Unfortunately, weather did not permit us to sail this time. We hope to revisit our transect line soon.

TEAL-SHIPS is lucky to sail on RV Savannah. Our team has packed up gear from 5 labs and we are on our way!

Winter weather made it impossible to get past the half-way point of our transect but we were able to sample the Cape Fear River plume and coastal areas. See some cool 360 photos of the Research Vessel Cape Hatteras and what the back deck looks like at night in wavy seas!

https://p.tourit.etx.asu.edu/v1fshqa2/oe2714w1yk7uimb/index.html (provided by Chris O’Connor, UNCW Marine Quest).

On Thursday, we conducted fish trawls at stations 3 and 4 – the deepest trawl stations. All trawls went smoothly, however, we did break the trawl net foot rope at station 4! fortunately, the excellent crew of the RV Hatteras was able to mend the net and get it back in working condition. Stations 3 and 4 are very exciting for fish trawling because we have the opportunity to capture unique deep-sea fishes. At station 3, we captured the highest overall catch and diversity (>20 species) of the cruise. Most species were reef-dependent, indicating patches of deep-water reefs at this station. At station 4, we caught some very cool deep-water species! Dr. McLean was particularly excited about the Spotfin Dragonet (Synchiropus agassizii), Fawn Cusk Eel (Lepophidium profundorum), and Shortnose Greeneye (Chlorophthalmus agassizi). Pictures courtesy of the Smithsonian Tropical Research Institute are shown below. Several unique specimens were collected for the UNCW Ichthyology teaching collection, while others were taken for stoichiometry analyses. We conducted nearshore trawls at stations 1 and 2 on the final working day. Catches were low and made-up of common coastal/estuarine species such as Pinfish (Lagodon rhomboides), Atlantic Bumper (Chloroscombrus chrysurus), and Striped Anchovy (Anchoa hepsetus). Low catches were not surprising as many coastal fishes migrate offshore prior to winter. Although we have only completed four cruises, we are already noticing a trend – the shallow, nearshore sites are showing pronounced seasonality, while the stable, deep sites have had similar catches in all seasons, highlighting the contrast between coastal and deep-sea ecosystems.

Spotfin Dragonet

https://biogeodb.stri.si.edu/caribbean/en/thefishes/species/4089

Fawn Cusk Eel

https://biogeodb.stri.si.edu/caribbean/en/pages/random/3983

Shortnose Greeneye

https://biogeodb.stri.si.edu/caribbean/en/thefishes/taxon/3019

One of our interests is to measure profiles of water column oxygen concentration. Oxygen is an indicator of biological activity and can also be used as a water mass tracer as different depths and ocean currents have distinct oxygen characteristics.

On TEAL-SHIPS cruises, we calibrate our full water column measurements of oxygen with “Winkler titrations” run on board the vessel. In these pictures, Melanie Cohn and Riley Morse perform a series of steps: First, water is collected from Niskin bottles at discrete depths (rinsed thoroughly and no air bubbles, please). Second, reagents manganese chloride and sodium iodide are used to spike the samples, preserving the oxygen concentration and inhibiting any microbial activity. The sample solutions are mixed and then stored in a dark place. Third, a titration is performed where a series of solutions are added to samples while they are mixed on a stirring plate. Once the reaction is at equilibrium, the titrated sample returns to a clear color. The initial and final volume of the thiosulfate titrant used for each sample is recorded at this equilibrium point and used to calculate the original oxygen concentration in the sample, generally 2-8 mg O₂ per liter of seawater.

During TEAL-SHIPS cruises, we stop at station 3C to “ping” our mooring that rests on the sea floor in 250 m of water. A transmit/receiver is lowered over the side of the deck and we have a brief conversation with the acoustic releases connecting instruments with the anchor. This time our “hello” ping received a report back that instruments were alive and well, with 85% battery, in an upright position, 260 m away from the vessel – right where we left it!

(Left) Our team “pinging” the mooring during TS4. (Right) Call back to TS2 mooring deployment. Pictures: Mel Cohn

So, what are we measuring out there? During TEAL-SHIPS II, we deployed an Acoustic Current Profiler, with a temperature-salinity sensor at this location. A satellite picture of sea surface temperature during the 3 days of TEAL-SHIPS IV shows that this location (green star) is a dynamic transition region between the cold coastal waters and the warm Gulf Stream offshore. The black lines in this figure denote surface temperature fronts that pass by just in this 3-day period. When all is said and done, we hope to have a whole year of data from this location, documenting the variable flow and water property exchanges.

Satellite sea surface temperature and fronts (courtesy NOAA) during TS4. Major (minor) station locations are indicated by black (red) dots. Mooring location is given by the green star and green arrow roughly indicates position and heading for RVCH on each day.

 

Our last full day was a day of casts! 5 CTD casts throughout the day, and 2 zooplankton towns and fish trawls were on the docket for the day, as we hit Station 2c, 2b, Major Station 2, 1c, AND Major Station 1! A full day for sure, but just like that, TEAL-SHIPS III completed successfully all of our stations. It will always amaze me how clear open ocean water is compared to the river water and plume! 

That night, some of the crew went fishing as a treat, catching many crazy fish with squids from a previous tow. We pulled several bluefish, and a cobia! The cobia, along with some other fish (batfish, goosefish) will be used in the ichthyology teaching collection by Dr. McLean. Dr. McLean’s top highlight was catching such a wide variety of fish across the transect! 

We started early and docked by 8 AM. While moving, we packed up gear and personal items. We had everything unloaded and unpacked at 1PM! TEAL-SHIPS moves quick. 

Until next time! 

 We awoke to heavy rain this morning, making work conditions feel like something out of Deadliest Catch. During this, we cast the first CTD deployment of the day at 5c. After our deployment, Captain Knight navigated us out of the storm, to give us perfect sunny weather for the rest of the trip. Upon our arrival at Station 6, we did our deepest catch, down to 1,300 meters deep! 

We filmed a brief video explaining what the CTD is, and how it works, then, sent our Styrofoam cups down to the depths to be crushed by the pressure. We’re looking forward to answering some questions from the 3^rd Grade class at Munson Elementary School on our next cruise, and hoping to crush some more cups! While here, we also deployed our DWB, which would allow our collaborators to measure wind speeds, wave movement, and much more oceanographic information. Stay tuned for more on these drifters! 

Later that night, the incubation experiment ended, and final samples were taken. We are expecting some exciting observations to come out of this, and it was a great demonstration of the new on-deck incubator that was built. Many more CTD casts along this day, with a lovely sunset to close out the night! 

 Day 1 began with our arrival at Station 3, for our first CTD cast of the trip! Extra samples were taken for some extra practice for this cruise’s new addition, titrations! Mel and crew utilized “Winkler” titrations, an assay to help determine dissolved oxygen to calibrate onboard sensors. 

CTD casts went without any hitches, for station 3, 3b, and 3c. One on Station 3c, we checked in on an old friend. For a quick throwback to TEAL-SHIPS II, Dr. Ata Suanda and crew deployed an Acoustic Current Profiler, with a temperature-salinity sensor, moored to the sea floor in 250-meter-deep water, approximately 80 kilometers offshore. Here, this mooring will remain for one year. We hovered above it for TEAL-SHIPS III and gave the mooring a little “hello” ping utilizing an overboard acoustic receiver. After anxiously waiting for a moment, we received a little ping back! The mooring reported back that it was alive and well, 89% battery and in an upright position, one kilometer away from where we stopped.

After a long day of sampling, we closed at station 4, conducting one last CTD cast, and fish trawl for the day. From this fish trawl, the McLean lab pulled up several pounds of a unique critter, squat lobsters! Despite their name, they are more related to a hermit crab than a lobster. Additionally, onboard incubation experiments were started for the Tolar/Johnson lab. After all this, we steamed off into the night towards 5c! 

Welcome back to TEAL-SHIPS, for our third departure to the Gulf Stream transect! This expedition, labelled “Third Time’s the Charm”, expanded on previous research, revisiting sites, moorings, and avoiding challenges from earlier this year. As usual, we were joined by collaborators from NC State, Eastern Carolina University, Cape Fear Community College, and University of North Carolina Chapel Hill. 

TEAL-SHIPS kicked off with an outing for a before-cruise dinner, where Chief Scientist, Dr. Christian Briseño-Avena coordinated lab placements and details and welcomed our first-time sailors with a few words to the wise on safe sailing. Boarding the vessel, we ran through safety training as always, with the new folks donning their gumby suits. As we steamed out to our first destination, Station 3, TEAL-SHIPS headed to bed early to prep for the next few days of hard work.