Collaborative Research: Southern Ocean Iron Experiments (SOFEX)

摘要：近年来，海洋中溶解铁的研究和开放海洋铁富集实验的结果表明，在溶解硝酸盐浓度高、叶绿素存量低的水域（“HNLC水域”），有效铁浓度低限制了浮游植物的生长和生物量。20世纪90年代初，在东赤道太平洋进行了开放水域铁施肥试验。从那时起，大量的新证据表明，在南极洲周围广阔的向东流动的南大洋中存在着一个更广泛的、具有全球意义的HNLS区域。在这个项目中，莫斯兰丁海洋实验室、罗格斯大学、俄勒冈州立大学、迈阿密大学和拉蒙特-多尔蒂地球观测站的研究人员将在南大洋的南极极地锋区（APFZ）以北和以南170'W的地区进行开放水域铁施肥实验，该地区主要营养物质含量高，溶解铁浓度极低。该团队将研究(1)铁在富含硅酸盐和缺乏硅酸盐的HNLC水中的生物泵中的作用，(2)铁介导主要营养物质的差异下降，(3)铁对地表水碳固定和输出的限制，(4)对添加铁的生物物理响应，以及(5)铁诱导碳输出对中水再矿化和反硝化的潜在影响。推动本研究的基本假设是，在主要生长季节，南大洋浮游植物的生产速度和植物生物量的数量在APFZ内受到iton和硅酸盐有效性的不同限制，这是导致HNLC条件持续存在的原因。这项工作的结果有望对我们了解南大洋重要的生物地球化学过程作出重大贡献。控制新生产速度的因素直接影响全球碳循环、大气二氧化碳浓度和气候控制。南大洋铁试验（SOFeX）将于2001-2002年夏季在南极区北部和南部进行一次实地考察。

ABSTRACTOCE-9911481, OCE-0000364, OCE-0000365, OCE-0000363, OCE-0000362, OCE-0000361In recent years, studies of dissolved iron in the ocean and the results of open-ocean iron enrichments experiments have demonstrated that the growth and biomass of phytoplankton are limited by low concentrations of available iron in waters characterized by high concentrations of dissolved nitrate and low standing stocks of chlorophyll ("HNLC waters"). The seminal open-water iron fertilization experiments were done in the early 1990's in the eastern equatorial Pacific Ocean. Since that time, abundant new evidence has come to light that an even more extensive, and globally significant, HNLS region exists in the broad eastwardly flowing Southern Ocean surrounding Antarctica.In this project, researchers at the Moss Landing Marine Laboratory, Rutgers University, Oregon State University, University of Miami, and Lamont-Dougherty Earth Observatory will perform an open-water iron fertilization experiment in the Southern Ocean in regions just north of and just south of the Antarctic Polar Frontal Zone (APFZ) along 170'W, an area characterized by high major nutrients and extremely low dissolved iron concentrations. The team will investigate (1) the role of iron on the biological pump in silicate-rich versus silicate-poor HNLC waters, (2) iron mediation of differential drawdown of major nutrients, (3) iron limitation of carbon fixation and export from surface waters, (4) the biophysical response to added iron, and (5) the potential effect of iron-induced carbon export on midwater remineralization and denitrification. The underlying hypothesis driving this field study is that the rate of phytoplankton production and the quantity of plant biomass in the Southern Ocean are differentially limited across the APFZ by iton and silicate availability during the major growth season and are responsible for the persistence of the HNLC condition. The results of this work are expected to contribute significantly to our understanding of important biogeochemical processes in the Southern Ocean. Factors that control the rate of new production bear directly on the global carbon cycle, atmospheric carbon dioxide concentration, and climate control.This Southern Ocean Iron Experiment (SOFeX), north and south of the APFZ, will be carried out in a single field expedition in the austral summer of 2001-2002.