Beatriz Beck Eichler

Water stratification in coastal lagoons: its influence on foraminiferal assemblages in two Brazilian lagoons

Abstract Foraminiferal assemblages were studied in two Brazilian stratified lagoons: the restricted Cananeia–Iguape lagoon which exhibits inclined water stratification and the choked Lagoa da Conceicao, where strong horizontal stratification occurs during the rainy season. Water stratification has been shown to influence the distribution of foraminiferal assemblages. In the restricted lagoon, the transition from marine to continental water conditions induces a progressive change in foraminiferal assemblage, both horizontally and vertically. In the choked lagoon, the presence of two different water masses separated by a halocline leads to the presence of two distinct assemblages. The first, located in the depressions, characterized by the dominance of rotaliids indicates a stronger marine influence. The second, present in the shallow water, characterized by textulariids, indicates more restricted conditions. The dominance of calcareous species in the depressions, where organic rich sediments are potentially liable to dissolve calcareous tests shows that, even if it may greatly modify the thanatocoenoses, the dissolution does not destroy all the information. The differential impact of stratification on foraminiferal assemblages from these two sites clearly demonstrate: (1) that it is impossible to propose a universal model for foraminiferal distribution in lagoons; but (2) that the foraminiferal assemblages can provide valuable information for modern hydrodynamics and, with some caution, also for fossil lagoonal environments.

PARAROTALIA CANANEIAENSIS N. SP.: INDICATOR OF MARINE INFLUENCE AND WATER CIRCULATION IN BRAZILIAN COASTAL AND PARALIC ENVIRONMENTS

ABSTRACT Pararotalia cananeiaensis, a new rotaliid species frommodern shelf sediments of southern Brazil is described.This small species is well-represented along the southerncoast of Brazil. It was recorded for the first time in thelaguno-estuarine complex of Canane´ia-Iguape in 1995. Ithad never been reported before, probably because it wasconfused with juveniles of Ammonia. Its distribution hasbeen studied in Brazilian coastal and paralic environ-ments from Cabo Frio (Rio de Janeiro state) near lati-tude 228509S, to Florianopolis (Santa Catarina state)near latitude 278359S. Very small tests of Pararotaliacananeiaensis are easily suspended in Brazilian high en-ergy coastal environments and are transported inwardby tidal currents. Their presence in the sedimentary re-cord can be used to gauge the extent of the effects of thistransport mechanism in the estuaries of southern Brazil.INTRODUCTIONForaminifera are emerging as reliable bioindicators of en-vironmental conditions (review in Alve, 1995 and Yankoand others, 1999). In paralic and coastal environments theymay indicate sources of pollution resulting from aquaculture(Schafer and others, 1995; Grant and others, 1995), heavymetals contamination (e.g., Alve, 1991, 1995), municipalwastes (e.g., Bandy and others, 1964; LeFurgey and St Jean,1976), fuel ash, coal, or hydrocarbon spills (e.g., Yanko andothers, 1994).Owing to methodological problems, including the moni-toring of life cycles, total assemblages (i.e., combined livingspecimens and empty tests) are often used for such envi-ronmental studies. However, this approach is still debatedsince, after the death of the cells, foraminiferal tests may betransported (e.g., Coulbourn and Resig, 1975; Boltovskoyand Wright, 1976; Murray and others, 1982; Debenay,1988). Passive test transport may introduce a bias in theinterpretation of total assemblages, but it may also yielduseful information on the hydrodynamics of paralic envi-ronments.The aims of this study are (1) to describe a new species,Pararotalia cananeiaensis n. sp. occurring along the Bra-

Ostracodes (crustacea) from Cananéia-Iguape estuarine/lagoon system and geographical distribution of the mixohaline assemblages in southern and southeastern Brazil

The ostracode assemblages from Cananeia-Iguape estuarine/lagoon system (southernmost State of Sao Paulo) are here discussed in detail for the first time. Thirty-four sites, approximately 1 km equidistant, were sampled along the system, including the Cananeia Sea, Pequeno Sea, Cubatao Sea, Ribeira de Iguape River and Itapitangui River. The ostracodes throughout this area have poor assemblages, with a total of 662 specimens of dead and living organisms. The majority of the ostracode fauna is composed of euryhaline species, as follows: Cyprideis multidentata Hartmann, 1955 (174 specimens), Minicythere heinii Ornellas, 1974 (54 specimens), Tanella gracilis Kingma, 1948 (96 specimens) and Whatleyella sanguinettiae Coimbra, Carreno & Ferron, 1994 (226 specimens). Although there are few studies on the Brazilian mixohaline ostracode faunas, including the euryhaline marginal marine taxa, the published data show that the group is best known in the south and southeast regions. Based on this review and with the new data presented in this paper, the geographical distribution of eight mixohaline key species in southern and southeastern Brazil is also discussed.

Recent benthic foraminiferal distribution and related environmental factors in Ezcurra Inlet, King George Island, Antarctica

Abstract This investigation attempts to determine which environmental parameters of the bottom water and sediment control recent foraminifera fauna at Ezcurra Inlet (King George Island, Antarctica), using data collected during four summers (2002/03, 2003/04, 2004/05 and 2006/07). The study revealed that Ezcurra Inlet contain typical Antarctic foraminifera fauna with three distinct assemblages and few differences in environmental parameters. The species Bolivina pseudopunctata, Fursenkoina fusiformis, Portatrochammina antarctica, and Adercotryma glomerata were abundant in the samples. An elevated abundance, richness and diversity were common at the entrance of the inlet at depths greater than 55 m, where the inlet was characterized by low temperatures and muddy sand. In the inner part of the inlet (depth 30–55 m), richness and diversity were low and the most significant species were Cassidulinoides parkerianus, C. porrectus, and Psammosphaera fusca. Shallow waters showed low values of richness and abundance and high temperatures coupled with coarser sediment. In areas with high suspended matter concentrations and pH values associated with low salinity the most representative species were Hippocrepinella hirudinea and Hemisphaerammina bradyi.

Sedimentacao acelerada de pontais e barras arenosos na enseada de caraguatatuba, sp : causas naturais e artificiais

Interpretacao de fotografias aereas nas escalas 1:25.000, 1:20.000 e 1:8.000 e medidas de campo efetuadas no periodo entre novembro/78 a agosto/81 permitiram detectar modificacoes morfologicas em um trecho da costa paulista, conhecido por Enseada de Caraguatatuba. Analises granulometricas, morfoscopicas e de agrupamentos de 53 amostras de sedimentos associados permitiram caracterizar suas propriedades texturais, ajudando a entender os processos costeiros envolvidos na evolucao da area durante os ultimos anos.

Distribution of benthic foraminifera in the southwestern zone of the estuarine-lagoonal system of Iguapé-Cananéia (Brasil)

One hundred species of benthic foraminifera were found in the study area (25oS - 48oW). The surface sediment of this lagoon contains from 0 to 3,000 tests per 50 cm3 and up to 32 species. The foraminifera fauna of the lagoonal system of Iguape-Cananeia is the richest among those described in other paralic environments of Brazil. The richness of foraminifera fauna can result from the strong marine influence in the Baia de Trapande. The foraminifera distribution in the study area is characterized by the occurrence of marine assemblages nearby the mouth, with a gradual increase in agglutinating species, such as,Ammotiwn salsum and Gaudryina exilis. In the confined areas, with low salinity, the assemblages are oligospecific and Milammina earlandi Is dominant. The abundance of Pararotalia in the Mar de Cananeia shows that this environment is less restricted than Mar de Cubatao, where the genus is absent. The distribution of foraminifera species shown to be also influenced by urbain sewages.

Distribuição da matéria orgânica nos sedimentos marinhos costeiros e nos solos hidromórficos da orla litorânea do Estado de São Paulo

The organic matter content in the fine-fraction of 200 marine sediments samples and in 50 whole continental samplel along the Estado de Sao Paulo coast, between Cananeia and Ubatuba, show a close relation between organic content and depositional environment. Samples were collected in coastal plains lagoon-estuarine mangroves and inner continental shelf environments representative of that coastal region.

Marine Pollution-Environmental Indicators in Marine Meiofauna from Brazil

To assess the primary stresses that affect environmental quality, recent benthic foraminiferal distribution in Brazilian domestic outfalls of Baixada Santista, Sao Paulo State (Santos Bay, Long Beach, Gurauja Cove), close to oil refineries in Todos Santos Bay (BA), Guanabara Bay (RJ), and Sao Sebastiao Channel, and from environments polluted by pesticides in Laguna (SC) were compared through foraminifera species in 250 sediment samples.