Elaine Bechler: Off the Back, July 23, 2011


NOAA Teacher at Sea
Elaine Bechler
Aboard R/V Fulmar
July 21 – 26, 2011 

Mission: Survey of Cordell Bank and Gulf of the Farallones NMS
Geographical Area of Cruise:  Pacific Ocean, Off the California Coast
Date: July 23, 2011 

Science and Technology Log

Today was day three of my Teacher at Sea experience aboard the R/V Fulmar.  It is a big eye-opener to have experienced this.  We have been documenting all birds, marine mammals and debris while we travel along  transects through the Gulf of the Farallones NMS (National Marine Sanctuary) and Cordell Bank NMS.

transects in the study area

Transects in the study area

At the back of the boat is where other important data was collected.  There, we deployed nets to collect plankton and krill.  We also gathered abiotic parameters about the water. This section is to inform you about the CTD, the hoop net and the tucker trawl.  Why would collecting plankton and krill be important?  What would be an example of some abiotic parameters that could be measured in ocean water?

Some of the transects on the map to the left are marked with black dots and yellow stars.  Black dots are where we would drop a device called a CTD into the water.  CTD stands for conductivity, temperature and depth sensor.  The boat would stop at the station and two of us would guide the CTD to the center of the back edge of the boat.  The two crew members (Captain Erik Larson and mate Dave Benet) would locate themselves at two stations on the boat where they could control the movement of the boat and the winch.  The winch wire could be attached o any heavier device that needed to be deployed off of the back.  We would use the computer to determine the depth at that location.  Then we would communicate with Erik and Dave to tell them how deep to drop the CTD. Why did we all have to wear hard hats?  Why are we wearing large orange jackets?

controlling the back deck operations

Controlling the back-deck operations

Another job we did off the back was to gather zooplankton with the hoop net.  We would attach the net to the winch. The crew would assist us in dropping it to the proper depth (approximately 50 meters which was as close to the bottom as we could get without dragging the net).  After a specific amount of time we would bring the net up and put the sample into collection bottles.  These bottles will be sent to a lab to be analyzed after the trip.  It was amazing to see the variability of organisms in the net.   We found krill in all stages of development.
Andrea and I positioning the CTD

Andrea and I positioning the CTD

Sometimes the sample would be ruined if we captured a jelly fish.  Having a jelly fish in the plankton net acts as a slimy block.  Our net would sometimes come up with a clean sample of plankton, other times the net would be covered with brownish slime (phytoplankton) which required a lot of cleaning afterwards. The science team was very interested in the status of the krill in the catch.

deploying the hoop net

Deploying the hoop net

the tucker trawl

The tucker trawl

Another net that was used to collect samples was called the tucker trawl.  We would deploy the tucker trawl when the vessel came to the continental shelf break (about 200 meters)  of transects 2, 4, and 6, 8 and 10.  This net required 3 to 4 people to launch it.  It had three plankton nets, each of which was set to close at specific depths.  Our first sample came up with mud from the bottom (the net hit the bottom by mistake). Included in that mud was a purple slimy hagfish and a few tiny sea stars.  A later sample was filled with krill.

Water nutrient samples were also gathered from the side of the boat.  Cordell Bank  and Gulf of the Farallones National Marine Sanctuaries can be rich in nutrients such as phosphorus and nitrogen due to upwelling.

obtaining water for nutrient samples

Obtaining water for nutrient samples

Upwelling occurs when strong winds drive warm, nutrient-poor surface waters away from the shore.  These surface waters are replaced by nutrient-rich deep water and provide nutrients for the unicellular algae. What is upwelling?  What importance are nutrients to algae? 

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