Deepwater Horizon Rapid Response Cruise


Wednesday, May 5. The NIUST/NOAA Oil spill response cruise with RV Pelican sailed from Cocodrie, LA, into the oil-contaminated area offshore Louisiana to conduct a survey of the extent and degree of the Deepwater Horizon oil spill, taking surface water samples and sediment samples from the seabottom for geochemical and microbiological anslysis. Chief Scientist is Dr. Arne Diercks, Univ. of Mississippi. The University of Mississippi maintains a website with cruise updates and pictures of the oil slicks from space:
Teske lab graduate student Luke McKay joined the cruise at very short notice as geochemistry/microbiology sampling expert and liaison to shorebased investigators at the University of Georgia (Mandy Joye) and the Teske and Martens labs at UNC Chapel Hill. This first cruise leg will focus on water column and sediment sampling. RV Pelican returns to shore on Sunday, May 9, and takes new personnel and equipment, before leaving for a second cruise leg.

Cruise info and images for May 5, 2010

May 5, morning: The first sediment cores from deep continental slope sediment are taken by Luke McKay (right); these are uncont-aminated reference cores west of the oil spill area. We expect to see originally similar sediments from similar depths near the spill site, but geochemical and microbially altered by the oil spill.









Bottom sediments are sampled using a large box corer, the  metal box on deck. Box corers collect a large chunk of seabottom and return it to the surface, where smaller sediment subsamples, for example sediment cores (the brown cylinder of sediment with yellow tape in the middle) are taken. Sediment cores preserve the original chemical and microbial structure and layering of the sediment
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Steaming to the spill site: The first oil is found; it forms brown-orange slicks on the water surface.














Email from Dr. Vernon Asper, RV Pelican, May 5: "The first [image] is of the edge of the actual plume of oil rising to the surface. This grades from solid dark brown to what I would describe as aggregates of tan oil and then to a thin sheen of oil.  In the heart of the slick, you can see intermittent clouds of gas hitting the surface and an occasional very black blob but those are rare.  Further away, maybe 6-10 miles, most of the oil has been “dispersed” and is rather orange in color.  Here in the slick, it’s mostly brown because they apparently haven’t applied the dispersants, most likely because of all of the ships in the area.  And of course the odor is impressive.  No one is on deck on the ships or the platform; we try to limit our exposure as well.
"This photo is of 3 of the large ships working over the leak.  Two of these are from Norway; all have at least one ROV in the water and they also have cranes with large cables lowered over the side.  We don’t see where they are pumping down dispersant to the actual leaks; no sign of large hoses or the like.  Also visible in this picture is the drilling rig that has been placed nearby to relieve the pressure from the leak.  We tried to contact anyone who would talk to us; on the “DD 3” (Development Driller III).  We asked how close we could get; they said to stay 500 meters away which is amazing; we expected a much larger “CPA” (closest point of approach0.
    There are also lots of large ships to the east of us; they are working to skim the oil off of the surface.  We saw one large plume of black smoke rising from a point several miles to the east so they are working to burn off some of the oil as well. One interesting observation is that the brown aggregates are mostly below the surface, some of them several meters down.  This raises the question of where all of this material is going and what effect it will have on the ecosystems.  As you know, there are lots of midwater organisms the feed on the normal, organic, marine aggregates that we call “marine snow” so I wonder if these potentially toxic aggregates might find their way into the food web as well.  
    We are now hove to about 1 mile from ground zero. We will be acquiring some water samples and then some sediment samples and I will be bringing some of this material back for us to study with the rest of it going to scientists at NOAA and other universities.  This sampling scheme was put together very quickly by our Principal Investigator (Ray Highsmith) working with Arne Diercks (the Chief Scientist on this cruise) with the help of others form NOAA and other agencies. We are going to be back in port on Sunday morning and hope to be able to pick up some gear and supplies so that the next leg of the cruise can apply more optimal sampling to address specific questions." End of quote.

Site Report for May 6, 2010 (Vernon Asper)

 We are still in the vicinity of Ground Zero and are continuing to collect sediment samples on several transects from the spill site to points north and west.  We are looking for the effects of the oil with seems to be leaving the surface and settling towards the seafloor at an unknown rate.  I have attached two photos:  The first 

shows the NIUST team in action, recovering the box corer.  This is a very heavy device that is more complicated than it looks and these guys are experts at making it work so we have had 100% success in obtaining useful cores.  Each core takes about 2-3 hours because of the time it takes to lower this device to 1500m, recover it, remove the box from beneath it, sub-sample the mud in the box, clean all of the excess mud up, and re-load it for the next core.  Pictured are, from left to right, Chris Berkey (the freelance photojournalist who has promised to give us copies of his excellent photos), Matt Lowe (from Ole Miss; a genius at getting things into and out of the water), Dr. Arne Diercks (USM grad and current employee, also Chief Scientist for the cruise), and Andy Gossett (also Ole Miss; can make anything or make anything work).  These guys are all masters at what they do and the coring operation always runs safely and without a hitch. 

The second photo shows the surface of the water at the current sampling location.  Okay, so it’s not all that photogenic but it gives you a really good idea of what we’re seeing out here. On the surface is a very light sheen of oil, as you’d expect to see with an oil spill.  Along with that are the tan clumps of oil ranging in size from pea to pancake.  Some of these can be very filamentous in shape but others are just ragged clumps of oil, appearing almost as if there were some kind of fiber involved.  Most interesting to us, however are the smaller clumps (I’m calling them oil aggregates) that appear below the surface.  It’s counter-intuitive to see “oil” sink below the surface but you have to remember that this isn’t motor oil, it’s crude oil and there are all kinds of compounds in it, including many that are heavier than water.  Apparently, the dispersants that they are spreading on the surface (using C-130’s and ancient DC-3s that have been retrofitted with turbo-prop engines) are causing this oil to coagulate into these relatively large clumps.  This reduces the amount of surface area, which causes drag, for the amount of oil volume, so if they’re heavier than water, they’ll sink more rapidly than they would have, had they not aggregated.  The question is, what happens to this oil after it leaves the surface?  How rapidly does it sink?  How far down has it been able to travel so far?  What effect is it having on the midwater ecosystem?  What will its ultimate fate be?  We are planning to bring some novel gear along next time to investigate some of these questions but it’s clear that some long term monitoring will be required to address many of these issues.  

One of the instruments that we’ll bring along next time is a small (some call it “micro”) Remotely Operated Vehicle (ROV).  We’ll use this to qualitatively describe the concentration of oil aggregates in the surface layer down to about 75m, which is as far as it can go. We’ll also be looking at the plankton in the water and maybe even the nekton (fish) if any come around.  In addition, NIUST has a really large ROV that is capable of placing and recovering relatively large instruments on the sea floor and we expect to have that on site in the weeks to come but not for the next leg.

Background info May 6 (Andreas Teske).

Posted May 6, 11 pm. The oil spill has occurred ca. 9 miles southeast to a long-term seafloor observatory, MC118, established by the Gas Hydrate Consortium at the University of Mississippi. 




The geological setting, topography, geo-chemistry and microbiology of the MC118 site, its massive surface-breaching hydrates and microbial mats, have been studied since 2002. These data serve now as a baseline for the state of the seafloor before the oil spill. 

Background info on the MC118 observatory is available under http://www.olemiss.edu/depts/mmri/programs/gulf_res.html

The bathymetric image of the seafloor at MC118 is based on data acquired by C&C Technologies and reprocessed by Leonardo Macelloni (University of Mississippi) and Alessandro Bosman (University of Rome). The regional image in the upper right corner was plotted by Brad Battista, a Consortium member who completed his Ph.D. at the Univ of South Carolina, developing novel processing strategies for seismic data from MC118.


 For more images, check out the picture gallery of The Guardian, UK:

http://www.guardian.co.uk/environment/gallery/2010/may/06/deepwater-horizon-oil-spill-oil-spills?picture=362271866


 















Cruise summary May 5/6, by Arne Diercks & Vernon Asper, NIUST/NOAA

Posted May 7, 10 am by Andreas Teske. 

We had another very productive day on board the Research Vessel Pelican and have acquired all of the sediment samples that were our highest priority and we are now moving on to collect those that had been assigned lower priorities.  We started by sampling along a transect from “ground zero” (the Deepwater Horizon platform) northwest towards the MC118 hydrates observatory site, acquiring box cores of sediment every 2 miles along the way.  Each box core was photographed, described, and subsampled for several analyses to be performed by investigators at UNC, USM and elsewhere.  While we are unable to perform chemical analyses on board the ship, none of the samples were obviously contaminated by oil.  However, there were many places where we did experience heavy concentrations of oil on the surface. 

Most of the areas were characterized by what we are calling “oil aggregates” which are apparently the result of the action of the dispersant on the floating oil. These aggregates are tan in color (photo left),closely resemble natural, organic aggregates (probably meant marine snow, but the resemblance is accidental; AT), and range in size from a few mm to more than a cm. They were distributed throughout the upper water column, indicating that the dispersants seem to be accomplishing the goal of preventing the floating oil from reaching the coastline. 

Upon reaching the MC188 site, for example, we found a several acre patch of very thick, colorful bands of oil that apparently had not received any application of dispersant yet (see picture left). This site is more than 40 miles from the closest point of land so this oil presents no immediate danger but it was surprising to see so much oil 10 miles northeast of ground zero while the areas in between had less.

Our next station was 10 miles due north of ground zero and the next 10 miles north of that.  In both cases, we saw no oil either at the surface or in the sediments.  We decided to make a transect towards Chandeleur Island where we had heard oil was washing ashore.  We visited two stations in 150m and then in 64m and again, no oil was detected.  By this time, it was quite late and our coring team needed a break so we ceased operations until tomorrow.  Our plans for the next two days will include a much wider scale of sampling, starting with a transect to the east and then a return, parallel transect moving due west towards ground zero and then back to Cocodrie on Saturday night.

Really Nasty Stuff

Update May 7, posted 11 pm. 

Luke McKay: Here's a picture of one of nastiest sites we've seen, almost directly above MC118!  we think that the dark stripe in the middle is the crude oil, and the orange edges are where dispersant is in contact with it and inducing the chemical transformation that maybe makes it sink. 







Cruise update May 7, by Arne Diercks & Vernon Asper, NIUST/NOAA

Posted May 10, 10 am by Andreas Teske

Today we continued our coring and covered a much wider area than yesterday but at lower sampling resolution.  We started a transect at a point due east of the Mississippi River Delta and took core samples roughly ever 30 miles. Following this, we turned southwest to a point at the same latitude as the Deepwater Horizon spill (28°N) but 20 miles to the east.  During the entire transect (108 n.m. total length), we watched diligently for signs of oil on the surface and noted when we could and could not detect an oil odor.

Based on the various maps and satellite images available to us, we were expecting to encounter a considerable amount of oil in this area but instead, found none except for a thin sheen at the station northwest of our present position (site 22 in the attached table below).  At that site, there was a distinct oil odor and a very faint but visible sheen on the surface.  This sheen was only apparent when the surface tension was broken by our instruments or the side of the ship.  At our current site, we can discern no sheen (well after sunset) and only a very faint oil odor, in spite of being within 20 miles of the spill site.  The wind has been nearly calm all day and is currently from the southeast at 9 knots with flat seas.

Our plan for tomorrow (May 8) is to traverse back towards the spill site and acquire more cores to the north and west, in areas where the latest projections predict the presence of oil on the surface.  In the evening, we will set course for Cocodrie where we will exchange personnel and pick up equipment on Sunday morning in preparation for our second leg next week. This work will involve more water sampling and the use of new sensors including a Wetlabs fluorometer intended to detect oil at depth.  We will perform transects in every direction outside the main cleanup area, to avoid conflicts with the skimming vessels, to investigation the potential advection of oil at depth.

Cruise update May 8, by Arne Diercks & Vernon Asper, NIUST/NOAA

Posted May 11, 10 pm, by Andreas Teske

This was an interesting day, with some surprises, including the announcement that the dome that was intended to capture the escaping oil had been clogged by the formation of gas hydrates. The irony of this report is that our Gulf of Mexico Gas Hydrates Consortium has been studying this phenomenon for nearly 10 years at a nearby site with funding from NOAA, MMS, DOE, and support from NIUST. As you probably know, hydrates are formed when, under the right conditions of temperature and pressure, gas and water combine to form a crystal lattice that resembles white ice. This material forms spontaneously in nature as well as inside pipes and equipment placed on the seafloor during hydrocarbon recovery efforts. Our studies have focused on investigating the rates of formation, the stability, and the composition of the hydrates as well as the interaction between the chemistry and the biological community living in proximity to the hydrates on the seafloor. Scientists from around the world have collaborated in this endeavor and an impressive array of novel sensors and sampling equipment have been developed and deployed at this site, including some that remain in place.

After our last core of the day yesterday, we once again hove to, this time at a site 20 miles due east of the Deepwater Horizon site. At that time (midnight), the winds were calm and no oil or odor were evident. At 04:00, however, the winds picked up from the west and a sheen of oil arrived and, along with it, a distinctive hydrocarbon odor. From there to our next station, sited at 2 miles due south of the DH rig, we recorded observations of the oil characteristics every 15 minutes (see attached “oil observations” table). As this table records, we passed through some areas of high concentrations of oil while others were moderate or clear. The skimmer fleet was north of us during this transit so we presume that the oil was even heavier in that area. This was truly an impressive sight. While the skimmer fleet is doing an amazing job of containing the oil, a considerable amount of it remains in a large slick that is extremely unpleasant to see or smell. I sincerely hope that the BP team is able to continue to keep this oil under control and that none of it ends up on and Gulf Coastbeaches!

Summary Leg 1 sampling stations, May 5-8

Following this transit, we acquired cores at 4 additional sites starting near the DH rig (site 24, see updated station map below) and progressing in to a site near the SouthwestPass of the Mississippi River (site 27). Nothing anomalous was seen in or on any of these sediment cores with the possible exception of roughly 6 dead euphausids at site 24. Although this is an unusual find and we see no definitive link to the oil, we do intend to follow up on this observation by acquiring an additional sample from this location for the express purpose of carefully preserving such organisms for further study.

The shallow site (27) was in only 17m of water and was adjacent to one of the areas in Louisiana where oil had been reported as washing ashore. Our intent here was to investigate whether oil had also been deposited on the seafloor but we saw none either on the surface or on the sediments. This site is characterized by rather fresh water (11ppt salinity) due to the river discharge both to the west and to the east. It can be expected that this discharge will displace the ocean surface water and help to buffer the shoreline from oil deposition except during strong southerly winds.

We are currently headed back to Cocodrie (expected et 06:30 on May 9) where we will exchange personnel and pick up new equipment for the second leg. This will include a towed package (Acrobat) with CDOM fluorometer tuned to detect hydrocarbons, an ROV for investigating subsurface oil aggregates, a multispectral sensor for ground-truthing NASA flyovers, an innovative pCO2sensor, an acoustic recorder intended to monitor marine mammals, and a collection of supplies for preserving plankton, water, and sediment samples. We hope to be paving the way for future, more detailed investigations of all critical aspects and impacts of this event.

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