Wootton J Timothy, Pfister Catherine A, Forester James D
Department of Ecology and Evolution, University of Chicago, 1101 East 57th Street, Chicago, IL 60637, USA.
Proc Natl Acad Sci U S A. 2008 Dec 2;105(48):18848-53. doi: 10.1073/pnas.0810079105. Epub 2008 Nov 24.
Increasing global concentrations of atmospheric CO(2) are predicted to decrease ocean pH, with potentially severe impacts on marine food webs, but empirical data documenting ocean pH over time are limited. In a high-resolution dataset spanning 8 years, pH at a north-temperate coastal site declined with increasing atmospheric CO(2) levels and varied substantially in response to biological processes and physical conditions that fluctuate over multiple time scales. Applying a method to link environmental change to species dynamics via multispecies Markov chain models reveals strong links between in situ benthic species dynamics and variation in ocean pH, with calcareous species generally performing more poorly than noncalcareous species in years with low pH. The models project the long-term consequences of these dynamic changes, which predict substantial shifts in the species dominating the habitat as a consequence of both direct effects of reduced calcification and indirect effects arising from the web of species interactions. Our results indicate that pH decline is proceeding at a more rapid rate than previously predicted in some areas, and that this decline has ecological consequences for near shore benthic ecosystems.
预计全球大气中二氧化碳浓度的增加将导致海洋pH值下降，这可能对海洋食物网产生严重影响，但记录海洋pH值随时间变化的实证数据有限。在一个跨度为8年的高分辨率数据集中，北温带沿海站点的pH值随着大气中二氧化碳水平的升高而下降，并因生物过程和物理条件的变化而有显著差异，这些变化在多个时间尺度上波动。通过多物种马尔可夫链模型应用一种将环境变化与物种动态联系起来的方法，揭示了原位底栖物种动态与海洋pH值变化之间的紧密联系，在低pH值年份，钙质物种的表现通常比非钙质物种更差。这些模型预测了这些动态变化的长期后果，即由于钙化减少的直接影响以及物种相互作用网络产生的间接影响，预测该栖息地中占主导地位的物种将发生重大转变。我们的结果表明，在某些地区，pH值下降的速度比之前预测的要快，而且这种下降对近岸底栖生态系统具有生态影响。
