Sir Wilfrid Laurier
Updates from the Laurier
Dispatch July 20th: The SubSea Camera
By: Will Burt and Markus Janout
Upon entering the shallow shelf waters of the Bering Sea, we started to apply a handheld camera system in order to film the sea floor. The system is protected by a metal frame and includes a subsea camera, temperature and pressure sensors, as well as two strong lights to illuminate the bottom. The reflection of two laser pointers helps to determine the distance between camera and the bottom. The camera system is connected to 130 m of sea cable which is lowered by hand and transmits video images from the seafloor to a deck unit and a handheld camcorder.
The procedure of the camera stations works as follows:
First, members of the crew or science party introduce the location by holding up a sign
that lets us later identify the name, location and time of recording (see picture). Stations are usually operated by two people, one lowering the camera system, and one person monitoring the live footage and give orders to lower or raise the camera. This way we can determine the length of each station based on how interesting the seafloor is at the location. Some recordings are short and not useable due to low visibility or too strong currents and others last for up to 40 minutes in biologically diverse regions. Once filming is done, we then directly download the footage onto a lab computer for review and some editing.
During the transect from the shelf south of SLI to the Chukchi Sea we crossed several regimes, each characterized by certain species. The bottom region south of St. Lawrence Island (SLI) is clearly dominated and densely populated by brittle stars, which have a small (1-2 cm) circular center with 5-6 thin arms. In the following we crossed Anadyr Strait, located between Russia and SLI. Currents there are very swift and the bottom is rocky as opposed to muddy areas with slow currents. The footage we recorded in Anadyr Strait shows lots of colorful critters on the rocky bottom, like sea urchins, corals, anemonies etc. Proceeding northward of SLI, the benthic landscape changed to mainly crabs and lots and lots of crater-like worm tubes often showing pink ampharetid worm heads receding into their homes as the camera passes by. The bottom of Bering Strait near Little Diomede Island, AK provided the most spectacular underwater scenes with boulders populated by corals, starfish, crabs, and anemones of different colors (see pictures). Also, currents in Bering Strait are very strong which makes it difficult to operate the camera. Finally, after crossing the Arctic Circle into the southern Chukchi Sea, where we found one area entirely covered by sand dollars, the landscape changed to very turbid, low-visibility waters, due to the outflow of highly productive waters through Bering Strait.
The pictures below provide extracted stillshots of the underwater recordings.
Tuesday-Wednesday July 10-12, 2007
by Jackie Grebmeier, Chief Scientist Dutch Harbor-Barrow, USA
The CGCS Sir Wilfrid Laurier arrived Dutch Harbor, Alaska, USA at 0845 local time on Tuesday, July 10 for a 5 hr port call. Chief Scientist Bill Williams disembarked to return to Canada and three US scientists arrived to the ship: Dr. Lee Cooper and myself from the University of Tennessee Knoxville and Ms. Betty Carvellas, a high school science teacher from Essex Junction, Vermont. The science and crew of the Laurier enjoyed their short visit to Dutch Harbor, taking in the shopping sites and walking the town. Scientists and crew visited the US WWII memorial site on Unalaska Island.
All personnel were onboard the ship by the 1500 sailing time and the C30 program continued on its northward journey to the Arctic. We completed another station within 2 hrs of departing Dutch Harbor, including ADCP (for currents), CTD (conductivity-temperature-depth) sensors, water sampling (chemistry and biology) and bongo nets (zooplankton). The water sampling crew continues to sample the CTD/rosette and smiles abound.
On July 11 we completed another slope station (1000m) as we moved into deeper waters of the SE Bering Sea on our way off the slope to a 3500m station, the deepest sampling station of the cruise. The science party and crew were busy designing colorful art on styrofoam coffee cups for the deep deployment of the CTD. Why? Because the pressure at this high depth causes the air to be pushed out of the styrofoam, thus shrinking the cup to a fraction of their original size. So, besides getting great scientific data from these deep casts, we have a “science experiment” that worked and had fun doing it. After collecting our cups, we began sampling upslope on July 12 to the shallow outer continental shelf (100m), doing ADCP, CTD, water sampling and bongo nets at multiple stations. Both a van Veen grab and box core were used to collect sediments, which were sandy, on the upslope basin-to-shelf transect.
July 6, 2007
When embarking on a field season that takes you through the Gulf of Alaska into the Bering Sea you never know what to expect. It is always and adventure. We are onboard the CCGS Sir Wilfrid Laurier steaming from Victoria, BC toward Dutch Harbor, AK with 15 scientists from the U.S. and Canada on board. There are lots of students on board who have never been to sea before. They are soaking in the experience. There is lots to see as the science party is taking a variety of samples during our transit. Water samples are being taken from a CTD rosette for dissolved oxygen, nutrients, salinity, barium, O-18, chlorophyll-a, and DMS/DMSP. Bongo nets are being deployed to sample zooplankton in the water column. Box cores will be taken at some of the deeper sampling stations. The weather has been agreeable thus far. Sampling continues.... Information provided by Rebecca Pirtle-Levy