POSTER SESSION 4
10:30–12:30, Thursday, September 17
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1236 | POSTER 64
EVALUATING THE “CASE 2” WATERS OF THE SOUTHERN OCEAN: THE OPTICAL PROPERTIES OF GLACIAL MELTWATER
The freshening of the coastal surface water over the summer months along the Antarctic coastal zone is largely influenced by the influx of glacial meltwater, which is projected to increase in the coming decades due to atmospheric warming trends. Seasonal variability in the amount and extent of the glacial meltwater plume plays a critical role in the functioning of the biota by influencing the physical dynamics of the water (e.g., stratification, turbidity). Here we show how glacial meltwater creates “Case 2” conditions nearshore with elevated particulate backscattering and remote sensing reflectance (Rrs) compared to shelf waters leading to inaccuracies in empirical chlorophyll algorithms. Field measurements of Rrs show how blue to green ratios become uncorrelated to Chlorophyll-a in nearshore waters with low salinity surface layers. Vertical profiles of particulate backscattering collected from the Western Antarctic Peninsula are consistent with the presence of sinking particles related to large glacial till particulates. Data from near Palmer Station and Andvord Bay suggest that these Case 2 conditions are generally confined to fjord systems and waters within a few km from shore. The sea surface glacial meltwater layer, however, forms a surface freshwater “lens” which can extend >100 km offshore of the WAP and is linked to higher phytoplankton biomass. Remote sensing of these nearshore waters is additionally confounded by adjacency effects near snow/ice features. Methods to identify Case 2 particle-laden waters and the dilution of glacial meltwater across the shelf will be discussed.
Heidi Dierssen, University of Connecticut Marine Sciences, [email protected], https://orcid.org/0000-0003-4276-5530
Eva Scrivner, University of Connecticut, [email protected]
Jessica Turner, Old Dominion University, [email protected]
Oscar Scofield, Rutgers University, [email protected]
Jack Pan, Ocean Motion Technologies, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
