Density and Absolute Salinity of the Baltic Sea 2006–2009

Abstract. The brackish water of the Baltic Sea is a mixture of ocean water from the Atlantic/North Sea with fresh water from various rivers draining a large area of lowlands and mountain ranges. The evaporation-precipitation balance results in an additional but minor excess of fresh water. The rivers carry different loads of salts washed out of the ground, in particular calcium carbonate, which cause a composition anomaly of the salt dissolved in the Baltic Sea in comparison to Standard Seawater. Directly measured seawater density shows a related anomaly when compared to the density computed from the equation of state as a function of Practical Salinity, temperature and pressure. Samples collected from different regions of the Baltic Sea during 2006–2009 were analysed for their density anomaly. The results obtained for the river load deviate significantly from similar measurements carried out forty years ago; the reasons for this decadal variability are not yet fully understood. An empirical formula is derived which estimates Absolute from Practical Salinity of Baltic Sea water, to be used in conjunction with the new Thermodynamic Equation of Seawater 2010 (TEOS-10), endorsed by IOC/UNESCO in June 2009 as the substitute for the 1980 International Equation of State, EOS-80. Our routine measurements of the samples were accompanied by studies of additional selected properties which are reported here: conductivity, density, chloride, bromide and sulphate content, total CO2 and alkalinity.

[1]  Rich Pawlowicz,et al.  A model for predicting changes in the electrical conductivity, practical salinity, and absolute salinity of seawater due to variations in relative chemical composition , 2010 .

[2]  K. Miyagawa,et al.  Numerical implementation and oceanographic application of the thermodynamic potentials of water, vapour, ice, seawater and air – Part 1: Background and equations , 2010 .

[3]  K. Miyagawa,et al.  Numerical implementation and oceanographic application of the thermodynamic potentials of water, vapour, ice, seawater and air – Part 2: The library routines , 2010 .

[4]  T. Lenton,et al.  The coral reef crisis: the critical importance of<350 ppm CO2. , 2009, Marine pollution bulletin.

[5]  S. Comeau,et al.  Impact of ocean acidification on a key Arctic pelagic mollusc ( Limacina helicina ) , 2009 .

[6]  F. Millero,et al.  Precipitation of solid phase calcium carbonates and their effect on application of seawater S A – T – P models , 2009 .

[7]  R. Feistel,et al.  Vertical mixing in the Baltic Sea and consequences for eutrophication - A review , 2009 .

[8]  N. Jones.  Metrology: The new and improved kelvin , 2009, Nature.

[9]  J. F. Waters,et al.  The effect of composition on the density of South Pacific Ocean waters , 2009 .

[10]  A. Omstedt,et al.  Modelling the uptake and release of carbon dioxide in the Baltic Sea surface water , 2009 .

[11]  Frank J. Millero,et al.  An algorithm for estimating Absolute Salinity in the global ocean , 2009 .

[12]  Rainer Feistel,et al.  A Gibbs function for seawater thermodynamics for -6 to 80 °C and salinity up to 120gkg-1 , 2008 .

[13]  Rich Pawlowicz,et al.  Calculating the conductivity of natural waters , 2008 .

[14]  Richard J.C. Brown,et al.  Consistency of practical salinity measurements traceable to primary conductivity standards: Euromet project 918 , 2008 .

[15]  H. Wolf.  Determination of water density: limitations at the uncertainty level of 1 × 10−6 , 2008 .

[16]  R. Feistel,et al.  State and Evolution of the Baltic Sea, 1952–2005 , 2008 .

[17]  J. F. Waters,et al.  The effect of composition on the density of Indian Ocean waters , 2008 .

[18]  D. Nehring,et al.  The Inflow of Highly Saline Water into the Baltic Sea , 2008 .

[19]  D. Nehring,et al.  Nutrient Concentrations, Trends and Their Relation to Eutrophication , 2008 .

[20]  R. Feistel,et al.  BALTIC: Monthly Time Series 1900–2005 , 2008 .

[21]  A. Omstedt,et al.  Distribution, long-term development and mass balance calculation of total alkalinity in the Baltic Sea , 2008 .

[22]  H. Meier.  Modeling the pathways and ages of inflowing salt- and freshwater in the Baltic Sea , 2007 .

[23]  R. Feistel,et al.  A Gibbs–Pitzer function for high-salinity seawater thermodynamics , 2007 .

[24]  F. Millero.  The marine inorganic carbon cycle. , 2007, Chemical reviews.

[25]  J. Sellschopp,et al.  Ventilation of the Baltic Sea deep water: A brief review of present knowledge from observations and models , 2006 .

[26]  F. Millero,et al.  Dissociation constants of carbonic acid in seawater as a function of salinity and temperature , 2006 .

[27]  Hans D. Jensen,et al.  Primary methods for the measurement of electrolytic conductivity , 2003 .

[28]  B. Schneider,et al.  The seasonal cycle of carbon dioxide in Baltic Sea surface waters , 1999 .

[29]  Rainer Feistel,et al.  New shoreline map-drawing data available , 1999 .

[30]  G. Wilhelm,et al.  Recent increase of the calcium concentrations in Baltic Sea waters , 1997 .

[31]  Andrzej Anderko,et al.  Computation of Electrical Conductivity of Multicomponent Aqueous Systems in Wide Concentration and Temperature Ranges , 1997 .

[32]  A. A. Ross,et al.  World ocean circulation experiment. WOCE operations manual. Volume 3. The observational programme. Section 3.1. WOCE hydrographic programme. Part 3.1.3. WHP operations and methods. (revision 1) , 1994 .

[33]  D. Dyrssen.  The Baltic-Kattegat-Skagerrak estuarine system , 1993 .

[34]  A. Stigebrandt,et al.  A time‐dependent budget model for nutrients in the Baltic Sea , 1989 .

[35]  F. Millero,et al.  The density of North Pacific Ocean waters , 1978 .

[36]  Frank J. Millero,et al.  The densities of Baltic Sea waters , 1976 .

[37]  R. Weiss.  Carbon dioxide in water and seawater: the solubility of a non-ideal gas , 1974 .

[38]  K. KREMLING,et al.  New Method for measuring Density of Seawater , 1971, Nature.

[39]  R. Cox,et al.  Sodium, potassium, magnesium, calcium and strontium in sea water , 1966 .

[40]  A. W. Morris,et al.  The bromide/chlorinity and sulphate/chlorinity ratio in sea water , 1966 .

[41]  Bogdan Kwiecinski.  The relation between the chlorinity and the conductivity in Baltic water , 1965 .

[42]  E. Zarins,et al.  Untersuchungen über die Zusammensetzung des Meerwassers im Rigaschen Meerbusen und an der lettländischen Küste des Baltischen Meeres , 1935 .

[43]  Rainer Feistel,et al.  The International Thermodynamic Equation Of Seawater 2010 (TEOS-10): Calculation and Use of Thermodynamic Properties , 2010 .

[44]  T. McDougall,et al.  The composition of Standard Seawater and the definition of the Reference-Composition Salinity Scale , 2008 .

[45]  R. Feistel,et al.  Is Practical Salinity conservative in the Baltic Sea , 2008 .

[46]  L. Anderson,et al.  Recent investigation of total carbonate in the Baltic Sea: changes from the past as a result of acid rain? , 1990 .

[47]  F. Culkin,et al.  Determination of the concentration of potassium chloride solution having the same electrical conductivity, at 15°C and infinite frequency, as standard seawater of salinity 35.0000 ‰ (Chlorinity 19.37394 ‰) , 1980 .

[48]  R. Perkin,et al.  The Practical Salinity Scale 1978: Fitting the data , 1980 .