Marine Debris Assessment Expedition
July 20-25, 2009
aboard the R/V Manta
Click on a link below to jump to a specific expedition blog or scroll down the page to read them all.
Monday, July 20 - Jennifer DeBose
Tuesday, July 21 - Scott Fowler
Wednesday, July 22 (a.m.) - Emma Hickerson
Wednesday, July 22 (p.m.) - Jeff Reid
Thursday, July 23 (a.m.) - Russ Green
Thursday, July 23 (p.m.) - Marissa Nuttall
Friday, July 24 (a.m.) - G.P. Schmahl
Friday, July 24 (p.m.) - Ryan Eckert
Saturday, July 25 (a.m.) - Greg McFall
Saturday, July 25 (p.m.) - Doug Kesling
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Click here to learn more about the Expedition Team.
Saturday, July 25, 2009
by Greg McFall
Gray's Reef National Marine Sanctuary
Line Office Diving Officer, Technical Diver
Azure blue--a color which beckons me and of which I never grow tired experiencing; this is the color of the water today at Bright Bank in the Gulf of Mexico.
|Three divers in azure blue water at Bright Bank. Photo: Scott Fowler/NURC
We’ll dive to about 190 feet to search for an area of damage resulting from excavation conducted in the 1980s to recover the supposed remains of a Spanish galleon. Following on the heels of Mel Fisher’s discovery of “Atocha” one could imagine the fervor and excitement of finding the next big shipwreck and becoming a wealthy and famous person. Apparently, several people in that decade decided that Bright Bank was a likely place for such a search to begin.
Bright Bank, named after Texas A&M researcher Tom Bright who conducted pioneering research in the Gulf of Mexico, lies on the outer continental shelf approximately twelve miles east of Flower Gardens Banks National Marine Sanctuary (FGBNMS). Though not currently contained within the sanctuary's boundaries, Bright Bank is being proposed for inclusion in the new Management Plan for FGBNMS due to the continued threat of impacts to its unique and fragile resources. The bank rises from the seafloor four hundred feet below to within one hundred feet of the surface. Contained on this one bank are organisms which range from shallow water sponges and fishes to corals that exist in the mesophotic, or twilight zone, where light starts to diminish but is sufficient to sustain growth and nutrition for photosynthetic organisms.
We’re all geared up and ready to get in the water. To make a dive like this requires much more equipment than what you’d normally have to take in the water to conduct a scientific dive. We have double tanks on our backs which hold the “bottom” mixture that we’ll be breathing from redundant regulators on the dive. Normally, the air we breathe at sea level contains 21% oxygen and 79% nitrogen; the mixture we’ll be inhaling contains 21% oxygen, 23% helium and 46% nitrogen; the helium helps to cut the narcotic effect of nitrogen at these depths. In addition, we’ll be carrying our decompression gasses which are comprised of a bottle of 36% oxygen under our left arm which is attached to our stainless steel backplate and harness and 100% oxygen in a bottle under our right arm.
|Technical diving requires a lot of gear! Redundancy is important, because you can't return to the boat for extras. Note the extra decompression tables taped to Scott's left fin (the white patch) in case both of his computers fail.
We have two cord reels on which to send two different lift bags to the surface, we have an emergency pouch with backup decompression tables, two knives, a flashlight, a mirrored signaling device, a whistle and wear two dive computers which are designed for use at this depth and for the mixture we breathe. Add to this, an underwater scooter, a collection bag for scientific samples and a camera to take pictures and we’re ready to jump in carrying about 125 pounds of gear each. Standing there, ready to enter the water makes you feel as if the ocean is where you belong, where you can find some comfort from the heavy burden you bear on the surface. One good splash and the thought is confirmed!
As we motored down the descent line towards our target site we began seeing the side of Bright Bank disappear into the abyss along with us. Moving past the light seeking corals and shallow water sponges to where few organisms cling to the surface of the limestone seafloor, we began to make out the plateau at around 190 where we would begin our search for an excavation site in the side of the bank where treasure salvors had attempted to “tunnel” under the reef to find the remains of a shipwreck.
At about 10 minutes into the dive we arrived at a site that could have fit that description. There was a large hole in the side of the bank with an anchor and chain draped across the ledge nearby. On the seafloor, there was a large metal tube (big enough for two divers to swim through) lying in waste, which may have been used for the salvage operation. We documented the site with video and took pictures to show those on the surface what we’d found.
|Mauritius and Scott motor past a large metal tube that lies on the seafloor at Bright Bank, probably left by treasure salvagers in years past. Photo: Greg McFall/ONMS
Moving further along the edge of the bank we encountered another large anchor which might indicate that a ship had been moored there to support salvage operations. Its quite odd to think that a treasure laden ship could wreck on a pinnacle which lies 100 feet below the surface; odder still to think that one would be “buried” by 60 feet of coral. Given that most of the corals which occupy the substrate at Bright Bank grow at the rate of one centimeter per year, even if there were a wreck under sixty feet of coral, it would have been buried not in the 1800’s or even the 1700’s but over 1800 years ago!
Its hard to believe that anyone would come to an area as remote and beautiful as this bank is and think that there might be a galleon sunk nearby. The “gold” for two of the divers was being able to see several large marbled grouper in their natural habitat; curious enough to want to know what we were doing down there but too timid to stay around for too long.
Much like the bubbles we exhaled, our narcotic dreams of bullion and doubloons burst as we headed back for the surface and the reality that this bank is a special place which requires special protection; protection not only for the unique and valuable natural resources which live on and near it but protection from further degradation and destruction by those who would seek to look past its intrinsic value and natural beauty.
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Saturday, July 25, 2009
by Doug Kesling
National Undersea Research Center (NURC)
Diving Safety Officer, Technical Diver
We just completed our final trimix dive of the NOAA Marine Debris mission. My dive team consisted of Russ Green, Jeff Reid and myself. We were asked to survey the deep side of East Flower Garden Bank.
We dropped in to 155 feet of water and began the survey using video camera recording scooters and utilized a hand-held HD video camera. We followed a 190 degree course heading and were instructed to make our way up the bank up to 90 feet while filming and surveying the surrounding coral reef habitat. There was a slight current, but we were able to proceed on our survey of the deeper parts of the bank as a buddy team.
The diver scooter cams we used proved to be a valuable tool for collecting a lot of video data of the dive site. We stopped to remove a few coral samples and left bottom after 25 minutes. The NOAA safety divers reached us at 100 feet and monitored our decompression phase while relieving us of the extra equipment we carried.
This dive was uneventful, and we made our way back to the surface completing the dive with an additional 55 minutes of in-water decompression stops using nitrox and oxygen to expedite the deco.
The deeper part of East Flower Garden Bank was an exciting place to visit. It represented good coral cover and diversity, with many fish. This marine environment appeared to be slightly different than what we had experienced at both Bright and Stetson Banks during the other deep diving operations of this cruise.
This dive mission was funded by NOAA and consisted of an assessment of marine debris removal in deep water. The NOAA Undersea Research Center at UNCW was asked to support and supervise the technical diving phase of this NOAA operation.
|A basket full of marine debris on the back deck of the R/V Manta.
In addition to the marine debris effort, the cruise served as a shake down cruise for the new R/V Manta research vessel utilizing a technical diving modality. This platform was ideal for this type of diving with loads of deck space to support all the extra tech diving equipment and specialized gas cylinders.
We operated in a “live-boat” mode which enabled us to drop divers on specific targets of opportunity. Ship's personnel and science party worked well together supporting all necessary safety roles and positions to make this technical diving operation and marine debris removal cruise an overall success.
The R/V Manta also was effective in supporting the NOAA chase boat requirement and allowed for effective utilization of the Hyperlite, Hyperbaric Stretcher for dive operational risk management.
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Previous Blog Page
For a general overview of this expedition, please visit the Marine Debris Assessment Expedition 2009 page.
To learn more about the scientists on this expedition, please visit the Expedition Team page.
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