July 5, 2009
60° 44.32 N
I enjoyed a conversation with David Shull, a professor from Western Washington University and chief scientist on the TN-250 cruise, this morning over breakfast. David, like me, comes from a family of teachers. His mom and sister taught at the elementary level and his dad at a local college. Teaching came naturally. I can tell he takes great pride in making sure that his students are pointed in the right direction when they leave his care. He says that the science is incredibly interesting but it is the teaching and sharing of science that he truly enjoys. It shows. Three of his former students have joined him on this summer cruise, their quest for more knowledge due in no small part to David's influence.
TN-250 is his first assignment as a chief scientist. The chief scientist has the unenviable task of coordinating, planning, and overseeing the research groups on the Thompson in addition to finding time to conduct his own sampling and processing. Dave takes his job seriously but not too seriously. He regularly drops by to see what the latest results were and has a laugh that is audible throughout the halls of the ship.
Since there was no sampling to be done this morning, I went out to the after deck to watch the coring team gather their samples. The multi-core has to be first moved into place with a crane before it can be hooked to the large a-frame on the stern. Four to five people are required to steady the 1-ton multi-core as it is lifted from the deck and swung over the back of the ship. At a rate of 20 meters/minute the corer only takes about 2.5 minutes to reach the bottom here. Once it reaches the bottom, it is allowed to sit for one minute to ensure that the pistons have driven the sampling tubes into the sediment. Then it is raised back to the surface where the team is waiting to bring it back on deck.
The coring team on the R/V Thompson consists of five members and is headed by David Shull. He is joined by Greg Brusseau and Rachel Allison, former students of David's at Western Washington, and Colin Smith from the University of Washington. Maziet Cheseby accompanies the team as the designated multi-corer tech from Oregon State University.
Both trips to the bottom today were successful, gathering a total of 12 samples of mud. The cores will each be processed in one of five ways. Three cores will be kept intact with the water layer above them and be brought to the cold lab. Here the gas flux both into and out of the sediment will be determined over a three day incubation period. Then the cores are frozen, stored, and brought back to dry land for a CAT scan. The CAT scan will reveal the length and diameter of any burrows created by benthic creatures inside of the core.
A fourth core will be analyzed for oxygen profiles. A fifth and sixth core are sliced at predetermined intervals for porosity and pore water analysis. The change in nutrient concentration can then be determined as a function of distance into the core sample. A seventh core is sectioned in a similar fashion (though not as deep) and is used for pigment and thorium analysis. The last two remaining cores are sieved for benthic organisms which are then preserved in a 10% formalin solution. The nine cores provide a great deal of data but for what purpose?
David's objective in this project is the functional role of macroscopic benthos in nutrient cycling. More specifically, he is interested in the burrows that are created by the benthos. These burrows add not only more surface area to the ocean floor but may also serve as conduits, allowing nutrients deep in the mud to be released into overlying water. Since the sediment's chemical composition changes with depth, the burrows would permit alternative pathways for the nutrients to either be removed from or recycled back into the water column.
The passion with which Prof. Shull must teach was in full display while he explained the reasoning behind his experiments. The fact that I was a captive audience who desired to gain the knowledge he possessed did not temper his enthusiasm one bit. I can only hope that the 100 or so students that file into my classroom this September will see the same passion in the front of the room.