A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization
A mesoscale phytoplankton bloom in the polar Southern Ocean stimulated by iron fertilization
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DOI：
10.1038/35037500
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发表时间：
2000-10-12
期刊：
影响因子：
64.8
通讯作者：
Zeldis, J
中科院分区：
文献类型：
--
作者：
Boyd, PW;Watson, AJ;Zeldis, J
海洋浮游生物铁供应的变化被认为通过改变碳固存速率对大气二氧化碳浓度产生重大影响，这一理论被称为“铁假说”。因此，了解远洋生物对铁供应增加的反应是很重要的。在这里，我们报告了在极地南大洋进行的中尺度铁施肥实验的结果，在那里，铁升高的藻类碳封存的潜力可能是最大的。铁供应的增加导致浮游植物生物量和地表水光合作用速率的增加，导致二氧化碳和大量营养物质的大量减少，13天后二甲基硫化物水平升高。这种减少主要是由于硅藻种群的增殖。但生物碳的向下输出并未增加。此外，30天后对这次大规模水华的卫星观测表明，添加的铁有足够比例保留在地表水中。我们的研究结果表明，铁供应控制着夏季南极海域浮游植物的生长和群落组成，但藻类碳的命运仍然未知，取决于控制出口、再矿化和水体俯冲时间尺度之间的相互作用。
Changes in iron supply to oceanic plankton are thought to have a significant effect on concentrations of atmospheric carbon dioxide by altering rates of carbon sequestration, a theory known as the `iron hypothesis'. For this reason, it is important to understand the response of pelagic biota to increased iron supply. Here we report the results of a mesoscale iron fertilization experiment in the polar Southern Ocean, where the potential to sequester iron-elevated algal carbon is probably greatest. Increased iron supply led to elevated phytoplankton biomass and rates of photosynthesis in surface waters, causing a large drawdown of carbon dioxide and macronutrients, and elevated dimethyl sulphide levels after 13 days. This drawdown was mostly due to the proliferation of diatom stocks. But downward export of biogenic carbon was not increased. Moreover, satellite observations of this massive bloom 30 days later, suggest that a sufficient proportion of the added iron was retained in surface waters. Our findings demonstrate that iron supply controls phytoplankton growth and community composition during summer in these polar Southern Ocean waters, but the fate of algal carbon remains unknown and depends on the interplay between the processes controlling export, remineralisation and timescales of water mass subduction.