Written by Matthew Tobin (Oceanography Intern), Edited by Claire Gabel
The Oceanography program takes students out on the waters of Cohasset Harbor to study the dynamic nature of the ocean in relation to latitude and longitude, along with the general health of the ecosystem. During expeditions, students use a YSI to measure salinity, temperature, and oxygen concentration, and collect several water samples to bring back to the lab. Our Niskin bottle allows us to collect samples at specific depths, and later compare chlorophyll-a levels based on how deep the water is. At several sites students also collect sterile water samples, which are used to measure bacteria levels. This summer CSCR has a new plankton net, and students have been able to collect copepods, larvae, and other plankton from the harbor and look at them under the microscope.
On days we meet, the Oceanography team arrives at 7:30 AM to gather the necessary supplies we need for the trip. This includes a cooler with ice packs for samples, gloves, sterile bottles, the YSI ProDSS, and the plankton net. From there, we head to the boat with our gear and go out to the harbor. After using the YSI and collecting our samples, we return to the lab and students test for enterococci, filter the water for chlorophyll-a, and make sure the plankton samples are preserved for later observation. They then import the YSI data to a laptop and upload it to our Google Drive folder, before working on our ArcGIS map of the area. Using ArcGIS allows students to visualize our data and share the information with others.
This summer, one of our main goals has been to develop a procedure for observing plankton. Up until this point, we were unsure how to measure plankton populations or interpret that data in the context of the harbor. The current process is rather long and still being refined, but involves looking at one milliliter of sample water under a microscope and tallying the number of copepod specimens we see. Given the total volume of water in the sample, students use an equation to get a rough estimation of how many total copepods are in the sample. One helpful tool is a new camera we have that attaches to the microscope and allows students to photograph the plankton. We keep a record of what we find in the harbor, and plan to share with the community and other teams at CSCR.