Characterization of the Sedimentation Associated with the Deepwater Horizon Blowout: Depositional Pulse, Initial Response, and Stabilization

2019 ◽  
pp. 235-252
Author(s):  
Rebekka A. Larson ◽  
Gregg R. Brooks ◽  
Patrick T. Schwing ◽  
Arne R. Diercks ◽  
Charles W. Holmes ◽  
...  
1992 ◽  
Vol 262 (1) ◽  
pp. G144-G149 ◽  
Author(s):  
M. S. Barnette ◽  
M. Grous

To study the potential of inflammatory mediators to alter colonic motility, we characterized the response of distal colonic smooth muscle to antigen challenge. Addition of ovalbumin to isolated segments of circular smooth muscle obtained from sensitized guinea pigs produced a biphasic contraction. The initial response consisted of a rapid contraction followed by a late response, which was a more sustained but smaller increase in tone and phasic activity. Interestingly, these two responses could be antagonized differentially. Pretreatment with mepyramine (10 microM) inhibited the initial response, whereas the leukotriene antagonist WY 48252 (10 microM) inhibited the late response. The mast cell stabilizer doxantrazole (0.1 microM) reduced only the late response. Inhibition of cyclooxygenase with meclofenamic acid (1 microM) potentiated both responses, whereas blocking neuronal activity with tetrodotoxin (1 microM) only enhanced the initial response. These data indicate clear differences between the inflammatory mediators important in the initial vs. the late response. The initial response is probably mediated by the release of histamine, with enteric neuronal interactions important in attenuating the magnitude of this response. In contrast, the late response appears to be mediated by the release of peptidyl leukotrienes. In this system, cyclooxygenase products apparently function to decrease the response of the smooth muscle to these mediators. These results suggest that release of mediators during an inflammatory response could profoundly alter colonic motility and that these alterations may be important in the pathophysiological manifestations associated with colonic inflammation.(ABSTRACT TRUNCATED AT 250 WORDS)


Author(s):  
Edward B. Overton ◽  
Buffy M. Meyer ◽  
M. Scott Miles ◽  
R. Eugene Turner ◽  
Puspa L. Adhikari

Abstract Coastal marshes were heavily impacted by the Deepwater Horizon (DWH) oil spill in 2010, with approximately 90% of shoreline impacts occurring in Louisiana's coastal wetlands. Spilled crude oils impact an environment through four major mechanisms: ecosystem exposure to reactive and toxic aromatic compounds; covering and smothering that hinders normal plant and animal physiology; depletion of dissolved oxygen; and disruption of the aquatic food web. Crude oil's ability to cause environmental harm depends upon its composition, which is a very complex mixture of many thousands of reduced carbon compounds made from the degradation of plant material deposited deep underground. This study reviews the results from the chemical characterization of petroleum hydrocarbons, at various weathering stages, in >2000 marsh surface sediments and select sediment cores samples collected from various sampling locations in Terrebonne Bay, Grand isle, and northern Barataria Bay from 2010 to 2018. The sediment samples were analyzed for target saturated alkanes, polycyclic aromatic compounds, and the forensic biomarker (hopane and sterane) compounds. The chemical characterization of the compositional changes of target compounds in DWH oil, from its pre-stranding stage just offshore in the Louisiana Bight, through stranding on marshy shorelines and through its degradation and weathering over eight years has given insights into the complexity of oil residues and potential for impacts in these varying environmental conditions. Stranded oil initially had two prominent fates: settling on surface sediment/soils of the marshes, and subsurface deposition primarily by means of settling into fiddler crab burrows. Both initial fates affected shorelines and 10–20 meters inward. Over time, surface oil residues were spread beyond initially impacted areas by Tropical Storm Isaac in 2012 and other weather events, and oil residues were quickly degraded. Subsurface stranded oil was degraded much more slowly under anaerobic conditions and some was re-released as fairly fresh oil during the coastal erosions caused by DWH surface oiling damage to the marsh plants. However, these re-releases were relatively slow and were quickly aerobically degraded once the stranded oil reached marsh surfaces. There was also evidence of anaerobic degradation of heavily weathered surface oil residues during the 2015 to 2018 timeframe. This eight-year study establishes a very complex narrative between the physical and chemical properties of stranded oil and its interactions with coastal marsh environments.


2019 ◽  
Vol 3 (1) ◽  
pp. 1-7
Author(s):  
Gregory D. Bothun

The initial estimate of the flow rate of now liberated crude oil following the explosion and sinking of the Deepwater Horizon oil platform turned out to be a factor of 50 times lower than the physical reality. This initial estimate, provided by the corporate owner of the oil platform, British Petroleum (BP), was a leak rate of 1,000 barrels per day (bpd). This number was not based on any scientific approach and was never put into context, for the media or the public, of whether this was a big or small number (i.e., how many bpd is equivalent to filling a bathtub for 24 h) and was simply accepted as the physical reality. As a consequence, the initial response to the disaster would plan for a scope that was much smaller than what ultimately unfolded. Furthermore, since 1,000 bpd turns out to be a small number, the initial strategy was based on the belief that the leak could be patched and therefore a fix was manageable. Here we show that (a) simple physical reasoning at the time of the occurrence would have lead to initial estimates that were close to the final estimate (determined 2 months after the initial incident) of about 50,000 bpd; (b) there was an unnecessarily slow time evolution to involve the scientific community to gather relevant data that would vastly improve the estimate and; (c) this slow evolution in unmasking the physical reality of the situation prevented a more robust governmental response to the problem. Even though the government, through National Oceanic and Atmospheric Administration (NOAA), revised the leak rate to 5,000 bpd one week after the disaster, another month would elapse before it was officially recognized that the leak rate was essentially 10 times higher.


2017 ◽  
Vol 2017 (1) ◽  
pp. 1020-1040
Author(s):  
Gary Shigenaka ◽  
Buffy Meyer ◽  
Edward Overton ◽  
M. Scott Miles

2017-185 ABSTRACT The response technique of in-situ burning was used to great effect during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico. An estimated 220,000-310,000 bbl of surface oil was consumed by operational in-situ burn activities. Post-burn residues were not recovered, as most were denser than seawater and sank after the burns. However, late in 2010, a relatively small deep-water shrimp fishery operating on the shelf north of the Macondo wellhead encountered tarballs on or near the bottom at around 200 m. We physically and chemically characterized samples of these submerged tarballs to confirm them as originating from Deepwater Horizon burns and to understand the features that distinguish them from other residual oil types encountered during the course of the spill response. The chance intersection between a commercial fishery and residues from the in-situ burn operations suggest that the fate of in-situ burn residue should be factored into future spill response tradeoff analyses.


Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1955 ◽  
Author(s):  
Felix Royo ◽  
Clotilde Théry ◽  
Juan M. Falcón-Pérez ◽  
Rienk Nieuwland ◽  
Kenneth W. Witwer

Research on extracellular vesicles (EVs) is growing exponentially due to an increasing appreciation of EVs as disease biomarkers and therapeutics, an expanding number of EV-containing materials under study, and application of new preparation, detection, and cargo analysis methods. Diversity of both sources and methodologies imposes challenges on the comparison of measurement results between studies and laboratories. While reference guidelines and minimal requirements for EV research have achieved the important objective of assembling community consensus, it is also essential to understand which methodologies and quality controls are currently being applied, and how usage trends are evolving. As an initial response to this need, the International Society for Extracellular Vesicles (ISEV) performed a worldwide survey in 2015 on “Techniques used for the isolation and characterization of extracellular vesicles” and published the results from this survey in 2016. In 2019, a new survey was performed to assess the changing state of the field. The questionnaire received more than 600 full or partial responses, and the present manuscript summarizes the results of this second worldwide survey. The results emphasize that separation methods such as ultracentrifugation and density gradients are still the most commonly used methods, the use of size exclusion chromatography has increased, and techniques based on tangential flow and microfluidics are now being used by more than 10% of respondents. The survey also reveals that most EV researchers still do not perform sample quality controls before or after isolation of EVs. Finally, the majority of EV researchers emphasize that separation and characterization of EVs should receive more attention.


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