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

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

Full text in pdf format

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 Export citation Share:    Facebook - - linkedIn