Submersed in Underwater Technology
Calculate and assess coral mortality data collected during an underwater research expedition from Aquarius and Jason.
- Name at least 3 types of underwater technologies or submersibles.
- Calculate, assess, and compare coral mortality rates.
- Describe the kinds of research that can be conducted using submersibles.
Submersible, ROV, AUV
Venturing into the underwater world is something we practically take for granted, yet the development of scuba diving is relatively new. It was 1943 when Jacques-Yves Cousteau made improvements on existing equipment and developed the basis for modern scuba gear. Since then we have reached far in our exploration of the oceans – we now have the technology to film an underwater movie, send submersibles (both manned and unmanned) down to the depths to conduct scientific research, and locate shipwrecks, among other things. Although we have only had a glimpse of our vast oceans, underwater technology is revealing to us a rarely seen but fascinating environment that is a critical part of our world.
A previous data activity focused on the Galapagos Islands and provided you with a behind-the-scenes look at the filming of the IMAX movie, 'Galapagos'. The making of an IMAX film is no small feat. The cameras are enormous, and the technology required to move the operation underwater is impressive. The filming of 'Galapagos' was accomplished with the help of both scuba divers and submersibles.
Recreational scuba diving requires a good deal of knowledge and concentration. Diving professionally (i.e., as a photographer or researcher) requires even more skill. Imagine trying to maneuver or even just stay in one place while conducting work underwater! Learn about the physics of this challenging sport and occupation with lesson plans from the website of Aquarius, the world's only underwater research habitat.
Aquarius completed a 15-day mission with the JASON Project, a distance learning program which allows students worldwide to experience the thrill of discovery in science and technology. The scientists involved in this mission were studying algae, sponges, and corals, among other things. With satellite links and live broadcasts, the students who participated actually helped scientists collect data about the condition of corals at Conch Reef near Key Largo, Florida!
Manned submersibles differ from Aquarius in that they are mobile, piloted vehicles which can explore the underwater environment. The National Undersea Research Program (NURP) Submersibles page gives you an idea of the existing fleet of submersibles. About half of the IMAX movie 'Galapagos' was filmed from the submersible Johnson Sea Link, which is based in Florida at the Harbor Branch Oceanographic Institution. The Johnson-Sea-Link is 25 feet long, weighs 12 tons, and can carry four people. During the filming, it descended several times to between 1,000 and 3,000 feet below sea level, and then inched along the sea floor at one mile per hour.
Unmanned submersibles include ROVs, or Remotely Operated Vehicles, and the latest addition, AUVs, or Autonomous Underwater Vehicles. ROVs are linked to the surface by a cable system and require support people above water to manipulate the robots and help them conduct their work. AUVs are battery powered, independent of the surface, and are programmed by computers to carry out their missions. Take a peek at some of these vehicles and their capabilities on the NURP Underwater Technology page. On the Woods Hole Oceanographic Institution Deep Sea Vehicles page, you will find detailed specifications of all their submersibles, including ABE (the first AUV), JASON (an ROV), and Alvin, most famous for its exploration of the Titanic. On its journey to survey the wreck, the Alvin was teamed with a specially designed robot, the Jason Jr., which photographed the inside of the ship.
In this exercise we'll explore some data from a previous Jason and Aquarius research project with Dr. Ellen Prager. One goal of Dr. Prager's study was to compare the health of corals at 65 feet to corals at 95 feet. In this exercise, we will compare Dr. Prager's estimates of coral health with those of the participating students and answer questions about the health of corals in the study.
- Coral mortality (%) was estimated by looking at 48 coral heads at each depth. Take a look at the raw data which compares the average of all student observations with Dr. Prager's estimate ("# PINS Observations" = the number of participating schools).
- Calculate the overall average coral mortality at 65 feet depth for the student estimates and for Dr. Pragers. Repeat for corals at 95 feet depth. Create a graph of these averages and compare the results. On the x-axis should be Coral Mortality (%), and on the y-axis should be Depth. So, at each depth, your graph should have two points: the students' estimate and Dr. Prager's estimate. At which depth did the students observe higher coral mortality? What about Dr. Prager? Compare your graph with theirs.
- How close were the students' estimates to Dr. Prager's? At which depth do the corals seem to be healthier? (Remember, the graphs show mortality) Why might that be?
There are a wide variety of underwater technologies that allow scientists to explore the depths of our oceans.