The AUVs are outfitted with an assortment of instruments that measure properties like temperature, the strength and direction of currents, the concentration of carbon dioxide gas dissolved in the water, and saltiness.
Such measurements provide data that are essential for building models that predict climate change, and improve daily weather forecasts. Discovering how much carbon dioxide is stored in the oceans, for example, is a critical factor in determining whether the oceans are a sink or source for continued emissions of this greenhouse gas.
Other plans are to load AUVs with sensors that detect a variety of environmental pollutants, or instruments that can sample and sort the microscopic life-forms lurking in the oceans' depths. Some researchers want sensors that will track jellyfish. Researchers anticipate that monitoring pollutants and water temperatures may help explain the loss of certain species of fish and aquatic plants, or the sudden appearances of toxic alga blooms. ABE (Autonomous Benthic Explorer) IIa model which looks something like a fusion of Noah's Ark and the Hindenbergis a more portly AUV designed for deep ocean missions where it will map, photograph, and possibly collect samples from ocean vents spewing black plumes. "The original ABE can scale steep cliffs, but it does so somewhat inefficiently and uses a lot of power. ABE II will be able to go over much more difficult terrain more efficiently and make maps of much larger areas," says Yerger, who works on ABE II.
In the last six months AUVs have triggered huge commercial interest. Oil and gas companies want them to scout out oil reserves and optimum locations for sinking drilling platforms. They are also great tools for inspecting underwater tunnels and communications hardware.
Enhancing the Ocean Experience
There is one major disadvantage to using AUVs. "AUVs don't have smart people controlling them," says Yerger. They can only perform limited tasks, but they do so with a relentless precision that produces very high quality data. "If we program a vehicle like ABE to fly in a grid pattern over the sea floor, it does exactly what we've asked and it doesn't get tired, it doesn't get bored, so it produces very high quality data."
While AUVs are a welcome tool to scientists, keeping them from dangerous locations and releasing them from the tedium of making repetitive measurements, it is clear they will never replace a human presence in the ocean. But they can enhance it.
"I had a very exciting moment when we were out with ABE making maps of the seafloor in an area where the manned submarine ALVIN was scheduled to dive later that day," says Yerger. "Using the data from ABE we made very detailed maps that we were able to share with the ALVIN crew as they ate breakfast. They were thrilled, they were excited and they got a lot of work done that day."
Watch television coverage of this story on National Geographic Today, only on the National Geographic Channel, 7 p.m. ET/PT in the United States. Click here to request it.
SOURCES AND RELATED WEB SITES