Bodega Marine Laboratory - University of California, Davis, CA, USA.
Bigelow Laboratory for Ocean Sciences, East Boothbay, ME, USA.
Glob Chang Biol. 2021 Jun;27(11):2580-2591. doi: 10.1111/gcb.15594. Epub 2021 Mar 31.
Global-scale ocean acidification has spurred interest in the capacity of seagrass ecosystems to increase seawater pH within crucial shoreline habitats through photosynthetic activity. However, the dynamic variability of the coastal carbonate system has impeded generalization into whether seagrass aerobic metabolism ameliorates low pH on physiologically and ecologically relevant timescales. Here we present results of the most extensive study to date of pH modulation by seagrasses, spanning seven meadows (Zostera marina) and 1000 km of U.S. west coast over 6 years. Amelioration by seagrass ecosystems compared to non-vegetated areas occurred 65% of the time (mean increase 0.07 ± 0.008 SE). Events of continuous elevation in pH within seagrass ecosystems, indicating amelioration of low pH, were longer and of greater magnitude than opposing cases of reduced pH or exacerbation. Sustained elevations in pH of >0.1, comparable to a 30% decrease in [H ], were not restricted only to daylight hours but instead persisted for up to 21 days. Maximal pH elevations occurred in spring and summer during the seagrass growth season, with a tendency for stronger effects in higher latitude meadows. These results indicate that seagrass meadows can locally alleviate low pH conditions for extended periods of time with important implications for the conservation and management of coastal ecosystems.
全球范围的海洋酸化激发了人们的兴趣，即研究通过光合作用，海草生态系统是否有能力在关键的沿海栖息地增加海水 pH 值。然而，海岸碳酸盐系统的动态变化阻碍了人们普遍认识到海草有氧代谢是否能在生理和生态相关的时间尺度上改善低 pH 值。在这里，我们提出了迄今为止对海草调节 pH 值的最广泛研究结果，该研究跨越了美国西海岸的七个海草场（Zostera marina）和 1000 公里，历时 6 年。海草生态系统的改善作用发生在 65%的时间里（平均增加 0.07±0.008 SE），与非植被区域相比。海草生态系统中 pH 值持续升高的事件表明低 pH 值得到了改善，其持续时间和幅度都大于 pH 值降低或恶化的情况。pH 值持续升高>0.1，相当于[H ]降低 30%，不仅限于白天，而是可持续长达 21 天。最大的 pH 值升高发生在春季和夏季海草生长季节，在高纬度的海草场中，这种影响的趋势更为强烈。这些结果表明，海草草地可以在较长时间内局部缓解低 pH 值条件，这对沿海生态系统的保护和管理具有重要意义。
