Microbiology on IODP Leg 330

Hi!  My name is Jason Sylvan.  I am a microbiologist at University of Southern California, and I will be keeping a blog throughout IDOP Leg 330 to the Louisville Seamount Chain describing some of the research that I do, the technology we use to collect samples from below the seafloor, and life on a research vessel.

I study deep-sea microbes, or unicellular organisms, from the Bacteria and Archaea, the two exclusively unicellular Domains of life.  I am very excited to sail with Leg 330, which is my first seafloor drilling cruise (so you will be learning at the same time that I do)!  I joined this cruise is because we will be collecting A LOT of subsurface (below the seafloor) basalt, which is all potentially home to interesting microbes for me to study. 

Much of the seafloor looks like a sandy beach, but below this sand, or sediment, lies old, volcanic rock (primarily basalt, just like you see if you visit Volcano National Park on Hawaii) that was originally formed at mid-ocean ridges (a 70,000 km long underwater mountain range) and then transported away from the ridges due to plate tectonics.  This basaltic rock is permeable, which means water can and does flow through it.  And anywhere water flows life can exist.  Leg 330 is particularly exciting because we will be sampling very old rocks: 55-80 million years old!  Before this cruise, nearly all of the microbiology studies of subsurface basalts, which I can count on one hand, were from young (<5 million years old, which is young on a geological scale!) rocks, so I am excited to see what I discover from the samples we will collect.   

One of my goals on this cruise is to culture, or grow, microbes from subsurface basalts.  To do so, I made artificial media in my lab that mimics the subseafloor environment and encourages specific types of microbes to grow (see the figure- below the different bottles, I indicate what types of microbes I hope to grow with those bottles).  You'll notice that the media are a range of colors from clear to pink to blue.  This is because I need to know if there is no oxygen (clear), some oxygen (pink) or a lot of oxygen (blue) in my media and therefore added an chemical indicator that tells me relatively how much oxygen may be present (none, some, or a lot).  Some of the different microbes I am interested in growing require that no oxygen be present because it is poisonous to them.  These include the methanogens and sulfate reducers, two types of microbes likely to be present in the rocks I will be collecting.  You can also see some chemicals I will add to some of these media later, including goethite, which is an iron oxide (rust!), and iron chloride, at the far right.  When we start collecting rocks, I will add them to bottles with these different media and keep my fingers crossed that something grows!

Stay tuned for more updates on microbiology, life on a research ship, and some of the amazing technology we are using to collect our samples!



iron oxidizers anyone?

by chance are you attempting to cultivate any iron oxidizing microbes?

Reply to comment | JOIDES Resolution - Ocean Drilling Research

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absolutely! my boss, Katrina

absolutely! my boss, Katrina Edwards, has published a few papers on Fe-oxidizers, and we're all big fans of them in our lab. i'm doing my best to grow some out here, we'll see how my luck is.

How do you know?

Hey Jason, this is Erik.

How do you know that the microbes are growing if they're in a 0 oxygen environment, I guess you can't take them out of the bottle or you'll kill the one you extract and possibly the ones you keep in there?

hi Erik, you are right- i

hi Erik,

you are right- i wont remove the samples unless in the anaerobic chamber back in my lab at USC. if there appears to be growth in anaerobic cultures, upon returning back to USC i will transfer some sample to fresh media to try to isolate single species and also analyze some of the sample for molecular biology, which can tell me who is growing in the enrichments (by looking at the 16S rRNA gene, a kind of fingerprint for prokaryotic species).

wonderful blog. I hope to

wonderful blog. I hope to learn more about microbes by exploring the sinkholes in Lake Huron in the spring with a ROV like the ones built on the JR in Exp 327. There are some interesting microbes down there, some that don't like oxygen too. I have a lot to learn. Perhaps I will comment again. Do you know much about these microbes in the Lake Huron sinkholes? They are listed at http://www.gvsu.edu/cms3/assets/1DD95C9E-F727-23D4-DE820C2CEBEC370A/publ...< -thanks, Jkane@toledosua.org<

Great Lake sinkholes

I don't know much about the Lake Huron sinkholes, but they appear to be similar to some my colleague is working on in Lake Michigan. Sinkholes are interesting environments due to the unusual geochemical gradients present that allow for the growth of some fascinating microbes- good luck learning about those!

do they use OsmoSamplers to

do they use OsmoSamplers to study the sinkholes in Lake Michigan? Jackie K

Thanks, Ill keep working and

Thanks, Ill keep working and be in touch.... jackie k

Sounds really exciting, I'm

Sounds really exciting, I'm looking forward to seeing what you discover! Good luck out there and have fun!