Field research of macrofaunal communities of sandy beaches at 10 sites of the central and southern coast of Quintana Roo State, was performed in 2011. For each beach 3 transects were conducted perpendicular to the coast with a variable number of levels depending on the length of the beach. The slopes of the beaches were also variable; however, as a recurring pattern, the southern part of each beach was wider than the northern part. The best represented fauna were mollusks (18 species), but also other groups were recorded such as crustaceans (4), annelids (4), sipunculids (1), nemerteans (1), foraminifera (4) and insects (1). The numerical analysis divided the coast of the state in areas of the Maya Rivera, that were more diverse and richness in fauna, while the sites located in the Gran Costa Maya were the least diverse. The assemblage sites representing the major groups show affinities between nearby sites, but are able to detect differences between areas in the same region. Using a content analysis divisive second-order information, for different groups, the species responsible for most decrease of information was obtained; in mollusks, was Terebra tuberculosa, whereas annelids was Scoloplos latum and for foraminifera Bigenerina angulata. A long-term study is proposed for this ecosystem.

Se realizó una investigación de campo de las comunidades de playas arenosas en 10 sitios al norte y sur del Estado de Quintana Roo, México, en 2011. Para cada playa se realizaron 3 transectos perpendiculares a la costa con un número variable de niveles dependiendo de la longitud de la playa. Las pendientes de las playas fueron también variables; sin embargo, como patrón recurrente, la parte sur de cada playa fue más extensa que la parte norte. La fauna mejor representada fue la de los moluscos (18 especies), aunque también se registraron otros grupos como: crustáceos (4), anélidos (4), sipunculidos (1), nemertinos (1), foraminíferos (4) e insectos (1). Los análisis numéricos dividieron el litoral de la costa en sitios de la Rivera Maya que tuvieron mayor riqueza y diversidad de la fauna y en sitios de ubicados en la Gran Costa Maya que fueron los menos diversos. El ensamblaje que formaron los sitios a partir de los grupos principales muestran afinidades entre sitios cercanos, pero también permitió detectar diferencias entre zonas en una misma región. Utilizando un análisis divisivo del contenido de información de segundo orden, para los diferentes grupos, se obtuvo las especies responsables de la mayor caída de información; en los moluscos, fue Terebra tuberculosa, mientras que para los anélidos fue Scoloplos latum y para los foraminiferos Bigenerina angulata. Se propone un estudio a mayor plazo para este ecosistema.

South Africa's extensive and topographically diverse coastline lends itself to interpreting and understanding sea-level fluctuations through a range of geomorphological and biological proxies. In this paper, we present a high-resolution record of sea-level change for the past ~1200 years derived from foraminiferal analysis of a salt-marsh peat sequence at Kariega Estuary, South Africa. A 0.94-m salt-marsh peat core was extracted using a gouge auger, and chronologically constrained using five radiocarbon age determinations by accelerator mass spectrometry, which places the record within the late Holocene period. Fossil foraminifera were analysed at a high downcore resolution, and a transfer function was applied to produce a relative sea-level reconstruction. The reconstructed sea-level curve depicts a transgression prior to 1100 cal years BP which correlates with existing palaeoenvironmental literature from southern Africa. From ~1100 to ~300 cal years BP, sea levels oscillated (~0.5-m amplitudes) but remained consistently lower than present-day mean sea level. The lowest recorded sea level of -1±0.2 m was reached between 800 and 600 cal years BP. After 300 cal years BP, relative sea level has remained relatively stable. Based on the outcomes of this research, we suggest that intertidal salt-marsh foraminifera demonstrate potential for the high-resolution reconstruction of relative sea-level change along the southern African coastline.

Saltmarsh foraminifera are used as indicators of sea-level change which occurs during the Holocene. In Chile however, the saltmarsh foraminifera have been poorly studied, so it is unknown the feasibility of using them for this purpose. To address this issue, a research was conducted in the intertidal Quillaipe Inlet, Chile, in order to determine the vertical distribution of foraminifera and to analyze the parameters that explain their distribution and determine the species that are useful as indicators of sea level. The results revealed 18 species (nine calcareous and nine agglutinated) distributed in two zones (I and II). Zone I was restricted to the saltmarsh and inhabited exclusively by agglutinated community. Here, diversity (H' = 0.567), pH (6.6) and salinity (18.7) values were low with a dominance of agglutinated species Haplophragmoides manilaensis. Zone II was restricted to tidal fíat and inhabited by a calcareous-agglutinated community. In contrast, diversity (H' = 0.909), pH (7.7) and salinity (32.8) values were higher, and the dominant species was the calcareous Ammonia beccarii. On the other hand, the agglutinated association Trochamminita salsa-Jadammina macrescens was restricted to the top of the saltmarsh and to low salinity and pH values. We conclude that the distribution of foraminifera is controlled by salinity, pH and the elevation of intertidal área and suggest that Trochamminita salsa-Jadammina macrescens association could be used as indicators of the maximum sea-level in the Quillaipe Inlet.

Los foraminíferos de las marismas salobres son utilizados como indicadores del cambio producido en el nivel del mar durante el Holoceno. No obstante, los foraminíferos de las marismas de Chile han sido escasamente estudiados por lo que se desconoce la factibilidad de utilizarlos para este fin. Para subsanar esto se desarrolló una investigación en el intermareal de la ensenada de Quillaipe, Chile, con los objetivos de determinar los foraminíferos y su distribución vertical; analizar los parámetros que explican su distribución y determinar las especies que son útiles como indicadoras del nivel del mar. Los resultados revelaron 18 especies (nueve aglutinadas y nueve calcáreas) distribuidas en dos grandes Zonas (I y II). La Zona I se restringió a la parte más alta y vegetada del intermareal (marisma) y estuvo habitada solo por taxa aglutinados. Aquí se registraron bajos valores de diversidad (H' = 0.567), pH (6.6) y salinidad (18.7) y un dominio de la especie aglutinada Haplophragmoides manilaensis. En cambio, la Zona II se limitó a la zona menos elevada y sin vegetación del intermareal (llanura de marea) y estuvo habitada por una comunidad calcárea-aglutinada. Contrariamente, los valores de diversidad (H' = 0.909), pH (7.7) y salinidad (32.8) fueron más altos, y la especie dominante fue la calcárea Ammonia beccarii. Por otro lado, la asociación aglutinada Trochamminita salsa-Jadammina macrescens se restringió a la parte más alta de la marisma y a los valores más bajos de salinidad y pH. Estos antecedentes permiten concluir que la distribución de los foraminíferos está controlada por la salinidad, el pH y la elevación del intermareal y que la asociación Trochamminita salsa-Jadammina macrescens son indicadoras del máximo nivel del mar en la ensenada de Quillaipe.