Decline in growth of foraminifer Marginopora rossi under eutrophication and ocean acidification scenarios

TitleDecline in growth of foraminifer Marginopora rossi under eutrophication and ocean acidification scenarios
Publication TypeJournal Article
Year of Publication2013
AuthorsReymond CE, Lloyd A, Kline DI, Dove SG, Pandolfi JM
JournalGlobal Change Biology
Date Published2013/01
Type of ArticleReview
ISBN Number1354-1013
Accession NumberWOS:000312155100025
Keywordsamphistegina-lobifera; bearing benthic foraminifera; biomineralization; calcite; coral calcification; eutrophication; foraminiferal physiology; great-barrier-reef; high-Mg; inorganic carbon; intracellular ph; larger foraminifera; nutrients; ocean acidification; planktonic-foraminifera; reduced calcification; water column

The combination of global and local stressors is leading to a decline in coral reef health globally. In the case of eutrophication, increased concentrations of dissolved inorganic nitrogen (DIN) and phosphorus (DIP) are largely attributed to local land use changes. From the global perspective, increased atmospheric CO2 levels are not only contributing to global warming but also ocean acidification (OA). Both eutrophication and OA have serious implications for calcium carbonate production and dissolution among calcifying organisms. In particular, benthic foraminifera precipitate the most soluble form of mineral calcium carbonate (high-Mg calcite), potentially making them more sensitive to dissolution. In this study, a manipulative orthogonal two-factor experiment was conducted to test the effects of dissolved inorganic nutrients and OA on the growth, respiration and photophysiology of the large photosymbiont-bearing benthic foraminifer, Marginopora rossi. This study found the growth rate of M. rossi was inhibited by the interaction of eutrophication and acidification. The relationship between M. rossi and its photosymbionts became destabilized due to the photosymbiont's release from nutrient limitation in the nitrate-enriched treatment, as shown by an increase in zooxanthellae cells per host surface area. Foraminifers from the OA treatments had an increased amount of Chl a per cell, suggesting a greater potential to harvest light energy, however, there was no net benefit to the foraminifer growth. Overall, this study demonstrates that the impacts of OA and eutrophication are dose dependent and interactive. This research indicates an OA threshold at pH 7.6, alone or in combination with eutrophication, will lead to a decline in M. rossi calcification. The decline in foraminifera calcification associated with pollution and OA will have broad ecological implications across their ubiquitous range and suggests that without mitigation it could have serious implications for the future of coral reefs.

Short TitleGlob. Change Biol.
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