Particle Export during the Southern Ocean Iron Experiment (SOFeX)

虽然铁的加入可以促进浮游植物的生长和改变上层海洋的生物地球化学，但对铁的有效性对下沉颗粒物通量的净影响却知之甚少。如果铁在过去二氧化碳的变化中发挥了重要作用，或者如果铁由于刻意操纵海洋生态系统而对二氧化碳产生长期影响，那么就有必要量化碳和相关元素出口通量对铁负荷的净变化。为此，PI将使用自然产生的放射性核素钍-234来量化南大洋铁实验(SOFEX)期间颗粒有机碳和颗粒有机氮出口的变化。利用在SOFEX研究区内外获得的第234年的时间序列轮廓，PI将能够研究出口对铁负荷和群落结构变化的响应，并协助计算碳和营养通量对铁添加的响应。关于上层海洋对铁浓缩的出口反应的信息将被用来了解过去海洋对铁/灰尘输入的反应，并评估为抵消二氧化碳排放而提议的刻意的铁施肥的未来影响。

ABSTRACTOCE-9987501While it has been shown that the addition of Fe can stimulate phytoplankton growth and alter upper ocean biogeochemistry, little is know about the net effect of Fe availability on sinking particle fluxes. If Fe played an important role in past variations in CO2 or if there will be long term effects of Fe on CO2 due to deliberate manipulation of ocean ecosystems, then it becomes essential to quantify the net change in export fluxes of carbon and associated elements in response to Fe loading. For this reason, the PI will quantify changes in particulate organic carbon and particulate organic nitrogen export during the Southern Ocean Iron Experiment (SOFeX) using the naturally occurring radionuclide thorium-234. Using time-series profiles of 234Th obtained both inside and outside of the SOFeX study area, the PI will be able to study the export response to changes in Fe loading and community structure, as well as assist in the calculation of the carbon and nutrient fluxes in response to the Fe additions. Information on the export response of the upper ocean to Fe enrichment will be used to understand past oceanic responses to Fe/dust inputs and assess future impacts of deliberate Fe fertilization proposed to offset carbon dioxide emissions.