The common and ecologically important cyanobacterial form-genus Leptolyngbya is widely distributed in numerous ecosystems over the Earth's biosphere. Several morphospecies dominate microbial communities in polar habitats, but their diversity and local ecological significance are little known. Several articles characterising strains isolated from Antarctic coastal habitats by molecular methods were published, but knowledge of their phenotype and ecological characters are indispensable for future detailed environmental studies. Distinct morpho- and ecotypes (ecologically important morphospecies) from maritime Antarctica are characterised in this article. Eight dominant Leptolyngbya types from subaerophytic and freshwater habitats were recognised, and four of them (L. borchgrevinkii, L. fritschiana, L. nigrescens and L. vincentii) are described as new distinct species.
An investigation of cyanobacterial microflora in the northern, deglaciated part of James Ross Island in the NW part of the Weddell Sea, Antarctica , was conducted during the Antarctic summer season 2005-2006. Five main types of habitats with dominant cyanobacterial assemblages were analyzed (soils, seepages, streams, wetted rocky walls and lakes), and main ecological variables were measured (pH, temperature, intensity of global radiation, conductivity and nutrients), as a background for further ecological and ecophysiological studies. The definable traditional cyanobacterial morphospecies were identified.
A total of sixty five taxa of marine phytoplankton (diatoms, dinoflagellates, silicoflagellates and cyanoprokaryotes) were recorded in the transect from the cold region of the Antarctic (Weddell Sea) up to La Plata Bay, Argentine in the late austral summer (March 1989). Diatoms were the dominant group in a south-north transect from the Seal-Bay (Princess Martha Land, the Antarctic). Most of the phytoplankton species of the cold Antarctic region disappeared around 50°S where there is a steep water temperature gradient. The diatom flora declined in the regions of increasing temperature, i.e. between 60° and 50° S and was replaced by dinoflagellates of the genus Ceratium. Large centric diatom genera Corethron, Rhizosolenia, Chaetoceros and Dactyliosolen represented the most apparent phytoplankton part. The most common of the small centric diatom genera were Thalassiosira, Asteromphalus, Actinocyclus and Coscinodiscus, while several species of Navicula and Nitzschia were the most abundant pennate forms. The presence of a considerable number of freshwater pennate diatoms, characterized as indifferent in the halobion spectrum and mostly periphytic, might be attributed to survival strategies during their development on the floating coastal ice.