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Benthic marine calcifiers coexist with CaCO 3 ‐undersaturated seawater worldwide
Author(s) -
Lebrato M.,
Andersson A. J.,
Ries J. B.,
Aronson R. B.,
Lamare M. D.,
Koeve W.,
Oschlies A.,
IglesiasRodriguez M. D.,
Thatje S.,
Amsler M.,
Vos S. C.,
Jones D. O. B.,
Ruhl H. A.,
Gates A. R.,
McClintock J. B.
Publication year - 2016
Publication title -
global biogeochemical cycles
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.512
H-Index - 187
eISSN - 1944-9224
pISSN - 0886-6236
DOI - 10.1002/2015gb005260
Subject(s) - seawater , benthic zone , ocean acidification , calcite , oceanography , benthos , saturation (graph theory) , carbonate , calcium carbonate , environmental science , environmental chemistry , geology , mineralogy , chemistry , mathematics , organic chemistry , combinatorics
Ocean acidification and decreasing seawater saturation state with respect to calcium carbonate (CaCO 3 ) minerals have raised concerns about the consequences to marine organisms that build CaCO 3 structures. A large proportion of benthic marine calcifiers incorporate Mg 2+ into their skeletons (Mg‐calcite), which, in general, reduces mineral stability. The relative vulnerability of some marine calcifiers to ocean acidification appears linked to the relative solubility of their shell or skeletal mineralogy, although some organisms have sophisticated mechanisms for constructing and maintaining their CaCO 3 structures causing deviation from this dependence. Nevertheless, few studies consider seawater saturation state with respect to the actual Mg‐calcite mineralogy (Ω Mg‐ x ) of a species when evaluating the effect of ocean acidification on that species. Here, a global dataset of skeletal mole % MgCO 3 of benthic calcifiers and in situ environmental conditions spanning a depth range of 0 m (subtidal/neritic) to 5600 m (abyssal) was assembled to calculate in situ Ω Mg‐ x . This analysis shows that 24% of the studied benthic calcifiers currently experience seawater mineral undersaturation (Ω Mg‐ x < 1). As a result of ongoing anthropogenic ocean acidification over the next 200 to 3000 years, the predicted decrease in seawater mineral saturation will expose approximately 57% of all studied benthic calcifying species to seawater undersaturation. These observations reveal a surprisingly high proportion of benthic marine calcifiers exposed to seawater that is undersaturated with respect to their skeletal mineralogy, underscoring the importance of using species‐specific seawater mineral saturation states when investigating the impact of CO 2 ‐induced ocean acidification on benthic marine calcification.