SEMINAR: Special Seminar - Thursday Feb 28

[Robert Cowen <rcowen@rsmas.miami.edu>]

Special Seminar

Thursday - Feb 28, 2013

NOON

SLAB 103

Lars Stemman

Observatoire Océanologique de Villefranche

Villefranche sur Mer, France

Observing particles in situ using optical cameras

Abstract

Quantifying chemical elements fluxes through trophic webs and from the surface to the deep ocean requires the ability to detect and identify all organisms and particles in situ and in a synoptic manner. An idealized sensor should observe both the very small particles and protozoa and the extremely large particles such as aggregates, and plankton. Such an instrument would reveal an astonishing amount and diversity of living and non-living particles present in parcel of water and help to understand their dynamics. It is very important to distinguish particles nature (living, non living, organic, minerals) because it has an impact on elements pathways within trophic webs and on vertical fluxes. Unfortunately past sensors did not achieve this goal easily because of their inability to determine particles nature or to be deployed in a synoptic manner.  However, recent technological developments now allow better measuring in situ particles and plankton optical properties and size distributions in a way that synoptic surveys are possible. Using recent examples from the literature, my presentation deals with particle and plankton size distributions to show how they help to understand the processes responsible for particulate organic carbon attenuations with depth and the impact of mesoscale hydrodynamics on particle and plankton accumulation or dispersion. I will present the future of imaging technologies to be mounted on autonomous vehicle in a way that coastal or open seas may be monitored using gliders and profiling floats (ARGO floats).  Finally, I will suggest how these new data sets could be integrated into size-structured mathematical models of biogeochemical fluxes.