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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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Latest on-line papers from the SEGH journal: Environmental Geochemistry and Health

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    Abstract

    Geophagy, the intentional consumption of earth materials, has been recorded in humans and other animals. It has been hypothesized that geophagy is an adaptive behavior, and that clay minerals commonly found in eaten soil can provide protection from toxins and/or supplement micronutrients. To test these hypotheses, we monitored chimpanzee geophagy using camera traps in four permanent sites at the Budongo Forest Reserve, Uganda, from October 2015–October 2016. We also collected plants, and soil chimpanzees were observed eating. We analyzed 10 plant and 45 soil samples to characterize geophagic behavior and geophagic soil and determine (1) whether micronutrients are available from the soil under physiological conditions and if iron is bioavailable, (2) the concentration of phenolic compounds in plants, and (3) if consumed soils are able to adsorb these phenolics. Chimpanzees ate soil and drank clay-infused water containing 1:1 and 2:1 clay minerals and > 30% sand. Under physiological conditions, the soils released calcium, iron, and magnesium. In vitro Caco-2 experiments found that five times more iron was bioavailable from three of four soil samples found at the base of trees. Plant samples contained approximately 60 μg/mg gallic acid equivalent. Soil from one site contained 10 times more 2:1 clay minerals, which were better at removing phenolics present in their diet. We suggest that geophagy may provide bioavailable iron and protection from phenolics, which have increased in plants over the last 20 years. In summary, geophagy within the Sonso community is multifunctional and may be an important self-medicative behavior.

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    Abstract

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  • Distribution, sources and health risk assessment of contaminations in water of urban park: A case study in Northeast China 2019-12-01

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