The VISUFRONT cruise

by Jean-Olivier Irisson, on July 16, 2013

The VISUFRONT scientific cruise is the main research action of our PUF-sponsored program this year. The goal of this cruise is to deploy an array of instruments to study physics and biology in the ocean at the same very high scale, as we initially described in our proposal.

We will deploy the In Situ Ichthyoplankton Imaging System, developed at RSMAS, coupled with the Underwater Video Profiler, developed at LOV. Both instruments take images of the plankton. The UVP focuses on small particles while ISIIS focuses on large, hence rarer, organisms (such as larval fish = ichthyoplankton). ISIIS also collects data about the physical properties of the water and this will be intercalibrated and compared with a CTD and gliders.

Armed with this data-collecting arsenal, we hope to understand how organisms such as fish larvae or jellies respond to their environment. We will focus on a region where physical forcings are strong: the front of the Ligurian current. This current separates coastal waters from more oceanic waters and the combination of the current and the mixing of those water masses makes for a very interesting environment.

As a first step, we plan to sample along transects both across and along the front, to capture the variability in both directions. The we will deploy drifters and floats which will track a parcel of water as it is moved by the current and we will sample this parcel of water repeatedly to see how it evolves through time.