Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 15, issue 22
Biogeosciences, 15, 6819-6832, 2018
https://doi.org/10.5194/bg-15-6819-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.
Biogeosciences, 15, 6819-6832, 2018
https://doi.org/10.5194/bg-15-6819-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 16 Nov 2018

Research article | 16 Nov 2018

Impact of carbonate saturation on large Caribbean benthic foraminifera assemblages

Ana Martinez1, Laura Hernández-Terrones2, Mario Rebolledo-Vieyra3, and Adina Paytan4 Ana Martinez et al.
  • 1Department of Earth and Planetary Sciences, University of California Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, USA
  • 2Universidad del Caribe, L-1. Mz 1, Esq. Fracc. Tabachines SM 78, Cancún, Quintana Roo, 77528, Mexico
  • 3Chipre 5, Resid. Isla Azul, Cancún, Quintana Roo, 77500, Mexico
  • 4Institute of Marine Science, University of California Santa Cruz, Santa Cruz, CA 95064, USA

Abstract. Increasing atmospheric carbon dioxide and its dissolution in seawater have reduced ocean pH and carbonate ion concentrations, with potential implications on calcifying organisms. To assess the response of large Caribbean benthic foraminifera to low carbonate saturation conditions, we analyzed benthic foraminifers' abundance and relative distribution in surface sediments in proximity to low-carbonate-saturation submarine springs and at adjacent control sites. Our results show that the total abundance of large benthic foraminifera was significantly lower at the low-pH submarine springs than at control sites, although responses were species specific. The relative abundance of high-magnesium, porcelaneous foraminifera was higher than that of hyaline foraminifera at the low-pH springs due to the abundant Archaias angulatus, a chlorophyte-bearing foraminifer, which secretes a large and robust test that is more resilient to dissolution at low-calcite saturation. The different assemblages found at the submarine springs indicate that calcareous symbiont-barren foraminifera are more sensitive to the effects of ocean acidification than agglutinated and symbiont-bearing foraminifera, suggesting that future ocean acidification will likely impact natural benthic foraminifera populations.

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Our study at low-pH submarine springs suggests that ocean acidification may reduce the number of Caribbean benthic foraminifera, particularly those species that form carbonate shells. This may have subsequent repercussions on the global carbon cycle and marine food webs that depend on benthic foraminifera.
Our study at low-pH submarine springs suggests that ocean acidification may reduce the number of...
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