Ocean acidification may increase calcification rates, but at a cost

Ocean acidification is the lowering of pH in the oceans as a result of increasing uptake of atmospheric carbon dioxide. Carbon dioxide is entering the oceans at a greater rate than ever before, reducing the ocean's natural buffering capacity and lowering pH. Previous work on the biological consequences of ocean acidification has suggested that calcification and metabolic processes are compromised in acidified seawater. By contrast, here we show, using the ophiuroid brittlestar Amphiura filiformis as a model calcifying organism, that some organisms can increase the rates of many of their biological processes (in this case, metabolism and the ability to calcify to compensate for increased seawater acidity). However, this upregulation of metabolism and calcification, potentially ameliorating some of the effects of increased acidity comes at a substantial cost (muscle wastage) and is therefore unlikely to be sustainable in the long term.

[1]  H. Thornton,et al.  Effect of increased atmospheric CO2 on shallow water marine benthos , 2005 .

[2]  T. Bowner.  Reproduction in Amphiura filiformis (Echinodermata: Ophiuroidea): Seasonality in gonad development , 1982 .

[3]  Yanzhen Fan,et al.  A new ratiometric, planar fluorosensor for measuring high resolution, two-dimensional pCO2 distributions in marine sediments , 2006 .

[4]  J. Lawton,et al.  Organisms as ecosystem engineers , 1994 .

[5]  J. Woodley.  The behaviour of some amphiur1d Brittle-Stars , 1975 .

[6]  H. Pörtner,et al.  Effects of long-term acclimation to environmental hypercapnia on extracellular acid–base status and metabolic capacity in Mediterranean fish Sparus aurata , 2007 .

[7]  H. Pörtner,et al.  Effects of long-term moderate hypercapnia on acid-base balance and growth rate in marine mussels (Mytilus galloprovincialis) , 2005 .

[8]  S. V. Smith,et al.  Measurement of community metabolism and significance in the coral reef CO2 source-sink debate. , 1999, Proceedings of the National Academy of Sciences of the United States of America.

[9]  M. Sköld,et al.  Passive suspension feeding in Amphiura filiformis (Echinodermata: Ophiuroidea): Feeding behaviour in flume flow and potential feeding rate of field populations , 1996 .

[10]  P. B. Duffy,et al.  Anthropogenic carbon and ocean pH , 2001 .

[11]  H. Pörtner,et al.  Biological Impact of Elevated Ocean CO2 Concentrations: Lessons from Animal Physiology and Earth History , 2004 .

[12]  E. Maier‐Reimer,et al.  Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms , 2005, Nature.

[13]  M. Thorndyke,et al.  Regenerative response and endocrine disrupters in crinoid echinoderms: arm regeneration in Antedon mediterranea after experimental exposure to polychlorinated biphenyls. , 2001, The Journal of experimental biology.

[14]  Richard A. Feely,et al.  Impact of Anthropogenic CO2 on the CaCO3 System in the Oceans , 2004, Science.

[15]  C. Heip,et al.  Impact of elevated CO 2 on shellfish calcification , 2007 .

[16]  C. Heip,et al.  Impact of elevated CO2 on shellfish calcification , 2007 .

[17]  R. Kennedy,et al.  Destruction of conspecific bioturbation structures by Amphiura filiformis (Ophiuroida): evidence from luminophore tracers and in situ time-lapse sediment-profile imagery , 2006 .

[18]  Basile Michaelidis,et al.  Synergistic effects of temperature extremes, hypoxia, and increases in CO2 on marine animals: From Earth history to global change , 2005 .

[19]  J. Hall‐Spencer,et al.  Effects of anthropogenic seawater acidification on acid-base balance in the sea urchin Psammechinus miliaris. , 2007, Marine pollution bulletin.

[20]  U. Siegenthaler,et al.  Atmospheric carbon dioxide and the ocean , 1993, Nature.

[21]  I. Bowen,et al.  A methacrylate embedding technique for combined autoradiography and acid phosphatase histochemistry , 1985, The Histochemical Journal.

[22]  M. C. Thorndyke,et al.  Afuni, a novel transforming growth factor-β gene is involved in arm regeneration by the brittle star Amphiura filiformis , 2005, Development Genes and Evolution.

[23]  S. Widdicombe,et al.  Impact of CO2-induced seawater acidification on the burrowing activity of Nereis virens and sediment nutrient flux , 2007 .

[24]  J. Spicer,et al.  Does the development of respiratory regulation always accompany the transition from pelagic larvae to benthic fossorial postlarvae in the Norway lobster Nephrops norvegicus (L.) , 2003 .

[25]  R. Rosenberg,et al.  Effect of the brittle star Amphiura filiformis (Amphiuridae, Echinodermata) on oxygen flux into the sediment , 2003 .

[26]  D. Wolf-Gladrow,et al.  CO2 in Seawater: Equilibrium, Kinetics, Isotopes , 2001 .

[27]  K. Caldeira,et al.  Oceanography: Anthropogenic carbon and ocean pH , 2003, Nature.

[28]  B. Keegan,et al.  Field survey of the occurrence and significance of regeneration in Amphiura filiformis (Echinodermata: Ophiuroidea) from Galway Bay, west coast of Ireland , 1983 .