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SEA Currents: SSV Robert C. Seamans

February 27, 2020

Ain’t No Plankton like Towed Plankton

Anna Roethler, Carleton College


Assistant Scientist Supi with students Etasha, Grace, and Ashby deploying the hydrocast.

Ship's Log

Souls on board

I felt like I was entering a small labyrinth the first time I stepped onto this ship. The number of doors and different areas made this ship feel much bigger than just 41.2 meters. Yet at only 2 weeks of calling this ship home, I can easily navigate this labyrinth at 3 AM in rough seas while doing a boat check. This is one of many examples of how much can be learned and changes in just 2 weeks when there is total immersion of a new environment. We have come so far in these short weeks but what is even more exciting is our potential to learn even more and master our new skills.

After our port in Kororareka Russell we have been able to focus more on data collection and research due to getting acclimated to life at sea and sailing. Many of us are in the elective Practical Oceanographic Research or Directed Oceanographic Research. This elective allows us to create a research question and conduct the research to answer these questions. The lab is constantly collecting some of the necessary data with automatic sensors. We also have a large role in this collection of data. I remember in Woods Hole not knowing how vast the capabilities of data collection were and just being excited about the potential of being able to conduct our own research. I slowly learned more about what kind of data we would be collect. Once at sea, I found the most exciting part to be participating and collecting the data for ourselves.

Every day a watch is split up into two major groups and these groups rotate. One group is on deck and the other is in the lab. Lab time typically consists of either deployments or processing what the previous watch collected. We have three main deployments: the hydrocast, phytoplankton net, and neuston tow. This is an all hands effort for each watch group because the deck half of the group must stop or slow down the boat, and the lab group of the watch must do the deployments.

The hydrocast is a piece of equipment that we lower into the ocean as deep as 600 meters. It has automatic sensors that take readings as it enters deeper water. There are also twelve bottles that collect water at different depths as it lowers. We later test the pH of these water samples, filter out the chlorophyll-a, and collect water samples for later processing of nutrients. The phytoplankton net is lowered 100 meters to collect the plankton. We then filter the phytoplankton out and preserve the samples for later analysis. The last deployment is the neuston net. This net skims the surface of the ocean and collects the larger zooplankton. We measure the amount of total biomass from these tows and count a random sample of 100 specimens under a microscope to get an idea of the general compositions of zooplankton found.

There are often three students in lab for each watch group in science. We all work together to process the samples but there are more specific roles during deployments. Roles are often split between the "dancer," "driver," and "data cop." These foreign words quickly made sense after we learned how to deploy our equipment. Besides the neuston tow, we use the winch and steel "J-frame" to lower the plankton net and hydrocast into the water. The dancer navigates putting the equipment into the water and gives the driver orders. The driver is at the control panel and lowers or raises the winch and controls the J-frame. Meanwhile, the data cop enters all data necessary for when the deployments are started and ended. These deployments that happen twice a day are always an exciting event.

Conducting this ocean research is such a great opportunity. We are slowly navigating this maze of new information by learning more about the processes and the data itself. Plus, this isn't even all of it, there is still so much more that are yet to come.

- Anna Roethler

P.S. Happy belated birthday, Mom!

Categories: Robert C. Seamans,The Global Ocean: New Zealand, • Topics: None • (3) Comments
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Leave a public comment for students and crew to read when they reach their next port and have access to the internet!

#1. Posted by Andra Roethler on February 28, 2020

Thank you and this is all just so awesome I can hardly stand it!  Continue to learn enjoy and have the time of your lives! Stay safe!

#2. Posted by Andra Roethler on February 29, 2020

Thank you Anna!
What a learning opportunity!  Just wonderful.  Safe continued travels.

#3. Posted by mama weyhrich on March 03, 2020

Thank you for all of your hard work!



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