Ocean acidification limits temperature-induced poleward expansion of coral habitats around Japan

[摘要] Using results from four coupled global carbon cycle-climate models combinedwith in situ observations, we estimate the effects of future global warmingand ocean acidification on potential habitats for tropical/subtropical andtemperate coral communities in the seas around Japan. The suitability ofcoral habitats is classified on the basis of the currently observed regionalranges for temperature and saturation states with regard to aragonite(Ω_arag). We find that, under the "business as usual" SRES A2scenario, coral habitats are projected to expand northward by severalhundred kilometers by the end of this century. At the same time, coralhabitats are projected to become sandwiched between regions where thefrequency of coral bleaching will increase, and regions where Ω_arag will become too low to support sufficiently high calcificationrates. As a result, the habitat suitable for tropical/subtropical coralsaround Japan may be reduced by half by the 2020s to 2030s, and is projectedto disappear by the 2030s to 2040s. The habitat suitable for the temperatecoral communities is also projected to decrease, although at a lesspronounced rate, due to the higher tolerance of temperate corals for lowΩ_arag. Our study has two important caveats: first, it does notconsider the potential adaptation of the coral communities, which wouldpermit them to colonize habitats that are outside their current range.Second, it also does not consider whether or not coral communities canmigrate quickly enough to actually occupy newly emerging habitats. As such,our results serve as a baseline for the assessment of the future evolutionof coral habitats, but the consideration of important biological andecological factors and feedbacks will be required to make more accurateprojections.

[学科分类] 地球化学与岩石