Cianobactérias planct？nicas de um lago artificial urbano na cidade de Goiania, GO

fish farms are numerous in goiás state and they are under intense recreational activity. however, studies about cyanobacteria in these environments are scarce, a concerning situation, since the occurrence of intense proliferation of phytoplankton in this kind of environments is common and there is the risk of blooms of toxic species. this paper aims to carry out the inventory of planktonic species of cyanobacteria occurring in a fishery pond (lake jaó - a shallow artificial lake) in the city of goiania (16o39'13" s-49o13'26" w). sampling was carried out during dry (2003 to 2008) and rainy periods (2009), when it was visually evident the occurrence of blooms. climatic, morphometric and limnological variables were measured. the dry period was representative in the sampled years presenting a maximum of 50 mm of monthly precipitation in 2005. thirty-one taxa of cyanobacteria were found belonging to the genera dolichospermum (5 spp.), aphanocapsa (4 spp.), microcystis (3 spp.), pseudanabaena (3 spp.), radiocystis (2 spp.), oscillatoria (2 spp.), and bacularia, coelosphaerium, cylindrospermopsis, geitlerinema, glaucospira, limnothrix, pannus, phormidium, planktolyngbya, planktothrix, sphaerocavum and synechocystis with one species each. in the years of 2003 to 2005 the blooms were formed predominantly by species of dolichospermum and in 2006 by species of microcystis, radiocystis and aphanocapsa. among all the species identified in this study, 21 are new records for the state and 13 have been referenced in literature as potentially toxic.