USFSP Open Ocean Week - Nathan Freeman

Safety briefing on the Weatherbird II, Photo: Amanda Schaaf

Open Ocean week at USFSP started with review of open ocean adaptations, including classifications of plankton and plankton-based food webs. In the afternoon we went over the plan for the trip on the Weatherbird II, including an overview of how to use the equipment on board. Tuesday was our longest day of the week. We gathered up our materials in the morning to board the Weatherbird II by 11am. We set out for a long cruise, making our way to our first site to be sampled, which was about four hours offshore. On the way out we split up into four groups to be prepared for the samples we would do at the site.

Deploying the CTD, Photo: Amanda Schaaf

The first group took water quality parameters with the CTD, measuring conductivity, temperature, depth, pH, nitrate, and phosphate. This was measured at depth and near the surface. Then two plankton samples were taken – one near the surface with a Neuston net, and one midway in the water column with a Bongo net. One container from each was preserved with formalin, and one was kept alive for observation. The third group was in charge of the otter trawl, which was designed to collect organisms just at or above the sea floor. There were some complications with the trawl, largely due to the trawl’s doors being the wrong size, so it was not held open vertically. Even so, we caught many interesting organisms, including a very large sea star. While organisms from the trawl were being identified, counted and measured, the Capetown dredge was deployed, to pull up organisms that lived on the sea floor. The whole process was repeated at the nearshore site, which was near the Sunshine Skyway, about an hour offshore.

The plankton nets had to be rinsed to collect the plankton in the bottles, Photo: Amanda Schaaf

Sorting and measuring organisms, Photo: Amanda Schaaf

A Red Cushion Sea Star, Photo: Dr. Heather Judkins

Wednesday in the lab we spent some time entering data from the ship, and double-checking names that may have been misspelled or outdated. A few invertebrates from the nighttime, inshore trawl were difficult to identify, and were preserved to be looked at in the lab for further identification, including a squid that needed to be dissected for verification of its species. Once that was done, we looked at plankton from our samples, to practice identifying them and get an idea of the diversity and density differences between the different samples. We saw several species of copepod, as well as larval pea crabs, lobsters, and barnacles. We spent some time making models of plankton as teams of four, which were intended to stay in the water column without sinking or floating. Our model floated just a touch too much, but it was a good way to explore different adaptations.

Identifying plankton under the microscope, Photo: Amanda Schaaf

The frenzy of Iridescent Swimming Crabs we saw, inspiring
our question, Photo: Amanda Schaaf

Thursday we changed gears from taxonomy to behavior. We learned how to use ethograms to describe the frequency of different animal behaviors, and took a trip to the Florida Aquarium to practice. It was a different exercise than anything else we have done this course, and it was interesting to discuss the experience with classmates afterward. There were certainly some difficulties, with losing track of fish and large groups of children getting in the way, but I liked having a way to focus my attention when observing animals that was different from looking for distinguishing characters. It was also nice to go to the aquarium at this point in the course, as I could see how much I have learned in terms of recognizing types of fish and birds I had only heard of before.

Friday we worked in pairs to present findings from questions about data from the Weatherbird II FIO trips since 2013. Lina and I looked at the average carapace width of Iridescent Swimming Crabs, and found that they really haven’t changed too much since their first recorded measurements in 2014.