The Impact of Mud Deposition on the Long Term Variability of the Surf-Zone Diatom Asterionellopsis glacialis (Castracane) Round at Cassino Beach, Brazil

The impact of mud deposition on the monthly variability (1994 to 2000) of the surf zone diatom A. glacialis at Cassino Beach, southern Brazil (32° 13' S; 52° 10' W) was evaluated. An outstanding episode of mud deposition in the shoreface, surf zone and foreshore of Cassino Beach was observ...

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Bibliographic Details
Published in:Journal of coastal research 2003-04, p.486-491
Main Authors: Odebrecht, C., Abreu, P. C., Fugita, C. C., Bergesch, M.
Format: Article
Language:English
Subjects:
Beaches
Chlorophylls
Coastal ecology
Diatoms
El Nino
Mud
Phytoplankton
Salinity
Sediments
Wave energy
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Summary:The impact of mud deposition on the monthly variability (1994 to 2000) of the surf zone diatom A. glacialis at Cassino Beach, southern Brazil (32° 13' S; 52° 10' W) was evaluated. An outstanding episode of mud deposition in the shoreface, surf zone and foreshore of Cassino Beach was observed in March 1998, which persisted for 14 months. However, the effect on A. glacialis concentration was longer (2 years). It is likely that the mud affected the dynamics of this surf zone diatom in two ways: 1) reducing the wave energy, responsible for suspending cells from the sediment and keeping them in the surface, attached to the foam and 2) burying the seeding cells normally present in offshore sediment. Although the 1998 mud depositon episode was of high magnitude, this phenomenon is recurrent at Cassino Beach. It is suggested that the 1998 large scale mud deposition was associated with increasing rainfall and freshwater and sediment discharge in the coast, characteristic of El Niño conditions in southern Brazil.
ISSN:0749-0208
1551-5036