Early last glacial maximum in the southern Central Andes reveals northward shift of the westerlies at ~39 ka

The latitudinal position of the southern westerlies has been suggested to be a key parameter for the climate on Earth. According to the general notion, the southern westerlies were shifted equatorward during the global Last Glacial Maximum (LGM: ~24–18 ka), resulting in reduced deep ocean ventilation, accumulation of old dissolved carbon, and low atmospheric CO<sub>2</sub> concentrations. In order to test this notion, we applied surface exposure dating on moraines in the southern Central Andes, where glacial mass balances are particularly sensitive to changes in precipitation, i.e. to the latitudinal position of the westerlies. Our results provide robust evidence that the maximum glaciation occurred already at ~39 ka, significantly predating the global LGM. This questions the role of the westerlies for atmospheric CO<sub>2</sub>, and it highlights our limited understanding of the forcings of atmospheric circulation

WHITE‐LIGHT RECONSTRUCTION OF COLOR IMAGES FROM BLACK‐AND‐WHITE VOLUME HOLOGRAMS RECORDED ON SHEET FILM

The method of ``white‐light reflection holography'' first described by Stroke and Labeyrie (Physics Letters 20, 368, March 1, 1966) and subsequently verified by a number of authors, has now been extended to the recording of volume holograms in 6–7‐μ‐thick Kodak 649F emulsions on sheet film, with a quality in the reconstructed images comparing favorably with the images reconstructed from the 17‐μ‐thick emulsions on glass plates used heretofore. The results presented have also permitted us to further verify a simple ``crystallographic'' theory of the method, first used by Stroke and Labeyrie (ibid.) and further described by G. W. Stroke in a subsequent paper.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70381/2/APPLAB-9-5-215-1.pd

Single tree effects on soil organic matter.

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Determination of ecologically relevant pools for soil organic matter stability in terra firme oxisols.

The study on soil pools identification which are sensitive to land-use changes in terra firme oxisols and yield easy to handle techniques for the evaluation of increasing te soil organic matter (SOM) porperties. For this purpose, it has studied the influence of ten different trees and annual crops on SOM properties on an oxisol near Manaus (Amazonas, Brasil). A combination of aggregate and density fractionation was found to be most suitable for physical SOM characterization. The particulate organic matter (POM, density less than 1.6g cm-3) varied by one order of magnitude between sites and could be used as a sensitive indicator of land-use changes. The obtained results are extremely important for the evaluation of the sustainability of the investigated lan-use systems and are the basis for soil ecological research on terra firme oxisols

Caractérisation -par spectrométrie RMN du 31P- de constituants phosphatés extraits de sols de rizières malgaches

Les composés phosphatés de six sols de rizières, riches en matière organique, originaires de Madagascar ont été extraits par une solution sodique. Ces composés ont été déterminés soit par une analyse chimique globale, soit par une spectrométrie RMN du 31P du phosphore qu'ils contenaien

Single tree-effects on denitrification and soil microbial biomass in agroforestry systems and natural forests of the Amazon region.

The aim of the present study was to find the effect of tree species used in agroforestry system in Amazonian region and natural forests on the total biomass of heterotrophic microorganisms (BH), which is mainly responsible for CO2 emission, and on the biomass of denitrifiers (BD), which control N2O emission

Significant subsoil accumulation of mineral nitrogen under perennial crops in a ferralitic Amazonian upland soil: effects of land use systems and single-tree patterns.

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Organic matter in termite mounds of an Amazonian rain forest.

This study investigates how termites alter the organic matter in rain forests near Manaus, Brazil. Samples were collected from the outer and inner parts of typical termite nests of Nasutitermes, Termes, Embiratermes, Cornitermes, Anoplotermes, and Constrictotermes genera, as well as from the surrounding topsoil (0cm-10cm) and potential wooden food. The termite nests were signficant sinks for organic matter and its associated nutrients. The organic C contents ranged between 100g kg-1 and 500g kg-1 in the nests, compared to 17g kg-1 to 42g kg-1 in the surrounding topsoils. As lignin contents of the mounds were higher than in wood, lignin may be accumulated in preference to other organic compounds. This findings also sugests that the interior part of the nests is a region of higher organic matter turnover and lignin degradation

Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal.

Inspired by the sustained fertility of anthropogenic Terra Preta soils in the central Amazon Basin, we studied the effect of charcoal as soil amendment