How Much Science Can We Accomplish in One Day?

Amanda Demopoulos watches as deck crew members Knott and Cornell deploy the CTD at Pea Island B. The CTD collects conductivity (salinity), temperature, and depth (pressure) data, plus it has sensors to detect dissolved oxygen, chlorophyll, and turbidity (particles in the water), as the instrument travels down to the seafloor. The CTD is also equipped with a rosette of Niskin bottles, which are specially designed water bottles that can be triggered to collect water at set depths.

Amanda Demopoulos watches as deck crew members Knott and Cornell deploy the CTD at Pea Island B. The CTD collects conductivity (salinity), temperature, and depth (pressure) data, plus it has sensors to detect dissolved oxygen, chlorophyll, and turbidity (particles in the water), as the instrument travels down to the seafloor. The CTD is also equipped with a rosette of Niskin bottles, which are specially designed water bottles that can be triggered to collect water at set depths. Image courtesy of DEEP SEARCH 2017, NOAA-OER/BOEM/USGS. Download larger version (jpg, 3.4 MB).

September 14, 2017

Caitlin Adams
NOAA Office of Ocean Exploration and Research

After the CTD has been recovered, Jason Chaytor attaches a tube to each Niskin bottle and transfers the water into plastic jugs, which will be brought into the lab and filtered.

After the CTD has been recovered, Jason Chaytor attaches a tube to each Niskin bottle and transfers the water into plastic jugs, which will be brought into the lab and filtered. Click image for credit and larger view.

Sentry expedition leader Sean Kelley remotely drives the AUV toward the ship after surfacing. Once within range, it will be connected to the ship’s crane and lifted back on board.

Sentry expedition leader Sean Kelley remotely drives the AUV toward the ship after surfacing. Once within range, it will be connected to the ship’s crane and lifted back on board. Click image for credit and larger view.

Sentry engineers (bottom, Ian Vaughn and Andy Billings) and the ship’s deck crew (GVA Fountain and CB Walker) work to secure tag lines on the vehicle. Once secured, these lines help them to steadily guide the Sentry onto the deck and into its cradle.

Sentry engineers (bottom, Ian Vaughn and Andy Billings) and the ship’s deck crew (GVA Fountain and CB Walker) work to secure tag lines on the vehicle. Once secured, these lines help them to steadily guide the Sentry onto the deck and into its cradle. Click image for credit and larger view.

The ship’s crane operator slowly moves the Sentry over the side and back onto the deck.

The ship’s crane operator slowly moves the Sentry over the side and back onto the deck. Click image for credit and larger view.

With a day lost for weather at the beginning of the cruise and Hurricane Jose still a potential threat offshore, the DEEP SEARCH team is working as efficiently as we can to accomplish our mission. Chief Scientist Amanda Demopoulos is in near-constant contact with the Pisces Operations Officer, LT Jamie Park; the two work together to plan and re-plan the order and timing of operations to maximize the utilization of our days at sea.

On a cruise like this, there are many operational considerations to weigh as plans are made. There’s the obvious factor of weather: open ocean conditions can change rapidly, and the ship is always monitoring multiple forecasts to ensure that science operations are possible and, more importantly, that everyone aboard stays safe. There’s the factor of time, too: each type of operation (Sentry dive, CTD deployment with monocore, shipboard multibeam mapping) we want to complete takes time, and Amanda and Jamie have to figure out the best sequence of events.

More importantly, each of these operations can’t be completed solely by scientists—the ship’s crew plays an integral role in all of these tasks, and we have to be sure to schedule around their needs as well. While we scientists may only be out here for 17 days, crew members are here nearly year-round, and we must be respectful of both their other duties on board as well as their free time. We try to schedule everything during daylight hours so that the crew doesn’t work outside their scheduled hours, especially because even with planning, they’re often needed to complete unscheduled tasks (like today, when they managed to re-terminate a failing CTD cable in the short transit between sites). The only exception to this is Sentry diving: while we schedule every launch and recovery during daylight hours, Sentry is fine to stay in the water overnight with the ship closely following it—after all, someone is always on the bridge driving the ship.

Finally, there is one other important factor to consider: location. Though we arrived at the ship with a detailed cruise plan in hand, many of those plans, including our order of sampling sites, have had to change. Because we started the expedition in Norfolk, Virginia, instead of Morehead City, North Carolina, we started at one of our most northern sites, the Kitty Hawk bubble plume seep sites (site 12). From there, we are working our way south, adjusting as needed.

A couple of our sites are too shallow for Sentry to dive and maintain communication with the ship, and a couple others may fall off the priority list given time constraints. Each day, we have to consider which sites make the most sense given all we want to accomplish once on station and how long it will take to transit between locations.

So with all of these factors to weigh, what exactly do we get done in a day? Quite a lot, actually! Today was our busiest day yet, and here’s an idea of how it went:

  • 0730-0800: Recover Sentry after 25-hour dive
  • 0800-0900: Transit to first CTD location
  • 0900-1200: Deploy CTD and monocore at depths of 250-1,340 meters at Kitty Hawk (Site 12)
  • 1200-1400: Process water samples from Kitty Hawk CTD casts
  • 1400-1645: Transit to Pea Island B (Site 7), collect multibeam mapping data during transit, and re-terminate CTD cable
  • 1645-1730: Deploy CTD and monocore at depth of 1,170 meters at Pea Island B
  • 1730-1900: Process water samples from Pea Island B CTD cast and and all the mud samples from monocore collections
  • 1830: Deploy Sentry at Pea Island-B for a dive until 1600 the following day

In the coming days, we’ll be sharing more about how and why we collect the Sentry, mapping, water, and mud data that we do, and you’ll get the chance to hear directly from a few of the scientists we have with us on the mission.

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