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THE MAINE EVENT: FALL 2003 Predation by Gelatinous Zooplankton in the Gulf of Maine MISSION DISPATCH 2 • Wednesday, September 10, 2003 Location: Georges Basin (42° 18'N, 67° 30'W) Dispatch by Harry Breidahl - Marine Education Society of Australasia [MESA] After a single JSL dive to 860 feet (260 meters) and two MOCNESS net tows at Wilkinson Basin, the R/V SEWARD JOHNSON headed east toward Georges Basin in anticipation of benign weather. We left Wilkinson Basin at 10.30 am and arrived at our second survey site just before 7 pm. Under clear night skies and a brilliant full moon, JOHNSON SEA-LINK II dive 3437 
splashed into the water around 8.30 pm and returned to the aft deck just before midnight. Colonies of Nanomia cara were
sufficiently numerous to at this site to allow detailed investigations of their feeding behavior.
The scientific party on board numbers 12. As the focus of research for The Maine Event is the siphonophore Nanomia cara we have three 'gelatinous gurus' leading the way. They are mission leader Dr Marsh Youngbluth from HBOI, Dr Per Flood from Bathybiologica, Bergen, Norway and Dr Francesc Pages from the Institute of Marine Science in Barcelona, Spain. Three graduate students on board conduct their own research programs. They are Aino Hosia, originally from Finland but studying at the University of Bergen in Norway, Whitley Saumweber from the University of Rhode Island and Brian Ortman from the University of New Hampshire. Dr Chuck Jacoby from the University of Florida leads a small team that provides support for all of the scientific programs on board. Included in this team are Helen Mayoral, a research assistant at HBOI, Nicole Shach, an undergraduate student at the University of Florida and Brennan Phillips, an undergraduate engineering student at the University of Rhode Island. The two remaining members of the scientific party are Brian Cousin and myself. 
Brian is a video production specialist at
HBOI and is aboard to document the research activities of scientists on this cruise. As an educator and author, my role
is to write these web dispatches and to gather information relevant to the development of ocean exploration programs
for schools.
As this voyage progresses we will highlight the scientific and technological efforts of the people on the R/V SEWARD JOHNSON. For today's dispatch we look at Whitley Saumweber's work. Whitley is currently in the fifth year of a project studying the population dynamics of the resting stage of the copepod Calanus finmarchicus (the main food source for Nanomia). On this cruise he is measuring the respiration rates of the resting stage of C. finmarchicus in order to understand how this torpid portion of the population is able to survive. Whitley uses live individuals collected by samplers attached to the JSL or sieved into the nets of a MOCNESS tow. Like all living animals, these tiny copepods need oxygen to survive. They extract this oxygen from the sea water. The more active a copepod is, the more oxygen it will use. For each test Whitley carefully selects a healthy number (30) of copepods places them into a known volume of water (300 ml) for 24 or 48 hours. During this period of incubation the copepods are kept in 
a cool, dark room that mimics
the chilly temperatures in their deep-sea habitat. By comparing the amount of oxygen in the water at the start and the end of a set
time, he can calculate the amount of oxygen consumed by the copepods.
Fun facts for the day • How many of you figured out that MOCNESS stands for Multiple Opening and Closing Net Environmental Sampling System? • Per Flood works at an institute called Bathybiologica. For those who are interested in the origins of words Bathybiologica means the study of deep life (bathos = deep, bios = life and logos = study). See how many other 'bathos' words you can find. • Having two systems of measurement can get tricky at times. The depth of JSL dives is recorded in feet but being from Australia I think in meters. So, to convert feet to meters we need to divide by 3.28, while to go the other way (meters to feet) we multiply by 3.28.   |  |
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