RAPID - Collaborative Research: Impact of the New Horizon Oil Spill on Ecosystem Metabolism and Gas Exchange in the Northern Gulf of Mexico Hypoxic Region

2010年4月20日，位于路易斯安那州海岸41公里外的“深水地平线”海上钻井平台发生井喷和爆炸，导致11人死亡，钻井平台沉没，油井失控排放，据估计每天有5- 2.5万桶原油泄漏。由于在1500米深处控制排放的挑战，预计油井将持续数周，并超过埃克森瓦尔迪兹，成为美国历史上最严重的石油灾难。此次石油泄漏可能会波及墨西哥湾北部每年一度缺氧的大片地区。由于缺氧对渔业的不利影响，墨西哥湾北部缺氧的发展和程度多年来一直受到关注（Rabalais et al., 2007; Turner et al., 2007）。在快速反应研究基金（Rapid）的资助下，密歇根州立大学和德克萨斯大学奥斯汀分校的科学家们将于2010年5月21日至27日参加RV Pelican即将进行的研究巡航，他们将在已经或很可能受到石油泄漏影响的站点进行采样。事实上，美国国家海洋和大气管理局对泄漏石油分布的预测与所有拟议的研究站都很接近。研究小组认为，石油泄漏将通过改变初级生产、呼吸和气体交换的速度，加剧ngoomex缺氧的发展。因此，他们将测试以下假设：假设1：溢油将通过(1)减少初级生产，(2)加强呼吸和(3)减少气体交换来加强ngoomex的缺氧。假设2：气体交换速率将是表层水层中表面活性剂丰度、组成和来源的函数。海面上的油层预计会减少光合作用的光穿透，从而降低初级生产的速度。由于油的可得性增加，呼吸作用可能得到加强；特别是当微生物群落代谢这种碳源时。海洋表面和大气之间的气体交换速率对表面有机薄膜的存在非常敏感。该团队将通过确定溶解O2的三重同位素组成的深度剖面以及N2:Ar和O2:Ar的比例来实现这些假设，这些比例共同产生了初级生产、呼吸和气体交换的速率。他们将进一步确定作为控制气体交换速率的表层有机层的丰度、组成和来源。更广泛的影响：虽然石油泄漏对环境的影响是多方面的，但鲜为人知的是，石油泄漏可能会在容易发生这种情况的地区加剧缺氧的发展。长期了解ngoomex和其他受漏油影响地区的缺氧情况，将提高社会预测这次和类似灾难的生态后果的能力。该项目将直接涉及两名本科生，该项目的结果将成为研究人员教学课程的重点，包括密歇根州立大学和德克萨斯大学奥斯汀分校分别开设的海洋学和海洋生物地球化学课程。此外，密歇根州立大学和德克萨斯大学都有适当的机制来促进向媒体展示研究成果，包括密歇根州立大学的环境科学与政策项目和奈特环境新闻中心，以及通过德克萨斯大学的全国广播电台节目：“科学与海洋”。

On April 20, 2010, the Deepwater Horizon offshore drilling rig, located 41 km off the coast of Louisiana, experienced a blowout and explosion that resulted in 11 deaths, the sinking of the drilling rig, and uncontrolled discharge from the well at an estimated rate of 5-25 thousand barrels of crude oil each day. Owing to the challenge of containing discharge at a depth of 1,500 m it is anticipated that the well will continue to flow for many weeks and exceed the Exxon Valdez as the most severe oil disaster in U.S. history. The oil spill is likely to encompass the extensive area that develops hypoxia on an annual basis in the northern Gulf of Mexico (NGOMEX). The development and extent of hypoxia in the northern Gulf of Mexico has been of concern for many years owing to, for example, its detrimental impact on fisheries (Rabalais et al., 2007; Turner et al., 2007). With funding through this Grant for Rapid Response Research (RAPID), scientists at Michigan State University and the University of Texas at Austin will participate in an upcoming research cruise of the RV Pelican from May 21-27, 2010, that will be sampling at stations that already are or are very likely to be impacted by the oil spill. Indeed projections by NOAA for the distribution of oil from the spill are in close proximity to all of the proposed research stations. The research team contends that the oil spill will exacerbate the development of hypoxia in the NGOMEX by altering rates of primary production, respiration and gas exchange. Consequently, they will test the following hypotheses: Hypothesis 1: The oil spill will enhance hypoxia in the NGOMEX by (1) reducing primary production, (2) enhancing respiration and (3) reducing gas exchange. Hypothesis 2: The gas exchange rate will be a function of the abundance, composition and origin of surfactants in the surface water layer. The layer of oil across the sea surface is expected to reduce penetration of light for photosynthesis thereby reducing rates of primary production. Respiration is likely to be enhanced by the increased availability of the oil; particularly as the microbial community metabolizes this carbon source. Rates of gas exchange between the ocean surface and atmosphere are very sensitive to the presence of surface organic films. The team will approach these hypothesis by determining depth profiles of the triple isotopic composition of dissolved O2 and ratios of N2:Ar and O2:Ar that collectively yield rates of primary production, respiration and gas exchange. They will further determine the abundance, composition and origin of the surface organic layer as a control on the rate of gas exchange.Broader Impacts: While the environmental impacts of oil spills are many, less well known is the potential for oil spills to enhance the development of hypoxia in regions prone to this condition. A long term understanding of hypoxia in the NGOMEX and other regions impacted by oil spills will enhance society's ability to predict the ecological consequences of this and similar disasters. This project will directly involve two undergraduate students and the results of this project will be a focus of the investigators' courses of instruction, including courses at MSU and UT Austin on Oceanography and Marine Biogeochemistry, respectively. Further, MSU and UT have mechanisms in place to facilitate presentation of research findings to the media including MSU's Environmental Science and Policy Program and Knight Center for Environmental Journalism and via UT's nationally broadcast radio program: "Science and the Sea".