How well do global ocean biogeochemistry models simulate dissolved iron distributions?
How well do global ocean biogeochemistry models simulate dissolved iron distributions?
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DOI：
10.1002/2015gb005289
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发表时间：
2016-02-01
影响因子：
5.2
通讯作者：
Yool, Andrew
中科院分区：
文献类型：
--
作者：
Tagliabue, Alessandro;Aumont, Olivier;Yool, Andrew
海洋生物地球化学数值模型被用于预测气候变化对海洋资源的影响，并检验关于过去气候和生态系统变化驱动因素的假设。在海洋的大片区域，铁的可利用性调节着海洋生态系统的功能，进而影响海洋碳循环。因此，我们在时空上量化海洋生态系统波动和碳循环的驱动因素及影响的能力，首先依赖于在模型中对现代海洋铁循环的恰当表述。当将13个全球海洋生物地球化学模型中的铁分布与地球化学海洋断面研究计划（GEOTRACES）的最新海洋剖面进行比较时，我们发现所有模型都难以重现观测到的空间模式的许多方面。那些反映了多种铁源的新证据或其内部循环微妙之处的模型，在捕捉观测特征方面比其更简单的同类模型表现要好得多，特别是在海洋内部。我们表明，铁输入通量的巨大不确定性导致不同模型中的停留时间范围非常宽泛，这对生态系统和全球碳循环对扰动的响应具有影响。鉴于这种巨大的不确定性，基于任何单一现有模型的铁施肥实验都应谨慎解读。需要改进这些模型对铁清除以及生物循环的表述方式，以提高对其海洋全球生物地球化学变化预测的可信度。
Numerical models of ocean biogeochemistry are relied upon to make projections about the impact of climate change on marine resources and test hypotheses regarding the drivers of past changes in climate and ecosystems. In large areas of the ocean, iron availability regulates the functioning of marine ecosystems and hence the ocean carbon cycle. Accordingly, our ability to quantify the drivers and impacts of fluctuations in ocean ecosystems and carbon cycling in space and time relies on first achieving an appropriate representation of the modern marine iron cycle in models. When the iron distributions from 13 global ocean biogeochemistry models are compared against the latest oceanic sections from the GEOTRACES program, we find that all models struggle to reproduce many aspects of the observed spatial patterns. Models that reflect the emerging evidence for multiple iron sources or subtleties of its internal cycling perform much better in capturing observed features than their simpler contemporaries, particularly in the ocean interior. We show that the substantial uncertainty in the input fluxes of iron results in a very wide range of residence times across models, which has implications for the response of ecosystems and global carbon cycling to perturbations. Given this large uncertainty, iron fertilization experiments based on any single current generation model should be interpreted with caution. Improvements to how such models represent iron scavenging and also biological cycling are needed to raise confidence in their projections of global biogeochemical change in the ocean.