Editor's Note: University of Southern California geobiologist Katrina Edwards is taking part in a three-week drilling project at the Atlantic's North Pond—a sediment-filled valley on the ocean floor—designed to locate and study what she calls the “intraterrestrials”: the myriad microbial life-forms living inside Earth's crust. This is her fifteenth blog post. To track her research ship's current position, click here. To see all her posts, see "60 Seconds in North Pond."

SOMEWHERE ABOVE THE NORTH POND (March 6, 2009)—After one round-the-pond final tour for final multibeam data (not seismics as I wrote the other day with a fried brain; see image of multibeam data to the left for what this looks like) we left the pond and are headed to Dakar, Senegal. I feel like I've really gotten to know North Pond over the past month. I've stared at our multibeam maps for hours and hours, day after day. All the contours on our maps are imprinted on my brain and I could probably sketch them from memory right now. We've had vigorous debates and discussions while poring over these maps and discussing data as it comes in, in order to decide what to do next.

It has been a roller-coaster ride, and now we are coasting in to dock. I am already looking forward to returning in a few years for the IODP (Integrated Ocean Drilling Program) drilling leg!

I am clean and free of mud. We polished off the last sample this afternoon and I immediately showered and ran to do laundry.

I don't think I've mentioned one bittersweet fact about this project and my own personal research agenda for North Pond. I'm heavily involved in all aspects of the broader project, but my own interests really lie with rocks—the aquifer system that is flowing underneath North Pond, and what kind of intraterrestrial microbes might colonize rock, inhabiting the nooks and crannies of volcanic basalt and catalyzing reactions that result in "weathering"—like what you can see on old buildings, roads and rock outcrops on the continents.

The person who dreamed up this project with me, Wolfgang Bach, is a petrologist—a rock guy. His interests are also in these reactions, and particularly the chemical changes that take place. I bring that up only to point out that this has not been a rock-gathering cruise: no rocks—well, big rocks, anyhow—were collected. We've spent a month at sea collecting mud. This is more than a bit removed from our normal "day jobs" and expertise.

That being said, it has been amazingly interesting and fun to collect mud. I was not really sure what to expect, but suffice it to say there are enough people in the world that deeply care about mud to argue the case that, of course mud is interesting. Now I know a little bit more of the "whys" behind their passion for mud, which is very satisfying.

I still miss my rocks though.

Image of bathemetry/multibeam data courtesy Katrina Edwards/USC