Sea salt concentrations across the European continent

The oceans are a major source for particles that play an important role in many atmospheric processes. In Europe sea salt may contribute significantly to particulate matter concentrations. We have compiled sodium concentration data as a tracer for sea salt for 89 sites in Europe to provide more insight in the distribution of sea salt across Europe. The annual average sea salt concentrations above land were estimated to range between 0.3 and almost 13 μg m^?3. Maximum concentrations are found at the Irish coast. At coastal sites along the Atlantic and North Sea coast concentrations tend to be around 5 μg m^?3. More inland locations up to about 300 km away from the coast tend to show concentrations between 2 and 5 μg m^?3, whereas sites further away from the coast are characterized by lower concentrations. An analysis of the representativity of the data with respect to a long term average showed that the long average is associated with a standard deviation of around 15%. The compilation of observations provides an improved overview of sea salt concentrations in Europe as well as an improved basis for model validation. Verification of the results of the LOTOS-EUROS model learned that the model represents well the spatial variability of the observed sea salt concentrations very well. However, the absolute concentrations are significantly overestimated due to large uncertainties in the emission and dry deposition parameterizations. Using the high explained variability in the gradients across Europe, the bias-corrected modelled distribution serves as a best estimate of the sea salt distribution across Europe for 2005.     

Sustainable development in a natural resource rich economy: the case of Chile in 1985–2004

Searching for practical means to assessing economic growth’s sustainability, we extend a standard theoretical model to calculate “true” income measures for Chile, during the 1985–2004 period, and use estimates of natural capital depreciation to obtain genuine national saving measures. We found that, for the period, Chile’s economic growth was sustainable, even when approximately 2.5% of the income recorded by national accounts corresponded to depreciation of natural resources plus costs of atmospheric pollution. This performance can be partially explained by policies implemented to force fiscal responsibility and to assure wise public investment and expending during a natural resource driven growth. This evidence reinforces recent findings contradicting the natural resource curse, and the indirect negative effect of resource abundance over growth that would operate through the quality of institutions.     

Sea-level rise vulnerability in the countries of the Coral Triangle

Sea-level rise is a major threat facing the Coral Triangle countries in the twenty-first century. Assessments of vulnerability and adaptation that consider the interactions among natural and social systems are critical to identifying habitats and communities vulnerable to sea-level rise and for supporting the development of adaptation strategies. This paper presents such an assessment using the DIVA model and identifies vulnerable coastal regions and habitats in Coral Triangle countries at national and sub-national levels (administrative provinces). The following four main sea-level rise impacts are assessed in ecological, social and economic terms over the twenty-first century: (1) coastal wetland change, (2) increased coastal flooding, (3) increased coastal erosion, and (4) saltwater intrusion into estuaries and deltas. The results suggest that sea-level rise will significantly affect coastal regions and habitats in the Coral Triangle countries, but the impacts will differ across the region in terms of people flooded annually, coastal wetland change and loss, and damage and adaptation costs. Indonesia is projected to be most affected by coastal flooding, with nearly 5.9 million people expected to experience flooding annually in 2100 assuming no adaptation. However, if adaptation is considered, this number is significantly reduced. By the end of the century, coastal wetland loss is most significant for Indonesia in terms of total area lost, but the Solomon Islands are projected to experience the greatest relative loss of coastal wetlands. Damage costs associated with sea-level rise are highest in the Philippines (US $6.5 billion/year) and lowest in the Solomon Islands (US $70,000/year). Adaptation is estimated to reduce damage costs significantly, in particular for the Philippines, Indonesia, and Malaysia (between 68 and 99%). These results suggest that the impacts of sea-level rise are likely to be widespread in the region and adaptation measures must be broadly applied.     

Long-Term Community Dynamics of Small Landbirds with and Without Exposure to Extensive Disturbance from Military Training Activities

Military training activities are known to impact individual species, yet our understanding of how such activities influence animal communities is limited. In this study, we used long-term data in a case study approach to examine the extent to which the local small landbird community differed between a site in northeast Kansas that experienced intensive disturbance from military training activities (Ft. Riley Military Installation) and a similar, nearby site that experienced minimal human disturbance (Konza Prairie Biological Station). In addition, we characterized how the regional pool of potential colonizers influenced local community dynamics using Breeding Bird Survey data. From 1991 to 2001, most species of small terrestrial landbirds (73%) recorded during breeding surveys were found at both sites and the mean annual richness at Ft. Riley (39.0 ± 2.86 [SD]) was very similar to that of Konza Prairie (39.4 ± 2.01). Richness was maintained at relatively constant levels despite compositional changes because colonizations compensated local extinctions at both sites. These dynamics were driven primarily by woodland species that exhibited stochastic losses and gains and were present at a low local and regional abundance. Our results suggest that military training activities may mimic natural disturbances for some species in this area because the small landbird community did not differ markedly between sites with and sites without extensive human disturbance. Although our results suggest that military training is not associated with large changes in the avian community, additional studies are needed to determine if this pattern is found in other ecological communities.     

Carbon Storage in Soil Size Fractions Under Two Cacao Agroforestry Systems in Bahia, Brazil

Shaded perennial agroforestry systems contain relatively high quantities of soil carbon (C) resulting from continuous deposition of plant residues; however, the extent to which the C is sequestered in soil will depend on the extent of physical protection of soil organic C (SOC). The main objective of this study was to characterize SOC storage in relation to soil fraction-size classes in cacao (Theobroma cacao L.) agroforestry systems (AFSs). Two shaded cacao systems and an adjacent natural forest in reddish-yellow Oxisols in Bahia, Brazil were selected. Soil samples were collected from four depth classes to 1 m depth and separated by wet-sieving into three fraction-size classes (>250 μm, 250–53 μm, and <53 μm)—corresponding to macroaggregate, microaggregate, and silt-and-clay size fractions—and analyzed for C content. The total SOC stock did not vary among systems (mean: 302 Mg/ha). On average, 72% of SOC was in macroaggregate-size, 20% in microaggregate-size, and 8% in silt-and-clay size fractions in soil. Sonication of aggregates showed that occlusion of C in soil aggregates could be a major mechanism of C protection in these soils. Considering the low level of soil disturbances in cacao AFSs, the C contained in the macroaggregate fraction might become stabilized in the soil. The study shows the role of cacao AFSs in mitigating greenhouse gas (GHG) emission through accumulation and retention of high amounts of organic C in the soils and suggests the potential benefit of this environmental service to the nearly 6 million cacao farmers worldwide.     

Analytical Solutions to the Linearized Boussinesq Equation for Assessing the Effects of Recharge on Aquifer Discharge1

Boggs, Kevin G., Robert W. Van Kirk, Gary S. Johnson, Jerry P. Fairley, and P. Steve Porter, 2010. Analytical Solutions to the Linearized Boussinesq Equation for Assessing the Effects of Recharge on Aquifer Discharge. Journal of the American Water Resources Association (JAWRA) 46(6):1116–1132. DOI: 10.1111/j.1752-1688.2010.00479.x Abstract: There is a need to develop a general understanding of how variations in aquifer recharge are reflected in discharge. Analytical solutions to the linearized Boussinesq equation governing flow in an unconfined aquifer provide a unified mathematical framework to quantify relationships among lag time, attenuation and distance between aquifer recharge and discharge and the effect of an up-gradient no-flow boundary. We applied this framework to three types of recharge: (1) instantaneous, (2) periodic, and (3) constant rate for a finite duration. When the temporal scale of recharge exceeds the diffusive aquifer time scale, recharge will be reflected in discharge quickly and with little attenuation. When aquifer time scale is large, most recharge events are shorter in scale than that of the aquifer, resulting in large attenuation. Attenuation is more sensitive to boundary effects than lag time, and boundary effects increase as recharge time scale increases. Boundary effects can often be ignored when the recharge source is farther than 1/3 of the domain length away from the no-flow boundary. We illustrate analytical results with application to the economically critical Eastern Snake River Plain Aquifer in Idaho. In this aquifer, detectable annual and decadal cycles in discharge can result from recharge no farther than 20 and 60 km away from the discharge point, respectively. The effects of more distant, long-term recharge can be detected only after a time lag of several decades.     

Oxygen distribution and potential ammonia oxidation in floating, liquid manure crusts

Floating, organic crusts on liquid manure, stored as a result of animal production, reduce emission of ammonia (NH3) and other volatile compounds during storage. The occurrence of NO2- and NO3- in the crusts indicate the presence of actively metabolizing NH3-oxidizing bacteria (AOB) which may be partly responsible for this mitigation effect. Six manure tanks with organic covers (straw and natural) were surveyed to investigate the prevalence and potential activity ofAOB and its dependence on the O2 availability in the crust matrix as studied by electrochemical profiling. Oxygen penetration varied from <1 mm in young, poorly developed natural crusts and old straw crusts, to several centimeters in the old natural crusts. The AOB were ubiquitously present in all crusts investigated, but nitrifying activity could only be detected in old natural crusts and young straw crust with high O2 availability. In old natural crusts, total potential NH3 oxidation rates were similar to reported fluxes of NH3 from slurry without surface crust. These results indicate that old, natural surface crusts may develop into a porous matrix with high O2 availability that harbors an active population of aerobic microorganisms, including AOB. The microbial activity may thus contribute to a considerable reduction of ammonia emissions from slurry tanks with well-developed crusts.