Phytoplankton Interannual Variability at Cassino Beach, Southern Brazil (1992–2007), with Emphasis on the Surf Zone Diatom Asterionellopsis glacialis

Abstract

A long-term study (monthly sampling, 1992 to 2007) was conducted in the surf zone of Cassino Beach, Southern Brazil, in order to detect possible natural and/or anthropogenic disturbances. Surface water temperature (6-29°C) was the only parameter with predictable seasonal variation; salinity (14-38) was inversely related to rainfall (3.1-485.2 mm month −1 ) and low values followed extreme precipitation periods in and 2002/2003. Asterionellopsis glacialis and chlorophyll a presented high concentrations and peak frequency until 1998, when an intense mud deposition occurred with concomitant extreme rainfall. It affected the surf zone and beach, changing the hydrology and dissolved inorganic nutrient availability. Six phytoplankton species groups were recognized with distinct responses to this mud deposition. We conclude that large-scale climatic changes, like El Niño Southern Oscillation, in conjunction with human activities significantly altered the phytoplankton ecology of the highly dynamic Cassino Beach surf zone.

Effect of low salinity on the yellow clam Mesodesma mactroides

“…Thus, the lethal low salinities for M. mactroides were not far from the extreme values recorded by Odebrecht et al (2010), and mortality might occur due to low salinities in some areas.…”

“…On Cassino Beach on the coast of Rio Grande do Sul where the yellow clam M. mactroides is frequently found, the salinity ranges from 14 g/L to 38 g/L (mean = 28 g/L), with the minimum values related to El Niño events (Odebrecht et al, 2010). Thus, the lethal low salinities for M. mactroides were not far from the extreme values recorded by Odebrecht et al (2010), and mortality might occur due to low salinities in some areas.…”

Biota of the Patos Lagoon estuary and adjacent marine coast: long-term changes induced by natural and human-related factors

“…The adjacent marine coast presents a gentle slope and wide continental shelf, and it is strongly influenced by freshwater run-off from the Patos Lagoon and Rio de La Plata (Ciotti et al 1995;Campos et al 2008;Pimenta & Kirwan 2014). The oceanic beaches in this region are intermediate to dissipative with regard to wave energy and are characterized by the accumulation of surf-zone diatoms that produce an enormous biomass, especially following the passage of atmospheric fronts (Odebrecht et al 2010a). …”

A review on macrobenthic trophic relationships along subtropical sandy shores in southernmost Brazil

“…The extensive southern Brazilian coast is predominantly of the intermediate type and presents high microalgae biomass mainly granted by accumulations of the surf-zone diatom Asterionellopsis glacialis (Castracane) Round throughout the year (Odebrecht et al 2010(Odebrecht et al , 2013. During high A. glacialis concentrations (10 7 to 9 cells L -1 ), high primary production rates (6.4 mg C L -1 h -1 ) and chlorophyll a values (up to 4.7 mg L -1 ) can be registered (Odebrecht et al 1995.…”

“…Based on references for southern Brazilian (a) intermediate beaches: Gianuca (1983Gianuca ( , 1997 Rodrigues & Vieira (2010); (e) zooplankton: Bersano (1994); (f) phytoplankton: Odebrecht et al (1995Odebrecht et al ( , 2010Odebrecht et al ( , 2013. Amarilladesma mactroides and Donax hanleyanus empty shells and Emerita brasiliensis debris are registered around large burrows of the ghost crab (pers.…”