Tracking ecological shifts across the Antarctic Polar Front: A regional remote sensing model for phytoplankton size classes
ID：1116
Oral Presentation
2027-01-12 15:35 （China Standard Time）
Session： Session 19 - Southern Ocean Bio-diversity Under Climate Change
Abstract
Accurate retrieval of phytoplankton size classes (PSCs), crucial ecological indicators of marine biogeochemical cycles, remains challenging in the highly dynamic Southern Ocean (SO) when using conventional global remote sensing models. Traditional Diagnostic Pigment Analysis (DPA) often introduces structural uncertainties due to the ambiguous mathematical partitioning of shared marker pigments. In this study, we demonstrate that a regionally optimized, taxonomically informed CHEMTAX scheme yields substantially more robust and ecologically consistent in situ PSC baselines. Building upon this foundation, we developed a novel suite of regional abundance-based PSC satellite inversion models tailored for the SO. Independent validation reveals that these models achieve high predictive accuracy relying solely on total chlorophyll-a. Notably, the framework yields highly accurate microphytoplankton estimates (MAPE=25.32%, R2=0.98) and superior improvements in nanophytoplankton retrievals (MAPE=49.94%, R2=0.63). Crucially, it effectively mitigates the severe overestimation of picophytoplankton commonly produced by global algorithms at low chlorophyll concentrations south of the Polar Front (PF). Applying these models to basin-scale satellite data significantly refines the spatial mapping of PSCs, revealing that microphytoplankton dominated, while nanophytoplankton also contributed a substantial fraction, particularly south the PF zone. Ultimately, this accurate, satellite-based framework provides an indispensable suite of monitoring indicators for assessing the efficiency of the biological carbon pump and tracking the response of fragile SO marine ecosystems to global climate change.
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Jan 30
2026
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Jan 12–15
2027
XMAS 2027