Gulf of Mexico research cruise: Studying the Loop Current
June 14, 2021
Retrieving a Current and Pressure recording Inverted Echo Sounder (C-PIES) from the Gulf of Mexico.
June 14, 2021
Words and photos by GSO Ph.D. student Ali Johnson.
A team of five GSO scientists recently returned from a two-week long research cruise in the Gulf of Mexico aboard the R/V Pelican. The purpose of the cruise was to retrieve an array of 24 Current and Pressure recording Inverted Echo Sounders (C-PIES) that have been operating on the seafloor of the Gulf of Mexico for the past two years.
The research cruise is part of an ongoing project, funded by the National Academies of Sciences Gulf Research Program, to increase understanding of the Gulf of Mexico Loop Current eddy separation process, with a long term goal of advancing Loop Current forecasting efforts. The ability to better forecast the Loop Current has implications for a wide range of human and natural systems, including oil and gas operations, storm and hurricane intensity, coastal ecosystems, and industries such as fishing and tourism. Specifically, the observations collected by the URI C-PIES group will be used to study the interaction between the Loop Current and bottom topography as a potential trigger for Loop Current eddy separation.
After two days of driving from Rhode Island to Louisiana, the team spent a few days in New Orleans. During a swamp excursion they came face-to-face with a 14-foot, 100 year old, one-eyed alligator named No-See!
After two days of driving from Rhode Island to Louisiana, the team spent a few days in New Orleans. During a swamp excursion they came face-to-face with a 14-foot, 100 year old, one-eyed alligator named No-See!
The URI C-PIES group spent two weeks on the Research Vessel Pelican which is owned and operated by The Louisiana Universities Marine Consortium (LUMCON) in Chauvin, La. The R/V Pelican is 116 feet long and while built to accommodate 14 scientists, was much more comfortable with only five during this cruise!
The URI C-PIES group spent two weeks on the Research Vessel Pelican which is owned and operated by The Louisiana Universities Marine Consortium (LUMCON) in Chauvin, La. The R/V Pelican is 116 feet long and while built to accommodate 14 scientists, was much more comfortable with only five during this cruise!
The URI C-PIES group spent two weeks on the Research Vessel Pelican which is owned and operated by The Louisiana Universities Marine Consortium (LUMCON) in Chauvin, La. The R/V Pelican is 116 feet long and while built to accommodate 14 scientists, was much more comfortable with only five during this cruise!
C-PIES recovery part 1: From the ship we are able to acoustically ‘talk’ to the instrument while it’s sitting on the bottom. We estimate our distance from the instrument using the acoustic round trip travel time which helps us position the ship, taking into account the speed and direction of both the wind and the current. Once we’re in place, we send the acoustic command to release the instrument. It continues to communicate with us as it rises through the water column so we can track our distance and its depth until it reaches the surface.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 2: Once the C-PIES is on the surface and has been spotted, we pull the ship up close and catch the line with a grappling hook. A large yellow flotation buoy is hauled onboard first and then the PIES is clipped and attached to the crane. When all the instrumentation is successfully on the deck, we clean and organize everything before moving it all into the lab where we immediately download and process the data.
C-PIES recovery part 3: Data is immediately downloaded, stored and processed before we remove the batteries in the C-PIES and prepare them to be shipped back to Rhode Island.
C-PIES recovery part 3: Data is immediately downloaded, stored and processed before we remove the batteries in the C-PIES and prepare them to be shipped back to Rhode Island.
Life at Sea! GSO graduate student Ali Johnson with a number of recovered C-PIES in the wet lab.
Life at sea! Dr. Randy Watts checks in with home on a makeshift bed of C-PIES foam.
Life at sea! A very intense mancala tournament between recoveries – Ali was the champion!
Along with near bottom velocity, bottom pressure and temperature, C-PIES are instruments that measure sound speed by sending an acoustic pulse to the sea surface and recording the amount of time it takes for the pulse to return to the seafloor. The acoustic travel time provides an estimate of the temperature and salinity structure in the water column every ten minutes. The team was successful in recovering the instruments, deploying four profiling floats and collecting 16 onsite temperature and salinity profiles.
