dementia complex (ALS/PDC). In the Baltic Sea N. spumigena is the main toxic and bloom-forming cyanobacterial species [7]. Nodularin concentration can temporarily reach over 20 mg dm-3. The toxin accumulates in different elements of the Baltic ecosystem, including sediments, mussels and fish. Apart from NOD-R, minor amounts of other NOD analogues have been characterized in N. spumigena cells: geometrical isomers, linear forms, three demethylated analogues and three analogues with additional methyl group. Nodularin is characterized by high stability. The loss of the toxin in water is mainly due to degradation by the naturally occurring bacterial community. However, the UV radiation as well as sorption on sediments and sus-pended particles has also some impact on nodularin concentration. In organisms microcystins are detoxified by conjugation with activated glutathione, however, the pathway of nodularin biotransformation has not been revealed yet.
3
Content available remote Toxic Nodularia spumigena blooms in the coastal waters of the Gulf of Gdańsk: a ten-year survey
Mazur-Marzec H., Krężel A., Kobos J., Pliński M.
Oceanologia
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2006
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No. 48 (2)
255-273
EN
In the Baltic Sea, summer blooms of the filamentous, nitrogen-fixing cyanobacterium Nodularia spumigena are favoured by high P concentrations at low N:P ratios and a salinity range of 5-13 PSU. The blooms are initiated by calm and sunny weather, an elevated surface water temperature and thermal stratification. The mass occurrence of N. spumigena in coastal waters is a matter of special concern, as the cyanobacterium produces nodularin, a potent pentapeptide hepatotoxin. In the Gulf of Gdansk, the large-scale occurrence of N. spumigena was recorded for the first time in 1994. Blooms of a similar intensity occurred in 2001, 2003 and 2004. Nodularin concentrations in freeze-dried bloom samples varied from 0.01 to 4.01 mg g-1 d.w. In the coastal waters of the Gulf of Gdańsk, cell-bound nodularin concentrations in 2004 and 2005 attained maxima of 25852 š 107 žg dm-3 and 3964 š 125 žg dm-3, respectively. Microscopic analysis revealed the presence of diverse N. spumigena forms, with the dominance of curved filaments in bloom samples. The results of in situ studies and remote sensing measurements indicate a high frequency and intensity of cyanobacterial blooms in the Gulf of Gdańsk in the last ten years.
4
Content available remote A simple tool for the early prediction of the cyanobacteria Nodularia spumigena bloom biomass in the Gulf of Finland
Lilover M-J., Laanemets J.
Oceanologia
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2006
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No. 48 (S)
213-229
EN
A fuzzy logic model for predicting the maximum biomass of the toxic cyanobacteria Nodularia spumigena bloom in the Gulf of Finland is suggested. The model bloom biomass depends on the phosphate conditions up to 15 June, including the excess phosphate left over after the spring bloom and on the phosphate inputs parameterised by wind mixing and upwelling from 1 May to 15 June. The surface layer temperature, set to vary from 14 to 23^(o)C, is regarded as a bloom regulating parameter. The model simulations showed that the predicted N. spumigena biomasses differ markedly from year to year and clearly depend on phosphate conditions up to 15 June.
5
Content available remote Influence of salinity on the growth of Nodularla spumigena mertens
Musial A., Plinski M.
Oceanological and Hydrobiological Studies
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2003
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Vol. 32, No. 2
45-52
EN
The plankton material was sampled in August 1997 from the Gulf of Gdansk. The Cyanobacterium Nodularia spumigena strain (NSG 0897) was isolated from the samples. The effect of salinity on the growth of Nodularia spumigena was studied in the laboratory. Salinity had a significant effect on the number of cells, optical density, concentration of chlorophyll a, dry mass and growth rate. The Nodularia spumigena strain grew well in salinities 4-16 PSU. A salinity of 8 PSU is the best for the growth of this strain.
6
Content available remote Nodularia spumigena blooms and the occurrence of hepatotoxin in the Gulf of Gdańsk
Mazur H., Pliński M.
Oceanologia
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2003
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No. 45 (2)
305-316
EN
Nodularia spumigena forms extensive summer blooms in the Baltic Sea. The occurrence of the blooms is determined by water temperature, light intensity and nutrient concentration; levels of nitrogen and phosphorus in particular are critical. The time of the seasonal maximum and intensity of the Nodularia bloom in the Gulf of Gdansk vary significantly from year to year. In 2001 a rapid and massive proliferation of N. spumigena was observed in late June - early July. The concentration of nodularin in water ranged from 90 to 18135 žg dm-3 and in lyophilised phytoplankton samples from 3000 to 3520 žg g-1 d.w. (dry weight). Such a high concentration of toxin in the recreational waters of the Gulf of Gdansk constitutes a health risk for users of bathing areas. In 2002, the N. spumigena bloom was less dense, but lasted longer, with a maximum in late July - early August. In 2002 the concentration of nodularin did not exceed 12.6 žg dm-3 in water and 919 žg g-1 d.w. in lyophilised phytoplankton samples. Other cyanobacterial toxins - microcystins and anatoxin-a - were also detected in the coastal waters of the Gulf of Gdansk.
7
Content available remote Is iron a limiting factor of Nodularia spumigena blooms?
Paczuska L., Kosakowska A.
Oceanologia
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2003
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No. 45 (4)
679-692
EN
It is well known that a deficiency of iron, a trace element essential to every living organism, limits the growth of algae and cyanobacteria. Nodularia spumigena Mertens is a blue-green algae species inhabiting the Baltic region that often forms toxic blooms. The aim of the study was to assess the growth of the toxic cyanobacteria with respect to iron bioavailability. The measured growth parameters were the numbers of cells (optical density), chlorophyll a and pheopigment a concentrations. The iron concentrations used ranged from 10-7 to 10-4 mol dm-3. Under iron stress conditions (<5 × 10-7 mol dm-3), growth inhibition, gradual pigment decay and cell mortality were observed. However, enriching the medium with complexing factors like citric acid and EDTA significantly stimulated the growth rate and chlorophyll a production. The citric acid - EDTA - Fe (5 × 10-7 mol dm-3) complex was demonstrably effective in stimulating the rate of cell division. Starting with 10-6 mol dm-3, the higher the iron(III) concentration used in the media, the more intensive the growth of the cyanobacteria populations. This was most rapid in the presence of high iron concentrations (10-4 mol dm-3), regardless of the presence of complexing agents. It appears that the growth of toxic cyanobacteria N. spumigena, and thus also its ability to form blooms, may well depend on iron availability in the environment
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