A concentration basin has a higher salinity than the outer ocean due to evaporation, and its water exchange consists of inflow of the fresher oceanic water in the upper layer and outflow of the saltier mediterranean water in the lower layer of the connecting channel.
The Eurafrican Mediterranean Sea is also a concentration basin as a whole, but the Black Sea and the Adriatic Sea are dilution basins (see below) owing to the Danube, Don, and Dnieper Rivers and the Po River respectively.
Dilution basin
A dilution basin has a lower salinity due to freshwater gains such as rainfall and rivers, and its water exchange consists of outflow of the fresher mediterranean water in the upper layer and inflow of the saltier oceanic water in the lower layer of the channel. Renewal of deep water may not be sufficient to supply oxygen to the bottom.
Having shallow channels and deep basins, the Sea of Japan could form a mediterranean sea, but the strong currents from the Pacific prevent it from having an independent water circulation.
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Kämpf, Jochen (2010). "5.5.2: Mediterranean Seas". Advanced Ocean Modelling: Using Open-Source Software. Heidelberg: Springer Science & Business Media. p. 138. ISBN9783642106101. Retrieved 2017-09-05. Mediterranean seas of the Indian Ocean are the Persian Gulf and the Red Sea, and the Australasian Mediterranean Sea, including the Banda, Sulu, Sulawesi and Java Seas, being connected with the Pacific Ocean.
^Tang, Charles C. L; Ross, Charles K.; Yao, Tom; Petrie, Brian; DeTracey, Brendan M.; Dunlap, Ewa (2004-12-01). "The circulation, water masses and sea-ice of Baffin Bay". Progress in Oceanography. 63 (4): 183–228. Bibcode:2004PrOce..63..183T. doi:10.1016/j.pocean.2004.09.005. ISSN0079-6611. "Baffin Bay is a mediterranean sea connected through restrictive straits to the Arctic Ocean and the Labrador Sea/Atlantic Ocean"