12 July, 2003

Science On the Sea

After a tour of the ship, a fire drill, an abandon ship drill, a science meeting and final frantic instrument calibrations and set up we arrive at our first survey site. Like bees swarming a hive or ants at a picnic or - well you get the idea. Everyone was excited and all crowded around the CTD lab and adjoining equipment deployment bay to watch the first instruments lowered into the water.

At 19:00 (7:00 PM) the ships engines stopped at latitude North 56.312 degrees and West -172.824 degrees. Below us lay roughly 1300 meters of Bering Sea saltwater and our first site. The site is one of five that we will stop at and collect samples and data that are clustered in a relatively small area. At each of these five stations the CTD equipment array, consisting of instruments to measure water depth, temperature, salinity and chlorophyll, will be lowered. A series of twelve water collection bottles form a rosette on the CTD frame. Each opening to the collection bottle has a trigger, which will open the bottle at prescribed depths programmed into the system, thus collecting water samples at various depths each instrument deployment.

The crew of the Laurier connects the CTD to a winch and the instruments are slowly lowered into the water. As the whole array descends real time data is collected on the waters temperature, salinity, depth and a fluorometer measures the chlorophyll. Jane Eert monitors the descent from the CTD lab and keeps track, through an electronic link, that all prescribed triggers have fired and appropriate water samples taken. Once the CTD has reached its depth the instruments are slowly raised back on deck.

Once the Laurier crew has secured the CTD back on deck water samples are drawn from the collection bottles. On this parcticular trip two separate teams are collecting samples for thier projects. Dr. Cooper and his associates are collecting samples as well as Dr. Lee and his assistant.

Dr. Cooper's group (the group I am assigned to) extracts the water from the bottles then runs it through a pump to filter out the phytoplankton. The phytoplankton is then frozen (to "crack" the cell membrane) in order to make the chlorophyll extraction easier. Once the chlorophyll is extracted and stabilized, using acetone, the sample is run through the fluorometer more accurate than the one deployed on the CTD) to measure the chlorophyll amounts.

Dr. Lee's team is also filtering out the phytoplankton but for a different reason. His interests are in the phytoplankton's dimethylsulfide (DMSO), dimethlsulfide (DMS) and dimethyl-sulfoniopropionate (DMSP), the pigments within the phytoplankton and the enzyme activity involved in the conversion of DMSP to DMS.

Dr. Cooper's work focuses on the first stages of the Arctic food chain and the fluctuations of the nutrients and phytoplankton in the region whereas Dr. Lee's work focuses on some of the trace biogenic gases that have been implicated in significantly affecting global climate change processes. Both projects have significant implications as to the health status of these fragile frigid waters and the Arctic ecosystem.

1. Preparing the CTD for deployment

CTD in water

1. Preparing the CTD for deployment