Our paper on the cultivation and genomics of the freshwater SAR11 strain LSUCC0530 has been published online in the ISME Journal (Here). The SAR11 LD12 lineage evolved to colonize freshwater ecosystems, and, like its marine cousins, occurs as one of the most abundant freshwater bacterioplankton worldwide. Strain LSUCC0530 represents the first cultivated representative of the LD12 clade and presented the Thrash lab with an unprecedented opportunity to provide new insights into the important evolutionary processes behind marine-freshwater transitions. Specifically, we demonstrated the capacity of strain LSUCC0530 to grow in salinities up to 5, provided evidence for LD12 ecotype differentiation based on temperature, and developed a hypothesis on how the loss of key genetic functions enabled the SAR11 clade to transition into fresh water. This work is only the beginning of our exploration into the SAR11 LD12 clade and its marine-freshwater transition, so be on the look out for more data soon!
If you have any questions or want to know more about LSUCC0530, please feel free to contact us! We are more than willing to answer any questions you may have.
It is with great excitement that I get to post that our manuscript on cultivating members of the microbial majority using an artificial seawater medium is finally out! This manuscript represents the hard work of not just myself, but Dr. Thrash, our undergraduates (past and present), and Austen Webber. Over the last two years, I have traveled to sites along the Gulf of Mexico collecting water for cultivation experiments (> 2000 miles traveled, > 4500 well inoculated). From the sites along the coasts of Louisiana, we have cultivated organisms from the Gulf of Mexico representing many important marine clades: SAR11, SAR116, OM43, OM252, Roseobacter, and many more. While isolating these organisms is important, it is also important to isolate organisms that represent abundant taxa within your source water. We compared OTUs from community sequencing of the source water to our isolate sequences to demonstrate that our method frequently captured some of the most abundant organisms in the system.
This work also represents the first instance where many of these clades were isolated from the Gulf of Mexico, and importantly, on an artificial seawater medium. While high throughput, dilution-to-extinction culturing using natural seawater has been highly successful, we hope that this new approach using artificial seawater media will help more researchers cultivate important microorganisms without the hassle of collecting large volumes of natural seawater and needing a boat.
If you have any questions, please feel free to contact us! We are more than willing to answer any questions you may have. You can check out our list of organisms isolated so far HERE!
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.
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.
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!
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).