The Effects of Wind-Driven Storm Events on Partly Sheltered Estuarine Beaches in Batemans Bay, New South Wales, Australia

Extreme wind-driven storm events have the potential to erode beach systems. Along the East Coast of Australia, storm events have been responsible for beach erosion in many coast-facing, open beaches. This paper investigates the potential impacts of wind-driven storms on partly sheltered estuarine beaches—a niche found within Batemans Bay, New South Wales (NSW), along the East Coast. It combines beach geomorphological data with meteorological and oceanographic data to evaluate the impacts of large storm events on three partly sheltered estuarine embayed beaches (Cullendulla Beach, Corrigans Beach, and Maloney’s Beach). The results show that while embayed beaches are protected from some storm events, storm impacts may vary with the season due to wind speed and direction changes, the presence of nearby rivers or creeks, and anthropogenic modifications such as dredging and coastline alterations. This study may contribute to the understanding of the erosive impacts of storms and help improve management strategies used to prevent recession, particularly on embayed beaches.

Morfodinâmica de praias estuarinas de baixa energia durante dragagem de aprofundamento do canal da Galheta, Paranaguá – PR

Estuarine beaches are generally classified as low-energy or sheltered due to the predominance of low waves and short periods, which favor the wave approach with large angles due to limited refraction, narrow beachface and narrow or nonexistent berm. The installation of ports in the interior of estuaries causes several negative effects, mainly due to the activities of dredging of navigation channels and secondly, due to the transit of vessels. The objective of the present work was to monitor four estuarine beaches, on the banks of the Paranaguá bay - PR, characterized as low energy beaches, with the purpose of following the short-term morphological and volumetric changes that occurred during a dredging of deepening in the Galheta navigation channel. For this purpose, cross-shore topographic surveys were carried out, before, during and after the dredging, between February 2017 and March 2019, at 10 monitoring sites. Among all the monitored sites, only the easternmost sites on the beaches of Amparo and Maciel show continuous erosion. The causes of this erosion may be related to tide currents associated with low altitudes of the beaches, storm surge events and dredging.

Occurrence of norovirus genogroups I and II in recreational water from four beaches in Belém city, Brazilian Amazon region

This study aimed to investigate the presence of norovirus (NoV) in recreational waters of four estuarine beaches located in Mosqueiro Island, Belém city, Brazilian Amazon, during two years of monitoring (2012 and 2013). NoV particles were concentrated on filtering membrane by the adsorption-elution method and detected by semi-nested RT-PCR (reverse transcription polymerase chain reaction) and sequencing. NoV positivity was observed in 37.5% (39/104) of the surface water samples, with genogroup GI (69.2%) occurring at a higher frequency than GII (25.7%), with a cocirculation of both genogroups in two samples (5.1%). This virus was detected in all sampling points analyzed, showing the highest detection rate at the Paraíso Beach (46.2%). Statistically, there was a dependence relationship between tide levels and positive detection, with a higher frequency at high tide (46.7%) than at low tide (25%) periods. Months with the highest detection rates (April 2012 and April/May 2013) were preceded by periods of higher precipitation (March 2012 and February/March 2013). Phylogenetic analysis showed the circulation of the old pandemic variant (GII.4-US_95-96) and GI.8. The NoV detection demonstrated viral contamination on the beaches and evidenced the health risk to bathers, mainly through recreational activities such as bathing, and highlighted the importance of including enteric viruses research in the recreational water quality monitoring.

Spatial distribution and abundance of Hemigrapsus crenulatus (H. Milne Edwards, 1837) (Decapoda, Varunidae) in the Puerto Cisnes estuary (44°S, Aysen region, Chile)

Our knowledge on the status of Hemigrapsus crenulatus (H. Milne Edwards, 1837) populations along the Chilean coast is scarce. The aim of the present study was to quantitatively estimate the spatial distribution and abundance of Hemigrapsus crenulatus in the Puerto Cisnes estuary (44°S, Aysen region, Chilean Patagonia). The spatial distribution appeared to be aggregated, with 3.64 ± 7.99 ind/m2 as gross density, and 10.50 ± 10.62 ind/m2 as a potential ecological density, i.e., if the quadrants with zero individuals are not taken into consideration. The equation of the negative binomial distribution was: where: . The average density of Hemigrapsus crenulatus under stones is lower if all beach surfaces are considered. Its abundance or dominance on estuarine beaches probably would be due to the fact that this species is one of the crustaceans of the lower intertidal level that can survive under a wide range of salinity values.