National Oceanic and Atmospheric Administration scientists have tracked krill populations in the southern oceans for years, but for the first time, they plan to use autonomous computer-driven drones to help with the basic research.
Krill are tiny crustaceans that are a key building block of the food web in the southern oceans. The shrimp-like creatures feed whales, seals, penguins and people.
The tiny animals are known for their large underwater swarms.
NOAA scientists have tracked fluctuating krill populations for years as part of an international effort to better understand the food web in the Antarctic.
“We study krill so we understand whether its trends and abundance are likely to be influenced by how much fishing effort we do, but also whether that fishing effort will impact the upper trophic levels like penguins and seals,” said Christian Reiss, a senior researcher at the Southwest Fisheries Science Center in La Jolla.
But packing up a research vessel and traveling to the bottom of the world takes time and money. Both are in short supply at a federal agency that is keeping a close eye on shrinking budgets.
That is why the Teledyne G3 Slocum drone is so attractive.
The eight-foot-long submersible can carry sophisticated acoustic devices that are high-tech fish finders. The autonomous machine can identify and measure how many krill there are when it encounters a swarm.
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“We can collect data on the water conditions. We can collect data on how much food is out there for the krill. And literally, we can collect data on how much biomass of krill there is,” Reiss said.
Testing The Gliders
On a recent day at NOAA’s state-of-the-art facility in La Jolla, NOAA Research Biologist Anthony Cossio operated a crane over a massive indoor saltwater tank.
The 66-foot-long and the 33-foot-deep tank holds more than 528,000 gallons of seawater. The sheer size of the pool allows researchers to test the gliders before they risk putting the drone into the ocean.
Cossio lowered the yellow and black tube with stubby wings into the water and waited for the machine’s communications equipment to connect to a satellite. That only happens when the drone’s trail breeches the surface.
“Then it’ll go get its GPS coordinates and make sure it knows where it’s at. Figure out where it’s going based on the directions we told it. And then it starts to dive, right now it’s starting to dive,” Cossio said.
On this day, the mission is a couple of routine dives inside the large tank, a job that was easily handled by the slow and deliberate watertight drone.
Proper testing is essential before the craft take on their first Antarctic mission.
“These are deep gliders so they go to 1,000 meters and these are also the biggest gliders that Teledyne has manufactured,” said Jen Walsh, NOAA research biologist.
Drones Do Not Require Constant Attention
Walsh is one of three pilots who will watch over the drones during the long winter mission. She said the machines do not require 24-hour-a-day piloting because the onboard computer will do most of the work when they are in the field.
They are pre-programmed to dive, surface and move back and forth over a preplanned survey area.
“If the glider is in an area of not very complex bathymetry, we’re not worried about ice where it is. Maybe it is pretty far offshore at this point. Sometimes it means keeping an eye on it, making sure it surfaces when we expect it to surface. And sometimes I won’t have to give it any direction at all,” Walsh said.
The vessels will have to navigate cold and possibly rough seas. A lot can go wrong.
When the drones surface and check-in, Walsh can monitor the gliders on any internet-connected computer.
“When the glider surfaces and connects to satellite it has a very specific ding-ding -- it is like a Pavlovian response. My husband at home would hear it. ‘Oh, your glider’s up.’ Which just means it’s connected, which is good. Because if it’s doing 1,000-meter dives, which it will in the Antarctic, that can take up to four hours,” Walsh said.
The drones were field-tested in the ocean a few weeks ago. Research Biologist Cossio dropped the drones into the water off the coast of San Diego. The gliders spent two weeks at sea practicing maneuvers over and around the San Diego Trough.
NOAA officials said the vessels will head south this fall for their first research mission in the Antarctic.
