In an effort that sounds like it came straight from a science-fiction movie, the Department of Defense has announced it’s exploring the use of genetically altered marine life forms to track enemy subs. The effort is part of a $45 billion initiative begun in 2017 and dubbed the Applied Research for the Advancement of Science and Technology Priorities Program on Synthetic Biology for Military Environments.

According to researchers at the Naval Research Laboratory, the program would use a relatively common type of sea life, altering its genetic makeup to make it "extra sensitive" to markers left by passing subs.

The new organisms would react in an identifiable way when exposed to "non-natural" substances like spent fuel left by subs as they pass by.

The research relies heavily on a scientific field called synthetic biology, which uses genetic engineering to modify existing organisms to enable them to function in new, beneficial ways.

In addition to modifying the sensor capabilities of sea life, DoD says genetically modified organisms could be used in areas like performance augmentation, materials synthesis and other applications. Genetically modified organisms are already in use in the civilian sector, but this initiative marks the first time the science is being explored in a defense setting.

The theory behind the technology is relatively straightforward: As a sub passes by, the chemicals and other traces it leaves behind would cause the organisms to change, triggering tiny electrical signals that could be captured, monitored and "translated" into actionable data. In a statement released by Defense Advanced Research Projects Agency, an agency spokesperson says the new technology, nicknamed PALS (Persistent Aquatic Living Sensors), could substantially change the way the seas are currently monitored.

"The U.S. Navy’s current approach to detecting and monitoring underwater vehicles is hardware-centric and resource intensive. As a result, the capability is mostly used at the tactical level to protect high-value assets like aircraft carriers, and less so at the broader strategic level, and less so at the broader strategic level," the statement read. "If we can tap into the innate sensing capabilities of living organisms that are ubiquitous in the oceans, we can extend our ability to track adversary activity and do so discreetly, on a persistent basis, and with enough precision to characterize the size and type of adversary vehicles."

The DARPA statement says evaluating marine organisms for their ability to be successfully modified is just the first step in the initiative. Researchers must also develop the technology to capture signals released by the organisms and to translate that data into information that can be used by military personnel.

In addition, the technology must be able to collect data from large distances, and it must be able to determine when signals are being released from other stimuli, like debris or other organisms, to eliminate false positives.

Researchers say the PALS initiative could be completed in four years, with modified organisms being tested in contained, secure facilities. No target date has been set for the actual deployment of modified genetic organisms.