5 research outputs found
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Oiling Of The Continental Shelf And Coastal Marshes Over Eight Years After The 2010 Deepwater Horizon Oil Spill
We measured the temporal and spatial trajectory of oiling from the April, 2010, Deepwater Horizon oil spill in water from Louisiana\u27s continental shelf, the estuarine waters of Barataria Bay, and in coastal marsh sediments. The concentrations of 28 target alkanes and 43 target polycyclic aromatic hydrocarbons were determined in water samples collected on 10 offshore cruises, in 19 water samples collected monthly one km offshore at 13 inshore stations in 2010 and 2013, and in 16-60 surficial marsh sediment samples collected on each of 26 trips. The concentration of total aromatics in offshore waters peaked in late summer, 2010, at 100 times above the May, 2010 values, which were already slightly contaminated. There were no differences in surface or bottom water samples. The concentration of total aromatics declined at a rate of 73% y(-1) to 1/1000th of the May 2010 values by summer 2016. The concentrations inside the estuary were proportional to those one km offshore, but were 10-30% lower. The oil concentrations in sediments were initially different at 1 and 10 m distance into the marsh, but became equal after 2 years. Thus, the distinction between oiled and unoiled sites became blurred, if not non-existent then, and oiling had spread over an area wider than was visible initially. The concentrations of oil in sediments were 100-1000 times above the May 2010 values, and dropped to 10 times higher after 8 years, thereafter, demonstrating a long-term contamination by oil or oil residues that will remain for decades. The chemical signature of the oil residues offshore compared to in the marsh reflects the more aerobic offshore conditions and water-soluble tendencies of the dissolved components, whereas the anaerobic marsh sediments will retain the heavier molecular components for a long time, and have a consequential effect on the ecosystems. (C) 2019 The Authors. Published by Elsevier Ltd
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A 1,000 year high-resolution hurricane history for the Boston area based on the varved sedimentary record from the Lower Mystic Lake (Medford/Arlington, Massachusetts)
The Lower Mystic Lake (Medford/Arlington, MA) is a 24 m deep, ectogenically meromictic, low elevation (1 m a.s.l.), coastal lake directly connected to Boston Harbor by the Mystic River. About 1,000 years ago, steadily rising sea level in the Boston area finally reached a point at which occasional marine water delivery events via the river channel could actually reach the lake basin. Since then, such events have continued with enough frequency to maintain the meromictic condition. Meromixis has allowed the Lower Mystic Lake to accumulate an exquisitely laminated, annually resolvable (i.e. varved) archive of sedimentation in the lake over the last 1,000 years. A varve chronology was developed from this record. Multiple lines of robust evidence verify and validate the accuracy of the chronology. A series of anomalous, graded beds was found in the stratigraphy, and they show excellent coordination with known historic hurricanes that have affected the Boston area. The graded beds appear to be the result of intense, hurricane-strength rains which cause erosive overland flow that entrains sediment which is carried into the lake where it is deposited as a graded bed. This is enhanced by hurricane-strength winds which disturb vegetation, and uproot trees to expose fresh, loose sediment. By analogy, similar graded beds in the prehistoric portion of the stratigraphy probably represent similar hurricane events. This record of hurricane activity was compared to a record of sand layers in nearby Belle Isle Marsh (Boston Harbor) which are presumably the result of storm surge overwash events. Such sand layers in low resolution coastal archives are the main form of proxy evidence that paleotempestology studies have used to piece together longer term records of hurricane activity. Even when using multiple techniques, chronologic control in such archives is difficult, and linking sand layers to any particular storm is only tentative at best. Importantly, the Belle Isle Marsh record shows an apparent 600-year quiescent period. However, this is not due to a lack of hurricanes or storms, but to an unknown geomorphic change which affected the marsh, and it therefore serves as a cautionary note for the use of such archives
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Oiling of the continental shelf and coastal marshes over eight years after the 2010 Deepwater Horizon oil spill
We measured the temporal and spatial trajectory of oiling from the April, 2010, Deepwater Horizon oil spill in water from Louisiana's continental shelf, the estuarine waters of Barataria Bay, and in coastal marsh sediments. The concentrations of 28 target alkanes and 43 target polycyclic aromatic hydrocarbons were determined in water samples collected on 10 offshore cruises, in 19 water samples collected monthly one km offshore at 13 inshore stations in 2010 and 2013, and in 16–60 surficial marsh sediment samples collected on each of 26 trips. The concentration of total aromatics in offshore waters peaked in late summer, 2010, at 100 times above the May, 2010 values, which were already slightly contaminated. There were no differences in surface or bottom water samples. The concentration of total aromatics declined at a rate of 73% y−1 to 1/1000th of the May 2010 values by summer 2016. The concentrations inside the estuary were proportional to those one km offshore, but were 10–30% lower. The oil concentrations in sediments were initially different at 1 and 10 m distance into the marsh, but became equal after 2 years. Thus, the distinction between oiled and unoiled sites became blurred, if not non-existent then, and oiling had spread over an area wider than was visible initially. The concentrations of oil in sediments were 100–1000 times above the May 2010 values, and dropped to 10 times higher after 8 years, thereafter, demonstrating a long-term contamination by oil or oil residues that will remain for decades. The chemical signature of the oil residues offshore compared to in the marsh reflects the more aerobic offshore conditions and water-soluble tendencies of the dissolved components, whereas the anaerobic marsh sediments will retain the heavier molecular components for a long time, and have a consequential effect on the ecosystems
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Transnational research for coastal wetlands conservation in a Cuba–US setting
Sharing information between different countries is key for developing sustainable solutions to environmental change. Coastal wetlands in the Gulf of Mexico are suffering significant environmental and human-related threats. Working across national boundaries, this research project brings together scientists, specialists and local communities from Cuba and the USA. While important advances have been made in strengthening collaborations, important obstacles remain in terms of international policy constraints, different institutional and academic cultures and technology. Overcoming these limitations is essential to formulating a comprehensive understanding of the challenges that coastal socioecological systems are facing now and into the future