Summer 2024 cruise

Submesoscale Upwelling Bay Frontal Exchange

Cruises Field work R/V Sproul

The first cruise of the SUB-F-Ex project took place from 26 June-7 July, 2024 on the R/V Robert Gordon Sproul. The cruise began with loading at the Scripps Nimitz Marine Facility (MarFac) in San Diego, then a two-day transit up to the field site in San Luis Obispo Bay.

R/V Sproul at the dock in San Diego

Two oceanographic moorings were deployed to collect observations of temperature, salinity, dissolved oxygen and currents below the ocean surface.

A team of scientists working on the deck of the ship during the deployment of a scientific mooring into the ocean

Work on the moorings began well before the cruise started at Dr. Ryan Walter’s lab at Cal Poly where instruments were tested, programmed and secured to the mooring lines.

Instruments organized on a lab bench Instruments being secured to a mooring line

After the moorings were deployed, several types of instruments were used in surveys of the physical oceanography of the bay. The measurements included “tow-yo” observations with an electric reel which allows profiles of water properties about every hundred meters while the ship moves in and out of the bay, and a microstructure profiler with sensitive shear probes to measure fine-scale turbulence as the insturment free-falls towards the seafloor. Once back in the lab, these data will be used to explore the connection between turbulence and frontal dynamics in this shallow upwelling bay.

An electric fishing reel being used to retrieve an oceanographic instrument from the ocean

Students downloading data from an oceanographic instrument

Two scientists at the stern of the ship about to deploy an oceanographic instrument

A team of scientists preparing to deploy an oceanographic instrument

Over the course of eight days of science time at San Luis Obispo Bay, the cruise was successful in collecting a wide range of physical and biogeochemical measurements during different wind conditions. We are grateful to the captain and crew of the R/V Robert Gordon Sproul and the entire resident technician group at Scripps for helping us achieve our science objectives.

Technicians installing an instrument on a long pole over the side of the ship while it is at the dock

This work also would not have been possible without the hard work of all the members of the science team, including graduate and undergraduate students from Virginia Institute of Marine Science, Cal Poly San Luis Obispo, UC Santa Cruz and Moss Landing Marine Labs.

Group photo of the science party