[Coral-List] High pCO2 and calcification in the far distant past

[Katharina Fabricius]

Hi all,

following up on the topic of carbonate saturation, this week we've published a paper on high pCO2 and calcification in the present - and probably in the not too far distant future - in Nature Climate Change. It is based on an ongoing AIMS study around cool volcanic CO2 seeps in PNG. The journal is new so most libraries don't have it yet. That's why I'm posting it here, since the issue of ocean acidification is urgent. I am happy to send out reprints. 

The abstract is: Experiments have shown that ocean acidification due to rising atmospheric carbon dioxide concentrations has deleterious effects on the performance of many marine organisms. However, few empirical or modelling studies have addressed the long-term consequences of ocean acidification for marine ecosystems. Here we show that as pH declines from pH 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750 ppm, consistent with some scenarios for the end of this century) some organisms benefit but many more lose out. We investigated coral reefs, seagrasses and sediments that are acclimatized to low pH at three cool and shallow volcanic carbon dioxide seeps in Papua New Guinea. At reduced pH, we observed reductions in coral diversity, recruitment and abundances of structurally complex framework builders, and shifts in competitive interactions between taxa. However, coral cover remained constant between pH 8.1 and ~7.8, because massive Porites corals established dominance over structurally complex corals, despite low rates of calcification. Reef development ceased below pH 7.7. Our empirical data from this unique field setting confirm model predictions that ocean acidification, together with temperature stress, will probably lead to severely reduced diversity, structural complexity and resilience of Indo-Pacific coral reefs within this century.

The link to the original article is
http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate1122.html

And there is a clip on Youtube showing the reefs exposed to CO2 bubbles:
http://www.youtube.com/watch?v=15isE36esMM


Regards
Katharina Fabricius

Reference: Fabricius KE, Langdon C, Uthicke S, Humphrey C, Noonan S, De’ath G, Okazaki R, Muehllehner N, Glas M, Lough JM (2011) Losers and winners in coral reefs acclimatized to elevated carbon dioxide concentrations. Nature Climate Change 1: 165-169 


-----------------------------------------
Dr. Katharina Fabricius
Principal Research Scientist
Australian Institute of Marine Science (AIMS)
Mail: AIMS, PMB 3, Townsville Q4810, Australia

Phone: +61 -7 4753 4412, or 4758 1747
Fax: +61 -7 4772 5852
Email: k.fabricius at aims.gov.au

   


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