Posted on behalf of Wendee Holtcamp, blogging for Nature aboard the research vessel Thomas G. Thompson.
We left port around 11pm on 16 June – still broad daylight in these northern latitudes – and cruised northeast along the Upper Alaska Peninsula for a couple of hours until we hit the first station. The scientists work night and day so they can complete their research in the short 28-day cruise.
I’m learning my way around the ship and the purposes of everyone’s research. It’s only been three days at sea but we’ve already spotted humpback whales and puffins in Unimak Pass, visited 17 stations and started several experiments. We skirted through Slime Bank where the equipment sucked a few Lion’s mane jellyfish on board. The largest ever documented had a 2-meter bell and tentacles longer than a blue whale, so it’s considered the world’s largest animal. Yet they only live one year.
The Bering Sea Project runs the gamut from nutrient cycling to birds, and on board the R/V Thompson, scientists collect three things at every station: water, mud, and critters.
The first order of business at every station is to collect water and Nancy Kachel, hydro-team leader, gets to be “water cop” to make sure that there’s enough to go around. The team deploys a CTD (Conductivity, Temperature, Depth), which has twelve 30-liter containers to gather sea water, plus an electronic sensor that sends data back on board. They use a winch to haul the CTD over the starboard side, and down it goes until it’s around five meters or so off the ocean floor. They remotely close the containers, and then haul it back up.
Next up: critters. The masters of the MOCNESS (Multiple Opening/Closing Net and Environmental Sampling System) are graduate students Elizabeth Siddon and Wesley Stasburger, from University of Alaska Fairbanks-Juneau. This beast, with its nine tapering nets, gets dragged behind the ship as we cruise at low speed for 30 minutes. Back on board, they spray it down and bring the collected fish larvae, krill and other pelagic zooplankton back to the lab to sort them out. Larger fish escape the nets. “Mostly we’re interested in Pacific cod, walleye pollock, and arrowtooth flounder,” explains Siddon. Commercially important pollock have declined in recent years and no one knows why. One hypothesis is that arrowtooth, which have dramatically increased recently, may be contributing to the decline. Could this be related to climate change?
Once a day, David Shull’s team sends the Multi-Core overboard. It has a series of removable plexiglass tubes connected to an iron-weighted frame that pushes into the ocean floor sediment. After bringing it on board, they transfer the mud into different tubes for slicing and dicing and making mud pies. Err, actually to study how benthic invertebrates influence nutrient fluxes between the overlying water and the sediment, among other things.
We are now headed into a storm within the next few days. That may bring 4-meter swells and 35-knot winds. After the storm, I’ll report back on some of the on-board experiments.
Images: Wendee Holtcamp