Sunday, October 11, 2009

Back on Solid Land!

Here are a few photos of our last day packing and of the entire team of scientists on the cruise.

Hg Team of scientists. From Left to Right, bottom row: Dr. Geraldine Nogaro, Katlin Bowman, Lisa Romas, Melissa Tabatchnick, Michael Finiguerra, Kathleen Munson, Susan Gichuki. Left to right, top row: Dr. Carl Laborg, Dr. Chad Hammerschmidt, Tristan Kading, Allan Hutchins, Lynne Butler, Dr. William Fitzgerald, Prentiss Balcom. Absent - Jenay Guardiani Aunkst.

Gale wind warning toward the end of the cruise

Jenay packing.

Melissa packing up her room.

Geraldine finishing up her experiments.
Well, we returned to port earlier than anticipated due to the gale winds and 20 foot swells. Much to my chagrin, I spent my last few days in the hold, sleeping and trying to quell my motion sickness. By the end of the cruise, I wanted so badly to stand on solid ground! This was in stark contrast to the previous cruise when I did not want to leave the ship! It's amazing how we are always subject to the power of mother nature. Although she made this cruise more difficult, it will prepare us for yet another cruise that the WSU team will be taking in June 2010.

We would like to extend our appreciation to the National Science Foundation for funding our research on mercury cycling in the oceans. Thank you, NSF!

Lisa's Inhibitor Experiments

Part of my reason for participating in the cruise is to collect samples for my Master's thesis project. It is hypothesized that bacteria are responsible for methylating mercury, or converting it from its inorganic form to its toxic form, MMHg. The current paradigm is that sulfate-reducing bacteria (i.e., bacteria that use sulfate to obtain their energy and live in hypoxic or anoxic sediments, such as sediments at the bottom of the ocean which have little or no oxygen and are disturbed rarely) are the primary functional group of bacteria methylating mercury to MMHg. However, recent studies have shown that other groups may be responsible (such as iron-reducers). The purpose of my thesis work is to figure out who is methylating mercury in various environments. I do this by adding inhibitor or promoter solutions to my samples to try and target specific groups. I also add stable enriched isotopes (not radioactive ones!) that allow me to track how much mercury is methylated and how much MMHg is demethylated (which, in combination, tell me what net methylation is like). Basically, I am seeking to answer the question, "Who is primarily responsible for converting mercury to its toxic form in the oceans?"

I start by collecting sediments as a part of the box coring team (first photo). Then, I homogenize my sediment by mixing it well in a nitrogen filled glove-box (second photo). I feel like a kid playing with mud! (third photo). Meanwhile, I make my inhibitor and promoter solutions (fourth photo). I add the sediment to my sample bottles (fifth photo), add 25 mL of a solution to each bottle, cap them, and flush the headspace with nitrogen gas to get rid of oxygen (sixth photo).
When I return to the WSU laboratory, I will analyze the isotope concentrations using our ICPMS instrument. I look forward to seeing what I find!

Monday, October 5, 2009

Pulling in the box corer!

Rough Seas

Box Corer 0
Ocean 1

We currently are at Station 17 which is about 4200 meters deep. The winds are 25 knots and the ocean swells are between 5-8ft. The waves are crashing over the back and sides of the boat creating some pretty challenging working conditions. We just finished box coring which was about an hour and a half ride to the bottom and the same coming up. From inside I watched the progress of the corer from the sound transmissions of the pinger and also kept an eye on the tension of the line. The tension reached over 4000lbs and showed continuous spikes as the boat bobbed up and down. In calm conditions, a clear drop in tension can be seen when the corer hits the bottom but today, it was almost impossible to tell when/if that happened. When the box corer reached the surface it was mangled and barely in one piece. There were bolts that had been stripped and bent and a few that were even missing, the pinger was hanging on from one arm and the actual box itself was cracked along one of the sides. The force from the waves may have caused the box to trigger on the way down, opening and slamming shut each time the boat rose up and crashed down. It is also possible that the box was dragged along the bottom.

None of the damage is unrepairable, and if necessary it all could be fixed at sea. However, the weather is projected to get much worse and the captain wants to head for the coast by 8AM Tuesday morning. On Wednesday we will be facing 40 knot winds and 15-20ft swells and unless that changes this will probably have to be our last station.


Sunday, October 4, 2009

Sending the box corer down!

Paul (Endeavor crew), Allen (UConn) and Dr. Hammerschmidt are attaching a "pinger" to the box core line. This sits 75 meters above the box corer and emits sound that can be tracked by the ship's computers to tell how far from the bottom the box corer is.