Sedimentation Pulse in the NE Gulf of Mexico following the 2010 DWH Blowout.
Sedimentation Pulse in the NE Gulf of Mexico following the 2010 DWH Blowout.
复制标题
DOI：
10.1371/journal.pone.0132341
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Hollander D
中科院分区：
文献类型：
--
作者：
Brooks GR;Larson RA;Schwing PT;Romero I;Moore C;Reichart GJ;Jilbert T;Chanton JP;Hastings DW;Overholt WA;Marks KP;Kostka JE;Holmes CW;Hollander D
本研究的目的是调查墨西哥湾东北部德索托峡谷地区底部沉积物中记录的深水地平线 (DWH) 石油排放对海底的影响。通过沉积学、地球化学和生物学方法的紧密结合，来自 2010 年 11 月/12 月采样的 11 个地点的多个独立证据显示，上部约 1 厘米深度区间与下面的沉积物不同，结果表明颗粒起源于海面。沉积物表面约 1 厘米的颗粒尺寸一致差异对应于超过 234Th 深度，这表明缺乏垂直混合（生物扰动），表明整个层是在 4-5 个月内沉积的。此外，在接下来的两年内对四个深海地点进行了最多三次采样的时间序列显示，在最初取芯后的几个月到几个月内，过量的 234Th 深度、积累率和 234Th 库存迅速减少。固相锰的分层证实了对快速沉积脉冲的解释，固相锰的分层与成岩作用和氧化还原变化以及表层沉积物中记录的底栖有孔虫密度的急剧下降有关。结果与先前关于沉积物和 2010 年夏季和秋季靠近井口的地表水中海洋积雪形成的研究中报告的短暂沉积脉冲一致。虽然来自密西西比河的沉积物输入和平流输送可能影响德索托峡谷地区海底的沉积，但我们根据多学科证据得出结论，2010 年末的沉积脉冲是海洋积雪形成的产物，并且可能与 到 DWH 放电。
The objective of this study was to investigate the impacts of the Deepwater Horizon (DWH) oil discharge at the seafloor as recorded in bottom sediments of the DeSoto Canyon region in the northeastern Gulf of Mexico. Through a close coupling of sedimentological, geochemical, and biological approaches, multiple independent lines of evidence from 11 sites sampled in November/December 2010 revealed that the upper ~1 cm depth interval is distinct from underlying sediments and results indicate that particles originated at the sea surface. Consistent dissimilarities in grain size over the surficial ~1 cm of sediments correspond to excess 234Th depths, which indicates a lack of vertical mixing (bioturbation), suggesting the entire layer was deposited within a 4–5 month period. Further, a time series from four deep-sea sites sampled up to three additional times over the following two years revealed that excess 234Th depths, accumulation rates, and 234Th inventories decreased rapidly, within a few to several months after initial coring. The interpretation of a rapid sedimentation pulse is corroborated by stratification in solid phase Mn, which is linked to diagenesis and redox change, and the dramatic decrease in benthic formanifera density that was recorded in surficial sediments. Results are consistent with a brief depositional pulse that was also reported in previous studies of sediments, and marine snow formation in surface waters closer to the wellhead during the summer and fall of 2010. Although sediment input from the Mississippi River and advective transport may influence sedimentation on the seafloor in the DeSoto Canyon region, we conclude based on multidisciplinary evidence that the sedimentation pulse in late 2010 is the product of marine snow formation and is likely linked to the DWH discharge.