Responses of coral gastrovascular cavity pH during light and dark incubations to reduced seawater pH suggest species-specific responses to the effects of ocean acidification on calcification
Responses of coral gastrovascular cavity pH during light and dark incubations to reduced seawater pH suggest species-specific responses to the effects of ocean acidification on calcification
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DOI：
10.1007/s00338-020-01995-7
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发表时间：
2020-09-01
期刊：
影响因子：
3.5
通讯作者：
Szmant, Alina M.
中科院分区：
文献类型：
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作者：
Bove, Colleen B.;Whitehead, Robert F.;Szmant, Alina M.
珊瑚虫有一个充满液体的内部隔间，胃血管腔（GVC）。呼吸和光合作用导致GVC氧浓度（O-2）和pH值的每日大幅波动，但很少有研究探讨这与钙化率的相关性。我们假设，GVC化学可以调解和改善海水pH值（pH值（SW））降低对珊瑚钙化的影响。在光照和黑暗条件下，采用微电极分别监测了海绵山藻（Montastraea cavernosa）和轴离Duncanopsammia axifuga的GVC内的O（2）和pH值，以及3个pH值（SW）水平（8.2、7.9和7.6）。在pH（SW）8.2时，GVC O（2）的范围约为0.001 ~ 0.001。0至超过400%的饱和度，在黑暗和光明，分别与过渡，从低到高（反之亦然）的几分钟内打开或关闭灯。对于所有三个pH值（SW）的治疗和两个物种，pH值（GVC）总是显着高于和低于pH值（SW），在光明和黑暗中，分别。ForM.在光照下，pH（GVC）达到pH 8.4-8.7的水平，在测试的pH（SW）处理之间没有差异;在黑暗中，pH（GVC）下降到pH（SW）以下，甚至在pH（SW）7.6的一些试验中低于pH 7.0。福特在光照和黑暗条件下，pH（GVC）随pH（SW）的降低而线性降低。在光下测量钙化速率，同时测量GVC O（2）和pH（GVC）。对于这两个物种，钙化率在pH（SW）8.2和7.9时相似，但在pH（SW）7.6时显著较低。因此，对于这两个物种，钙化保护海水酸化的内在珊瑚生理pH值（SW）7.9，但不是7.6。M的钙化与pH（GVC）无相关性。cavernosabut是福特.这些结果突出了珊瑚对pH值变化的不同反应（SW），它们控制pH值的不同能力（GVC），因此它们对海洋酸化的敏感性。
Coral polyps have a fluid-filled internal compartment, the gastrovascular cavity (GVC). Respiration and photosynthesis cause large daily excursions in GVC oxygen concentration (O-2) and pH, but few studies have examined how this correlates with calcification rates. We hypothesized that GVC chemistry can mediate and ameliorate the effects of decreasing seawater pH (pH(SW)) on coral calcification. Microelectrodes were used to monitor O(2)and pH within the GVC ofMontastraea cavernosaandDuncanopsammia axifuga(pH only) in both the light and the dark, and three pH(SW)levels (8.2, 7.9, and 7.6). At pH(SW)8.2, GVC O(2)ranged from ca. 0 to over 400% saturation in the dark and light, respectively, with transitions from low to high (and vice versa) within minutes of turning the light on or off. For all three pH(SW)treatments and both species, pH(GVC)was always significantly above and below pH(SW)in the light and dark, respectively. ForM. cavernosain the light, pH(GVC)reached levels of pH 8.4-8.7 with no difference among pH(SW)treatments tested; in the dark, pH(GVC)dropped below pH(SW)and even below pH 7.0 in some trials at pH(SW)7.6. ForD. axifugain both the light and the dark, pH(GVC)decreased linearly as pH(SW)decreased. Calcification rates were measured in the light concurrent with measurements of GVC O(2)and pH(GVC). For both species, calcification rates were similar at pH(SW)8.2 and 7.9 but were significantly lower at pH(SW)7.6. Thus, for both species, calcification was protected from seawater acidification by intrinsic coral physiology at pH(SW)7.9 but not 7.6. Calcification was not correlated with pH(GVC)forM. cavernosabut was forD. axifuga.These results highlight the diverse responses of corals to changes in pH(SW), their varying abilities to control pH(GVC), and consequently their susceptibility to ocean acidification.