[Eoas-seminar] COAPS SEMINAR: “Seeding snow: Mississippi River plume interaction with surface oil in the northern Gulf of Mexico” by Catherine Edwards - November 13 at 3pm

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Wed Oct 30 10:29:00 EDT 2019

Dr. Catherine Edwards
Skidaway Institute of Oceanography
University of Georgia
“Seeding snow: Mississippi River plume interaction with surface oil in the northern Gulf of Mexico”
Wednesday, November 13  - 3:00 pm
COAPS seminar room 255,  Research Building A
Directions:  https://www.coaps.fsu.edu/about-us/visitor-information
Glider data collected in the upper 200 m during a month-long mission in the northern Gulf of Mexico indicate formation of marine oil snow (MOS) after the arrival of fresh river plume water over the continental slope site approximately 200 nm offshore. The putative MOS signal, captured near Green Canyon lease block 600 (GC600), appears in the fluorescence data as large particles with high concentration of both colored dissolved organic matter (CDOM) and chlorophyll-a fluorescence, extending well below the photic zone to at least 190 m depth. Closer examination of the time series suggests a strong diel cycle in concentration of MOS aggregates, with distribution through the upper 190 m during the day and zero signal between local sundown and sunrise.  ADCP backscatter from a nearby ship shows diel vertical migration of scatterers of approximately 800 μm in radius. The size and behavior of the scatterers is consistent with mesozooplankton. Direct measurement of MOS concentration or zooplankton population was not possible with this data set; however, the data are consistent with MOS formation under a fresh water plume, with diel clearing of the aggregates each night by zooplankton grazing. The implications for this previously unknown process of MOS formation and zooplankton-mediated export are explored with respect to system dynamics of natural seeps and the anomalous nature of the 2015 fresh water event.

Eric Chassignet
Professor and Director
Center for Ocean-Atmospheric Prediction Studies (COAPS)
Florida State University
2000 Levy Avenue, Building A, Suite 292
P.O. Box 3062741
Tallahassee, FL  32306-2741

Office : (1) 850-645-7288
COAPS  : (1) 850-644-3846
Cell   : (1) 850-524-0033 (urgent matters only)
FAX    : (1) 850-644-4841
E-mail : echassignet at fsu.edu<mailto:echassignet at fsu.edu>

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