POSTER SESSION 1
15:30–17:30, Monday, September 14
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1098 | POSTER 201
SOUTHERN OCEAN PHYTOPLANKTON PIGMENT ESTIMATION ALGORITHM: A REMOTE SENSING – MACHINE LEARNING APPROACH
The Southern Ocean is one of the most important and most difficult regions to observe from space. Its phytoplankton communities play a crucial role in ocean productivity, carbon cycling, and the wider food web, yet their optical signatures are unique and no region-specific pigment retrieval algorithm currently exists.
To address this, we developed a supervised machine-learning model that estimates phytoplankton pigment concentrations from satellite remote sensing reflectance (Rrs) using in situ Southern Ocean HPLC and matched-up satellite Rrs data. The model uses a two-headed mixture density network — an artificial neural network designed to handle the strongly zero-inflated nature of pigment datasets. This allows the method to handle both whether a pigment is present and how much is present, offering a novel solution for pigment retrieval in this region. For one Rrs signal (observation), a distribution of probable pigment concentrations is given. It is also a multivariate approach, capable of capturing the inter-correlated nature of the different phytoplankton pigments.
Beyond retrieval, this work also explores whether the Southern Ocean phytoplankton community is shifting. The results support evidence for compositional change, which could have major consequences for ecosystem functioning and the transfer of energy through the food web. This is particularly significant considering earlier findings that phytoplankton community composition affects the foraging behavior of southern elephant seals in the region.
Together, these results show the value of regionally tailored ocean-colour methods for the Southern Ocean and provide new evidence that changes in phytoplankton composition may already be underway.
Ziad Sari El Dine*, LOG – CEBC, [email protected], https://orcid.org/0009-0004-9195-2484
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
