Sapropel

Sapropel (a contraction of Ancient Greek words sapros and pelos, meaning putrefaction and mud (or clay), respectively) is a term used in marine geology to describe dark-coloured sediments that are rich in organic matter.

Sapropels develop during episodes of reduced oxygen availability in bottom waters, such as an oceanic anoxic event (OAE).

Detailed process studies of sapropel formation have concentrated on the fairly recent eastern Mediterranean deposits,[1] the last of which occurred between 9.5 and 5.5 thousand years ago.

They record a higher organic carbon concentration than non-sapropel times; an increase in the δ15N and corresponding decrease in δ13C tells of rising productivity as a result of nitrogen fixation.

Here, under the conditions of relative stagnation, can be observed uninterrupted cross-sections because this area was under the sea level during the entire Pleistocene and Holocene.

It is generally accepted that the main source of hydrogen sulfide in the Black Sea today are the processes of anaerobic decomposition of organic matter by sulfate-reducing bacteria (SRB).

The organic substance that is fixed at the bottom of the basin in the form of organogenic-mineral sediments (sapropels) is a product of the mass extinction of the plankton biomass as a result of the Black Sea flood.

There is an excess of a huge amount of organic matter, which creates favorable conditions for the development of bacterial sulfate reduction.

[3] Bulgarian Professor Petko Dimitrov is the creator of the idea for the application of sapropel sediments from the bottom of the Black Sea as a natural ecological fertilizer and biological products.