Smetacek V, Naqvi S W A
Alfred Wegener Institute for Polar and Marine Research, 27570 Bremerhaven, Germany.
Philos Trans A Math Phys Eng Sci. 2008 Nov 13;366(1882):3947-67. doi: 10.1098/rsta.2008.0144.
Of the various macro-engineering schemes proposed to mitigate global warming, ocean iron fertilization (OIF) is one that could be started at short notice on relevant scales. It is based on the reasoning that adding trace amounts of iron to iron-limited phytoplankton of the Southern Ocean will lead to blooms, mass sinking of organic matter and ultimately sequestration of significant amounts of atmospheric carbon dioxide (CO2) in the deep sea and sediments. This iron hypothesis, proposed by John Martin in 1990 (Martin 1990 Paleoceanography 5, 1-13), has been tested by five mesoscale experiments that provided strong support for its first condition: stimulation of a diatom bloom accompanied by significant CO2 drawdown. Nevertheless, a number of arguments pertaining to the fate of bloom biomass, the ratio of iron added to carbon sequestered and various side effects of fertilization, continue to cast doubt on its efficacy. The idea is also unpopular with the public because it is perceived as meddling with nature. However, this apparent consensus against OIF is premature because none of the published experiments were specifically designed to test its second condition pertaining to the fate of iron-induced organic carbon. Furthermore, the arguments on side effects are based on worst-case scenarios. These doubts, formulated as hypotheses, need to be tested in the next generation of OIF experiments. We argue that such experiments, if carried out at appropriate scales and localities, will not only show whether the technique will work, but will also reveal a wealth of insights on the structure and functioning of pelagic ecosystems in general and the krill-based Southern Ocean ecosystem, in particular. The outcomes of current models on the efficacy and side effects of OIF differ widely, so data from adequately designed experiments are urgently needed for realistic parametrization. OIF is likely to boost zooplankton stocks, including krill, which could have a positive effect on recovery of the great whale populations. Negative effects of possible commercialization of OIF can be controlled by the establishment of an international body headed by scientists to supervise and monitor its implementation.
在为缓解全球变暖而提出的各种宏观工程方案中，海洋铁施肥（OIF）是一种可以在相关规模上短时间内启动的方案。其依据的推理是，向南大洋铁含量有限的浮游植物中添加微量铁会导致藻华爆发、有机物质大量下沉，并最终将大量大气中的二氧化碳（CO₂）封存于深海和沉积物中。约翰·马丁于1990年提出了这一铁假说（马丁，1990年，《古海洋学》第5卷，第1 - 13页），五个中尺度实验对其进行了验证，这些实验为其第一个条件提供了有力支持：刺激硅藻大量繁殖并伴随显著的CO₂吸收。然而，一些关于藻华生物量的归宿、添加铁与封存碳的比例以及施肥的各种副作用的争论，仍使其有效性存疑。这个想法在公众中也不受欢迎，因为它被视为对自然的干预。然而，这种对海洋铁施肥明显的共识还为时过早，因为已发表的实验中没有一个是专门设计来测试其与铁诱导有机碳归宿相关的第二个条件的。此外，关于副作用的争论是基于最坏情况的设想。这些作为假说提出的疑问，需要在下一代海洋铁施肥实验中进行测试。我们认为，这样的实验如果在适当的规模和地点进行，不仅会表明该技术是否可行，还将揭示关于整个远洋生态系统，特别是以磷虾为基础的南大洋生态系统的结构和功能的大量见解。目前关于海洋铁施肥有效性和副作用的模型结果差异很大，因此迫切需要来自精心设计实验的数据进行实际参数化。海洋铁施肥可能会增加包括磷虾在内的浮游动物数量，这可能对鲸鱼种群的恢复产生积极影响。通过建立一个由科学家领导的国际机构来监督和监测其实施，可以控制海洋铁施肥可能商业化带来的负面影响。
