Research about Sao Paulo

USGS2018

The occurrence of the invasive foraminifera Trochammina hadai Uchio in Flamengo Inlet, Ubatuba, São Paulo State, Brazil

The agglutinated foraminifera Trochammina hadai Uchio (1962), a dominant species in Japan, first appeared as an invasive species in San Francisco Bay, US, in 1983. Trochammina hadai's first appearance in the Brazilian coastal waters of Flamengo Inlet, Ubatuba, Sao Paulo State, is recorded nearly three decades later, in two of thirty-four sediment samples collected in the western portion known as "Saco do Ribeira" in 2010. By 2014 and 2015, the species was found alive in 78% of the samples with relative abundance reaching 18%. We suggest this recent colonization was most likely the result of an introduction by anchor mud on commercial fishing boats and recreational vessels or from fishing bait, and the species' proliferation due to its suitability to live in anthropogenically-induced stressed environmental conditions of the inlet that has affected the ecological dominance of this benthic community.

Sao Paulo↗

USGS2007

Homogeneity of the geochemical reference material BRP-1 (paraná basin basalt) and assessment of minimum mass

Reference materials (RM) are required for quantitative analyses and their successful use is associated with the degree of homogeneity, and the traceability and confidence limits of the values established by characterisation. During the production of a RM, the chemical characterisation can only commence after it has been demonstrated that the material has the required level of homogeneity. Here we describe the preparation of BRP-1, a proposed geochemical reference material, and the results of the tests to evaluate its degree of homogeneity between and within bottles. BRP-1 is the first of two geochemical RM being produced by Brazilian institutions in collaboration with the United States Geological Survey (USGS) and the International Association of Geoanalysts (IAG). Two test portions of twenty bottles of BRP-1 were analysed by wavelength dispersive-XRF spectrometry and major, minor and eighteen trace elements were determined. The results show that for most of the investigated elements, the units of BRP-1 were homogeneous at conditions approximately three times more rigorous than those strived for by the test of “sufficient homogeneity”. Furthermore, the within bottle homogeneity of BRP-1 was evaluated using small beam (1 mm 2 ) synchrotron radiation XRF spectrometry and, for comparison, the USGS reference materials BCR-2 and GSP-2 were also evaluated. From our data, it has been possible to assign representative minimum masses for some major constituents (1 mg) and for some trace elements (1-13 mg), except Zr in GSP-2, for which test portions of 74 mg are recommended.

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