Changes in wintertime pH and hydrography of the Gulf of Finland (Baltic Sea) with focus on depth layers

  • Anna-Karin AlménEmail author
  • Olivier Glippa
  • Heidi Pettersson
  • Pekka Alenius
  • Jonna Engström-Öst


We studied changes in sea water pH, temperature and salinity with focus on two depth layers, along the Gulf of Finland (the Baltic Sea) using long-term monitoring data from 1979 to 2015. Data from the most frequently sampled monitoring stations between western and eastern Gulf of Finland were used. The main result of the study reveals that pH has decreased both in surface and deep-water in the western Gulf of Finland with values ranging between −0.005 and −0.008 units year−1. We also demonstrate a rise in temperature (~2 °C) and decrease in salinity (~−0.7 g kg−1) at several stations over the last 36 years. In general, the changes are shown to be more pronounced in the western part of the gulf. This paper also stresses the importance of improving the sampling frequency and quality of monitoring measurements.


pH Trends Deep-water Climate change Salinity Temperature 



This work would not have been possible without people involved in the sampling campaigns and we would like to thank them. We also would like to acknowledge Kirsi Järvenmäki, Marja Kauppi, Mirja Leivuori, Maarit Matilainen, Teemu Näykki, Riikka Pöntinen, Mika Raateoja, Maarit Risto, Mika Sarkkinen, Kimmo Tikka and Pentti Välipakka for their help with the methodology as well as Andreas Lindén for statistical advices. The study was supported by the Academy of Finland (project nr. 276947) and Victoriastiftelsen.


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Copyright information

© Springer International Publishing Switzerland 2017

Authors and Affiliations

  • Anna-Karin Almén
    • 1
    • 2
    Email author
  • Olivier Glippa
    • 2
  • Heidi Pettersson
    • 3
  • Pekka Alenius
    • 3
  • Jonna Engström-Öst
    • 2
  1. 1.Environmental and Marine Biology, Faculty of Science and EngineeringÅbo Akademi UniversityÅboFinland
  2. 2.Novia University of Applied SciencesEkenäsFinland
  3. 3.Finnish Meteorological InstituteHelsinkiFinland

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