MEPS 511:297-302 (2014)  -  DOI: https://doi.org/10.3354/meps10912

NOTE
Ocean acidification rapidly reduces dinitrogen fixation associated with the hermatypic coral Seriatopora hystrix

Nils Rädecker1,2*, Friedrich W. Meyer1, Vanessa N. Bednarz1, Ulisse Cardini1, Christian Wild1,2

1Leibniz Center for Tropical Marine Ecology (ZMT), Fahrenheitstr. 6, 28359 Bremen, Germany
2Faculty of Biology and Chemistry (FB2), PO Box 330440, University of Bremen, 28334 Bremen, Germany
*Corresponding author:

ABSTRACT: Since productivity and growth of coral-associated dinoflagellate algae is nitrogen (N)-limited, dinitrogen (N2) fixation by coral-associated microbes is likely crucial for maintaining the coral-dinoflagellate symbiosis. It is thus essential to understand the effects future climate change will have on N2 fixation by the coral holobiont. This laboratory study is the first to investigate short-term effects of ocean acidification on N2 fixation activity associated with the tropical, hermatypic coral Seriatopora hystrix using the acetylene reduction assay in combination with calcification measurements. Findings reveal that simulated ocean acidification ( pCO2 1080 µatm) caused a rapid and significant decrease (53%) in N2 fixation rates associated with S. hystrix compared to the present day scenario ( pCO2 486 µatm). In addition, N2 fixation associated with the coral holobiont showed a positive exponential relationship with its calcification rates. This suggests that even small declines in calcification rates of hermatypic corals under high CO2 conditions may result in decreased N2 fixation activity, since these 2 processes may compete for energy in the coral holobiont. Ultimately, an intensified N limitation in combination with a decline in skeletal growth may trigger a negative feedback loop on coral productivity exacerbating the negative long-term effects of ocean acidification. 


KEY WORDS: Acetylene reduction assay · Nutrient limitation · Carbon fixation · Calcification · Coral holobiont


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Cite this article as: Rädecker N, Meyer FW, Bednarz VN, Cardini U, Wild C (2014) Ocean acidification rapidly reduces dinitrogen fixation associated with the hermatypic coral Seriatopora hystrix. Mar Ecol Prog Ser 511:297-302. https://doi.org/10.3354/meps10912

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