Meyer Friedrich W, Vogel Nikolas, Diele Karen, Kunzmann Andreas, Uthicke Sven, Wild Christian
Department of Ecology, Leibniz Center for Tropical Marine Ecology (ZMT), Bremen, Germany.
Faculty of Biology and Chemistry, University of Bremen, Bremen, Germany.
PLoS One. 2016 Mar 9;11(3):e0149598. doi: 10.1371/journal.pone.0149598. eCollection 2016.
Coral reefs are facing major global and local threats due to climate change-induced increases in dissolved inorganic carbon (DIC) and because of land-derived increases in organic and inorganic nutrients. Recent research revealed that high availability of labile dissolved organic carbon (DOC) negatively affects scleractinian corals. Studies on the interplay of these factors, however, are lacking, but urgently needed to understand coral reef functioning under present and near future conditions. This experimental study investigated the individual and combined effects of ambient and high DIC (pCO2 403 μatm/ pHTotal 8.2 and 996 μatm/pHTotal 7.8) and DOC (added as Glucose 0 and 294 μmol L-1, background DOC concentration of 83 μmol L-1) availability on the physiology (net and gross photosynthesis, respiration, dark and light calcification, and growth) of the scleractinian coral Acropora millepora (Ehrenberg, 1834) from the Great Barrier Reef over a 16 day interval. High DIC availability did not affect photosynthesis, respiration and light calcification, but significantly reduced dark calcification and growth by 50 and 23%, respectively. High DOC availability reduced net and gross photosynthesis by 51% and 39%, respectively, but did not affect respiration. DOC addition did not influence calcification, but significantly increased growth by 42%. Combination of high DIC and high DOC availability did not affect photosynthesis, light calcification, respiration or growth, but significantly decreased dark calcification when compared to both controls and DIC treatments. On the ecosystem level, high DIC concentrations may lead to reduced accretion and growth of reefs dominated by Acropora that under elevated DOC concentrations will likely exhibit reduced primary production rates, ultimately leading to loss of hard substrate and reef erosion. It is therefore important to consider the potential impacts of elevated DOC and DIC simultaneously to assess real world scenarios, as multiple rather than single factors influence key physiological processes in coral reefs.
由于气候变化导致溶解无机碳（DIC）增加以及陆地来源的有机和无机养分增加，珊瑚礁正面临着重大的全球和局部威胁。最近的研究表明，不稳定溶解有机碳（DOC）的高可用性对石珊瑚产生负面影响。然而，关于这些因素相互作用的研究却很缺乏，但迫切需要了解当前和不久的将来条件下珊瑚礁的功能。这项实验研究调查了环境和高DIC（pCO2 403 μatm/pHTotal 8.2和996 μatm/pHTotal 7.8）以及DOC（以葡萄糖形式添加，浓度为0和294 μmol L-1，背景DOC浓度为83 μmol L-1）可用性对来自大堡礁的石珊瑚多孔鹿角珊瑚（Ehrenberg，1834）在16天时间间隔内的生理特性（净光合作用和总光合作用、呼吸作用、暗钙化和光钙化以及生长）的单独和综合影响。高DIC可用性并未影响光合作用、呼吸作用和光钙化，但分别使暗钙化和生长显著降低了50%和23%。高DOC可用性分别使净光合作用和总光合作用降低了51%和39%，但未影响呼吸作用。添加DOC并未影响钙化，但显著使生长增加了42%。高DIC和高DOC可用性的组合并未影响光合作用、光钙化、呼吸作用或生长，但与对照和DIC处理相比，显著降低了暗钙化。在生态系统层面，高DIC浓度可能导致以鹿角珊瑚为主的珊瑚礁的堆积和生长减少，在DOC浓度升高的情况下，初级生产率可能会降低，最终导致硬底质丧失和珊瑚礁侵蚀。因此，同时考虑升高的DOC和DIC的潜在影响对于评估现实世界情况很重要，因为多个而非单一因素会影响珊瑚礁中的关键生理过程。
