TY - JOUR

T1 - Dynamics of Hypoxic Zones in the Baltic Sea in the Late XX–Early XXI Century

AU - Litina, E. N.

AU - Zakharchuk, E. A.

AU - Tikhonova, N. A.

PY - 2020/5/1

Y1 - 2020/5/1

N2 - Abstract: The data of shipboard measurements of oxygen concentration at international monitoring stations in the Baltic Sea were used to assess the year-to-year variations of oxygen regime in the late XX–early XXI century (1989–2017). The obtained results were compared with similar studies in 1951–1988. The water areas with hypoxic conditions were found to increase as well as their vertical development. The deterioration of oxygen regime was most considerable in the Gulf of Finland. While in the previous 30 years (1959–1988), hypoxic conditions were recorded only in the western part of the gulf and not in all years, since 1993, hypoxic zones were recorded here every year, developing eastward and appearing more and more often in its central and eastern parts. The analysis of variations of temperature and salinity revealed an increase in the difference between seawater densities in the surface and bottom layers of the Baltic Sea. An assumption was made that the deterioration of the oxygen regime in the Baltic Sea in the recent decades could be due to a stronger stratification of sea water masses.

AB - Abstract: The data of shipboard measurements of oxygen concentration at international monitoring stations in the Baltic Sea were used to assess the year-to-year variations of oxygen regime in the late XX–early XXI century (1989–2017). The obtained results were compared with similar studies in 1951–1988. The water areas with hypoxic conditions were found to increase as well as their vertical development. The deterioration of oxygen regime was most considerable in the Gulf of Finland. While in the previous 30 years (1959–1988), hypoxic conditions were recorded only in the western part of the gulf and not in all years, since 1993, hypoxic zones were recorded here every year, developing eastward and appearing more and more often in its central and eastern parts. The analysis of variations of temperature and salinity revealed an increase in the difference between seawater densities in the surface and bottom layers of the Baltic Sea. An assumption was made that the deterioration of the oxygen regime in the Baltic Sea in the recent decades could be due to a stronger stratification of sea water masses.

KW - hypoxic conditions

KW - quantile analysis

KW - stratification

KW - the Baltic Sea

KW - year-to-year variations

UR - http://www.scopus.com/inward/record.url?scp=85085321714&partnerID=8YFLogxK

U2 - 10.1134/S0097807820030082

DO - 10.1134/S0097807820030082

M3 - Article

AN - SCOPUS:85085321714

VL - 47

SP - 478

EP - 485

JO - Water Resources

JF - Water Resources

SN - 0097-8078

IS - 3

ER -