Cyanobacteria planktonic

In the field of fresh water plankton chemical ecology microcystins from cyanobacteria have stimulated much research and discussion. A critical reflection on the ecological function of these non-ribosomal peptides has recently been published (Babica et al. 2006). Surveys of methods for the quantification of these peptides (McElhiney and Lawton 2005 Msagati et al. 2006) and on the effects on fish (Malbrouck and Kestemont 2006) can be found as well. 

Marino R, Howarth RW, Chan F, Cole JJ, Likens GE (2003) Sulfate inhibition of molybdenum-dependent nitrogen fixation by planktonic cyanobacteria under seawater conditions a non-reversible effect. Hydrobiol 500 277-293... 

The photo synthetic aquatic biomass comprises cyanobacteria (formerly called blue-green algae), planktonic, filamentous and macrophytic algae, and vascular macrophytes. The net productivity of the floodwater depends on the level of primary production by the photosynthetic biomass versus its consumption by grazing animals, particularly cladocerans, copepods, ostracods, insect larvae and molluscs. Their role will change as the canopy develops and at a leaf area index of about 6-7 there will be no more photosynthetically active radiation available to them. 

Carmichael WW, Status report on planktonic cyanobacteria (blue-green algae) and their toxins, Report 149, 1992. 

Eukaryotic plants and cyanobacteria. Photosynthetic dinoflagellates, which make up much of the marine plankton, use both carotenoids and chlorophyll in light-harvesting complexes. The carotenoid peridinin (Fig. 23-29), which absorbs blue-green in the 470- to 550-nm range, predominates. The LH complex of Amphidinium carterae consists of a 30.2-kDA protein that forms a cavity into which eight molecules of peridinin but only two of chlorophyll a (Chi a) and two molecules of a galactolipid are bound (Fig. 23-29).268... 

In recent years, the unicellular nature of planktonic algae has been exploited for the construction of whole-cell based biosensors capable of real-time response on critical change of the aquatic ecosystems caused by pollutant emissions. Most of the proposed devices are based on the electrochemical detection of the inhibiting effect on the photosynthetic activity of algae and cyanobacteria exerted by some toxicants. 

Despite these problems, flow cytometry has had some noted success in aquatic research, particularly in relation to studies on the phytoplankton. Because all phytoplankton possess chlorophyll, but only the cyanobacteria possess the phycobiliproteins, autofluorescence signatures from water samples, based on the chlorophyll (fluorescence >630 nm), phycoerythrin (fluorescence <590 nm), and forward scatter of particles, have been used to characterize the changes that occur in plankton at different depths or at different locations (Figs. 11.5 and 11.6). 

Kallqvist, T. and R. Romstad (1994). Effects of agricultural pesticides on planktonic algae and cyanobacteria Examples of interspecies... 

Carpenter, E.J. and Roenneberg, T., The marine planktonic cyanobacteria Trichodesmium spp. photosynthetic rate measurements in the SW Atlantic Ocean, Mar. Ecol. Prog. Ser., 118, 267, 1995. 

Howarth, R.W., Chan, F., and Marino, R. (1999) Do top-down and bottom-up controls interact to exclude nitrogen-fixing cyanobacteria from the plankton of estuaries explorations with a simulation model. Biogeochemistry 46, 203-231. 

One key factor for tropical diazotrophs may be water temperature. For example, the distribution of Trkhodesmium spp. is roughly limited by the 20°C isotherm, and other planktonic cyanobacteria are likewise primarily tropical or subtropical in distribution. MetabolicaUy active populations of Trkhodesmium have been observed at 18.3°C in the North Atlantic (McCarthy and Carpenter, 1979), but activity was low, and substantial growth is typically not seen until water temperature exceeds 20°C (Carpenter, 1983a,b). Moreover, water temperature co-varies inversely with surface nutrient concentrations (Kamykowski and Zentara, 1986). Indeed, in previous studies we have used sea surface temperature as a proxy for oligotrophic waters in order to estimate the areal range of Trkhodesmium (Capone et al., 2005). 

Paerl, H. W., Prufert-Bebout, L. E., and Gou, C. (1994). Iron-stimulated N2 fixation and growth in namral and cultured populations of the planktonic marine cyanobacteria Trichodesmium spp. Appl. Environ. Microbiol. 60, 1044—1047. 

The temi symbioses was first defined loosely by De Bary (1879) as two or more difFerendy named organisms bving together. Although symbiotic interactions are ubiquitous in nature, few of the marine planktonic systems have been well characterized, and comparatively less is known of the functional role of the symbiont for the host and vice versa. Many of the planktonic symbioses are between eukaryotic hosts and cyanobacterial symbionts, or cyanobionts. Cyanobacteria are photosynthetic, and many are capable of nitrogen (N2) fixation, thus often it is presumed... 

Most heterocystous cyanobacteria dominate brackish and freshwater environments where they occur in the plankton and the benthos as free-Hving cells and are seldom found in the open ocean. Few report Richelia and Calothrix as free-living (Gomez et al., 2005 White et al., 2007), thus both are the exception and have made their successful transition to the open ocean as symbionts. 

Foster, R. A., CoUier, J. A., et al. (2006). Reverse transcription PCR amplification of cyanobacteria symbiont 16S rRNA sequences from single non-photosynthetic eukaryotic marine planktonic host cells. J. Phycol. 42, 243-250. 

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