Black Sea chemistry and biodiversity is highly coupled with the lack of vertical currents, present in oceans or bigger seas. Some of the effects are low salinity in the top layers - many ocean fish species cannot tolerate the Black Sea salinity, and limited space for life (below 50 meters there is no oxygen)
Can the jellyfish population (which is exploding now) change the stratification of water layers enough that the highly saline waters from bottom go up, and oxygen goes to the deeper layers, allowing a completely new ecosystem here?
If yes, what are the outcomes of such prospects? Besides the potentially catastrophic release of hydrogen sulphide form the bottom, can it be an improvement for the biodiversity here?