Marine Biology

, Volume 160, Issue 8, pp 1875–1888 | Cite as

Future ocean acidification will be amplified by hypoxia in coastal habitats

  • Frank MelznerEmail author
  • Jörn Thomsen
  • Wolfgang Koeve
  • Andreas Oschlies
  • Magdalena A. Gutowska
  • Hermann W. Bange
  • Hans Peter Hansen
  • Arne Körtzinger
Original Paper


Ocean acidification is elicited by anthropogenic carbon dioxide emissions and resulting oceanic uptake of excess CO2 and might constitute an abiotic stressor powerful enough to alter marine ecosystem structures. For surface waters in gas-exchange equilibrium with the atmosphere, models suggest increases in CO2 partial pressure (pCO2) from current values of ca. 390 μatm to ca. 700–1,000 μatm by the end of the century. However, in typically unequilibrated coastal hypoxic regions, much higher pCO2 values can be expected, as heterotrophic degradation of organic material is necessarily related to the production of CO2 (i.e., dissolved inorganic carbon). Here, we provide data and estimates that, even under current conditions, maximum pCO2 values of 1,700–3,200 μatm can easily be reached when all oxygen is consumed at salinities between 35 and 20, respectively. Due to the nonlinear nature of the carbonate system, the approximate doubling of seawater pCO2 in surface waters due to ocean acidification will most strongly affect coastal hypoxic zones as pCO2 during hypoxia will increase proportionally: we calculate maximum pCO2 values of ca. 4,500 μatm at a salinity of 20 (T = 10 °C) and ca. 3,400 μatm at a salinity of 35 (T = 10 °C) when all oxygen is consumed. Upwelling processes can bring these CO2-enriched waters in contact with shallow water ecosystems and may then affect species performance there as well. We conclude that (1) combined stressor experiments (pCO2 and pO2) are largely missing at the moment and that (2) coastal ocean acidification experimental designs need to be closely adjusted to carbonate system variability within the specific habitat. In general, the worldwide spread of coastal hypoxic zones also simultaneously is a spread of CO2-enriched zones. The magnitude of expected changes in pCO2 in these regions indicates that coastal systems may be more endangered by future global climate change than previously thought.


Hemocyte Ocean Acidification High pCO2 Elevated pCO2 Hypoxic Zone 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



F. Melzner and A. Körtzinger were supported by the DFG Excellence Cluster project ‘Future Ocean’ CP0816: ‘Carbonate system variability in Kiel Bay’; F. Melzner, M.A. Gutowska, W. Koeve and A. Oschlies are supported by the German National Project ‘Biological impacts of ocean acidification (BIOACID)’, funded by BMBF. The Boknis Eck Time Series Station (BE) is operated by the Chemical Oceanography department at IFM-GEOMAR: The authors would like to thank the crew of FK ‘Littorina’ and all researchers and students involved in the BE data collection efforts between 1986 and 1995, especially G. Behrends, H. Giesenhagen, U. Horstmann and H. Johansen. Between 1985 and 1992, BE was funded by BMFT project 03F0547A (‘Biologisches Monitoring der Ostsee’) and between 1993 and 1996 by BMFT project 03F0166A (‘Kieler Bucht Projekt’).


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Copyright information

© Springer-Verlag 2012

Authors and Affiliations

  • Frank Melzner
    • 1
    Email author
  • Jörn Thomsen
    • 1
  • Wolfgang Koeve
    • 2
  • Andreas Oschlies
    • 2
  • Magdalena A. Gutowska
    • 3
  • Hermann W. Bange
    • 4
  • Hans Peter Hansen
    • 4
  • Arne Körtzinger
    • 4
  1. 1.Marine EcologyHelmholtz Centre for Ocean Research (GEOMAR)KielGermany
  2. 2.Biogeochemical ModellingHelmholtz Centre for Ocean Research (GEOMAR)KielGermany
  3. 3.Biological OceanographyHelmholtz Centre for Ocean Research (GEOMAR)KielGermany
  4. 4.Chemical OceanographyHelmholtz Centre for Ocean Research (GEOMAR)KielGermany

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