BP / Gulf Oil Spill – Are Shrimpers Inadvertently Churning Up Oil?

There have been conflicting reports coming from coastal Lousiana since October 22, suggesting that large areas of East and West Bays near Southwest Pass are covered with long streamers of what appears to be weathered oil, possibly originating from the BP / Deepwater Horizon spill. Some of the local fishermen insist it’s oil; the Coast Guard thinks it’s an algal bloom. Samples taken by the Coast Guard are awating analysis. [UPDATE 10/28/10 10:00 am ET – LSU scientists confirm the substance is mostly algae with only trace amounts of oil]

Oil or algae? Photo of West Bay, Louisiana taken October 22. Source: Matthew Hinton via the Times-Picayune. Photo gallery here.

At SkyTruth we’re concerned that fishing activity could potentially stir up any oil that’s sitting on the seafloor, resuspending it in the water column. We don’t know if that’s what has happened near Southwest Pass. But we do know that bottom-trawling for shrimp in the Gulf routinely churns up the muddy seafloor, creating long sediment-laden plumes that trail for miles behind the trawlers and can be seen on satellite images. Check out our gallery of trawling images, and read more about it on this blog.

Google Earth image showing muddy plume of sediment raised by a shrimp trawler at work along the Louisiana coast. Image taken before the BP spill.

NOAA reports they haven’t yet found any signs of oil sitting on the Gulf seafloor. Other scientists claim they found inches-thick layers of oil on the seafloor on research cruises in September and “vast amounts” of oil on the seafloor in October. It seems reasonable to assume that if those scientists are correct, and if bottom-trawling for shrimp is occurring now in places where layers of oil are sitting on the seafloor, that oil will be disturbed by trawling.

We don’t know what the effects of that could be. It might help the oil biodegrade more quickly. But it will also repeatedly expose marine life, including commercially important species, to oil that would otherwise remain on the ocean floor.

This suggests to us that it’s very important to quickly, accurately and thoroughly survey the Gulf seafloor for residual oil, so we can let shrimpers know what areas to avoid for now.

Shrimp trawler working in mysterious substance floating in West Bay, Louisiana on October 23. Note plume behind the trawler. Source: Erika Blumenfeld via Trouthout.

BP / Gulf Oil Spill – Continuing Impacts

From our remote satellite perspective here at SkyTruth, most of the observable impacts from the BP / Deepwater Horizon oil spill in the Gulf of Mexico were dissipating in late July, in the wake of Tropical Storm Bonnie.

But up close and personal, people are still dealing with the oil. We just received this report today on our Gulf Oil Spill Tracker site:

We live on Navarre beach Florida. While walking along the Santa Rosa Sounds yesterday 10.14.2010, I say many, many tar balls that had washed up on the beach of the Sound. There were still others attached to the sea weed still in the water.

News accounts have provided cause for optimism, including good numbers of some fish species and birds in the area, but also note that oil continues to persist in a variety of environments. And for other economically and biologically important species, such as bluefin tuna, it may take some time for spill-related problems to manifest themselves.

BP / Gulf Oil Spill – Cumulative Oil Slick Footprints

Thought it might be interesting to take a look at the work done by others on the BP / Deepwater Horizon oil spill in the Gulf of Mexico, and compare SkyTruth’s total cumulative oil slick analysis to theirs. Here is our analysis, based on visual assessment of dozens of satellite images acquired from late April through mid July:

Cumulative BP / Deepwater Horizon oil slick footprint (red). Analysis by SkyTruth.

And here’s the official analysis done by NOAA, using many of the same satellite images, but also including many full-resolution radar satellite images that the public did not have access to (the US doesn’t operate any civilian radar satellites, so the radar images were purchased from foreign companies that don’t allow NOAA to “redistribute” the images):

Cumulative BP / Deepwater Horizon oil slick footprint (orange). Analysis by NOAA, compiled by SkyTruth.

The folks at ROFFS (Roffer’s Ocean Forecasting Service) also analyzed satellite images and other oceanographic data throughout the duration of the spill, and just released their preliminary cumulative analysis. We don’t have it digitally yet, but we’ve clipped their graphic to roughly show the same area in our two Google Earth-based maps above:

Cumulative BP / Deepwater Horizon oil slick footprint (brown). Analysis by ROFFS.

Overall, the NOAA and ROFFS analyses are in general agreement. The total NOAA oil-slick footprint covers 46,299 square miles (119,915 km2). SkyTruth’s analysis is similar except for our inclusion of possible oil sheen entrained in the Loop Current and entering Florida Straits late in May, before a large clockwise eddy (Eddy Franklin) got organized and effectively kept the slick bottled up the the northern Gulf for the remainder of the summer. The total oil-slick footprint in our analysis is 68,000 square miles (176,119 km2).

BP / Gulf Oil Spill – This Dragon Is Dead

Finally — after killing 11 people, injuring 17 others, spewing 172 million gallons of oil and untold amounts of natural gas into the ocean, and tormenting the entire Gulf of Mexico region for almost 5 months — the BP / Deepwater Horizon dragon has been declared officially dead by the US Coast Guard. After some tense last-minute complications, a relief well successfully intersected the failed Macondo well 13,000′ beneath the seafloor last Thursday (September 16). Cement was pumped into the base of the Macondo well, and pressure testing conducted over the weekend confirmed that this cement job had sealed the well.

Hallelujah. It’s a relief, but the BP / Deepwater Horizon Oil and Gas Disaster is far from over. There is a lot of work to do to fully measure and understand the impact of this event, to monitor its impacts over time, to apply all the lessons learned to our offshore drilling practices, and to help the Gulf ecosystem and communities recover.

Hurricane Earl and Virginia Offshore Drilling (Lease Area 220)

What if Virginia had active offshore oil and gas development?

We got the latest wind-history data from NOAA, showing the extent of hurricane-force and tropical-storm-force winds as Hurricane Earl moved along the East Coast today. We overlaid these “wind envelopes” on the proposed drilling area designated Lease Area 220. Here is the result, using a satellite image of the storm taken at 3pm EDT as backdrop:

Most of the drilling area would have experienced hurricane conditions today. The western part, along with the coastal support facilities onshore – pipelines, storage tanks, refineries, etc. – would have faced tropical storm conditions.

Here is the source for the wind history data, current through 11am EDT today. We’ll update this map as more complete wind-history data become available: