Chapter 10
Ocean Colour Remote Sensing of Harmful Algal
Blooms in the Benguela System
Stewart Bernard, Grant Pitcher, Hayley Evers-King, Lisl Robertson,
Mark Matthews, Andy Rabagliati and Christelle Balt
Abstract The Benguela, as a highly productive upwelling system, suffers from the
occurrence of a variety of harmful algal blooms, most of which are associated with
elevated biomass; a feature common to the shelf environment of upwelling systems.
Most harmful blooms have in the past been attributed to one or another dinoflagellate species, but more recently harmful impacts have also been ascribed to other
groups of phytoplankton, including diatom and autotrophic ciliate species. Typical bloom assemblages, forcing mechanisms and harmful impacts are outlined, and
bloom types most amenable to detection with ocean colour radiometry are identified. Inherent and apparent optical properties of these algal assemblage types are
described, and a preliminary evaluation is made of the suitability of available ocean
colour data and algorithms. The evolution of several bloom events is described using
various algorithms applied to ocean colour data from the Medium Resolution Imaging Spectrometer (MERIS), and recommendations are made about optimal ocean
colour usage for high biomass algal blooms in coastal zones.
S. Bernard ()
Council for Scientific and Industrial Research, Natural Resources
and Ecosystems, Cape Town, South Africa
e-mail: sbernard@csir.co.za
S. Bernard · H. Evers-King · L. Robertson · A. Rabagliati
Department of Oceanography, University of Cape Town, Cape Town, South Africa
M. Matthews
Department of Oceanography, University of Cape Town, Cape Town, South Africa
Also at: University of Cape Town, Cape Town, South Africa
G. Pitcher
Fisheries Research and Development, Department of Agriculture,
Forestry and Fisheries, Cape Town, South Africa
C. Balt
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
V. Barale, M. Gade (eds.), Remote Sensing of the African Seas,
185
DOI 10.1007/978-94-017-8008-7_10,
© Springer Science+Business Media Dordrecht 2014
Ocean Colour Remote Sensing of Harmful Algal
Blooms in the Benguela System
Stewart Bernard, Grant Pitcher, Hayley Evers-King, Lisl Robertson,
Mark Matthews, Andy Rabagliati and Christelle Balt
Abstract The Benguela, as a highly productive upwelling system, suffers from the
occurrence of a variety of harmful algal blooms, most of which are associated with
elevated biomass; a feature common to the shelf environment of upwelling systems.
Most harmful blooms have in the past been attributed to one or another dinoflagellate species, but more recently harmful impacts have also been ascribed to other
groups of phytoplankton, including diatom and autotrophic ciliate species. Typical bloom assemblages, forcing mechanisms and harmful impacts are outlined, and
bloom types most amenable to detection with ocean colour radiometry are identified. Inherent and apparent optical properties of these algal assemblage types are
described, and a preliminary evaluation is made of the suitability of available ocean
colour data and algorithms. The evolution of several bloom events is described using
various algorithms applied to ocean colour data from the Medium Resolution Imaging Spectrometer (MERIS), and recommendations are made about optimal ocean
colour usage for high biomass algal blooms in coastal zones.
S. Bernard ()
Council for Scientific and Industrial Research, Natural Resources
and Ecosystems, Cape Town, South Africa
e-mail: sbernard@csir.co.za
S. Bernard · H. Evers-King · L. Robertson · A. Rabagliati
Department of Oceanography, University of Cape Town, Cape Town, South Africa
M. Matthews
Department of Oceanography, University of Cape Town, Cape Town, South Africa
Also at: University of Cape Town, Cape Town, South Africa
G. Pitcher
Fisheries Research and Development, Department of Agriculture,
Forestry and Fisheries, Cape Town, South Africa
C. Balt
Graduate School of Oceanography, University of Rhode Island, Narragansett, RI, USA
V. Barale, M. Gade (eds.), Remote Sensing of the African Seas,
185
DOI 10.1007/978-94-017-8008-7_10,
© Springer Science+Business Media Dordrecht 2014