Publications

Luz, LFG; Noernberg, MA (2022). Spectral changing during a massive bloom event of Dinophysis cf. accuminata in south Brazil. REGIONAL STUDIES IN MARINE SCIENCE, 56, 102681.

Abstract
Harmful algal blooms (HABs) are deleterious ecological phenomena that can severely impact coastal ecosystems, fisheries resources, and public health worldwide. Different HABs species have distinct spectral characteristics due to the specific absorption of their accessory pigments, allowing us to monitor them through remote sensing. In June 2016, a massive Dinophysis cf. acuminata bloom hit the southern Brazilian coast causing damage to the local mariculture along its trajectory. In order to observe its passage and evolution, we performed weekly sampling cruises in the coastal waters of Parana, Brazil. Remote sensing reflectance (Rrs) data were performed with FieldSpec ASD, along with oceanographic variables (water temperature, salinity, Secchi depths, chlorophyll fluorescence, and particulate matter concentration). Satellite images from MODIS and OLI were used to quantify the magnitude of the HAB. During its peak, the bloom reached an area of 201 km2 along the Parana coast with abundances of 6.85 x 106 cells.L-1, the highest cell density ever recorded for this species. The event was associated with low salinity and temperature from a high chlorophyll plume from the La Plata River. The in situ Rrs were grouped by hierarchical clustering, separating the spectral signature of the Dinophysis bloom through principal component analysis. The same spectral shape was observed in the K-means clustering of both MODIS and OLI images, attesting to the method's suitability. We address the first characterization of a Dinophysis bloom, and the results can contribute to a better understanding of the spectral response of this toxic dinoflagellate and optimize the satellite algorithms for the detection of HABs.(c) 2022 Elsevier B.V. All rights reserved.

DOI:
10.1016/j.rsma.2022.102681

ISSN: