Heavy seas and 35-45 knot winds kept us off the decks and inside as we counted down the last 24 hours of our VERTIGO cruise (see storm photos). Up until that point, we had been very lucky and have not had to suspend operations at all due to weather, but as fate would have it, we still had 3 important experiments floating around in the open seas and a series of samples to collect before we could call it a day for VERTIGO.
We arranged to wait out our storm and planned to delay the start of picking up gear until the morning of our departure. So at 5am , we were assessing conditions and indeed, the predictions of calmer weather after 24 hours were correct and it was time to start our work again. The next several hours were a blur of activity. By the time 9 am rolled around, we had already brought aboard 2 of the 3 remaining free floating experiments and were pulling CTD/Rosette #86 out of the ocean for our last water samples of the cruise (see photos).
Not everything went smoothly that last day as the final mooring had become separated from its GPS positioning buoy sometime during the storm. This meant we had nothing but a prior prediction of its path along the surface ocean to go by in our old fashioned search with binoculars for the missing gear. Lady Luck was kind to VERTIGO that day, with the fog lifting, the sun coming out (was this only the second time we had seen blue skies?) and a red float spotted only 30 minutes in to our search some 1.5 miles off the port side of the ship.
All in all, VERTIGO launched and successfully retrieved every piece of equipment we sent off on their 2-7 day missions away from the ship. This included tracking and bringing in/out of the water 17 free vehicle neutral traps (NBSTs), 7 “CLAP” traps, 3 deployments of the “optical trap”, 2 of the settling velocity trap, and 4 in situ respirometer experiments from a drifting array. Along with these experiments, we sampled the vertical distributions of chemical, physical and biological properties on 86 CTD/Rosette casts, 8 multidepth zooplankton samples from the IONESS, 4 deployments of the large volume pumping system, numerous smaller plankton net tows and some specialized water sampling casts for trace metals and radionuclides.
We have reached the end of a successful 24 days of oceanographic studies in the NW Pacific thanks to a great ship and crew, a strong scientific team and a bit of luck. However, the stories don’t stop here, so expect a few “daily updates” and more photos on our way to Hawaii after we catch up on some much needed rest. With 1000’s of samples and data from our sensors, VERTIGO scientists have opened up a new view of the ocean that will help us unravel over the months and years ahead some of the many secrets of the ocean’s twilight zone.
— Ken Buesseler