Oceanography The Official Magazine of
The Oceanography Society
Volume 21 Issue 03

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Volume 21, No. 3
Pages 82 - 91


Contrasting Bays and Red Tides in the Southern Benguela Upwelling System

Grant C. Pitcher | Marine and Coastal Management, Cape Town, South Africa
Stewart Bernard | Council for Scientific and Industrial Research, Stellenbosch, South Africa
Joyce Ntuli | Marine and Coastal Management, Cape Town, South Africa

First Paragraph

In late summer and autumn of 2007, red tides were present in two prominent bays of the southern Benguela upwelling system, False Bay and St. Helena Bay. In False Bay, the dinoflagellate Gonyaulax polygramma attained concentrations of 20 x 106 cells l-1 and posed a serious environmental threat through bloom decay and anoxia. In St. Helena Bay, the toxic dinoflagellate Alexandrium catenella reached concentrations of 5 x 105 cells l-1 and posed a threat to human health by rendering shellfish highly toxic. Multiscale observations obtained from coastal monitoring stations, ship-based transects, and aircraft and satellite remote sensing were used to identify the scale and physical forcing of these blooms, which appear to be localized manifestations within adjacent subsystems of the southern Benguela upwelling region.


Pitcher, G.C., S. Bernard, and J. Ntuli. 2008. Contrasting bays and red tides in the southern Benguela upwelling system. Oceanography 21(3):82–91, https://doi.org/10.5670/oceanog.2008.39.

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