Natural and medical sciences

2020 Issue №4

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Chlorophyll «a» concentration in the South-Eastern Baltic Sea in summer 2018 (on satellite data)



The study focuses on chlorophyll "a"concentration variability in the South-Eastern part of the Baltic sea in summer 2018. The data of the MODIS radiometer installed on Aqua and Terra satellites were used for the analysis. The average concentration of chlorophyll "a" in the warm period of 2018 (May-August) was 3.8 mg/m3 while the average sea surface temperature was 17.7° С. The Maximum concentration of chlorophyll "a" (8.1 mg/m3) was rec­orded in May. However, the most massive development of phytoplankton oc­curred in July — the average monthly concentration of chlorophyll "a" was the highest and exceeded 4.2 mg/m3. August was the warmest month, when the peak sea surface temperature (24.7° С) was observed, and the average monthly temperature reached 21.8° С, which is higher than the average annu­al value for August (2.8° С). Thus chlorophyll "a" concentration for the peri­od under study was revealed at the average multiyear level, and the sea sur­face temperature was higher than the average for 2003—2016 by 2.4° С. The direct influence of the weather anomaly of 2018, which caused the water warming above the long-term average level, on the monthly average concen­trations of chlorophyll “a” was not revealed, that indicates a sustainable state and strength of the south-eastern Baltic Sea ecosystem towards the variability of environmental conditions over several years.