Physiological and ecological performance differs in four coral taxa at a volcanic carbon dioxide seep.
Around volcanic carbon dioxide (CO2) seeps in Papua New Guinea, partial pressures of CO2 (pCO2) approximate those as predicted for the end of this century, and coral communities have low diversity and low structural complexity. To assess the mechanisms for such community shifts in response to ocean acidification, we examined the physiological performance of two hard corals that occur with increased or unaltered abundance at a seep site (mean pHTotal=7.8, pCO2=862 μatm) compared to a control site (mean pHTotal=8.1, pCO2=323 μatm), namely massive Porites spp. and Pocillopora damicornis, and two species with reduced abundance, Acropora millepora and Seriatopora hystrix. Oxygen fluxes, calcification, and skeletal densities were analyzed in corals originating from the seep and control site. Net photosynthesis rates increased considerably in Porites spp. and A. millepora and slightly in P. damicornis at increased pCO2, but remained unaltered in S. hystrix. Dark respiration rates remained constant in all corals investigated from both sites. Rates of light calcification declined in S. hystrix at high pCO2, but were unaffected by pCO2 in the other three coral taxa. Dark and net calcification rates remained unchanged in massive Porites and P. damicornis, but were drastically reduced at high pCO2 in A. millepora and S. hystrix. However, skeletal densities were similar at both seep and control sites in all coral taxa investigated. Our data suggest that the pCO2-tolerant corals were characterized by an increased ability to acclimatize to ocean acidification, e.g. by maintaining net calcification. Thus, robust corals, such as Porites spp. and P. damicornis, are more likely to persist for longer in a future high pCO2 world than those unable to acclimatize.
Australian Institute of Marine Science, PMB 3, Townsville MC, 4810 QLD, Australia. Electronic address: j.strahl@aims.gov.au.
J
J
Strahl
Carl von Ossietzky University of Oldenburg, Ammerländer Heerstr. 114-118, 26129 Oldenburg, Germany.
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I
Stolz
Australian Institute of Marine Science, PMB 3, Townsville MC, 4810 QLD, Australia.
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S
Uthicke
Australian Institute of Marine Science, PMB 3, Townsville MC, 4810 QLD, Australia; Leibniz Center for Tropical Marine Ecology, Fahrenheitstr. 6, 28359 Bremen, Germany; Faculty of Biology and Chemistry (FB 2), University of Bremen, 28359 Bremen, Germany.
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N
Vogel
Australian Institute of Marine Science, PMB 3, Townsville MC, 4810 QLD, Australia.
S H C
SH
Noonan
Australian Institute of Marine Science, PMB 3, Townsville MC, 4810 QLD, Australia.
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KE
Fabricius
D000818:Animals; D037421:Anthozoa / Q000502:physiology*; D002245:Carbon Dioxide / Q000378:metabolism*; D004463:Ecology; D018707:Volcanic Eruptions
D002245:Carbon Dioxide
Calcification; Ocean acidification; Photosynthesis; Respiration; Scleractinia; Volcanic carbon dioxide seep