Satellite-Respondent Buoys Identify Ocean Debris
- Sunday, 01 November 2009
Originating Technology/NASA Contribution
NASA operates a series of Earth-observing satellites, which help scientists learn more about our home planet. Through partnerships with universities and other government agencies, like the National Oceanic and Atmospheric Administration (NOAA), the Space Agency helps scientists around the world capture precise movements of the Earth’s crust to learn more about the underground processes related to earthquakes and volcanic eruptions, create accurate assessments of wind resources for future energy use, and preserve endangered species by generating much-needed data about their environments. This work, done primarily from space with satellites using a variety of complex instruments to take readings of the surface below, generates leagues of valuable data that aid scientists on the ground—or in some cases—on the water.
As much of the Earth is covered in water—liquid, frozen, saltwater, or fresh—much of NASA’s remote sensing work focuses on the oceans and their health. This valuable, mammoth (yet fragile) resource provides insight into the overall health of our planet, as water, in addition to being abundant, is a key ingredient to all known life on Earth.
As part of its ocean-observing work, NASA partnered with NOAA and private industry to develop remote sensing technologies for protecting the seas of the North Pacific from a nefarious and pervasive problem: derelict fishing gear.
Airborne Technologies Inc. (ATI), of Wasilla, Alaska, is a specialist in airborne marine surveying. Having been in business flying the northernmost state for over 25 years, the small company has developed a history of remote sensing from aircraft, aerial mapping, near-shore ocean aerial surveying for fisheries and oceanographic research, and satellite-based asset tracking and monitoring.
In 2001, company president Tim Veenstra attended a workshop in Anchorage where he learned of a new research opportunity sponsored by NASA and the State of Alaska. His company had already been conducting remote sensing for a number of years on a variety of projects including locating fish for commercial ventures and tracking sea birds and marine mammals for research, so this new opportunity to develop systems to track high seas debris was well within his range of expertise. ATI’s proposal was to use satellite and airborne remote sensing to locate lost and abandoned commercial fishing gear: errant drift nets known as ghost nets.
Drift netting is a commercial fishing practice using large (between 75 feet to over 30 miles in length) nets weighted at the bottom edge and with buoys floating the top edge. They create a vertical wall of netting in the ocean sometimes several hundred meters deep. Not anchored or attached to a boat, these huge fishing nets are sometimes inadvertently left behind or lost in storms, becoming ghost nets.
While these floating ghost nets prove to be navigation hazards for unsuspecting ships whose propellers can get entangled, they have an even more devastating impact on the environment. Unattended nets damage coral reefs; suffocate marine mammals, sea turtles, and birds when they wash ashore; and, if left afloat, bunch up and then begin a perpetual cycle of mass fish kills—dense balls of nets heavy with trapped fish sink, are cleaned by bottom-dwelling scavengers, and float back to the surface to start the cycle over. Modern synthetic netting can sustain this cycle indefinitely while drifting over a vast range: Ghost nets from around the Pacific have washed ashore on beaches as far apart as Alaska and the outer Hawaiian Islands.