Metals background and enrichment in the Chiloé Interior Sea sediments (Chile). Is there any segregation between fjords,channels and sounds?

The range and spatial distribution of metal concentrations in the Chiloé Interior Sea were investigated from 37 surface sediment samples collected during the ‘CIMAR 10 Fiordos’ cruise. Grain size distribution, total organic carbon and nitrogen, δ¹³C, major (Al, Fe, and biogenic opal) and trace (Cd, Co, Cu, Ni, Pb, and Zn) elements were determined. Metal background concentrations of each metal in sediment were defined from linear regression equations of metal versus Al, as baseline information for future research on the status of sediment contamination in the Northern Patagonian marine area. Metal levels in Chiloé sediments were of the same order of magnitude as uncontaminated sediments around the world and contamination can be considered negligible-moderate (normalized enrichment factors lower than 3) in this Southern Pacific Region. The Chiloé Interior Sea can be segregated into two zones on the basis of metal content by applying a principal component analysis. The first pertains to inner fjords and it has terrestrial origin (associated to Co, Cu, Pb, Zn) and the second zone features channels and gulfs of a predominantly marine source (Cd, Cu). Nevertheless, only one background equation is needed to predict metal concentrations in the natural sediment of the Chiloé Interior Sea.     

Reproductive cycle,size at first maturation and fecundity in the golden ling,Genypterus blacodes,in Chile

Reproductive aspects of the golden ling, Genypterus blacodes, from the southern Chilean fishery are presented. Gonad samples were obtained from commercially caught fish between September 1999 and October 2000. Stage of sexual maturity, gonadosomatic index (GSI), and size of females at 50% maturation determined by logistic methods and by plotting the mean GSI by total length, are presented for both years. Batch fecundity was calculated from subsampling mature ovaries containing oocytes in advanced stages of maturity. Changes in GSI and monthly diameters of oocytes showed that ling had a spawning season which extended between August and November. The sizes at first maturity in 1999 and 2000 were 86.6 and 84.8 cm total length (TL), respectively, using the logistic model, and 84 cm for both years using the mean GSI‐size plotting method. The mean batch fecundity was 333 330 oocytes per individual for fish sized 85–120 cm TL. Fecundity increased with increasing weight and total length.     

The environment of early Mars and the missing carbonates

Abstract– A model is presented in which the aqueous conditions needed to generate phyllosilicate minerals in the absence of carbonates found in the ancient Noachian crust are maintained by an early CO₂‐rich atmosphere, that, together with iron (II) oxidation, would prevent carbonate formation at the surface. After cessation of the internal magnetic dynamo, a CO₂‐rich primordial atmosphere was stripped by interactions with the solar wind and surface conditions evolved from humid to arid, with ground waters partially dissolving subsurface carbonate and sulfide minerals to produce acid‐sulfate evaporitic deposits in areas with upwelling ground water. In a subsequent geochemical state (Late Noachian to Hesperian), surface and subsurface acidic solutions were neutralized in the subsurface through interaction with basaltic crust, allowing the precipitation of secondary carbonates. This model suggests that, in the early Noachian, the surface waters of Mars maintained acidity because of a drop in temperature. This would have favored increased dissolution of CO₂ and a reduction in atmospheric pressure. In this scenario, physicochemical conditions precluded the formation of surface carbonates, but induced the precipitation of carbonates in the subsurface.     

Spatial and temporal variations of atmospheric aerosol optical thickness in northwestern Mexico

The purpose of this paper was to study aerosol particles in the Northwestern region of Mexico (NWM) through Aerosol Optical Thickness (AOT) parameter in the atmosphere. This parameter represents one of the extinction coefficients of solar radiation and the rate of suspended particles in the atmosphere. For determination of AOT, we considered the use of remote sensors outside of the atmosphere. In particular, Moderate Resolution Imaging Spectroradiometer (MODIS) which can measure the atmospheric AOT thickness. Data from the MODIS sensor must be validated before they are considered reliable. For this task, we required surface measurements to obtain a correlation with the data acquired with the remote radiometer. The paper describes the validation process performed for data obtained with MODIS through measurements provided by an AErosol RObotic NETwork (AERONET) photometer located in the city of Hermosillo, Sonora, NWM. Additionally, we carried out a temporal analysis based on the behavior of the AOT graphics and spatial analysis supported in maps with sufficient information.     

A local spatial decision support system for developing countries based on MCA,fuzzy sets and OWA – case study of a municipality in Cuba

This paper presents a Spatial Decision Support System for local governments of developing countries. It allows municipality government, enterprises, scientific community and civil society to address decision problems using GIS. The framework is supported by four modules of information technologies: Environmental Decision Support Database, Data Manipulation, Decision Support, and Mapping. A case study is presented covering the implementation of this framework in one municipality of Cuba. An example of land suitability planning for coconut crops is used to evaluate the system performance and usability. Results show local municipalities are able to use this framework to solve local decision problems using state of the art decision making even with low infrastructure development.     

On the landslide event in 2010 in the Monarch Butterfly Biosphere Reserve, Angangueo, Michoacán, Mexico

In February 2010, 19 fatalities and economic damage were caused by a regional landslide episode in the state of Michoacán, México. The municipalities of Angangueo, Ocampo, Tiquicheo de Nicolás Romero, Tuxpan, and Tuzantla were severely damaged, with Angangueo being the most affected. The event involved a series of debris flows, of which four were the most significant; these four caused 16 deaths in addition to considerable damage to roads, electricity, and the water supply system, with indirect consequences in crop production, cattle farming, and tourism. The area affected by these four flows was calculated as 282?km², with an estimated 697,346?m³ of mobilized material. General observations indicated that the initiation sources of the debris flows were on deforested zones. The present research is concentrated on the Angangueo basin, an area situated within the Monarch Butterfly Biosphere Reserve. Given the lack of rain gauges in the area of interest, records from neighboring points were used to build a comprehensive overview of the extreme precipitation event that triggered the devastating debris flows. The nearest rain gauge, Laguna del Fresno, situated 21?km to the south, recorded 204?mm of rainfall from 1 to 5 February, equivalent to 30% of the mean annual rainfall. Moreover, during a 24-h period the El Bosque rain gauge recorded 144.5?mm of precipitation, the equivalent of 2,270% of the mean rainfall for the same month (6.36?mm). The occurrence of a hailstorm preceding the rainfall event is notable; conditions in the superficial soil layer would have included an increased pore water pressure. Presumably, before the 2,000-year return period extreme rainfall event, thawing of hail and consequent moisture and/or pore-pressure increase result in decreased frictional strength. This paper presents a spatial analysis of the distribution of these landslides, mainly debris flows, as well as general observations on the triggering mechanism, the strength properties of the materials involved, and the societal impact.