Update: Morgan and Carol on the ship pointed out a few mistakes in the latest post. Apparently all that down-time made me error-prone! The mooring site we were headed to was to the northeast of our hide-out in Akun Bay, and the mooring ball that showed so much bio-fouling had been deployed for 12 months in Pavlof Bay (not 6 months in Shelikof). These changes have been made in the post!
Yesterday we were in hiding. We kept re-positioning ourselves in various bays of the Aleutian Islands as a second storm system brought sustained winds of 30-40 knots and gusts up to 60 knots offshore. The winds were at first coming out of the northwest, and during an afternoon station on Saturday we sampled from the Niskin bottles while fat, heavy snowflakes fell almost horizontally onto the ship’s decks. We were anchored in Akun Bay for most of Sunday, but sadly no trips to the island were in order. It was pretty dismal weather outside, so even a sojourn to the nearby hot springs would not have attracted many participants. We did, however, keep ourselves busy with movies and books and a 1500-piece jigsaw puzzle that Peter, Scott, and I decided was an appropriately ambitious project!
In the reflective downtime this weather has afforded, I’ve realized that the name for this blog may be a bit misleading. While we are indeed studying the effects of sea ice on phytoplankton blooms in the Bering Sea, we have yet to actually encounter any ice. Our interests mainly focus on the impacts of year-to-year changes in sea ice extent and timing of its melt-back on the phytoplankton communities and bloom dynamics in the Bering Sea. The sea ice itself has remained an invisible factor in our cruise so far… but potentially not for much longer.
We are currently headed northeast to attempt recovery and redeployment of two oceanographic moorings that are part of the NOAA Fisheries-Oceanography Coordinated Investigations (FOCI) project. Recovery and turn-around of these moorings is one of the main goals for this cruise, but we have delayed heading north until now since the sea-ice was still intact in the surrounding area. The R/V Oscar Dyson is not an ice-breaker, and as such is only permitted to enter areas with less than 60 percent ice cover or where the ice is known to be less than an inch thick. So we are heading north, keeping our fingers crossed that springtime warming and the recent winds and storms may have broken up the ice enough for the Oscar Dyson to get in and run mooring operations.
Oceanographic moorings are strings of instruments, anchored using a 1600 pound old railroad wheel to the sea floor and kept upright by a series of floats submerged underwater. The instruments on these moorings measure physical characteristics including temperature, salinity, current direction and speed, dissolved oxygen, particle load, nitrate (the main form of nitrogen in the ocean), and chlorophyll concentration. There are also instruments that use sound to locate fish and zooplankton populations and listen for vocalizations from whales and other marine mammals. The moorings are deployed for up to 12 months at a time, and the site that we’re heading to has been studied for the past 20 years using these systems. When it is time for the mooring to come back, as it is now, a specialized sound signal is sent from a microphone on the boat to a release mechanism attached just above the anchor. After release, all of the valuable instruments, data, and floats return to the surface where the ship and crew are waiting for them.
We have already recovered and redeployed two moorings on this trip, and I can tell you that these operations involving hundreds of feet of cable, a huge heavy anchor, and many sensitive instruments that all need to be handled and arranged just so can be very exciting to watch! Bill Floering from NOAA tends to call the shots on deck, while Scott McKeever (NOAA) and Dan Naber (University of Alaska, Fairbanks) back him up and tend to the instruments. The Oscar Dyson deck crew operate the heavy machinery needed to manipulate such large equipment, while our fearless chief scientist, Carol DeWitt (NOAA), preps the instruments for deployment and handles all of the logistics for the mooring operations and general cruise plan and progress. We should reach our destination, weather and ice permitting, late tonight or early tomorrow morning. This will leave just enough time to collect some water, turn around the moorings, and start heading back towards the islands.
There are only three days left on this short cruise, and by Tuesday night we will be all packed and ready to jump ship as soon as she docks in Dutch Harbor on Wednesday morning. We continue to hope for improving weather, despite less-than-sunny forecasts, and will continue to keep ourselves busy with science, fun shipboard activities, and of course a giant puzzle!
(All photos: B. Stauffer)