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.
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!
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….
On March 23rd, research on the microbial variation across a 5500 km transect of Antarctic surface sediment that Dr. Thrash and I had worked on with Dr. Deric Learman from Central Michigan University was finally published in Frontiers in Microbiology under the special topic: Microbiology of the rapidly changing polar environments. Since then, the article has had >1200 views from around the globe and was one of the top ten articles in Frontiers in Microbiology for the month of March. The research began when I was a Masters student in Dr. Learman’s lab. When I came here to LSU, Dr. Thrash was added to the project. This research would of never happened without the help of Dr. Andrew Mahon (CMU), Dr. Scott Santos (Auburn), Dr. Kenneth Halanych (Auburn), and Dr. Pamala Brannock (Auburn). Each one helped collect our sediment samples while they were out to sea doing their own research. I’d also like to thank Dr. Ben Temperton (University of Exeter) who helped with our analyzes. We are excited to finally have it published!
Here is a quick blurb on it:
Western Antarctica, one of the fastest warming locations on Earth, is a unique environment that harbors under explored levels of biodiversity. Our work focuses on the seemingly “invisible” inhabitants of the ocean floor that boarder the western and peninsula portion of the Antarctic continent. While microorganisms are the smallest forms of life on Earth, they are abundant (typically more than 10 million cells per gram of sediment) and influence the cycling of important nutrient such as carbon and nitrogen. They also represent the foundation of the food chain that supports larger and more complex forms of life. To study this environment, ocean sediment samples from the continental shelf of western Antarctica were collected over a 5,500 km transect from the Ross Sea to the Weddell Sea. By using 16S and 18S rRNA amplicon sequencing, this work has shown these sediments to be incredibly diverse and were distinguished by their correlations to organic matter and stable isotope fractions (TN, δ13C, etc.). Our work further demonstrates the versatility of marine microbial life and its ability to persist at near zero temperatures as well as greatly increases the available information for this region.
Learman, Deric R., Michael W. Henson, J. Cameron Thrash, Ben Temperton, Pamela M. Brannock, Scott R. Santos, Andrew R. Mahon, and Kenneth M. Halanych. (2016) Biogeochemical and microbial variation across 5500 km of Antarctic surface sediment implicates organic matter as a driver of benthic community structure. Frontiers in Microbiology7:284. doi: 10.3389/fmicb.2016.00284
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.
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.
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.
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.
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!
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).
Unlike the NGOM Shelfwide Hypxoia cruise, we will be focusing this cruise on two sampling sites within the Hypoxia transect over 24 hours.
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).
Two weeks ago, I was able to take part in the 6 day Northern Gulf of Mexico research cruise. This is its 31st year that it is going on and our third year taking part in it (see 1, 2). This year I was the lucky one to go instead of Dr. Thrash. This was my first official collection cruise so I was pretty excited to finally get out on a boat and put into practice everything I had learned while at the CMORE summer course.
Once again, our lab was working with Dr. Olivia Mason from Florida State University and her graduate student Lauren Gillies (@GilliesLE), who recently published a paper with Dr. Thrash from the 2013 research cruise: Archaeal enrichment in the hypoxic zone in the northern Gulf of Mexico. Congrats to them!
Though for the most part the set up and collection was the same as past years, this year I added a little twist to the game: Culturing.
The cruise was a lot of fun and as usual I learned a ton about the Northern Gulf of Mexico and hypoxia. The main focus of the rest of the cruise was determining the size and nature of the 2015 “dead zone”. Dr. Rabalais (LUMCON) and her team worked countless hours to make sure all the data was collected and ready to be sent to NOAA, the EPA, and the public. This year we found that the dead zone was larger then scientists had predicted. This year’s dead zone extended over more than 6,400 square miles.
A few more pictures of me with some of the awesome graduate researchers (Mary Kate Rogener (@mkrogener) from Dr. Samantha Joye’s lab (UGA)) and Post Doc Ari Chelsky (Brian Roberts, LUMCON) also on board the RV Pelican.
Keep an eye out for more publications from the Mason and Thrash groups on this exciting research area!