In situ changes of tropical crustose coralline algae along carbon dioxide gradients.
In situ changes of tropical crustose coralline algae along carbon dioxide gradients.
复制标题
热带壳状珊瑚藻沿二氧化碳梯度的原位变化。
DOI：
10.1038/srep09537
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发表时间：
2015-04-02
影响因子：
4.6
通讯作者：
De'ath G
中科院分区：
文献类型：
--
作者：
Fabricius KE;Kluibenschedl A;Harrington L;Noonan S;De'ath G
壳状珊瑚藻在珊瑚礁中具有重要的生态功能，包括稳定礁体骨架和诱导幼体定居。为了原位调查高二氧化碳对CCA群落的影响，我们在巴布亚新几内亚沿着pH值从8.1到7.4的梯度上，在三个热带火山CO2渗漏处部署了定居瓦片。在部署5个月和13个月后，在pH值7.8（660 μatm pCO2）附近，从CCA存在到不存在有一个陡峭的过渡：98%的瓦片在pH值> 7.8时有CCA，而只有20%的瓦片在pH值≤ 7.8时有CCA。 随着pH值从8.0下降到7.8，最不敏感和最敏感的CCA物种分别失去了43%和85%的覆盖。社区向上面临的表面暴露于强光和高放牧压力表现出较低的陡峭的损失比那些在阴影表面低放牧。CO2对早期生命阶段的直接影响是决定CCA覆盖的主要机制，而不是与其他底栖动物群体的竞争性相互作用。重要的是，在接近环境pH值的情况下，下降幅度最大，这表明由于最近海水pH值下降了0.1个单位，CCA的丰度可能已经下降，随着海洋酸化的加剧，未来可能会出现严重的损失。
Crustose coralline algae (CCA) fulfill important ecosystem functions in coral reefs, including reef framework stabilization and induction of larval settlement. To investigate in situ the effects of high carbon dioxide on CCA communities, we deployed settlement tiles at three tropical volcanic CO2 seeps in Papua New Guinea along gradients spanning from 8.1 to 7.4 pH. After 5 and 13 months deployment, there was a steep transition from CCA presence to absence around pH 7.8 (660 μatm pCO2): 98% of tiles had CCA at pH > 7.8, whereas only 20% of tiles had CCA at pH ≤ 7.8. As pH declined from 8.0 to 7.8, the least and most sensitive CCA species lost 43% and 85% of cover, respectively. Communities on upward facing surfaces exposed to high light and high grazing pressure showed less steep losses than those on shaded surfaces with low grazing. Direct CO2 effects on early life stages were the main mechanisms determining CCA cover, rather than competitive interactions with other benthic groups. Importantly, declines were steepest at near-ambient pH, suggesting that CCA may have already declined in abundance due to the recent seawater pH decline of 0.1 units, and that future severe losses are likely with increasing ocean acidification.