by Laura Lilly
We have officially begun our cruise’s scientific measurements! Tuesday evening, we deployed the SeaSoar, a small yellow airplane-shaped vehicle about the size of a bicycle. We will tow the SeaSoar behind the ship for three days as we sail in a radiator grid pattern (long lines from south to north and back south) off Monterey, California. The SeaSoar descends from the surface down to 300 meters and then back up, changing the pitch of its wings to control its direction. It will repeat this yo-yo pattern continuously the whole time it is deployed. SeaSoar measures water temperature, salinity, oxygen, fluorescence (an indicator of how much chlorophyll is produced by phytoplankton), and several other biogeochemical variables. We combine the SeaSoar dives into cross-sectional profiles to give us an image of what the subsurface waters off central California look like.
We do this profiling transect at the beginning of our cruise to identify and determine the water ‘feature’ that we will sample throughout the month. Our goal is to find a newly-upwelled water filament (think a triangular-shaped parcel of water, with the wide base along the coast and the tip pointing offshore) and to follow that filament as it moves progressively offshore. We have identified a potential filament off Monterey using satellite measurements of sea surface temperature and water currents, so we are cruising through the area with the SeaSoar to get additional information about the subsurface structure of the feature. We hope that this emerging filament continues to grow and move offshore, so that we have time to sample various areas of it!
We have been graced by lots of animal sightings while we do the SeaSoar survey. As we were preparing to deploy the SeaSoar on Tuesday evening, a mola mola floated by at the surface! Molas are oval-shaped bony fish with very flat bodies. They often float on their sides at the surface of the ocean, resembling large pancakes. Sharks and killer whales have been known to sample them (or perhaps use them as frisbees), but overall they are rather unpalatable. We have also seen albatrosses and other seabirds. Wednesday afternoon the sky cleared for a beautiful sunset with pods of dolphins and whales cruising alongside the ship!