Assessment of the ecological quality status of the Sepetiba Bay (SE Brazil): When metabarcoding meets morphology on foraminifera.

In recent years, the region surrounding Sepetiba Bay (SB; SE Brazil) has become a hub of intense urban expansion and economic exploitation in response to ore transport and industrial and port activities. As a result, contaminants have been introduced into the bay, leading to an overall worsening of the environmental quality. The present work applies for the first time a foraminiferal morphology-based approach (M) and eDNA-based metabarcoding sequencing (G), along with geochemical data to assess the ecological quality status (EcoQS) in the SB.

First putative occurrence in the fossil record of choanoflagellates, the sister group of Metazoa.

Choanoflagellates are microeukaryotes that inhabit freshwater and marine environments and have long been regarded as the closest living relatives of Metazoa. Knowledge on the evolution of choanoflagellates is key for the understanding of the ancestry of animals, and although molecular clock evidence suggests the appearance of choanoflagellates by late Neoproterozoic, no specimens of choanoflagellates are known to occur in the fossil record. Here the first putative occurrence of choanoflagellates in sediments from the Cretaceous (Cenomanian-Turonian) is described by means of several cutting-edge petrographic techniques, and a discussion of its paleoenvironmental significance is performed.

Early diagenesis and clay mineral adsorption as driving factors of metal pollution in sediments: the case of Aveiro Lagoon (Portugal).

This work aims to define the factors driving the accumulation of metals in the sediment of the lagoon of Aveiro (Portugal). The role of initial diagenetic processes in controlling trace metal retention in surface sediment is traced by mineralogy, magnetic susceptibility and geochemical analyses. Although several studies have focused on the metal distribution in this polihaline and anthropized coastal lagoon, most of them have been solely focused on the total metal concentrations.

Organic matter and pyritization relationship in recent sediments from a tropical and eutrophic bay.

The degree of pyritization (DOP) and the extension of metals incorporation into pyrite was investigated at Guanabara Bay sediments. Maximum concentrations of total organic carbon (TOC), total sulfur, biopolymers and viable bacteria cells were observed in silted stations close to discharge points of sewage and minimum concentrations at sandy stations at the entrance of the bay. Pyrite iron concentrations (Fepy) was always lower than the reactive iron and Fepy were below the detection limit at sandy stations.

Polycyclic aromatic hydrocarbons (PAHs) in burning and non-burning coal waste piles.

The coal waste material that results from Douro Coalfield exploitation was analyzed by gas chromatography with mass spectrometry (GC-MS) for the identification and quantification of the 16 polycyclic aromatic hydrocarbons (PAHs), defined as priority pollutants. It is expected that the organic fraction of the coal waste material contains PAHs from petrogenic origin, and also from pyrolytic origin in burning coal waste piles. The results demonstrate some similarity in the studied samples, being phenanthrene the most abundant PAH followed by fluoranthene and pyrene.

Geomicrobiology of cores from Suruí Mangrove--Guanabara Bay--Brazil.

The aim of this work was to quantify the biopolymers associated to esterase enzymes and identify bacterial respiratory activity in four cores collected in Suruí Mangrove, Guanabara Bay - RJ. Biopolymer concentration was 1000 times lower than previously reported in the literature, indicating the need for creating and establishing eutrophication indicative rates and records compatible with tropical coastal systems. The biochemical representative relationships in the cores were equivalent to those from studies on coastal marine environments made in the Northern Hemisphere.

Lipid biomarkers profile--presence of coprostanol: recent sediments from Rodrigo de Freitas Lagoon-Rio de Janeiro, Brazil.

Coprostanol (contribution characteristic from anthropogenic pollution) and other lipid biomarkers (sterols, fatty alcohols and fatty acids) were identified and quantified in recent sediment extracts from Rodrigo de Freitas Lagoon, a touristy spot of Rio de Janeiro-Brazil, using gas chromatography with mass selective detector (GC-MSD). The determination of lipid biomarkers profile indicates an autochthonous biogenic contribution due to the presence of phytoplankton, zooplankton, bacteria and dinoflagellates. The allochthonous biogenic contribution was confirmed by detection of biomarkers from higher plants in the sediments due to the influence of the Atlantic Forest inserted in the studied region.

Polycyclic aromatic hydrocarbons in sediments from Rodrigo de Freitas Lagoon in the urban area of Rio de Janeiro, Brasil.

Regular (non-alkylated) polycyclic aromatic hydrocarbons (PAHs) and their alkylated homologues were determined in sediments from Rodrigo de Freitas Lagoon using gas chromatography with mass selective detector (GC-MSD). Concentrations varying from 405 to 11734 ng x g(-1) were found for total PAHs (regular and alkylated homologues). The study showed a pyrogenic and petrogenic contribution, probably due to the incomplete burning of fossil fuels as a result of the intense traffic of boats and motor vehicles added to the anthropogenic activity of several gas stations present in the region of Rodrigo de Freitas Lagoon.