Biogeochemistry of selenium compounds in the water column of warm monomictic Lake Kinneret

The biogeochemistry of dissolved selenium (Se) was investigated over 3 years (2015–2017) in the subtropical, warm monomictic and meso-eutrophic Lake Kinneret (Sea Galilee, Israel). We monitored seasonal variation vertical distribution total Se (T.Se), inorganic oxyanions (Se(IV) & Se(VI)), reduced fraction (Red.Se), organic (Org.Se) volatile compounds. T.Se varied between ~ 100 160 ng L−1 with Red.Se comprising 40–80% inventory, Se(VI) dominating Se(IV) most time. species correlated winter holomixis vs. summer fall stratification periods. annual cycle includes: (a) increase from fall/winter to spring, representing increased allochthonous input flux, along recycling via holomixis; (b) decrease spring end year, diminishing inputs evolving output fluxes lake’s bottom atmosphere. Org.Se variations are directly associated Chlorophyll-a primary production attesting for significant role phytoplankton activity cycle. An important flux comprises uptake by further compounds volatilization accounting 10% estimated input. similarity concentrations this work mid 1990s attests long-term stability inventory. TVSe lacustrine systems being similar that estuary systems, biological eventually degradation material may produce