Diving the Dead Zone

Back in August, I accompanied Nancy Rabalais and LUMCON dive safety officer Ben Acker on a dive trip to station C6C. That location is an oil platform south of Terrebonne Bay with equipment for monitoring water conditions such as temperature, salinity, and dissolved oxygen. I’ve posted before about our work there exchanging equipment and taking samples. I’m involved with the LUMCON dive team through my continued collaboration with Nancy in researching seasonal hypoxia (a.k.a. the Dead Zone) in the region. For example, see our most recent paper on dead zone microbiology. The purpose of this particular trip was to show CBS News the heart of the Dead Zone. Nancy’s recent NOAA-sponsored hypoxia cruise (see Celeste’s trip report) revealed that this year’s zone of hypoxia was the largest ever, and it has attracted a lot of attention as a result. Below is the full-length GoPro footage of the dive, in three parts. A big chunk of the second and third parts are in blackness, at the bottom of the dive, where we searched, in vain, for a lost piece of equipment. But there is some beautiful footage of the rest of the water column if you scroll through the individual videos. A portion of this was included in the CBS News profile. UPDATE 10/4/17: Times-Picayune reporter Sara Sneath found this post and put together a cool summary and link for us at NOLA.com.

 

 

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The Dead Zone on CBS News

After the research cruise in which Celeste helped Nancy Rabalais and her team measure the largest Dead Zone yet, news agencies are taking notice. Yesterday I dove with Nancy and Ben Acker of LUMCON at a site in the heart of the Dead Zone, station C6C (featured in many previous posts). Nancy maintains multiple SONDEs on a leg of the oil platform to measure dissolved oxygen, temperature, salinity, and other important parameters. Our purpose yesterday was to search for a SONDE lost on a previous dive and introduce the CBS News team to the region of hypoxia. We also wound up providing footage for the CBS News crew to use in their segment that you can watch HERE. I shot the underwater footage. We’ll be posting the full video later. Here are some shots from the R/V Acadiana yesterday.

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Station C6C under stormy skies.
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Captain Carl and CBS News Producer Warren Serink look on as we approach C6C.
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Through a condensation-laden window, you can just see Nancy interviewing with Jeff Glor on the left while cameraman Max Stacy gets additional footage.
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On the drive out, rain on the western horizon.

Breathless: Mike’s Journey to Find Elusive Bacteria in the Oxygen-less Ocean

By Paige Jarreau. LSU biological sciences graduate student Mike Henson recently conducted field research in the great big blue! Mike works in Dr. Cameron Thrash’s lab. We asked him to tell us more about his field experience at sea below. Enjoy!

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Port is now behind us! The R/V Oceanus and crew is headed to sea. Credit: Mike Henson.

Waves stretch far into the horizon. The sun’s rays pierce the crystal clear blue water. The ocean here gives no hints about its oxygen-less waters beneath its depths. Yet, about 100 miles west of Manzanillo, Mexico in the Eastern Northern Tropical Pacific is one of largest anoxic bodies of water, or oxygen minimum zones (OMZ), in Earth’s oceans.

OMZs form when nutrient rich bottom waters from the Pacific Ocean are brought up to the surface, causing large blooms or growth explosions of photosynthetic algae. As the algae begin to die, other microscopic organisms (or backterioplankton) in the water consume oxygen to metabolize organic matter produced by the algal cells. Once you reach 100 meters below the surface, oxygen levels begin to decrease. At 300 meters, the oxygen has been completely consumed. Any organisms such as fish passing through these areas that are incapable of living without oxygen will die unless they can escape to the more oxygenated surface waters.

This may sound familiar to many Louisianans. However, unlike the hypoxia (a.k.a. the “dead zone”) that occurs seasonally in the Gulf of Mexico from nutrient pollution, this naturally occurring oxygen minimum zone is present year-round.

In the Thrash lab, we study the microbiology of northern Gulf of Mexico hypoxia. We are also collaborating with Chief Scientist Dr. Frank Stewart of the Georgia Institute of Technology, who has National Science Foundation funding to study the oxygen minimum zone in the Eastern Northern Tropical Pacific. Scientists from eight different countries, including USA, Canada, Mexico, Iceland, Denmark, Austria, Spain, and Germany, myself included, recently spent three weeks aboard the R/V Oceanus collecting water and sediment to elucidate the organisms and processes involved in forming this peculiar area of the ocean….

See the full interview with Mike and Paige Jarreau, including some epic photos, at The Pursuit LSU College of Science Blog HERE.

Ending the first Diel sampling set


Enjoy some time pictures from time points 0200 and 0600 as we completed our 24 hour survey at the C transect site. The video I have uploaded is of the Platform and its fog horn that sounds every 20 seconds or so. Its a real joy to work and sleep to.

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The sunrise at 0600 this morning. To be cheesy #nofilter
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Sunrise on the Northern Gulf of Mexico after our last CTD cast
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The rain has come back on our way to the 2nd 24 hour survey site

Diel Sampling: Update

Well Day 1 has come and starting to end though my day will still go on for another 10-12 hours. When I woke up this AM, the ship was tossing and rolling quiet a bit for being in the Gulf. The first time point was at 0600 and between lack of sleep, an early morning, and some good waves, I wasn’t exactly feeling bright eyed and bushy tailed, nor was anyone else. Alas, the day went on and the time points began to come and go.

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Waiting for the first CTD cast…also a snap of Lauren Gillies thinking hard about what what their game plan is

The first and second time points were split up by a trip just past the site C6B where Dr. Nancy Rabalais (LUMCON) and Dr. Brian Roberts (LUMCON) took sediment cores for experiments they wanted to run back at LUMCON.

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Setting up the box corer for sampling on the RV Pelican

The second time point was quiet, it was just me sampling so I had the whole CTD to myself. But of course the day isn’t complete without some type of problem ! HA! I am three for three on cruises that have some sort of issue, but some say thats oceanography. Anyways, thanks to the awesome crew of the RV Pelican, and some patience, we got the hydraulics fixed and were able to once again deploy the CTD.

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The sampling set up…woo! Make sure you secure your Yeti things.

While on the water, you get to see a lot of things : dolphins, fish, jelly fish, etc. But today, between time point three and four, I got to see a Water Spout which I was really excited about. It was pretty far away and the only picture we got is thanks to Mary Kate.

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Look to the left of the oil rig and there is a line from the water to the clouds. That is the water spout! Thank again to Mary Kate Rogener for the photo. 

Overall, all is going well. I am waiting for time point 5 to come (2200) and then hopefully get a nap in before time point 6 (0200). Follow my twitter account (@Hensonmw_08) for more live updates. Enjoy some pictures!

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1800 Time Point means everyone is out sampling
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Setting up on the station C6B. Thanks Ari for the photo! 
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Sunset on the Northern Gulf Of Mexico

Cheers,

Mike

Diel sampling: Cruise number two with the LUMCON team

Today, we board the RV Pelican for a second time in two weeks. The Thrash lab will be sampling with Mary Kate Rogener (@mkrogener) from Dr. Samantha Joye’s lab (UGA), Post Doc Ari Chelsky (Brian Roberts, LUMCON), Lauren Gillies and Erin (@GilliesLE) from Dr. Olivia Mason (FSU), and Wokil Bam from Dr. R. Eugene Turner‘s lab (LSU) under the lead of Dr. Nancy Rabalais (LUMCON).

The RV Pelican sitting in Port at LUMCON.
The RV Pelican sitting in Port at LUMCON.

Unlike the NGOM Shelfwide Hypxoia cruise, we will be focusing this cruise on two sampling sites within the Hypoxia transect over 24 hours.

the 2015 NGOM Shelfwide Hypoxia transect. We will be sampling two sites from two transects over 24 hours time periods. Figure credit to Dr. Nancy Rabalais and Dr. Leslie Smith
The 2015 NGOM Shelfwide Hypoxia transect. We will be sampling two sites from two transects over 24 hours time periods. Figure credit to Dr. Nancy Rabalais and Dr. Leslie Smith.

Sampling will once again include three depths, while collecting water for nutrient data and filters for microbial community data. The idea will be similar to our Fronts sampling.

Others on the cruise will be working on sediment cores (I am excited for this!) as well as work on biogeochemistry rates.

Follow along as we go on our five day journey! And don’t be afraid to ask some questions! And Make sure to follow me on Twitter for live updates (@Hensonmw_08) as well as Mary Kate (@mkrogener) and Lauren (@GilliesLE).

Back of the RV Pelican
Back of the RV Pelican
LUMCON at night
LUMCON at sunset
The LUMCON emblem on the RV Pelican
The LUMCON emblem on the RV Pelican

Cheers,

Mike