Public Release: 

Using the ocean's living light shows to fight terrorism or track the planet's most massive migration

Harbor Branch Oceanographic Institution



Glow from the jellyfish Atolla vanhoeffeni, as seen by SPLAT-Cam
Credit: © Edith Widder/Harbor Branch

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Biloxi, Mississippi, Oct. 29, 2002 -- Today at the Oceans 2002 conference, HARBOR BRANCH bioluminescence expert Dr. Edith Widder will unveil plans for a unique new device for studying, identifying, and mapping the myriad ocean creatures from bacteria to fish that give off chemical-based light or bioluminescence. Potential applications range from improving the safety of covert operations to tracking the world's most massive migration. Thanks to recently approved appropriations, the program is now receiving nearly $1 million per year in federal funding because of its potential importance in fighting terrorism.

Few oceanic phenomena are more beautiful or surreal than the cosmic light shows put on by the ocean's ubiquitous bioluminescent sea creatures. The shows are seen from the surface, where a swimming dolphin or turbulence from a moving ship can excite living trails of light, to the darkest depths, where bioluminescent creatures constantly create ever-changing constellations of light.

The military has long been interested in studying bioluminescence because, when excited by ships and submarines, those light shows can give away vessels' positions, jeopardizing them and their crews. By the same token, bioluminescence can help the military spot and track enemy vessels. Indeed, in 1918, it was bioluminescence that gave away the position of the last German U-boat sunk during World War I.

While bioluminescence is extremely common in all ocean waters, it is also variable. At certain times there might be few or no bioluminescent organisms to give off light in the wake of a ship or submarine. If the Navy could reliably predict such events it could, for instance, increase the safety of covert missions. Though progress has been made, such a feat has proven difficult because the vast soup of sea creatures involved remains poorly understood. Better understanding of bioluminescence could also lead to its use as a sensitive detection tool for anti-submarine and countermine warfare.



SPLAT-Cam system installed on the Johson-Sea-Link submersible
Please credit: © S. Haddock

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The equipment Widder and her colleagues are developing will be the first ever to allow measurement of the amount of bioluminescent light in a given area while simultaneously identifying who is making the light. With it she will produce data that could vastly improve the Navy's ability to forecast the level of bioluminescence to expect at a specific location and time, and its ability to use bioluminescence as a detection tool, while also shedding light on a number of other important research pursuits.

The new equipment will include two main components, both co-developed by Widder and built by HARBOR BRANCH engineers. The first is called the HIDEX-BP, or High Intake Defined EXcitation BathyPhotometer. This is a light-tight chamber that rapidly draws seawater in past a wide mesh screen measuring the light given off by the organisms present. Bioluminescent animals are stimulated to give off light by just about any agitation, so they glow either when hitting the mesh, or due to the motion of water passing through it.

A prototype HIDEX-BP has been deployed around the globe to gather bioluminescence data, but it does not given any information about the type or kind of animals creating the light. This is critical to full understanding of the phenomenon because the same amount of light might be created by a small isolated patch of jellyfish as by widely dispersed algae, and each would have profoundly different effects on the bioluminescent characteristics of a given area. "If you're going to forecast, you've got to know who is making the light," says Widder.

The second component will fill this gap. Called the SPLAT Cam (Spatial PLankton Analysis Technique), it was originally developed for use on HARBOR BRANCH's deep-diving submersibles the Johnson-Sea-Links. SPLAT-Cam identifies individual bioluminescent animals based on their glow. The current system includes a one-meter-square wide mesh screen mounted on the front of a submersible or remotely operated vehicle (ROV), that has a similar effect to that on the HIDEX-BP. A video camera focused on the mesh records the entire light show as a vehicle moves through the water at a set pace.



A deep-sea shrimp (Meganyctiph) and and its glow as captured by SPLAT-Cam
Credit: © Edith Widder/Harbor Branch

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Widder and her team have developed a library of light signatures for various ocean creatures based on telltale characteristics of each such as the shape and duration of the glow. A computer essentially stacks each frame of video footage to create a three-dimensional image of the bioluminescence captured by the camera during a given period of time and then automatically identifies the animals seen, how many there were, and their proximity to each other.

In conjunction with the Navy and HARBOR BRANCH's Engineering Division, Widder is now miniaturizing the SPLAT-Cam system to mount it on a single frame with the HIDEX-BP. This will allow easy deployment around the world, whereas submersible work is limited by cost and logistics. The Widder group is also working toward creating additional devices that could be used as part of a military bioluminescence detection system.



HIDEX-BP instrument
Credit: © Edith Widder/Harbor Branch

Full size image available through contact

Widder says that beyond Navy applications, a better understanding of bioluminescence is intimately tied to a better understanding of the oceans. "We've been treating the ocean like one big soup, and of course it's not," she says. "It's extremely structured, but because it is this great watery mass, it's very difficult to identify that structure." However, bioluminescence is so prevalent that studying it is an effective way to map the distribution of marine creatures in general in order to make sense of that soup.

Using the new instrument, Widder hopes to better understand and track the planet's most massive migration--the daily movement of a colossal and varied mass of sea creatures inhabiting the depths up to the surface for night feeding when they are not as likely to be seen and eaten. Study of the migration has been severely hampered by the general difficulty of doing research in the ocean's largely unexplored and unexamined midwaters. However, the HIDEX/SPLAT system could be lowered to gather precise data about the migration because most of the creatures involved are bioluminescent.

Other potential applications include helping researchers determine the geographical boundaries of blooms of toxic algae such as red tides and assessments of the population size of food sources for important commercial fisheries. Because bioluminescence can diminish in response to the presence of toxic chemicals, the phenomenon could also be used as an indicator of water quality once better understood.

Widder's Oceans 2002 talk is scheduled for 4:00 p.m. on Tuesday, October 29. In March, she will be using the original SPLAT-cam system to explore the Sea of Cortez. She can be reached at 772-465-2400 ext. 315, or widder@hboi.edu. To reach her during the conference from October 28-30 please contact Mark Schrope at 772-465-2400 ext. 433, schrope@hboi.edu.

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HARBOR BRANCH Oceanographic Institution, Inc., is one of the world's leading nonprofit oceanographic research organizations dedicated to exploration of the earth's oceans, estuaries and coastal regions for the benefit of humankind.

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