Behind the scenes

M1 mooring turnaround

April 5, 2017

MBARI’s M1 mooring is an important data collection station that floats above the seafloor in the center of Monterey Bay, at the mouth of the underwater canyon. It is continuously taking a variety of measurements to give researchers a clear picture of oceanographic conditions. At the surface, it looks like a tower sitting on a large, doughnut-shaped buoy and is sometimes seen with sea lions lounging on it. Below the surface, the M1 buoy is tethered by a 1,500-meter-long (4,900 feet) cable extending down through the water column to a 2,500-kilogram (5,500-pound) anchor at a depth of 1,100 meters (3,600 feet). Attached to the buoy and along the length of cable from the surface to 300 meters depth are various scientific instruments that measure environmental conditions such as conductivity (salinity), temperature, depth, oxygen, chlorophyll, and currents. These scientific data are collected around the clock and are made available online.

Observatory Engineer Jared Figurski and Operations Engineer Chris Wahl work on the M1 mooring buoy floating in Monterey Bay.

The M1 mooring collects and transmits data all year long. Equipment that is deployed at sea for long-term monitoring must be checked regularly to ensure proper working order. Thus, the Mooring Operations Group performs maintenance on the mooring throughout the year and coordinates SCUBA divers to clean and inspect the instruments beneath the surface every few months. Despite having a specialized coat of anti-fouling paint designed to deter “biofouling” or settlement of biological growth, such as goose barnacles and algae, it still gets covered with growth over time.

The M1 mooring is brought back to shore on an annual cycle called the mooring turnaround and replaced with a refurbished mooring. Ocean Observatory Engineer Jared Figurski oversees the refurbishing process which begins when the old mooring is pulled up onto the deck of the ship, and large clusters of barnacles, algae and other marine life are scraped off. Sitting out in the ocean for one year, the mooring becomes a perfect substrate for larval goose barnacles to settle and grow. The mooring is disassembled, removing all instruments and sending them out for factory calibration. The tower, bridle and buoy are taken apart, cleaned and repainted on-site. After all the instruments return from calibration, they are set up and configured, then connected to a central controller in the lab for testing to ensure they are all working properly. Finally, the instruments are reinstalled with new cables onto the cleaned and newly-painted buoy and ready for the next mooring turnaround.

Article by Melinda Nakagawa