Plankton Net

Scientists prepare to deploy a plankton collection net aboard the RV Palmer.

By Geoffrey Gearheart

Feb. 24, 2013
Drygalski Ice Tongue, West-Ross Sea

The RV Palmer is a 300-foot haven of peace floating in a sea of climatic mayhem. We can see white plumes of snow flow off the mountains like waterfalls—the katabatic winds thundering down the glaciers.

While the ship remains stationary, owing to its “dynamic positioning system,” the sea is a conveyor belt driven by the winds. Long streaks of new ice slush and large floes pass by the Palmer, which every now and then has to dodge one of these behemoths. Meanwhile, inside the ship we are taking hot showers and wondering what gourmet dessert will be served at lunch.

But don’t get me wrong; there is a lot of work going on, too! On the aft deck, powerful cranes and winches lower instruments that our fellow scientists use to sample water at depth, film the seafloor, collect organic carbon, and catch plankton. Their main instrument is the conductivity, temperature, and depth (CTD) profiler, which measures key characteristics of the water column, enabling scientists to identify our planet’s water masses. It has large “Niskin bottles,” which can be closed remotely to collect water at different depths. Once the CTD surfaces, a group of very competent students from different U.S. universities drain the bottles and work together to analyze the water samples.

CTD_Rosette_and_winch_redux_web

A conductivity, temperature, and depth (CTD) profiler and winch.

CTD

A CTD profiler being deployed off the RV Palmer.

In the “wet lab,” they look at biological aspects such as phyto- and zooplankton (which are caught separately in special nets), and also at microbial activity. To measure the latter, Roberta Hansman from University of Vienna (who studied at Scripps Institution of Oceanography!) incorporates radioactive substrates into the water samples and examines how fast these compounds are integrated into organic matter created by bacteria. This gives a measure of how fast bacteria degrade detritus (dead organic matter) in the water column or on the sea floor. Learn why this information is critical on her team’s cruise blog, TRACERS.

Wet Lab

A scientist works in the “wet lab” aboard the RV Palmer.

Moving along, we arrive at the “dry labs” that house the computers. Along with the bridge, this is a neural center of the ship. The principal investigators (PIs) gather here to study the latest weather charts, satellite images of chlorophyll a (indicating phytoplankton blooms), and sea ice distribution to plan the next scientific move.

The decisions are communicated to the Captain and his mates on the bridge. Will we stay one more day and hope the wind dies out so we can deploy our instruments? Where shall we go next? Shall we take the short route through the ice or the longer one through open water? We are hoping for the former, as there way more animals to see on the ice!

Dry Lab

The “dry lab,” one of the neural centers of the RV Palmer, contains the ship’s computers.

For the last few days, we’ve been chasing a phytoplankton bloom visible on satellite images. The close coordination between the PIs and the Captain have enabled the scientists to sample different parts of the bloom as it matured. One of the key aspects they are trying to address is how carbon (from carbohydrates contained in the phyto- and zooplankton) is “exported” to lower levels of the ocean. This is important because it tells us the capacity of the ocean to absorb and sequester carbon dioxide.

At 11:30 sharp, it’s lunchtime. The galley, or dining room, is in the front of the ship, under the bow. It is spacious and equipped with a modern restaurant kitchen. Complete with our French-Canadian chef, Dany, the Palmer’s galley must be one of the best in the business. Dany prepares gourmet meals that he describes course by course to the diners. The desserts are so sweet and irresistible they have some of us counting how many hours on the treadmill are required to wear off the calories.

Lunch on the RV Palmer.

Lunch on the RV Palmer.

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