USAP-DC

A 50+ year warming trend in the Southern Ocean has been most dramatic in Drake Passage and likely impacts ecosystem structure here. Acoustic Doppler Current Profiler (ADCP) records from multiple ?L.M. Gould? supply transits of Drake Passage from 1999 to present demonstrate spatial and temporal variability in acoustics backscattering. Acoustics backscattering strength in the upper water column corresponds to zooplankton and nekton biomass that supports predator populations. However, for much of Drake Passage the identity of taxa contributing to this acoustically detected biomass is not known. This project would introduce a biological component to ?L.M. Gould? transits of Drake Passage with the goal of determining the identity of taxa responsible for the backscattering records obtained by ADCP and relating these to higher trophic levels (seabird/marine mammal). Net sampling during spring, summer and fall transits will permit assessment of diel and seasonal changes in the abundance and taxonomic composition of zooplankton and top predators represented between Patagonia and the Antarctic Peninsula. Net samples and depth-referenced video records taken in conjunction with ADCP profiles will permit the identification of the dominant acoustic backscatters in the 3 biogeographic regions represented here, the Subantarctic, Polar Frontal, and Antarctic Zones. The validity of dominant backscattering taxa in the Antarctic Zone will be tested by comparing the ADCP records with abundant zooplankton data collected off the Antarctic Peninsula during January-March 1999-2009 as well with long-term top predator surveys. The broader impacts also include a cruise blog, the production of an article for an online outreach publication based at Moss Landing Marine Labs and a YouTube video featuring shipboard research in the Southern Ocean.

Person	Role
Loeb, Valerie	Investigator
Santora, Jarrod	Co-Investigator

Antarctic Organisms and Ecosystems

Award # 1347911

USAP-1347911

None in the Database

Repository	Title (link)	Format(s)	Status
BCO-DMO	Zooplankton samples, analyses, and underwater video.	None	exist

1. Loeb, V. J., & Santora, J. A. (2015). Climate variability and spatiotemporal dynamics of five Southern Ocean krill species. Progress in Oceanography, 134, 93–122. (doi:10.1016/j.pocean.2015.01.002)
2. Loeb, V., & Santora, J. (2017). Seabird and marine mammal observations from the Drake Passage transits aboard RV Laurence M Gould (LMG1410, LMG1504, LMG1509) and coastal zone operations from 2014 to 2015. Biological and Chemical Oceanography Data Management Office. (doi:10.1575/1912/bco-dmo.705477.1)
3. Loeb, V., & Santora, J. (2017). IKMT samples and underwater video recordings collected in the Drake Passage from R/V Laurence M. Gould (LMG1504, LMG1509, LMG1410) from 2014-2015. Biological and Chemical Oceanography Data Management Office. (doi:10.1575/1912/bco-dmo.705556.1)