Mercury methylation and bacterial activity associated to tropical phytoplankton.

摘要: Abstract The methylated form of mercury (Hg), methylmercury (MeHg), is one the most toxic pollutants. Biotic and/or abiotic methylation, often associated to sulfate-reducing bacteria metabolism, occurs in aquatic environments and many tropical areas, mostly periphyton floating macrophyte roots. Data about methylation by phytoplankton are scarce aim this study was verify biotic influence process Microcystis aeruginosa Sineccocystis sp. laboratory strains natural populations from two different systems, mesotrophic Ribeirao das Lajes reservoir hypereutrophic oligohaline Jacarepagua lagoon, Rio de Janeiro state, Brazil. Adapted radiochemical techniques were used measure sulfate-reduction, bacterial activity samples. Methyl- 203 Hg formation added inorganic 3 H-Leucine uptake measured liquid scintillation as well estimated H 2 35 S produced Na SO 4 . There no significant difference low potentials (0.37%) among cyanobacterium species studied conditions. At reservoir, there sulfate-reduction surface sediment between sampling points. Methylation sediments (3–4%) higher than (1.5%), opposite being true for (sediment mean 6.6 against 150.3 nmol gdw − 1 h samples). an expressive (477.1 × 10 at a concentration 1000 nM leucine) (∼21% trapped) (mostly cyanobacteria M. ) observed, but not detected.