The Pulley Ridge Ecosystem Connectivity Project
Special requests come at the strangest moments, usually at times when all of the facets of decision making are lagging because of pure exhaustion. “Yes” is my standard answer for unique and adventurous requests that require me and my crew to “stretch” a bit. The familiar life coaching words I’ve replayed so many times in my mind ring again, “That’s not fear, that’s excitement!” At that moment I agreed to charter our vessel Premium Time out of A&B Marina in Key West to help with the final step needed to complete the Pulley Ridge Ecosystem Connectivity Project.
The Mission
Grant Rawson who is a NOAA affiliate at the University of Miami and my contact was in charge of coordinating the trip that would require a seventy-five mile trek west and then south past Fort Jefferson to the west side of Riley’s Hump loaded with enough gear and human assets to get the job done. The gear needed to make the dive had to be rebreathers and the divers were to be the some of the best in their field. Grant had assembled the team that included Rick Riera-Gomez from the University of Miami, Casey Coy and Mike Terrell from the Florida Aquarium in Tampa with another Florida Aquariam expert Lauren Freeman as topside support.
This was no easy mission. The plan was to deploy the final data gathering Acoustic Doppler Current Profiler to a subsurface mooring left in place last August to record current speed and movement among other key data points. Hurricane Isaac had caused this final phase of the project to be postponed from last year until now. The other two subsurface moorings were set and complete making this one number three to complete the triangle. The first obstacle was to find the visible subservice mooring ball set at 15 feet below the surface with only one set of Lat/Long numbers. The seas were running 2-4 feet with a southeast wind direction of 10-15 knots and the water temperature was averaging 74 degrees. The weather conditions and wind direction allowed a full speed approach from Key West to this “needle in a haystack” seventy five miles west. After passing over and through the RNA known as Riley’s Hump the numbers did not directly expose the location of the sub-surface mooring ball so a marker was deployed at the coordinate location. A grid search was the next step and having the sun behind us would help illuminate the ball if it was still in the area. There were multiple strong storms that moved through last year including the very memorable Hurricane Sandy. Hopefully the ball was still attached to the railroad tie that was used to anchor the marker in place. Heading south and then east was effective and one of the crew pointed to the location. Once next to the ball a free diver was deployed to attach a surface marker ball to keep the dive zone in easy eyesight as the divers prepared to perform the operation.
Time to Dive
One by one, each pack was mounted on the backs of the highly trained and serious divers. This was all business now with danger involved. The dive would be 214 feet with less than twenty-five minutes of bottom time. First, they had to find the subsurface mooring mounting structure and then attach the data gathering device. There would be two signs that would help us at the surface to gauge how far along in the operation the team was. One would be the inflating of a balloon lifting the mooring harness to the surface and the other clue was the tool bag also brought to the surface by an inflated balloon launched from the bottom. Other than those two clues, we would have no idea what was happening close to a football field deep, seventy five miles west of Key West on the bottom of the ocean. They were on their own. Eight minutes into the program, the harness balloon surfaced and shortly after, the tool bag popped up as well. Grant Rawson knew that this project was on it’s way to being a success.
Lauren suited up and rolled into the blue water to support this highly efficient team as they went through the process of decompression. Well over an hour of deco time was needed to fully expell all of the nitrogen bubbles that were in each of the divers systems. Lauren’s job was to watch the process the entire time and assist if needed. She too was now deeply involved in the final hour of the project.
Reporting back through hand signals it became clear the project would be complete without injury or drama. As the team re-entered the safety of the Premium Time the final briefing took place. A few sharks, a couple of amberjack and a system set up to help understand the relationship of the currents around Pulley Ridge. To ease the pounding of a southeast swell we moved north into the Gulf of Mexico to give us a smooth surface to travel so the divers could sleep their way back to Key West knowing there work was done. It hit me again,that same life coach saying I’ve heard so many times “This isn’t fear, this is EXCITEMENT!
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Grant Rawson (PhOD) lead a team of technical divers from the University of Miami to the southern Dry Tortugas on a two-day cruise to install instrumentation on a surface mooring deployed there last August. The mooring is part of the Pulley Ridge Ecosystem Connectivity Project’s moored oceanographic array. This 3-year study is a collaboration between many institutions including UM/RSMAS and NOAA/AOML, and is designed to look at the physical and biological connections between Pulley Ridge (a mesophotic reef approximately 70 km west of the Dry Tortugas) and the rest of the Florida Keys reef tract. The three moorings which make up the array are all now fully instrumented with acoustic Doppler current profilers (ADCP) and conductivity/temperature recorders (CT). The collected on site data will aid validation of a high-resolution version of HYCOM configured for the Gulf of Mexico and developed for this project at AOML/PhOD and RSMAS/MPO.
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