Findings

Oceanographic fieldwork is always challenging. It can take months to prepare for a couple of weeks at sea. Once you set sail, oceanic and atmospheric conditions can unexpectedly change, equipment breaks and repairs must be done with what you have onboard, and supplies run out and you have to exercise your creativity. This is why one of the most important things when going out on a research cruise is assembling a great team of scientists, engineers, and crew to face and overcome these challenges. We were lucky to have one of those great teams for the first cruise of the CYCLE project.

What We Did

Glimpse of a sea turtle swimming by Swiftia exerta colonies at Alderdice bank, 90 meters (295 feet) deep.

Glimpse of a sea turtle swimming by Swiftia exerta colonies at Alderdice Bank, 90 meters (295 feet) deep. Image courtesy of Connectivity of Coral Ecosystems (CYCLE) in the Northwestern Gulf of Mexico 2019. Download larger version (jpg, 6.8 MB).

On R/V Pelican (April 25–May 12), we:

  • Collected samples for genetic and chemical analyses of key sessile species. During our research cruise, we conducted 16 remotely operated vehicle (ROV) dives with the ROV Global Explorer, totaling 158 hours of work underwater. During our dives, we captured high-definition and 4K video and images of the seafloor and collected over 430 samples of corals, sediments, and water that will enable us to examine the genetic and chemical connectivity of coral ecosystems between the Flower Garden Banks National Marine Sanctuary (FGBNMS) and its proposed expansion areas to the east.
  • Deployed Autonomous Reef Monitoring Structures or ARMS. We also used the ROV to deploy 44 ARMS along with instruments measuring temperature, salinity, and oxygen. The ARMS and instruments will help us understand the biodiversity and physical characteristics of the different reefs. The ARMS will be left on the seafloor for two years before being retrieved for analyses.
  • Characterized the water column over the reefs of interest. We conducted several conductivity-temperature-salinity (CTD) casts to characterize the properties of the water column above the banks and reefs to the east of the FGBNMS.
  • Explored reefs and banks to the east of the FGBNMS. We explored new areas of the banks to the east of the FGBNMS that we believed would be suitable for corals to grow, but had not been documented before. We made some remarkable observations, including sea turtles swimming among sea fan gardens of Swiftia exserta at 90 meters (295 feet) deep and aggregations of large basket stars on top of steep carbonate outcrops. We also learned that there are many fishes living on these banks, and that they love ROV lights, making it sometimes exceedingly difficult to see the seafloor when diving at night!

Overall, we had a successful research cruise, despite losing four days to bad weather, i.e., being chased by thunderstorms, 30 to 40 knot winds, and waves as high as 11 feet. The hard work and professionalism of everyone onboard made this expedition a success.

Basket stars, feather stars, and corals colonizing the top of a carbonate outcrop at Alderdice Bank, 86 meters (282 feet) deep.

Basket stars, feather stars, and corals colonizing the top of a carbonate outcrop at Alderdice Bank, 86 meters (282 feet) deep. Image courtesy of Connectivity of Coral Ecosystems (CYCLE) in the Northwestern Gulf of Mexico 2019. Download larger version (jpg, 6.4 MB).

School of curious small fish attracted by the ROV lights while diving at night.

School of curious small fish attracted by the ROV lights while diving at night. Image courtesy of Connectivity of Coral Ecosystems (CYCLE) in the Northwestern Gulf of Mexico 2019. Download map (jpg, 5.8 MB).

The second research cruise of this field season on R/V Southern Journey (May 17–26) was also met with severe weather. The team endured the rough seas for two days, making significant fish collections for the project. However, sea conditions worsened, becoming unsafe to continue the work. Thus, this expedition was unfortunately cut short. Not to worry, we are already making plans to go back out and complete the work later this year.

The samples and data we collected over this first field season will be complemented with field seasons in 2020 and 2021 and will be analyzed over the next few years to enhance our of understanding of the patterns of connectivity of coral ecosystems in the northwestern Gulf of Mexico and the processes that structure these patterns. This information will be help resource managers better protect, restore, and conserve these resources.

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