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SEGH Member participated in the Antarctic Circumpolar Expedition

02 July 2017
Francois De Vleeschouwer, researcher at EcoLab, (CNRS, Toulouse France) and SEGH secretary, had the opportunity to embark onboard the RV Akademik Treshnikov to participate in the ACE Expedition


François De Vleeschouwer, researcher at EcoLab, (CNRS, Toulouse France) and SEGH secretary, had the opportunity to embark onboard the RV Akademik Treshnikov to participate in the ACE Expedition. From December 2016 to March 2017, scientific teams from all over the world joined into an unprecedented expedition around Antarctica. From biology to climatology to oceanography, researchers from 22 selected projects worked on a number of interrelated fields revolving around Antarctica.

 

François De Vleeschouwer is involved in a British Antarctic Survey-supervised project dealing with « Measuring the changes in the ocean’s capacity to absorb CO2 ». Concentrations of CO2 in the atmosphere have increased since 1750 AD as a result of human activity. This is linked to warming of the atmosphere and oceans, changes in climate, recession of ice sheets and sea level rise. More than one quarter of this CO2 is absorbed by the oceans; the Southern Ocean accounting for 43%. The capacity of the Southern Ocean to absorb CO2 has recently been limited (according to some models) by an increase in the strength of the Southern Hemisphere Westerly Winds (SHW), which draw CO2 saturated waters back to the surface. This will potentially drive up atmospheric greenhouse gases and accelerate rates of global warming.Reconstructing past changes in the SHW and their impact on the oceanic CO2 sink is therefore a major priority for palaeoclimate science.

 

François De Vleeschouwer participated to the leg 2 of the ACE navigation from Hobart, Tasmania to Punta Arenas, Chile. After an unfortunate storm that obliged the expedition to cancel the sampling at Macquarie Island, the boat navigated throuhgh Antarctic waters to then cross the Drake’s Passage. F. De Vleeschouwer sampled soils, mosses and peatlands on various islands from the Antarctic (Scott, Maher, Lauft, Siple) and sub-Antarctic (Diego Ramirez Archipelago).

 

The main objective of this project is to determine the Holocene (last 12000 yrs) changes in the strength of the SHW over the Southern Ocean by generating records of wind-driven aerosols and other proxies in sediment records from lakes and bogs on the west coasts of sub-Antarctic islands and, These data will be further used in global climate models to test if past changes in the SHW explain past variations in atmospheric CO2.

Further information can be found on : http://spi-ace-expedition.ch/

 

Francois de Vleeschouwer, CNRS, Toulouse, France

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    Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils, and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high, medium and low population density and a natural area were selected and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000–850, 850–180, 180–106, 106–50, 50–20, 20–10, 10–2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined, and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, and Cr was highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human-induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.

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    Abstract

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  • Concentration, fractionation, and ecological risk assessment of heavy metals and phosphorus in surface sediments from lakes in N. Greece 2020-01-13

    Abstract

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