Evaluation of coral reef carbonate production models at a global scale
Evaluation of coral reef carbonate production models at a global scale
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DOI：
10.5194/bg-12-1339-2015
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发表时间：
2014-09
期刊：
影响因子：
4.9
通讯作者：
N. Jones;A. Ridgwell;E. Hendy
中科院分区：
文献类型：
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作者：
N. Jones;A. Ridgwell;E. Hendy
据估计，珊瑚礁群落的钙化作用占浅水环境中产生的所有碳酸盐的一半，占全球海洋沉积物中埋藏的碳酸盐总量的 25% 以上。因此，珊瑚礁生产的碳酸钙是全球碳循环的重要组成部分；它还受到未来全球变暖和其他全球变化压力的威胁。需要珊瑚礁碳酸盐生成的数值模型来了解碳酸盐沉积如何响应环境条件，包括过去和未来的大气二氧化碳浓度。然而，在做出任何预测之前，基本测试是建立重建当今钙化率的模型技能。在这里，我们评估了四个已发表的关于珊瑚礁碳酸盐生产的模型描述，以评估其在当地和全球范围内的预测能力。我们还编译了有关珊瑚礁钙化的可用全球数据，以生成一个基于独立观测的数据集，用于碳酸盐预算输出的模型评估。四种钙化模型基于对光可用性、文石饱和度（a/和温度）组合敏感的函数，并在专门开发的全球框架“全球珊瑚礁增生模型”（GRAM）中实施。没有模型能够重现整个珊瑚礁钙化的独立速率估计，并且仅基于温度的方法的输出是唯一与珊瑚钙化速率显着相关的模型 观察。即使在单个珊瑚的规模上保持一致，整个珊瑚礁系统也缺乏任何预测能力，这表明珊瑚覆盖估计在计算中具有压倒性的重要性。我们的工作强调了在估计全球珊瑚礁碳酸盐预算时需要采用生态系统建模方法，在死亡率和补充方面考虑种群动态，从而考虑钙化物丰度。此外，对珊瑚礁的验证 珊瑚礁规模观测方法有限且不一致，严重阻碍了碳酸盐预算。
Calcification by coral reef communities is esti- mated to account for half of all carbonate produced in shal- low water environments and more than 25 % of the total car- bonate buried in marine sediments globally. Production of calcium carbonate by coral reefs is therefore an important component of the global carbon cycle; it is also threatened by future global warming and other global change pressures. Numerical models of reefal carbonate production are needed for understanding how carbonate deposition responds to en- vironmental conditions including atmospheric CO2 concen- trations in the past and into the future. However, before any projections can be made, the basic test is to establish model skill in recreating present-day calcification rates. Here we evaluate four published model descriptions of reef carbon- ate production in terms of their predictive power, at both lo- cal and global scales. We also compile available global data on reef calcification to produce an independent observation- based data set for the model evaluation of carbonate bud- get outputs. The four calcification models are based on func- tions sensitive to combinations of light availability, arago- nite saturation (a/ and temperature and were implemented within a specifically developed global framework, the Global Reef Accretion Model (GRAM). No model was able to re- produce independent rate estimates of whole-reef calcifica- tion, and the output from the temperature-only based ap- proach was the only model to significantly correlate with coral-calcification rate observations. The absence of any pre- dictive power for whole reef systems, even when consistent at the scale of individual corals, points to the overriding impor- tance of coral cover estimates in the calculations. Our work highlights the need for an ecosystem modelling approach, accounting for population dynamics in terms of mortality and recruitment and hence calcifier abundance, in estimat- ing global reef carbonate budgets. In addition, validation of reef carbonate budgets is severely hampered by limited and inconsistent methodology in reef-scale observations.