Calcification by crustose coralline algae on the northern Great Barrier Reef, Australia
Calcification by crustose coralline algae on the northern Great Barrier Reef, Australia
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DOI：
10.4319/lo.2000.45.7.1476
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发表时间：
2000-11-01
影响因子：
4.5
通讯作者：
Chisholm, JRM
中科院分区：
文献类型：
--
作者：
Chisholm, JRM
通过结合O-2、pH和总碱度的测量以及描述海水碳酸盐平衡的方程，对澳大利亚大堡礁北部蜥蜴岛迎风珊瑚礁上四种甲壳珊瑚藻类的钙化作用进行了评估。钙化(C)与辐照度(T)进行回归，并使用一般指数函数进行建模。C-I模型估计的总钙化范围为0 m处的9.6 mmolCaCO3 m(-2)h(-1)到18 m处的2.0 mmolCaCO3 m(-2)h(-1)。相当大比例的样品在黑暗中表现出CaCO3的溶解，结合C-I模型和全天辐照度的半正弦曲线近似得到估计的净沉积速率为0.82到9.1g CaCO3 m(-2)d(-1)。24小时净钙化与正午照度呈线性相关。每日CaCO3沉积作为礁面起伏的函数(峰顶为3.1，坡度为5.0)表明，假设100%珊瑚覆盖，对珊瑚礁沉积的潜在贡献为4.1-28.1gm(-2)d(-1)。这些估算值预测的年沉积率为1.5至10.3公斤CaCO3 m(-2)yr(-1)，前提是在夏末到仲冬之间的测量结果代表了全年的钙化。由于观测到的吸积量远远低于这些测量所预测的数量，侵蚀机构必须清除每年由迎风珊瑚礁边缘的结壳珊瑚藻类沉积的大量CaCO3。
Calcification by four species of crustose coralline algae was estimated on the windward reef at Lizard Island, northern Great Barrier Reef, Australia, by combining measurements of O-2, pH, and total alkalinity with equations describing the seawater carbonate equilibrium. Calcification (C) was regressed against irradiance (T) and modeled using a general exponential function. C-I models yielded estimates of gross calcification that ranged from 9.6 mmol CaCO3 m(-2) h(-1) at 0 m to 2.0 mmol CaCO3 m(-2) h(-1) at 18 m. A significant proportion of all samples exhibited CaCO3 dissolution in the dark, integration of C-I models with half sine-curve approximations of whole-day irradiance yielded estimated net deposition rates of 0.82 to 9.1 g CaCO3 m(-2) d(-1). Net 24-h calcification was linearly correlated with noontime irradiance. Daily CaCO3 deposition as a function of reef surface relief (3.1 for the crest and 5.0 for the slope) indicated potential contributions to reef accretion of 4.1 to 28.1 g m(-2) d(-1), assuming 100% coralline cover. These estimates predict annual deposition rates of 1.5 to 10.3 kg CaCO3 m(-2) yr(-1), provided that measurements made between late summer and mid-winter are representative of calcification throughout the year. Since observed accretion falls far short of the quantities predicted by these measurements, erosive agencies must remove much of the CaCO3 deposited annually by crustose coralline algae on windward reef margins.