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THE MAINE EVENT: SUMMER 2002 Predation by Gelatinous Zooplankton in the Gulf of Maine Dispatch 2 Saturday, June 29 2002 Latitude: 40°02.9380"N • Longitude: 69°02.2820"W Dispatch by Heather Holberger, HARBOR BRANCH Oceanographic Institution 
The R/V SEWARD JOHNSON encountered rough seas again on its way to
Hydrographer Canyon. Just before lunch, we had a customary safety session
on how to done the survival suits, where the life rafts are, and what to do
for the different alarms. During the briefing on the O1 deck, two sunfish
were spotted warming themselves in the chilly surface water. After the
safety lesson, we continued outfitting the sub for its excursion into the
deep blue sea.
Outfitting the JOHNSON-SEA-LINK (JSL) manned submersible involves first checking all the samplers to make sure they work properly and do not leak. Then we dressed the sub, equipping the vehicle with 8 detritus samplers and 24 'critter gitters.' While sub 
preparations were ongoing, a school of pilot whales was seen off the port
stern. After the sub went down, the whales circled the ship, checked us out
and then headed off on their own business.
The first dive of the trip, and the sub's 3264th, began at 2:15 PM. Excitement fills the air as the sub crew, Phil Santos and Hugo Morrero, and the scientific party, Dr. Marsh Youngbluth and Brandy Ninesling, climb into the sub. Everybody is out on deck, watching as the sub is lifted into the air and gently placed in the water. We wait to watch it descend, breath a sigh of satisfaction, then head back to the labs or the lounge. 
During the descent, the sub was met by millions of amphipods. Other
transparent and bioluminescent organisms were attracted to the sub's lights
such as snipe eels and ghostly gempylid fishes that hovered vertically.
Around 2800 feet deep, sub pilot Phil Santos maneuvered the sub to
catch a creamy squid, a red octopus, a pink ctenophore, an orange
ctenophore, and four diaphonous siphonophores. On the way up, all the
lights on the sub were turned off so an awesome bioluminescent light show
could be seen.
Once the sub arrived on board, the samplers containing specimens were placed in the cold room for further observation. At 9 PM, the sub went down again into Hydrographer Canyon and came back up around 1 am with most of the 32 samplers filled with deep water animals. A long night followed as we picked out gastrozooids from the preserved samples of siphonophore colonies. Dr. Marsh Youngbluth and Dr. Chuck Jacoby dissected the stomachs and learned that the colonies had fed exclusively on small calanoid copepods.  |  |
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