Relationship between thermohaline and biochemical patterns in the levantine upper and intermediate water masses, Southeastern Mediterranean Sea (2013–2021)

The relationships between the interannual variations of Levantine intermediate water (LIW) core properties and corresponding biochemical in euphotic zone were systematically studied Southeastern Mediterranean during 2013–2021 since 2002 based on a previous study. Salinity temperature fluctuations LIW continue to follow Adriatic–Ionian Bimodal Oscillating System (BiOS) mechanism, with salinity peaks years 2008–2010, 2014–2015, 2018–2019 coinciding periods anticyclonic circulation North Ionian Gyre (NIG). During these periods, transport Atlantic Water into Levant is reduced together out basin. These are superimposed long-term warming trend clearly evident from studies, showing maximal 2018–2019, higher than previously mentioned by ~0.7°C ~0.4°C. enhanced has caused decrease density (sigma) values core, which gave way shallowest record this mass (~110-m depth), bringing it well within lower photic zone. We suggest that level nutrients became available, supporting observed rise intergraded chlorophyll (Chl. ) (0.89 mg m ?2 year ?1 ), maximum recorded 2018–2019. mixed layer depths shows no significant change; thus, uplift winter mixing cannot support integrated Chl. . Additional biological parameters specific pico-phytoplankton populations bacterial production abundance measured 2013–2021, but measurements too sparse clear dynamics. Yet significantly average levels for primary abundances period (as ). combined impacts BiOS mechanism global warming, hence increase residence time buoyancy, may impact producers’ biomass at This latter feedback slightly counter oligotrophication due stratification.