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MISSION DISPATCH 12 • 09/07/01 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 "Per, what's this?" That's a phrase frequently heard here on the R/V SEWARD JOHNSON, especially when we're sorting through the freshly caught bounty of a plankton tow. With characteristic patience, visiting scientist Per Flood will slip the creature in question under a dissecting scope, examine it intently for a moment, and then, invariably, not only 
put a name to it, but go on to relate fascinating details about its physical structure,
behavior, or importance in the marine environment.
Hailing from Bergen, Norway, Per is a noted authority on gelatinous marine zooplankton, particularly appendicularians (also called larvaceans), little animals that dwell inside extremely fragile and startlingly complex mucous "houses" of their own making (see " Drifting Houses of the Gulf Stream - @Sea Mission Coverage"). In fact, these master builders of the sea prompted Per to make a major change in his academic career. In the 1970's, when he was a professor of human anatomy who specialized in detailed histological studies utilizing scanning electron microscopy, Per was told that the mucous houses of appendicularians, such as those of Oikopleura labradoriensis, were "far too delicate" for SEM work. Per was in the process of trying to perfect several of his microscopy techniques when he heard this comment about Oikopleura. The "appendicularian challenge" was one he couldn't resist. Not only did he succeed in taking beautiful SEMs of this species, but was so captivated 
by appendicularians that they, as well as other gelatinous zooplankton, soon became the focus
of his life's work. Per's research has taken him to oceans around the globe, but probably most
often to Norway's fjords, where gelatinous zooplankton abound in the cold, deep waters of
these narrow inlets that slice far into the country's rugged coastline.
Here on board the ship, Per can usually be found in the dry lab, ensconced in front of his marvelous collection of microscopes and still and video cameras, where he examines with infinite patience and meticulous care the structural details of Nanomia and many of the other life forms we've collected on this cruise. In those details, he frequently encounters the unexpected, the chance discoveries that make fieldwork so exhilarating. For example, several days ago Per noticed tiny dots in the nectophores of many of the Nanomia colonies being brought up from the deep. On closer inspection, these dots appear to be some kind of parasite - a find that demands further investigation. This afternoon, Per has been scrutinizing a small menagerie of planktonic creatures under his microscopes: a feathery colonial hydroid that was attached to a bit of seaweed; a tiny marine snail that flaps its fleshy "wings" like a bizarre aquatic butterfly; and a diminutive colonial ciliate that slowly opens like a blossoming flower, only to contract into a compact bundle so 
quickly your eye can't track the movement. Per records the features and behaviors of these and
other zooplankton digitally and on film, creating a visual record of some of the often-overlooked
animals with which
Nanomia shares its watery domain.
Many of the tiny creatures that end up under Per's microscopes are bioluminescent - they produce their own light. Bioluminescence is without a doubt one of nature's most splendid feats, although quite faint when seen out of the water. We couldn't resist sending along this photograph of Per at his microscope - but we admit that what looks like a astonishing burst of bioluminescence is actually the result of a prematurely triggered flash! 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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