Space and time regularities in the distribution of dissolved and suspended manganese forms in Novosibirsk Reservoir water

Resumo

The space and time regularities in the distribution, migration, and turnover of dissolved and suspended manganese forms in Novosibirsk Reservoir water are considered. The flux of dissolved manganese forms (Mn²⁺) from bottom sediments into the water mass is shown to reach its maximum in the under-ice period (since the late February to the mid-April), as well as in the period of maximal abundance of biota (August–early September), when reduction conditions form everywhere in reservoir bottom sediments. In this period, bottom sediments are the main source of manganese input into the reservoir water, their contribution reaching 250–400% relative to the inflowing river water; manganese vertical distribution in water is opposite to that of dissolved oxygen, and its concentration is in excess of the hygienic standards. The maximal flux of dissolved manganese forms (Mn⁴⁺) from water into bottom sediments is recorded in August–September (on the average, 0.17 g/(m² day)); it drops to 0.06 g/(m² day) during spring flood, and practically vanishes in the under-ice period.