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MISSION DISPATCH 10 • 4/25/01 Today's Weather - images courtesy of NOAA & RSMAS 0100 - Science Team Pulls All-nighter, Sub Crew Preps JSL The Science Team has one more JSL I sub dive left to complete before the R/V SEWARD JOHNSON heads back to home port at HARBOR BRANCH Oceanographic Institution, Fort Pierce, Florida. Launch time for the last dive of the cruise is slated for 0230 this morning. But there is a lot of shipboard lab work that still needs to be done before the gear is broken down for offloading later today. Three individual appendicularians of species Bathochordaeus stygius, collected on the previous sub dive, have been set up in a Latex microsphere experiment described in the last dispatch. The scientists want to see if 
the animals will inflate new feeding houses and initiate normal
feeding behavior under controlled laboratory conditions. If they do,
uptake of variously-sized microspheres suspended in the water will
provide some information about particle size selection in this species.
Members of the two deepwater appendicularian species collected during the cruise were also employed in microsphere experiments, although they failed to inflate new houses during the trials. The Science Team is more optimistic about their chances for success with Bathochordaeus, however. An initial experimental trial performed earlier in the cruise revealed that the animals will generate new houses in the lab. The new houses were abandoned before completion in the earlier experiment, most likely because high-frequency vibrations from the ship's engines were transmitted to experimental chambers to negatively affect natural house-forming behaviors. The problem has been alleviated by suspending the chambers with shock cord from lab benches in the ship's environmental room; conditions experienced by experimental animals should now more closely reflect natural conditions. As the live animal studies continue, taxonomic and feeding house architecture investigations are also pursued. 0200 - @Sea Mission Correspondent Hitches a Sub Ride Dr. Per Flood changes gears in anticipation of the approaching early morning sub dive. I begin to get ready for my first-and-only aft chamber sub trip of the cruise as well, putting on long pants and 
gathering up a notebook, camera, and a long-sleeved shirt. The dive
will be shallow and short (2 hours), but the aluminum rear compartment
of he JSL I can be cool at times (Note: it wasn't on this dive!).
After a quick pre-dive briefing, we climb in and are ready for launch. The last time I had the opportunity to accompany the JSL on dives was back in 1993, so I am thankful for the safety briefing provided by chamber diver Frank Lombardo as the A-frame crane hoisted our air-tight conveyance out over the water behind the ship. "...That's the air scrubber - don't block it... These are demand regulators attached to compressed gas cylinders if we need them... Flick the switches here, here, and here to bring the sub to the surface unassisted in the event that the three other occupants are incapacitated..." Between the sub's onboard safety features and the PANTHER rescue ROV back on the ship, I am absolutely convinced I am safer inside JOHNSON SEA-LINK I than I have ever been in my own truck on the Florida highways. 0236 - JOHNSON SEA-LINK I - DIVE #4286 27°31.52'N • 79°43.34' W • Western Gulf Stream, off of Fort Pierce Personnel - Sphere • Sub Pilot: Phil Santos • Scientist Observer: Per Flood Personnel - Aft Chamber • Tender: Frank Lombardo • Diver: Jim Masterson Launch Time: 0236 • Time to Surface: 0430 • Dive Duration: 1 hour, 54 minutes 
We are just about an hour into the dive. I have contorted my very inflexible body into an unnatural position allowing the best view out of one of the aft chamber's 8-inch view ports. I can also look at a small gel screen displaying a video feed from the camera mounted on the front of the sub. I can choose either of the view ports, because Frank is attentively reading the paperback novel he brought down with him. I guess it is understandable that the chamber divers don't get as thrilled by all of this as the tag-along passengers do -- to them it's another day at the office. Frank has made over 100 JSL dives in the two and-a-half years he has been with the Sub Crew. But to me the view is amazing. My prior JSL dive experiences were daytime-only dives, and most were conducted in shallow waters, so a first-hand look at the nighttime zooplankton community is a new experience. 
By 0400, Phil and Per have filled the detritus samplers and they begin a couple of 5-minute video transects. Interestingly, all but one of the specimens collected on this dive consisted of an abandoned feeding house only, with no associated animal. Per is not sure why this was the case, since there is really not that much that is known about these animals. I am sure the weary Science Team back on the ship will not be terribly disappointed, however, as they have neither the time nor the stamina to begin a final set of live animal experiments. The sub surfaces shortly before 0430. By 0500, we are back in the lab processing the new samples as we head back to Fort Pierce. Time for me to take a couple of days at home, to get reacquainted with my wife and kids. Next week, I'll be back with a mission wrap-up, and hopefully a few other goodies. See you then. This expedition is made possible through a grant from the Biological Oceanography Program of the National Science Foundation with additional support from Harbor Branch Oceanographic Institution.  | |
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