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Bunicontro, M.P.; Marcomini, S.C., and López, R.A., 2020. Coastal morphology and human intervention in Golfo Nuevo, Patagonia Argentina. Journal of Coastal Research, 36(4), 780–794. Coconut Creek (Florida), ISSN 0749-0208. The Patagonian coastal zone is a complex and dynamic macrotidal environment that is sparsely urbanized, except locally where large cities are located. This human occupation has affected the natural beach dynamics and induced drastic coastal changes in the past 40 years that demand a redirection of initiatives to provide a basis for management efforts. This study analyzes the coastal morphology and beach characteristics of Golfo Nuevo (Chubut, Argentina) for modelling coastal behaviour through field measurements along 17 beach profiles. Beaches were classified into four types according to their sediment grain size, morphology, and morphometric parameters (beach width and gradient). Also, the coast was divided into five categories according to the coastline morphologies and environmental quality: (1) littoral pediments, (2) cliff-top dunes and aeolian ramps, (3) active cliffs, (4) beach ridge terraces, and (5) dunes. Additionally, different human interventions were analyzed to determine how they have affected the natural coastal equilibrium. The coast was divided into low, moderate, and high levels of intervention according to the status of the landscape modification. The most shocking activities were identified as mining (gravel and sand extraction), coastal armouring with hard defences, and urban building. Indeed, the most affected and vulnerable coastal areas have been beach ridge terraces and coastal dunes. It was determined that the coastal extension affected by these human activities reaches at least 37% of the study zone, increasing beach and coastal erosion susceptibility. The coastal classification and the evaluation of human intervention were combined and used to perform an accurate zoning map of the coastal environment. This map represents an essential tool for decision makers of Puerto Madryn city, showing clearly the most vulnerable places where coastal planning strategies urgently need to be applied for a sustainable use of resources. [ABSTRACT FROM AUTHOR]

Savoya, V.; Gómez Otero, J., and Schwindt, E., 2015. Toward a better understanding of the native-nonnative status of Mytilus mussels in the southwestern Atlantic: comparing pre-European middens and modern populations. The aim of this study is to determine the degree of similarity of the Mytilus mussels currently found along the Patagonian coast of Argentina to those found in pre-European colonization middens, in order to approach an understanding of whether the former are native or not. An elliptic Fourier analysis between pre-European archaeological (native) and modern mussels (cryptogenic) was performed, and the resulting data were analyzed with multivariate approaches (principal component analysis, discriminant function analysis, and cluster analysis). Our results showed that when all samples belonging to the Patagonian coast were included on a single analysis, modern and archaeological mussels were clustered in two major groups, matching the macroregional marine biogeographic scheme. In addition, morphometric differences were detected when modern and archaeological mussels from similar latitudes were compared. We discuss these results in light of the natural and anthropogenic changes that occurred along the Argentinean coast together with the environmental changes occurring between the biogeographic provinces along the SW Atlantic coast. El objetivo del presente trabajo es realizar un estudio morfológico entre valvas de mejillones Mytilus actuales y arqueológicos de la costa patagónica de Argentina, a fin de brindar una nueva perspectiva que permita mejorar el conocimiento sobre el origen nativo o invasor de los mejillones Mytilus actuales. Valvas arqueológicas (nativas) y actuales (criptogénicas) se estudiaron mediante el análisis elíptico de Fourier, y los datos obtenidos se analizaron con análisis multivariados (análisis de componentes principales, análisis de función discriminante, análisis de conglomerados y MANOVAs). Por un lado, los resultados muestran que en un análisis conjunto de todas las muestras ( i.e. actuales y arqueológicas) éstas se agruparon siguiendo el esquema biogeográfico del mar argentino. Por otro lado, las valvas actuales y arqueológicas procedentes de latitudes similares de la costa patagónica se diferenciaron morfométricamente. Los resultados se discuten a la luz de los cambios naturales y antropogénicos ocurridos a lo largo de la costa argentina, y considerando además las diferencias ambientales entre ambas provincias biogeográficas del mar argentino. [ABSTRACT FROM AUTHOR]

Coastal areas contain interfaces between complex depositional systems as a consequence of the convergence of marine and continental environments. The knowledge of such complex depositional systems is important in understanding of coastal evolution and for coastal management. The present study deals with the subsurface identification of interfaces between fluvial and beach/shallow marine systems, using Ground Penetrating Radar (GPR). GPR profiles were measured along dip direction, at two sites on the coastal plain of Santa Catarina state (Pinheira and Passo de Torres), where deposits of fluvial and beach/foredune ridge systems occur. GPR data showed that fluvial and beach deposits are interdigitated in subsurface, with reflectors showing different downlap directions. The results of this study allow a more complete knowledge of the complex interfaces between marine and continental systems. Also, the identification of hidden older fluvial deposits in the subsurface of coastal plains gives important geotechnical information to be considered in the use and occupation of coastal areas and during prospection for placer deposits. [ABSTRACT FROM AUTHOR]

Plant zonation is one of the most conspicuous ecological features of salt marshes worldwide. In Patagonian salt marshes the cordgrass Spartina alterniflora forms dense monospecific stands along the lowest marsh level, while the higher levels are dominated by Spartina densiflora or Sarcocornia perennis. In this study, we coupled field transplants combined with neighbor exclusion treatments and greenhouse experiments to evaluate the effect of submersion and waterlogged anoxic soil in the determination of the lower distribution limit of S. densiflora in Central Patagonian salt marshes within its native range. In the field experiment, no S. densiflora survived the frequent tidal submersion by approximately 2 m of seawater in the low marsh, independent of the S. alterniflora neighbor's presence, while in the greenhouse experiment, all plants were able to tolerate strongly reducing soil conditions. Our results suggest that the absence of S. densiflora in the low marsh level is a consequence of the effect of the submersion, independent of the presence of S. alterniflora neighbors and of the strong soil anoxia. Our results contribute to optimize the efforts addressed to control or eradicate this exotic species in salt marshes where it is invading. [ABSTRACT FROM AUTHOR]