Monimolimnion

Mermomictic^([sic – meaning meromictic]) lakes may have an extremely high calcium carbonate content in the monimolimnion.

The resulting pH-drop causes a dissolution of carbonate material which has been biogenically precipitated in the epilimnion. This carbonate is recycled to the surface waters during the autumn and winter circulation and can be transported through the outflowing rivers to the oceans. A similar situation exists in temporary or permanently stratified waters of freshwater, brackish and marine environments. Examples of such environments are the monimolimnions of meromictic lakes, the Baltic Sea […] and Norwegan fjords where a high CO₂ input is maintained by vigorous degradation of organic matter.

The higher salinity of the monimolimnion, and therefore the greater density, prevents wind-driven mixing. The cause of meromixis in Green Lake is the inflow of saline ground-water springs below a depth of about 20 m.

The monimolimnion is not a static state but is subject to change, depending mainly on the weather conditions, because of basin's shallowness and the almost stable temperature of the spring waters.

The steps develop in the upper part of the monimolimnion, when in autumn cooling mixolimnion temperatures have dropped below temperatures of the underlying monimolimnion.

Hypolimnia of stratified eutrophic lakes or the monimolimnia of meromictic lakes may contain appreciable quantities of the very soluble gas H₂S.

Due to the density differences between acidic bottom waters in the mine void, groundwater seepage and river water, stable, chemically distinct layers formed and persisted in two of the local depressions (marked as XN3 and XP4[…]). Here, we focus on site XP4 since disappearance and reformation of the monimolimnion happened only at this site, while the thin monimolimnion at XN3 disappeared for good after the flood.