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MISSION DISPATCH 13 • 09/08/01 Today's Weather - images courtesy of NOAA & RSMAS Dispatch by Rebecca Johnson - HARBOR BRANCH Oceanographic Institution Latitude: 40°21'15"N • Longitude: 68°8'42"W 
On one of the
JOHNSON SEA-LINK's last dives, we came upon a Goliath of the deep. No, not a sperm whale
or giant squid or basking shark, but a mammoth cousin of
Nanomia. At about 360 meters down
in Oceanographer Canyon, in the same general area where we've been diving for the past few
days, a huge siphonophore glided unexpectedly into the sub's pool of light.
From their vantage point in the sphere, PI Marsh Youngbluth and pilot Phil Santos got an unparalleled view of a magnificent animal. "Almost every time we visit deep water we are rewarded with glimpses of the unexpected," said Marsh. "In one moment a dive can change from routine to exciting. Our encounter with this unusual gelatinous animal was breathtaking." As the siphonophore sashayed in front of the sphere, Phil trained twin beams of laser light on the upper part of its body - the nectosome - where crimson-tinged swimming bells, or 
nectophores, were rhythmically pulsing. Because the beams are a known distance apart, the
animal's size was determined quickly and accurately. The colony was about 2 m long with its
4.5 cm diameter stem contracted. If the stem were fully extended, the animal might stretch
6 m in length!
Scientist and pilot watched, enraptured, as the siphonophore danced before them, aglow with sunset colors against the darkness. The temptation to collect this animal and take it to the 
surface for study was acute. But Marsh decided this extraordinary animal was simply too
lovely to abduct. After a few more minutes of filming, the submersible turned slowly away
from the siphonophore to continue its descent. Remarkably, the delicate animal left a parting
gift, a single cast-off nectophore. That prize was quickly snared and will allow us to catalog
this life form as new or match it up to similar specimens collected in the past. Compared to
the nectophores of Nanomia, this swimming bell was huge, about 50 mm wide at the base and
40 mm from side to side across the middle. To either side of the velum (the opening through which
water is pumped in and out) was another surprise - a patch of exceptionally large nematocysts.
These stinging cell batteries may help the colony defend itself against predators.
Back aboard the R/V SEWARD JOHNSON, Marsh quickly emailed a digital image of the nectophore, along with estimates of the animal's dimensions, to a colleague in Britain. Nectophores are very distinctive. This single clue may make it possible to put a proper species name to our gelatinous leviathan. Do you have a question for the researchers on this ocean expedition? Just ask a question @Sea in our MISSION FORUM!  | |
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