POSTER SESSION 1
15:30–17:30, Monday, September 14
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ABSTRACT 1350 | POSTER 189
INFLUENCE OF DOMINANT GENERA ON THE REMOTE-SENSING REFLECTANCE OF CYANOBACTERIA-DOMINATED FRESHWATER ENVIRONMENTS
Hyperspectral remote sensing enables exploration of how phytoplankton dominance changes the light field in aquatic systems. In freshwater cyanobacteria-dominated environments, phycocyanin is expected to have a substantial influence on light absorption, therefore impacting the remote-sensing reflectance (Rrs) spectra. However, the cyanobacteria group comprises genera with a wide range of cell morphology and size, which may produce different effects in the light field. In this work, we selected a set of 135 cyanobacteria-dominated stations from eutrophic reservoirs and Amazon floodplains, and compared the influence of Microcystis dominance (at least 50% of organism abundance, 79 stations) with two other situations: 30 stations without a single dominant genus, and 26 stations dominated by other cyanobacteria genera. The in situ Rrs spectra were resampled to match the Environmental Mapping and Analysis Program (EnMAP) mission. Results indicate that the second-order derivative of the normalized Rrs at the chlorophyll-a and phycocyanin absorption peaks (440 nm, 674 nm, and 620 nm, respectively) responds primarily to site-specific changes and to chlorophyll concentration, with no clear distinctions between the dominance scenarios. The potential effects of Microcystis cell morphology on Rrs were likely masked by other optically-active components; but uncertainties in both Rrs and, especially, the microscopy-derived cell density data cannot be ruled out. Based on these initial results, the next step is trying to isolate the effect of Microcystis dominance on the phytoplankton signal alone (i.e., on the phytoplankton absorption spectra at stations where these data are available) to investigate whether genus-specific variations are detectable at the studied sites.
Bruno Rech*, National Institute for Space Research, [email protected], https://orcid.org/0000-0003-2787-2450
Áurea Ciotti, University of São Paulo, [email protected]
Daniel Maciel, National Institute for Space Research, [email protected]
Júlio Santos, National Institute for Space Research, [email protected]
Cláudio Barbosa, National Institute for Space Research, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
