Fluxes of carbon and nutrients through the inflows and outflow of Lake Võrtsjärv, Estonia

We determined the incoming fluxes of total organic carbon (TOC), dissolved inorganic (DIC) and organic carbon (DOC), nitrogen, phosphorus, and silicon via four main inflows into Lake Vortsjarv and compared these with the outgoing fluxes from the lake during 2008-2009. The discharge and loads of the studied substances from the four main rivers alone were higher than the amounts carried out of the lake in 2008. In 2009, the outflow of water exceeded the inflows and this was the case with the amounts of TOC, DIC, and DOC as well. However, the incoming load of nutrients was continuously higher than the outgoing load. The lake accumulated nutrients (nitrogen, phosphorus, and silicon) irrespective of whether water retention was positive or negative, but the balance between carbon accumulation and carbon emission depended on the lake's water budget.