Picoplankton and other non-bloom forming Cyanobacteria in lakes

摘要: Studies on the picocyanobacteria, major non-bloom forming group in lakes, have increased markedly past two decades.These cyanobacteria fall into groups, those that predominantly occur as solitary cells (here termed Pcy) and primarily colonies (CPcy). The single-celled picoplankton received most ecological study, though colonial forms are better known taxonomically.The groups distributed worldwide ubiquitous all types of lakes varying trophic condition. Pcy populations tend to be predominant large, deep oligo-mesotrophic while species (CPcy) find optimal conditions warmer, shallower more nutrient rich (meso-eutrophic) during summer.The euryphotic appear capable adapting a wide variety light conditions, with CPcy surface oriented often reaching sub-surface peaks at irradiance levels 20–50% values. Growth ranges from 0.1 d-1 about 3.0 doubling times 7 h d.Their natural population growth rates highly variable cases balance loss rates, grazing. contribute substantially total primary production within euphotic zone, significantly ultra-oligotrophic but also some meso- eutrophic showing high N:P ratios (>20 molar) limitation by nitrogen than phosphorus.