| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | June 18, 2010 |
| Latest Amendment Date: | September 2, 2010 |
| Award Number: | 1045330 |
| Award Instrument: | Standard Grant |
| Program Manager: |
David Garrison
OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | July 1, 2010 |
| End Date: | June 30, 2012 (Estimated) |
| Total Intended Award Amount: | $67,025.00 |
| Total Awarded Amount to Date: | $79,903.00 |
| Funds Obligated to Date: |
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| History of Investigator: |
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| Recipient Sponsored Research Office: |
3227 CHEADLE HALL SANTA BARBARA CA US 93106-0001 (805)893-4188 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
3227 CHEADLE HALL SANTA BARBARA CA US 93106-0001 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): |
BIOLOGICAL OCEANOGRAPHY, Chemical Oceanography |
| Primary Program Source: |
01001011DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
The accident at the BP oil well in the Gulf of Mexico in April 2010 resulted in an oil spill of unprecedented magnitude and consequences. Preliminary data collected in the beginning of May at the site of the accident show very high concentrations of marine snow in the water, especially in close proximity to the oil/ dispersants. The goal of this project is to evaluate the role these large marine snow-like particles play in the ecosystem during the following weeks to months. Neither the formation mechanisms nor the aggregate composition are known. These investigators will monitor the distribution of marine snow, characterize these particles and measure sedimentation rates to try to understand the role of snow formation and sedimentation in the ecosystem response.
Intellectual Merit
The characteristics and the potential fate of these marine snow like aggregates, which may potentially sink or float, be grazed, degraded or remain suspended in the water for a long period of time, is unknown. This accident is an opportunity to evaluate and expand our knowledge on reactions of marine ecosystems to such large disturbances in general and more specifically to study the role of aggregation and sedimentation in the process. Marine snow formation and its sedimentation are an essential component of elemental cycling. It has been postulated that sedimentation of material "cleans" the water column from particles. Marine snow is also thought to be hotspots of microbial activity. Potentially this oily marine snow could not only represent hotspots of activity for oil degrading organisms, but may also function to isolate oil into small volumes. However, rapid sedimentation of such oil aggregates may lead to anoxia at depths. Scientifically we do not understand the possible interactions between marine snow, marine particles, oil and dispersant.
Broader Impacts
The need to understand the impact of this largest oil spill to date on ecosystems and biochemical cycling is self evident. The consequences of the disaster and accompanying clean up measures (e.g. the distribution of dispersants) need to be evaluated to guide further mediating measures and to develop and improve responses to similar disasters in the future. Would it be advantageous if such oil aggregates sink, or should it rather remain suspended? Possibly measures can be developed to enhance sinking or suspension (e.g. addition of ballast minerals) once we understand their current formation and fate. Understanding the particle dynamics following the input of large amounts of oil and dispersants into the water is a prerequisite to develop response strategies for now and in the future.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
RAPID Deepwater Horizon Oil Spill:
Marine Snow and Sedimentation
Uta Passow, Vernon Asper and Arne Diercks
It is important to understand the distribution of the accidentally released oil after the explosion of the Deep Water Horizon rig in the Gulf of Mexico (GoM) in April 2010. Damage assessment and mediation can only be achieved if we understand the pathway of the oil in the environment and through ecosystems. The released oil consisted of a mixture of chemically very diverse substances. Some of these fractions of the oil reached the surface, whereas other fractions remained at different depths, some forming a subsurface plume at about a 1000m. What is the fate of these different fractions of the spilled oil?
At the surface we observed the formation of cm-sized very mucus-rich marine snow in the vicinity of the oil slicks. Within our NSF funded project we investigated how this marine snow may have formed. Experimentally we simulated different environmental conditions to determine which circumstances promote the formation of such large mucus rich marine snow. Spider-web like mucus webs formed in our experiments at the water-oil-air interface in the presence of aged oil from the spill, but not in the presence of sterile, non-weathered oil. We suggest that the presence of specific bacteria combined with environmental conditions favorable to these organisms resulted in the formation of these mucus webs. The mucus webs collapsed as they aged. The resulting marine snow looked like that observed in the GoM near the oil. Similar mucus rich marine snow was also formed when phytoplankton, especially the blue-green algae Trichodesmium spp. aggregated including oil droplets within the aggregates. In the absence of oil such aggregates remained green and algae viable and identifiable. In the presence of oil, however, these algae were decomposed rapidly and within hours mucus rich marine snow was formed. Both of these mechanisms presumably contributed to the formation of the large amount of mucus rich marine snow in the vicinity of the oil spill.
Our research within this project furthermore suggests that the marine snow displayed high (100’s meters per day) sinking velocities when aged. This was observed on snow formed in experiments and on snow collected from the surface waters of the GOM after the spill. We thus believe that at least some of the marine snow in the GoM sank to the seafloor, where it was deposited. Many marine organisms feed on marine snow and another fraction of this sinking marine snow was presumably eaten during transit and entered the food chain. Our colleagues have tracked the signature from the oil into the food web of the GoM.
Within our project we also deployed a funnel-shaped particle interceptor trap, which collects sinking particles. This trap was deployed near the site of the accident after the spill, just above the sea floor and collected sinking particles continuously for 15 months. Currently these twenty samples which represent twenty 3-week collection intervals are being analyzed. The data from these traps will reveal how much oil and dispersant reached the seafloor and when it arrived there. It will also show us if large sinking events, e.g. from affected organisms, were the consequence of the spill.
Last Modified: 07/03/2012
Modified by: Uta D E Passow
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