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FATHOMING THE GULF STREAM - Nature's Pharmacy and Eyes In The Sea MISSION DISPATCH 9 • 08/27/02 Today's Weather - images courtesy of NOAA & RSMAS Dispatch by Brian Cousin - HARBOR BRANCH Oceanographic Institution As it hurtles northeastward, the powerful Gulf Stream affects everything that enters its path. Countless marine organisms-from teeming legions of delicate jellies and plankton to endangered loggerhead sea turtles-are gathered up and swept along to meet their destiny. After thousands of miles, tiny larvae break free, and set about colonizing the bottom near the European continent. 
Others drift forever at sea, making their home in the vast mid-water region of the open ocean. The unfortunate perish, trapped
in spin-off currents and eddies that meander into colder water and lose their life-sustaining warmth, or fall prey to predators
higher up the food chain. After years at sea, female loggerheads return instinctively to their hatching beach, ready to plant
the seeds of succeeding generations. Exactly where the currents have taken them, no one knows for sure. What is known, is that
the Gulf Stream is one of the most powerful natural forces on the planet.
As the massive volumes of water power this ocean-going escalator, so too do they precipitate rapid, often dramatic changes in weather. Yesterday, with the Johnson-Sea-Link II just unloaded following the evening dive, a summer squall blew up with surprising speed. While not the worst one could expect at sea, its impact was considerable. In moments, the clear sky was displaced by a threatening line of boiling black clouds. The needle on the anenometer, that indicates wind speed on the bridge of the R/V Seward Johnson, jumped in an instant from about 10 knots to 42 knots, the wind whipping spray off the agitated water. Jagged bolts of lightning pierced the darkening sky. Rain came in torrents as the front hit full force and then tapered off to a downpour, and finally, a light rain fell as the squall passed to our stern and finally disappeared from the sky. At 10pm, the moon shone through broken clouds. Dr. Tammy Frank's team lowered her fourth Tucker trawl into the deep blue water behind the ship and then moved into the CTD lab to monitor temperature and salinity as the trawl sank into the depths. 
Previous trawls have proved relatively unproductive for the visual ecology team. Contrary to the hoped-for abundance of animals,
each has rendered only a small handful of animals, mostly unsuitable for study on the physiological prep, and too small for
Dr. Eric Warrant's research into optical physiology. The samples are preserved however, for future study.
Three hours after hitting the water, the trawl net returns to the surface and the team quickly moves the detachable cod end into the refrigerated darkness of the environmental room. Under dim red light the canister is opened and a few animals are flushed into a large container for sorting. Floating among dozens of tiny amphipods, there is a small reddish orange squid, Histioteuthis. Histioteuthis is covered with photophores (complex light producing organs that have structures such as shutters, reflectors, and lenses) and has remarkable unmatched eyes. One is small. The other has a large, yellow-pigmented lens over it. Why? Dr. Frank related one suggestion that the squid might swim with the large eye oriented upward, the yellow pigmented lens revealing prey that are counter-illuminating in an attempt to escape detection. The small eye, pointing down, presents the smallest shape shadow to potential predators below. The pursuit of scientific knowledge is never an easy venture, and not for the faint of heart. Even aboard a modern research vessel with a state-of-the-art undersea vehicle and some of the most experienced technicians and researchers in the world, setbacks are not uncommon. Even the most user-friendly technology can become a scientists worst enemy when exposed to the hostile effects of salt water and pressure. Dr. Edie Widder has been struggling with her Eye-in-the-Sea camera, attempting to duplicate on the bench, faults that have been occurring when the unit is deployed in the sea. It's frustrating work and tedious at times, as the computer control enters an uncancelable diagnostic mode that takes hours to complete. After two long days and numerous tests in the lab and the cold environmental room, she has resolved some issues but others are beyond repair 80 miles out at sea. Unfortunately, the camera will not be redeployed on this mission. 
The Johnson-Sea-Link II submersible has made two dives today, successfully collecting samples for the biomedical marine research group and retrieving Dr. Frank's cylindrical benthic traps. Some of the traps are empty though the bait is gone, indicating that something is getting in and out again before the magnesium catches dissolve and the doors close. She is pleased however, that none of the traps contain loathsome hagfish, and there's even a fish that Dr. Eric Warrant can use to measure electrical signals from its eyes. In addition, John Reed led the first blue-water scuba dive of the mission. The dive party rolled off a small boat about a mile away from the R/V Seward Johnson into water over 1,700 feet deep. Tethered together and to the surface on a blue water rig, Drs. Tammy Frank and Sonke Johnson are armed with mesh bags filled with glass jars that they hope to fill with small shallow water specimens. Dr. Johnson is especially interested in pigmented organisms to make color measurements for his studies. They capture a few salps and other small organisms, but the consensus is unanimous: there just isn't much living in the water column in this part of the stream. 
Dr. Johnson offers a possible reason for the lack of diversity and abundance. "It's warm. The surface water's warm and
there's not much of a thermocline as you go deeper. It's like it's oligotrophic, meaning there's no food, basically.
There's not the phytoplankton to support the larger organisms and so on like you can find in colder water. Especially
where currents meet - like the Gulf of Maine for example. But I don't think anyone expected it be this barren out here."
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