Monday, March 31, 2014

Deep-C Researchers On-Site at Oil Spill in Galveston Bay

Thick, tar-like oil collected at Seawolf Park in Galveston Bay.
(Photo credit: Robert Nelson, WHOI)
There is an old adage that soldiers are always preparing to fight the last war. So it’s not a stretch to think that future spills in the Gulf of Mexico will be similar to the Deepwater Horizon (DwH) disaster. But a recent spill in Galveston Bay (near Texas City, Texas) proves otherwise, and we are collecting samples in our continued quest to understand the fate and transport of oil in the Gulf and elsewhere. 

On March 22, 2014, a container ship, the M/V Summer Wind, collided with the oil barge, Kirby 27706. One of the starboard tanks on the Kirby was ruptured and released 168,000 gallons of fuel oil; the Summer Wind did not leak any oil. The Houston Ship Channel and Intracoastal Waterway were closed for three days. Over the course of the next week a large plume of oil that washed out of the channel into the Gulf of Mexico drifted south to impact shorelines up to 200 miles away on Matagorda Island and Mustang Island. 

The Kirby spill could not be any more different than the DwH that spilled an estimated 160 million gallons of light, sweet crude oil nearly four years ago in the Gulf of Mexico at the bottom of the ocean floor from an uncontrolled well for 87 days. The Kirby spilled much less oil than the DwH but it was a thick, black viscous product called an intermediate fuel oil. 

WHOI’s Bob Swarthout collecting oil over 50 miles
from the spill location near Freeport, Texas.
(Photo credit:  Robert Nelson, WHOI)
Fuel oils are prepared from high-viscosity refinery residues remaining after crude-oil distillation (think bottom of the barrel) that are blended with low viscosity distillates, such as kerosene, to enable transport and use. Because the residues from crude oils and the distillate can vary, there is no standard fuel oil. While this variability provides some challenges to the oil spill community, spills of fuel oils are often called “dirty bathtub” spills as they leave a ring of oil along coastlines. 

To understand how the oil changes or “weathers” we have begun a sampling campaign along the beaches and shores of Galveston Bay and the impacted Gulf of Mexico coastline. We are particularly keen to observe if any massive changes due to oxidation, similar to what we saw following the DwH, is occurring. And we can compare it to three other fuel/oil spills we are investigating: Prestige (2002; Spain); Bouchard 120 (2003; Buzzards Bay, MA); and Cosco Busan (2007; San Francisco Bay, CA). 

Me (Bob Nelson) collecting sticky, tar-like oil from an
impacted marsh. (Photo credit:  Bob Swarthout, WHOI)
During our initial trip to the region, we collected scrapings of oil from marine debris and oil coated marsh grasses near the site of the spill. At Seawolf Park, with a World War II era destroyer as a backdrop, we sampled large amounts of pooled oil from divots in concrete rip-wrack. We also drove south along the coast to find oil that had been exposed to different weathering conditions. Numerous response crews working along the coast showed us that oil was washing up for tens of miles along the Gulf coast, and we collected samples of apparently fresh oil along approximately 50 miles of coastline between Galveston and Freeport. 

We have a lot more work to do before we will have any answers. But first, we have to get the samples back to our laboratory (we also plan to share the samples with the Florida State University National High Magnetic Field Lab and with Christoph Aeppli at the Bigelow Lab).  We will “fingerprint” the samples to confirm the samples share the same source and then examine “weathering” patterns. 
Galveston Marine Corp Base, March 31, 2014 (Photo credit: Robert Nelson, WHOI)

Oiled rip-wrack at Seawolf Park with trapped pockets of oil.
(Photo credit: Robert Nelson, WHOI)




Posted by: 

Robert Nelson, Research Specialist
Woods Hole Oceanographic Institution 

Bob Swarthout, Post-Doc
Woods Hole Oceanographic Institution

Wednesday, March 26, 2014

Emily Hladky's Internship, Spring 2014 - Part 5

How did oil from the Deepwater Horizon oil spill reach the sea floor? Last week, I talked about the “flocculent blizzard” hypothesis which, for review, describes the aggregation and flocculation of hydrocarbon particles and other component particles which forms marine snow (Passow et al., 2012). When the marine snow sinks, it covers the top sediments, having lethal effects (Passow et al., 2012; Brooks et al., In Press), often gradual suffocation of benthic organisms (Passow et al., 2012).

This week I will be talking about the second hypothesis of how the oil reached the sea floor: the “bathtub ring” hypothesis. To give you a brief background, when the oil was released from the well, it was released at a depth of about 1500 meters. When oil is released at great depth it is under high pressure (~160 atm) and low temperature (4°C), which causes it to act differently than oil at the surface (Thibodeaux et al., 2011). The substance released from the wellhead contained many soluble hydrocarbons (Ryerson et al., 2012) that dissolved in the water column and remained at depth, forming plumes (Hazen et al., 2010; Valentine et al., 2010). Two plumes were detected: one deep, persistent plume between 1000-1200 meters deep and a slightly shallower plume between 800-1000 meters deep, northeast of the wellhead (Passow et al., 2012; Valentine et al., 2010).

The “bathtub ring” hypothesis describes the movement of these plumes through the water column; these plumes come in direct contact with the sediment surface causing lethal and sub-lethal effects, most likely a sudden mortality event caused by the toxic hydrocarbons (Schwing et al., In Press). With this hypothesis, the heaviest impacted areas would be expected to occur where the plumes are located (Brooks et al., In Press), between 800-1000 meters and between 1000-1200 meters, which has been seen in some studies. The sudden presence of toxic hydrocarbons would have had a dramatic impact on foraminifera that had not previously been adapted to the presence of hydrocarbons.

Both hypotheses are believed to have occurred and both had negative effects on most benthic foraminifera, though there are some species that are adapted or considered opportunistic species, which are species that take advantage of abundant food and are able to thrive in lower oxygen environments (Sen Gupta and Machain-Castillo, 1992). Though some species flourish, there was a great decrease in the number of benthic foraminifera present after the spill. Hopefully in the next few weeks I will have more data and we will be able to determine which hypothesis affected the sites and how they are recovering.

References:
Brooks, G.R., Larson, R.A., Flower, B., Hollander, D., Schwing, P.T., Romero, I., Moore, C., Reichart, G.-J., Jilbert, T., Chanton, J., Hastings, D., In Press. Sedimentation Pulse in the NE Gulf of Mexico Following the 2010 DWH Blowout

Hazen, T.C., Dubinsky, E.A., DeSantis, T.Z., Andersen, G.L., Piceno, Y.M., Singh, N., Jansson, J.K., Probst, A., Borglin, S.E., Fortney, J.L., Stringfellow, W.T., Bill, M., Conrad, M.E., Tom, L.M., Chavarria, K.L., Alusi, T.R., Lamendella, R., Joyner, D.C., Spier, C., Baelum, J., Auer, M., Zemla, M.L., Chakraborty, R., Sonnenthal, E.L., D'Haeseleer, P., Holman, H.-Y.N., Osman, S., Lu, Z., Van Nostrand, J.D., Deng, Y., Zhou, J., Mason, O.U., 2010. Deep-Sea Oil Plume Enriches Indigenous Oil-Degrading Bacteria. Science, 204.

Passow, U., Ziervogel, K., Asper, V., Diercks, A., 2012. Marine snow formation in the aftermath of the Deepwater Horizon oil spill in the Gulf of Mexico. Environmental Research Letters 7, 11 pp.

Ryerson, T.B., Camilli, R., Kessler, J.D., Kujawinski, E.B., Reddy, C.M., Valentine, D.L., Atlas, E., Blake, D.R., de Gouw, J., Meinardi, S., Parrish, D.D., Peischl, J., Seewald, J.S., Warneke, C., 2012. Chemical data quantify Deepwater Horizon hydrocarbon flow rate and environmental distribution. Proceedings of the National Academy of Sciences of the United States of America 109, 20246-20253.

Schwing, P.T., Flower, B.P., Romero, I.C., Brooks, G.R., Hastings, D.W., Larson, R.A., Hollander, D.J., In Press. Effects of the Deepwater Horizon Oil Blowout on Deep Sea Benthic Foraminifera in the Northeastern Gulf of Mexico, pp. 1-22.

Sen Gupta, B.k., Machain-Castillo, M.L., 1992. Benthic foaminifera in oxygen-poor habitats. Elsevier Science Publishers B.V., Amsterdam, Marine Micropaleontology, pp. 183-201.

Thibodeaux, L.J., Valsaraj, K.T., John, V.T., Papadopoulos, K.D., Pratt, L.R., Pesika, N.S., 2011. Marine Oil Fate: Knowledge Gaps, Basic Research, and Development Needs; A Perspective Based on the Deepwater Horizon Spill. Environmental Engineering Science 28, 87-93.

Valentine, D.L., Kessler, J.D., Redmond, M.C., Mendes, S.D., Heintz, M.B., Farwell, C., Hu, L., Kinnaman, F.S., Yvon-Lewis, S., Du, M., Chan, E.W., Tigreros, F.G., Villanueva, C.J., 2010. Propane Respiration Jump-Starts Microbial Response to a Deep Oil Spill. Science, 208  

Posted by:
Emily Hladky - St. Petersburg, FL

Monday, March 10, 2014

Emily Hladky's Internship, Spring 2014 - Part 4

How did oil from the Deepwater Horizon oil spill reach the sea floor? For the next two weeks, I will be talking about the two current hypotheses that explain how oil reached the seafloor and affected benthic foraminiferal communities.

According to NOAA’s calculated Oil Budget, 17% of the spilled oil was directly recovered from the well head, 13% was naturally dispersed, 23% was evaporated or dissolved, 16% was chemically dispersed, 5% burned, and 3% skimmed at the surface, leaving about 23% of oil unaccounted for (Lohr et al., 2010), which could have fallen to the sea floor, greatly effecting benthic foraminifera. With more recent evidence, it is believed that about 60% of oil released reached the surface and 40% of oil and dispersant is unaccounted for (Brooks et al., In Press). There are many ways that oil from either the surface or plumes could have reached the seafloor, leading to two hypotheses that could explain the deposition of hydrocarbons on the seafloor: the “flocculent blizzard” hypothesis and the “bathtub ring” hypothesis (Schwing et al., In Press; Brooks et al., In Press).

This week I will talk about the “flocculent blizzard” hypothesis. The “flocculent blizzard” hypothesis describes the aggregation and flocculation of hydrocarbon particles and other component particles that form marine snow (Passow et al., 2012). Marine snow is very sticky and collects both organic and inorganic particles in the surrounding area and as it moves throughout the water column (Brooks et al., In Press). Once the marine snow loses its buoyancy, it rapidly sinks to the sea floor, where it covers the top of the sediments (Passow et al., 2012; Brooks et al., In Press) and could have lethal effects, including gradual suffocation of benthic organisms (Passow et al., 2012), specifically benthic foraminifera (Schwing et al., In Press). If the “flocculent blizzard” hypothesis is true, large amounts of a combination of organic matter and oil would have fallen to the sea floor, increasing respiration and therefore decreasing oxygen. Foraminifera that had not previously adapted to anoxia would not have been able to survive long periods without oxygen, though tolerance limits for foraminiferal species to oxygen are not clearly understood (Sen Gupta and Machain-Castillo, 1992). Once these deep sea communities are affected, they may be very slow to recolonize and could take years for full recovery (Montagna et al., 2013).

Next week I will talk about the “bathtub ring” hypothesis!

References: 

Brooks, G.R., Larson, R.A., Flower, B., Hollander, D., Schwing, P.T., Romero, I., Moore, C., Reichart, G.-J., Jilbert, T., Chanton, J., Hastings, D., In Press. Sedimentation Pulse in the NE Gulf of Mexico Following the 2010 DWH Blowout

Montagna, P.A., Baguley, J.G., Cooksey, C., Hartwell, I., Hyde, L.J., Hyland, J.L., Kalke, R.D., Kracker, L.M., Reuscher, M., Rhodes, A.C.E., 2013. Deep-Sea Benthic Footprint of the Deepwater Horizon Blowout. PLoS ONE 8, 1-8.

Passow, U., Ziervogel, K., Asper, V., Diercks, A., 2012. Marine snow formation in the aftermath of the Deepwater Horizon oil spill in the Gulf of Mexico. Environmental Research Letters 7, 11 pp.

Schwing, P.T., Flower, B.P., Romero, I.C., Brooks, G.R., Hastings, D.W., Larson, R.A., Hollander, D.J., In Press. Effects of the Deepwater Horizon Oil Blowout on Deep Sea Benthic Foraminifera in the Northeastern Gulf of Mexico, pp. 1-22.

Sen Gupta, B.k., Machain-Castillo, M.L., 1992. Benthic foaminifera in oxygen-poor habitats. Elsevier Science Publishers B.V., Amsterdam, Marine Micropaleontology, pp. 183-201.  

Posted by:
Emily Hladky - St. Petersburg, FL

Monday, March 3, 2014

Ben LaBelle's Internship, Spring 2014 - Part 3

Hey everyone,

I thought you might like to see a little more of what the sorting process looks like here in the lab. First, the sample starts out looking something like this, lots of mud and organisms in a jar filled with formalin and seawater. Now all we have to do is separate the animals from the mud.

To start that process, the sample is emptied into a sieve and rinsed with clean water to remove as much of the fine clay particles as possible.

Once the clay has been removed, the sample is stained with rose bengal. This stain turns the organisms in the sample a bright red color, but leaves the sediment uncolored, making it easier to sort the sample.

The samples are stained overnight before being rinsed again to remove any unused stain from the sample. The samples are then placed into petri dishes for sorting under the microscope. Each sorter has their own system that they prefer to use to ensure that all the organisms are sorted out of a sample. I prefer to use a very large dish with small gridlines added to the back so I can spread out the sample and systematically search line by line for organisms.

Any organisms that are found are sorted into major groups and placed into small, labeled glass vials to be further identified by Arvind.

Once the sample has been fully sorted, the remaining sediment is placed into a small jar for storage.

Here’s what a pre and post sorting sample look like side by side. As you can see, a lot of the sediment is washed away during the rinsing process making the sorting process much easier. It’s still a lot of work to sort the organisms out of the sand, shell pieces, and clay balls that are left over, but it’s certainly easier than trying to find copepods and polychaetes in a giant jar full of mud!

Posted By:
Ben LaBelle, Florida State University