Oral Session 8

Mapping Phenoregions and Phytoplankton Seasonality in Northeast Pacific marine coastal ecosystems via a satellite-based approach

Phytoplankton phenology is an important ecological indicator that characterizes the timing of annually occurring phytoplankton growing periods and has been typically synthesized into a set of indices encompassing the timing, duration, and magnitude of bloom events. Observing changes in phytoplankton phenology requires vast spatial coverage and short temporal frequencies, which is achieved through ocean color satellite imagery. This study evaluated the GlobColour interpolated product in British Columbia coastal waters via a statistical match-up analysis and a qualitative analysis to determine whether the data reflect the region’s large-scale seasonal trends and latitudinal dynamics. The statistical performance of the GlobColour interpolated product was compared to the original GlobColour and Ocean Colour Climate Change Initiative merged chlorophyll-a products based on in situ observations. A suite of phenological indices were then derived on a pixel-by-pixel basis, and used to partition the study area into phenological bioregions using the Hierarchical Agglomerative Clustering method. The delineated bioregions described region-specific phytoplankton phenological patterns associated with bloom magnitude, frequency, duration, and timing. The GlobColour interpolated product performed relatively well and was comparable to the best performing product for each water type (RMSE = 0.28, r2 = 0.77, MdAD = 1.5, BIAS = 0.90). Four coherent bioregions were identified with distinctive phytoplankton phenological properties: two coastal, one shelf and offshore region. This is the first study to perform a satellite-based 23-year phenology bioregionalization considering multiple bloom events in the British Columbia and SE Alaska coast, thus enabling this heterogenous marine domain to be simplified into coherent spatial regions.

*Sejal Pramlall, Spectral Remote Sensing Laboratory, University of Victoria, Canada, https://orcid.org/0000-0003-1786-9178

Jennifer M. Jackson, Fisheries and Oceans Canada

Christian Marchese, European Molecular Biology Laboratory (EMBL), Italy

Karyn D. Suchy, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Canada

Brian Hunt, Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Canada

Marta Konik, Spectral Lab, Department of Geography, University of Victoria, Canada

Maycira Costa, Spectral Lab, Department of Geography, University of Victoria, Canada

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