Ocean acidification increases phytobenthic carbon fixation and export in a warm-temperate system
Ocean acidification increases phytobenthic carbon fixation and export in a warm-temperate system
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DOI：
10.1016/j.ecss.2020.107113
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发表时间：
2021-03-05
影响因子：
2.8
通讯作者：
Hall-Spencer，Jason M.
中科院分区：
文献类型：
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作者：
Wada，Shigeki;Agostini，Sylvain;Hall-Spencer，Jason M.
光合生物对CO2浓度升高的响应是海洋酸化研究中的一个重要课题。这一领域的大部分工作都集中在缺乏生态现实主义的实验室条件下的生理反应。利用渗漏作为海洋酸化的天然模拟物的研究表明，藻类群落组成发生了变化，但二氧化碳对碳固定和输出的影响仍不清楚。在这里，我们部署了人工基质在日本的暖温带地区收集藻类群落使用的CO2渗漏关闭志根岛。硅藻成为占主导地位的解决substrata在地区的CO2水平升高，而大型藻类占主导地位，在当今的CO2水平（参考网站）。这是支持的色素成分;岩藻黄质含量，硅藻的特点，是较高的高CO2网站，而更多的叶绿素b，这是绿藻门的特点，被发现在参考网站。在高浓度CO2的水体中生长的藻类群落光合作用速率提高。藻类生物量是相似的所有结算面板，无论CO2浓度。藻类在高CO2条件下固定的大部分碳都被输出了，可能是由于从底层分离。在高CO2条件下占主导地位的硅藻更容易被运走，因为它们没有固定物，而新定居的大型藻类在当今的CO2水平下变得牢固。这些结果表明，海洋酸化可能会从根本上改变沿海碳循环，增加光合作用和碳出口的沿海生态系统在暖温带海洋地理区域，由于在群落组成的转变，从多年生短命藻类。
The response of photosynthetic organisms to rising CO2levels is a key topic in ocean acidification research. Most of the work in this field has focused on physiological responses in laboratory conditions which lack ecological realism. Studies using seeps as natural analogues for ocean acidification have demonstrated shifts in algal community composition, but the effect of CO2on carbon fixation and export remains unclear. Here, we deployed artificial substrata in a warm-temperate region of Japan to collect algal communities using a CO2seep off Shikine Island. Diatoms became dominant on settlement substrata in areas with elevated CO2levels, whereas macroalgae dominated at present-day levels of CO2(reference site). This was supported by pigment composition; fucoxanthin content, characteristic of diatoms, was higher at the high CO2site, while more Chlorophyllb,which is characteristic of Chlorophyta, was found in the reference site. Algal communities that recruited in water with high levels of CO2had elevated rates of photosynthesis. Algal biomass was similar on all settlement panels, regardless of CO2concentration. Much of the carbon that was fixed by algae in the high CO2conditions was exported, likely due to detachment from the substratum. Diatoms that dominated under high CO2conditions are more easily transported away as they have no holdfast, whereas newly settled macroalgae became firmly attached at present-day levels of CO2. These results show that ocean acidification may fundamentally alter coastal carbon cycling, increasing photosynthesis and carbon export from coastal ecosystems in warm-temperate biogeographic regions due to a shift in community composition from perennial to ephemeral algae.