title: Changes in wintertime pH and hydrography of the Gulf of Finland (Baltic Sea) with focus on depth layers.
abstract: 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.
authors.affiliation: Environmental and Marine Biology, Faculty of Science and Engineering, Åbo Akademi University, Artillerigatan 6, FI-20500, Åbo, Finland. anna-karin.almen@novia.fi.|Novia University of Applied Sciences, Raseborgsvägen 9, FI-10600, Ekenäs, Finland. anna-karin.almen@novia.fi.
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Almén
authors.affiliation: Novia University of Applied Sciences, Raseborgsvägen 9, FI-10600, Ekenäs, Finland.
authors.forename: Olivier
authors.initials: O
authors.lastname: Glippa
authors.affiliation: Finnish Meteorological Institute, P.O. Box 503, FI-00101, Helsinki, Finland.
authors.forename: Heidi
authors.initials: H
authors.lastname: Pettersson
authors.affiliation: Finnish Meteorological Institute, P.O. Box 503, FI-00101, Helsinki, Finland.
authors.forename: Pekka
authors.initials: P
authors.lastname: Alenius
authors.affiliation: Novia University of Applied Sciences, Raseborgsvägen 9, FI-10600, Ekenäs, Finland.
authors.forename: Jonna
authors.initials: J
authors.lastname: Engström-Öst
mesh_terms: D001454:Baltic States; D004784:Environmental Monitoring; D005387:Finland; D006863:Hydrogen-Ion Concentration; D009792:Oceans and Seas; D054712:Salinity; D012623:Seawater / Q000737:chemistry*
keywords: Climate change; Deep-water; Salinity; Temperature; Trends; pH