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THE MAINE EVENT: FALL 2004 Predation by Gelatinous Zooplankton in the Gulf of Maine MISSION DISPATCH 10 • Thursday, September 23, 2004 Dispatch by Ebba Olsson - University of Lund, Sweden The morning started with another intensive program. Ulf, Calle, Sofie and Ebba hauled a 1-meter diameter net at the surface and then conducted CTD casts consecutively to 10 m, 500 m and 50 m. 
As sometimes happens,
the water samplers malfunctioned andcame up empty on the 500 m cast. But
the second attempt was successful and Sofie, who needed the water, could now
continue with studies of copepod respiration rates. However, she had to wait
half a day for repairs to be completed on the micro-optode system. A sensor
control mechanism had failed.
Per and David continue to record still and video images of various animals collected with the Johnson-Sea-Link submersible in order to illustrate morphological characters and to document swimming, feeding and bioluminescent behaviors. Per says "it is very important to make observations every day and make sure everything is written down. Even if you think you will remember truly uncomplicated things, in the long run you are not so certain!" 
Francesc is examining the physonect siphonophore Bargmannia obtained on the
night dive yesterday. This particular colony with a 4-cm
long nectosome was the first of
its kind that has been collected in slope waters
of the North Atlantic. "The morphology of the nectophores is fascinating"
says Francesc and smiles.
The afternoon dive started as scheduled at 1300. Chuck made his first plunge on this cruise, and Brian his second. Phil was the pilot; Frank shared the dive chamber. A highlight of this dive was the collection of a relatively large but unknown appendicularian in the genus Fritillaria. Per and Marsh will describe and name this new and other previously unknown appendicularian species that reside in the benthic boundary zone of Oceanographer and other nearby canyons. The second dive of the day commenced at 2000 and provided an opportunity for Franz, David, Phil and Frank to continue explorations in the midwater zone. When they returned 3.5 hours later David was cold, cramped and stiff but remarked excitedly, "You expect a big black world down there but that is definitely not true. It's full of marine snow particles and bioluminescent animals." 
Marsh, Chuck, Jessica and Celeste continued to measure metabolic rates of mesopelagic gelatinous animals. Jessica and Celeste started a new set of experiments at 2200 with two physonect siphonophore Nanomia cara , one cirrate octopus Stauroteuthis syrtensis and two control chambers (=with no animals inside). Before and after each run Celeste draws samples for Winkler titrations to measure oxygen concentrations and crosscheck these data with records from the micro-optode probes. Jessica pipettes water for ammonia and orthophosphate analyses to estimate excretion rates. 
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