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by Matthew Cimitile

In November 2010, the U.S. Geological Survey (USGS) Dive Safety Board received the U.S. Department of the Interior's Safety and Occupational Health Excellence Award in the Group category at a ceremony in Washington, D.C. The award is a reflection not only of the board's exemplary service but of the increasing use of scuba diving in USGS studies of the aquatic environment.

 "Use of scuba diving is expanding so much within the USGS due to the capabilities of new technology. As the technology develops, we are able to deploy instruments underwater and learn about the marine environment as we have never been able to before," said Marc Blouin, USGS Dive Safety Program Manager.

Some recent USGS research and fieldwork involving diving include:

• Studying the impacts of invasive species on native species in the Great Lakes, where researchers and research divers created and installed various sampling devices to look at the effects that exotic gobies are having on sturgeon and their eggs. (View "Invasive Species" video clip.)
• Monitoring groundwater and surface-water flow in real time using Acoustic Doppler Current Profilers (ADCPs). Research divers install and maintain these instruments in rivers, lakes, and estuaries nationwide. Data obtained are extremely valuable for estimating the magnitude of floods and when floodwaters will recede. (View "Acoustic Doppler Current Profilers" video clip.)
• Acquiring data on coral calcification rates and coral health as ocean conditions change. Divers set up equipment and also monitor stations that measure baseline calcification rates and map metabolic characteristics of benthic communities off South Florida and in the Caribbean Sea. (View "Coral Reefs" video clip.)

"The research that we do pertaining to coral reefs couldn't be done without scuba diving," said Don Hickey, a geologist and Eastern Region Dive Safety Officer at the St. Petersburg Coastal and Marine Science Center in Florida. "You need divers to set up instruments and collect data. Scuba is another tool used to conduct the science, and it needs to be done safely." (View "Coral Reefs" video clip.)

Video Clips

Invasive Species: USGS scientists monitor the impact that invasive species are having in the Great Lakes region, including that caused by gobies (being caught underwater on hook and line by divers in the St. Clair River in Michigan), lamprey (caught in a trap in the Detroit River), and zebra mussels (close-up video captured in Lake Ontario). Video shot by Jeffrey Allen (USGS) and edited by Matthew Cimitile (USGS). (View "Invasive Species" video clip.)

Acoustic Doppler Current Profilers: Divers retrieve an Acoustic Doppler Current Profiler (ADCP) from the bottom of Lake Michigan. ADCPs provide key information on water flow and are capable of measuring velocities of both groundwater and surface water. Video shot by Jeffrey Allen (USGS) and edited by Matthew Cimitile (USGS). (View "Acoustic Doppler Current Profilers" video clip.)

Coral Reefs: In 2003, USGS researchers dove on coral reefs off the coast of Honduras to document damage caused by Hurricane Mitch, a category 5 storm that hit the area in 1998. Video shot by Don Hickey (USGS) and edited by Matthew Cimitile (USGS). (View "Coral Reefs" video clip.)

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Setting up the tools and technology to study, monitor, and acquire underwater information takes expertise and extensive safety training in scuba diving. This is where the USGS Dive Safety Board comes in. The six members of the board—all active scientific divers—help manage USGS scuba diving activities and formulate the agency's dive-safety policies. They approve dive plans, identify dive-related safety issues, and develop annual program goals. Another 19 Dive Safety Officers in field facilities keep track of dive records, such as medical exams and training.

To be authorized to dive, USGS employees need to obtain supervisory approval, complete scuba certification, pass a dive medical exam, gain certifications in cardiopulmonary resuscitation (CPR) first aid and emergency oxygen administration, and pass an open-water checkout dive with a Dive Safety Officer. The authorization process ensures that USGS diving personnel have the training and experience necessary to dive safely while carrying out fieldwork.

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The rigorous safety planning and preparation needed for a successful research dive were exemplified in fieldwork conducted almost a year ago at the Florida Middle Grounds, a roughly 460-mi2 area about 120 mi off the northwest coast of Florida. The Middle Grounds support stony corals, nearly 200 fish species, sponges, and other marine life, as well as giant limestone pinnacles and ledges whose origins have long been a mystery to scientists. In early August 2010, 11 USGS research divers, along with an additional diver from the Florida Department of Environmental Protection and another from the National Coral Reef Institute, took shifts in pairs to descend 85 ft to the floor of the Gulf of Mexico, where they drilled into the seafloor to recover cores. The cores will  reveal what lies beneath the modern ecosystem.

"There has always been an effort over the last 30 years to try and drill the Florida Middle Grounds because we didn't know if they accumulated in place like a coral reef or if they were erosional features," said Hickey. "Retrieved cores could provide information to help us answer that question, and dating the core could help us determine the timing of past sea levels in the region." Previous attempts at obtaining geologic information at the Florida Middle Grounds had been difficult because of the extreme depths and thus the high pressures in which scientists must work.

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Before making the research dives, several USGS researchers and dive safety officers conducted reconnaissance to determine precise diving depths and to familiarize themselves with conditions, currents, and water temperatures at the site. "There is a lot of reconnaissance that is done prior to a dive. We run trips out to the dive site to see what the conditions are and what we will have to deal with," said Blouin. Information obtained through prior reconnaissance is vital to plan for the type of air to dive on, the tanks to use, the amount of bottom time, and the surface interval for each diver. Seismic-reflection profiles were also recorded and provided the science team with an idea of the subsurface structure.

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Using Nitrox 36, a gas mixture composed of 36 percent oxygen and 64 percent nitrogen, researchers slowly dived to the ocean floor with tools in hand. These included hammers, wrenches, bolts, and other equipment necessary to construct a tripod on the seafloor and attach a drill. As the drill stem of core barrels churned deeper into the ocean floor, additional segments were attached to recover cores as long as 60 ft. The divers were split up into six dive teams that alternated descents. Each team spent about 40 minutes on the seafloor before ascending back to the surface. When the work was complete, the team members had collected four geologic cores ranging from 2 to 57 ft long that will tell the story of how the Florida Middle Grounds formed. Overall, 13 divers conducted 65 dives and collectively spent 101 hours underwater.

Years ago, the ability to obtain geologic information at such depths, as well as constantly monitor biologic and hydrologic activity in the marine environment, would have seemed impossible. Today, such research is becoming more common and is a testament to improved diving techniques and enhanced technological capabilities.