By Benjamin S. Giese
We met in Charleston, South Carolina, on a hot July day. There were seven undergraduate students participating in the research cruise: Celia and Paul from Texas A&M University, Eric from Oklahoma State, Nathan from Harvard, Jeff from Southwestern, Leonard from Colorado College, and Adrienne from Agnes Scott. All of the students were participating in a 10-week Research Experience for Undergratuates (REU) program at Texas A&M, sponsored by the National Science Foundation. These REU students had accepted the opportunity to participate in an 8-day cruise aboard the R/V Gyre.
In Charleston we boarded the Gyre for a cruise that would take us across the Gulf Stream twice, into the Gulf of Mexico, and finally back to home port in Galveston, Texas. We left Charleston at 10:00 pm on July 17 on an absolutely still evening. In fact, the ocean remained remarkably quiet for the entire cruise, a mild disappointment to those of us hoping to experience some weather. After a good night's sleep and hearty breakfast, we arrived at our first station in mid-morning, just off the coast of northern Florida.
Our first task was to make a hydrographic survey of the Gulf Stream, and to test the assumption of geostrophic flow in a western boundary current. To accomplish this we took CTD and XBT measurements in a section that crossed the Gulf Stream at 29N. We also ran the Acoustic Doppler Current Profiler (ADCP) to make simultaneous measurements of current strength. The students teamed up into three groups, each responsible for two four-hour shifts per day. During their shift, the students prepared water bottles for the cast, collected samples when the CTD was brought back on board, and took XBT casts while the ship was under way. They also operated the shipboard computer, and made sure all of the data were properly archived for analysis back in College Station.
After a successful transect at 29N we steamed south to 27.5N for a second transect across the Gulf Stream, where the current is more narrow, and presumably more intense. Glad to have a break from midnight watches, the students worked up preliminary data, relaxed, and sunbathed on deck. The transect at 27.5N was equally successful, leaving us just off the coast of Florida, north of Miami. From there we steamed along the coast of Florida, to Key West, where we met Doug Biggs, who replaced me as chief scientist. From Key West we steamed into the Gulf of Mexico for more CTD and XBT casts, as well as a planned encounter with an eddy. A surface drifter was deployed in the eddy, and its path is still being tracked by satellite measurements. From the middle of the Gulf we headed toward home. Before arriving at port we checked the status of an oil seep just off the coast of Galveston. With samples of the bottom sediment, the students identified a natural source of hydrocarbons leaking into the water column.
Eight days after leaving Charleston, South Carolina, the R/V Gyre docked at Galveston, Texas, with seven very tired undergraduates. This was the first experience at sea for many of the students, and the first exposure to scientific research for some. The energy and enthusiasm the students showed toward their work impressed me greatly. Their dedication paid off; the cruise was a tremendous success, both scientifically and educationally.
Oceanography, Texas A&M University
Updated July 24, 1995