POSTER SESSION 3
15:30–17:30, Wednesday, September 16
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1249 | POSTER 207
SPATIAL AND TEMPORAL VARIABILITY IN PARTICULATE ABSORPTION PROPERTIES OF ANTARCTIC COASTAL WATERS ACROSS FOUR FIELD SEASONS
The Southern Ocean connects the major ocean basins and regulates global carbon cycling, yet the magnitude and direction of regional carbon exchange remain largely uncertain. This is due, in part, to the unique bio-optical properties of coastal Antarctic phytoplankton communities. In situ radiometry reveals an underestimation of Chl-a by a factor of 2-2.5 at high concentrations using empirical blue-green ratio algorithms. Here we use field data to investigate the spatiotemporal variability of particulate absorption in the Western Antarctic Peninsula and their contributions to observed remote sensing reflectance, Rrs. Data from four cruises in austral spring 2021 and summer 2023, 2024, and 2026 include filter-pad particulate absorption (QFT-ICAM), pigment composition (HPLC), flow-through particle imaging (IFCB), and Rrs via a solar tracking radiometer (HyperSAS, 350–800 nm) and handheld spectroradiometer (ASD, 350-2500 nm). On-shelf summer phytoplankton assemblages exhibit reduced blue light absorption per unit Chl-a compared to off-shelf waters; this pigment packaging is also greater than other temperate upwelling systems. Absorption by depigmented particles (ad) per Chl-a is also twofold lower than global trends. We further assess variability in ad components, including phytoplankton and microbial cell bodies, detritus, and minerogenic particulates. Together, decreased on-shelf a*phyt and a*d contribute to elevated blue reflectances at high Chl-a concentrations, and parameterizing for these reduced Chl-specific absorptions can improve retrievals of pigments, biomass, and carbon uptake in Antarctic coastal waters. Ongoing work will examine variability of low CDOM absorption and particulate backscattering coefficients at green wavelengths to achieve optical closure in this dynamic Antarctic coastal system.
Eva Scrivner*, University of Connecticut Department of Marine Sciences, [email protected], https://orcid.org/0009-0008-6852-611X
Jessica Turner, Old Dominion University, [email protected]
Oscar Schofield, Rutgers University, [email protected]
Michael Cappola, University of Delaware, [email protected]
Heidi Dierssen, University of Connecticut, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
