scholarly journals Influence of the “Great Acceleration” of the Anthropocene on the fluxes of trace elements in sediments of the Santos and São Vicente estuarine system, southeastern Brazil

Author(s):  
José Lourenço Friedmann Angeli ◽  
Julie Sartoretto ◽  
Bianca Kim ◽  
Paulo Ferreira ◽  
Michel Mahiques ◽  
...  

Abstract The worldwide evidence of human activities on the environment led the scientific community to recognize a new geologic time unit known as the Anthropocene. Since the twentieth century, the estuaries have been largely impacted by urbanization and industrialization needs driven by population and economic growth. To assess the contamination, provenance, and fluxes of trace elements (As, Cr, Cu, Ni, Pb, Sc, V and Zn) over the last century, a geochemical and chemometric technique was employed in sediment cores of the Santos and São Vicente Estuarine System (SSVES), an industrial and port region of international importance. The results indicated low contamination, with the highest enrichment factors (EF) for Cu (EF = 3.1), Pb (EF = 2.7), Zn (EF = 2.4) and As (EF = 2.3) found next to the harbor area. The Pre-industrial records confirm the relatively high concentrations of As and its naturally enriched occurrence on the Brazilian shelf. Sediment accumulation rates and trace element fluxes showed a general increase over the years, since the early 1960s, associated with the “Great Acceleration” of the mid-twentieth century. These alterations are human-induced and include urbanization and industrialization. Nonetheless, as the contents and enrichment of trace elements indicate that the region is not severely polluted, we hypothesize that the contamination in the SSVES is likely related to the drainage and erosion of the urbanized adjacent area, rather than direct disposal of inorganic contaminants from the industrial activity.

Radiocarbon ◽  
2020 ◽  
Vol 62 (2) ◽  
pp. 289-311
Author(s):  
Alex da Silva de Freitas ◽  
Javier Helenes Escamilla ◽  
Cintia Ferreira Barreto ◽  
Alex Cardoso Bastos ◽  
Estefan Monteiro da Fonseca ◽  
...  

ABSTRACTMicropaleontological and geochemical data were applied to sediments from southeastern Brazil to study the hydrodynamics associated with the Holocene sea level rise. Sediment cores were taken around Vitória Bay, examined for dinoflagellate cysts and subjected to isotopic analysis. The cyst assemblage mainly dominated by autotrophic species most notably O. centrocarpum, L. machaerophorum and T. vancampoae. The influence of the marine transgression and subsequent regression observed during the Holocene along the coast of Brazil could have initially favored the establishment of an oligotrophic and higher energy environment. The inflow of continental water from tributaries combined with a higher inflow of saline water into the estuarine system could have favored the establishment and subsequent deposition of the dinocysts.


2019 ◽  
Vol 45 (1) ◽  
pp. 56-65 ◽  
Author(s):  
Aline B. de Mello ◽  
Julia M. B. Molina ◽  
Maja Kajin ◽  
Marcos C. de O. Santos

Estuaries ◽  
2002 ◽  
Vol 25 (1) ◽  
pp. 57-69 ◽  
Author(s):  
Andrew E. Laursen ◽  
Sybil P. Seitzinger ◽  
Robert Dekorsey ◽  
James G. Sanders ◽  
Denise L. Breitburg ◽  
...  

2017 ◽  
Vol 68 (9) ◽  
pp. 1704 ◽  
Author(s):  
Leandro Bergamino ◽  
Mark Schuerch ◽  
Adriana Tudurí ◽  
Silvina Carretero ◽  
Felipe García-Rodríguez

We investigated carbon isotopic ratios (δ13C) v. carbon to nitrogen (C : N) ratios for surface sediments throughout a large estuarine system (Río de la Plata, RdlP), combined with sediment cores from adjacent marshes to infer main carbon sources. We also evaluated the influence of the El Niño–Southern Oscillation (ENSO) and associated high freshwater-discharge events on the organic-matter transport within the estuary. The isotopic pattern in surface sediments of the RdlP showed the upper reaches to be influenced by riverine particulate matter (δ13C range: –24 to –26‰). Similarly, in the sediment cores from marshes of the upper reaches, δ13C values decreased from –24‰ in ancient sediments to –28‰ in recent sediments, reflecting an increased contribution of organic matter from land, including C3 plants and freshwater phytoplankton, during the past 50 years. However, the lower reaches represent a depositional environment of marine algae (δ13C range: –21 to –23‰), with no influence of detritus from adjacent marshes, indicating minor erosion of the marshes in the lower reaches operating as carbon-sink habitats. Our isotopic analysis showed that the transport and deposition of terrigenous organic matter within the RdlP and adjacent marsh habitat appear to be both temporally and spatially linked to hydrology patterns.


1991 ◽  
Vol 48 (3) ◽  
pp. 472-486 ◽  
Author(s):  
James P. Hurley ◽  
David E. Armstrong

Fluxes and concentrations of a phorbins and major algal carotenoids were quantified in sediment trap material and sediment cores from two basins of Trout Lake, Wisconsin (TrDH and TrAB). The basins were chosen to contrast the influence of oxygen content at the sediment–water interface (TrDH, oxic and TrAB, reducing), sediment accumulation rate, and focusing. Pigment diagenesis occurred in both basins, but transformations and destruction were more extensive in TrDH. Although untransformed chlorophyll a was the major phorbin deposited at the sediment surface of both basins (51–64 mol%), pigment destruction, coupled with transition to pheophytin, accounted for substantial losses, especially in oxic TrDH sediments. Fucoxanthin, peridinin, and diadinoxanthin, despite representing > 70% of the deposited carotenoid flux, were substantially degraded or transformed in both basins. However, preservation was relatively high for secondary carotenoids, such as diatoxanthin and β-carotene, and for a major cryptomonad pigment, alloxanthin. Residual profiles in sediments show that pigment sedimentation from the epilimnion and accumulation in the permanent sediments are not directly related and that diagenesis must be considered in interpreting sedimentary pigments.


Zootaxa ◽  
2011 ◽  
Vol 2758 (1) ◽  
pp. 26 ◽  
Author(s):  
R. A. MAGRIS ◽  
L. F. LOUREIRO FERNANDES

Decapod larvae assemblages were studied in the tropical estuaries off southeastern Brazil (Piraquê-açú and Piraquê-mirim rivers estuaries). A total of 32 taxa of decapod larvae were recorded. Brachyuran larvae dominated in Piraquê-açú estuary, with 62% of the relative abundance, and 49% in Piraquê-mirim estuary. Mean larvae concentrations ranged from 17.2 m -3 at Piraquê-mirim (August 2003) to 221.1 m -3 at Piraquê-açú (April 2003). The assemblage of larvae in both estuaries was diverse, especially at Piraquê-mirim, which showed higher ecological stability. The high spatial heterogeneity of the Piraquê-açú and Piraquê-mirim estuarine system resulted in the division of the assemblage into two well-defined groups (truly estuarine and euryhaline). Salinity spatial gradient was a key factor in the structure and distribution of larvae.


2002 ◽  
Vol 57 (1) ◽  
pp. 22-31 ◽  
Author(s):  
Hartmut Schulz ◽  
Kay-Christian Emeis ◽  
Helmut Erlenkeuser ◽  
Ulrich von Rad ◽  
Christian Rolf

AbstractThe Toba volcanic event, one of the largest eruptions during the Quaternary, is documented in marine sediment cores from the northeastern Arabian Sea. On the crest of the Murray Ridge and along the western Indian continental margin, we detected distinct concentration spikes and ash layers of rhyolithic volcanic shards near the marine isotope stage 5–4 boundary with the chemical composition of the “Youngest Toba Tuff.” Time series of the Uk′37-alkenone index, planktic foraminiferal species, magnetic susceptibility, and sediment accumulation rates from this interval show that the Toba event occurred between two warm periods lasting a few millennia. Using Toba as an instantaneous stratigraphic marker for correlation between the marine- and ice-core chronostratigraphies, these two Arabian Sea climatic events correspond to Greenland interstadials 20 and 19, respectively. Our data sets thus depict substantial interstadial/stadial fluctuations in sea-surface temperature and surface-water productivity. We show that variable terrigenous (eolian) sediment supply played a crucial role in transferring and preserving the productivity signal in the sediment record. Within the provided stratigraphic resolution of several decades to centennials, none of these proxies shows a particular impact of the Toba eruption. However, our results are additional support that Toba, despite its exceptional magnitude, had only a minor impact on the evolution of low-latitude monsoonal climate on centennial to millennial time scales.


1985 ◽  
Vol 7 ◽  
pp. 12-19 ◽  
Author(s):  
A.L. Dick ◽  
D.A. Peel

Measurements of trace elements in snow and ice are frequently used to describe past atmospheric composition although there is no firm basis for assuming a direct connection. Trace-element concentrations have been measured on samples of aerosol and freshly fallen snow collected simultaneously from two sites in the Antarctic Peninsula during summer. Following improvements in contamination control, the reported concentrations and crustal enrichment factors of Cd, Cu, Pb and Zn in the aerosol are lower than any values previously reported from Antarctica. Even tighter controls will be required in the future.For a crustal element (A1) and for the marine cations (Na, Ca and K) a consistent ratio (0.48±0.31) for the concentration in air (pg m−3)/concentration in snow (pg g−1) is obtained for simultaneously collected samples. This supports a simple model of aerosol scavenging proposed by Junge which considers aerosol removal over polar ice sheets to be dominated by in-cloud processes. Averaged data for Cd, Cu, Pb and Zn from samples collected at different times appear to behave similarly. These findings suggest that there is no preferential scavenging by snowfall of either crustal or heavy metal components in contemporary aerosol. If proved more general in Antarctica this may help to simplify the interpretation of time series data from ice cores.


2017 ◽  
Vol 44 (1) ◽  
pp. 142-149 ◽  
Author(s):  
Luciana M Sanders ◽  
Kathryn H Taffs ◽  
Debra Stokes ◽  
Alex Enrich-Prast ◽  
Christian J Sanders

AbstractAnthropogenic radionuclide signatures associated with nuclear testing are increasingly utilized in environmental science to explore recent sedimentation. In this study, we assess the suitability of Pu radioisotope analysis in floodplain lake environments in the Amazon Basin to form geochronologies during the 20thcentury. The240Pu +239Pu (240+239Pu) signatures in six sediment cores indicate sediment accumulation rates in the floodplain lakes of the major rivers; Amazon (2.3 mm year-1), Tapajos (10.2 and 2.4 mm year-1) and Madeira (3.4, 4.2 and 6.2 mm year-1). The results from this study show that240+239Pu fallout activities, and the well documented (240Pu/239Pu) atomic ratios of the above ground nuclear tests which began in the 1950’s, are sufficient and well preserved in Amazon floodplain lake sediments to infer chronologies. Lead-210 dating analyses in the same sediment cores produced comparable sediment accumulation rates at three of the six sites. The differences between dating methods may be attributed to the different time scale these dating methods represent and/or in the solubility between Pb and Pu along the sediment column. The geochronologies derived from the240+239Pu and210Pb dating methods outlined in this work are of interest to identify the effects of changing sediment accumulation rates during the previous century as a result of development, including deforestation, along the Amazon Basin which increased towards the middle of the 20thcentury. This study shows that Pu dating provides a viable alternative geochronology tool for recent sediment accumulation (previous ~60 years) along the Amazon Basin.


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