Seeing the forest not for the carbon: why concentrating on land-use-induced carbon stock changes of soils in Brazil can be climate-unfriendly

Regional Environmental Change - Soil carbon stocks of 29 plots along a transect through tropical Brazil showed only minor soil carbon losses after land use shift, although replacement of...     

Assessing the ecological effects of human impacts on coral reefs in Bocas del Toro,Panama

Environmental and biological reef monitoring was conducted in Almirante Bay (Bahía Almirante) in Bocas del Toro, Panama, to assess impacts from anthropogenic developments. An integrated monitoring investigated how seasonal temperature stress, turbidity, eutrophication and physical impacts threatened reef health and biodiversity throughout the region. Environmental parameters such as total suspended solids [TSS], carbon isotopes (δ¹³C), C/N ratios, chlorophyll a, irradiance, secchi depth, size fractions of the sediments and isotope composition of dissolved inorganic carbon [DIC] of the water were measured throughout the years 2010 and 2011 and were analysed in order to identify different impact sources. Compared to data from Collin et al. (Smithsonian Contributions to the Marine Sciences 38:324–334, 2009) chlorophyll a has doubled at sites close to the city and the port Almirante (from 0.46–0.49 to 0.78–0.97 μg l^?1) and suspension load increased, visible by a decrease in secchi depth values. Visibility decreased from 9-13 m down to 4 m at the bay inlet Boca del Drago, which is strongly exposed to river run off and dredging for the shipping traffic. Eutrophication and turbidity levels seemed to be the determining factor for the loss of hard coral diversity, most significant at chlorophyll a levels higher than 0.5 μg l^?1 and TSS levels higher than 4.7 mg l^?1. Hard coral cover within the bay has also declined, at some sites down to <10 % with extremely low diversities (7 hard coral species). The hard coral species Porites furcata dominated the reefs in highly impacted areas and showed a strong recovery after bleaching and a higher tolerance to turbidity and eutrophication compared to other hard coral species in the bay. Serious overfishing was detected in the region by a lack of adult and carnivorous fish species, such as grunts, snappers and groupers. Study sites less impacted by anthropogenic activities and/or those with local protection showed a higher hard coral cover and fish abundance; however, an overall loss of hard coral diversity was observed.     

WRF-Chem simulation of East Asian air quality: Sensitivity to temporal and vertical emissions distributions

This study develops fine temporal (seasonal, day-of-week, diurnal) and vertical allocations of anthropogenic emissions for the TRACE-P inventory and evaluates their impacts on the East Asian air quality prediction using WRF-Chem simulations in July 2001 at 30-km grid spacing against available surface measurements from EANET and NEMCC. For NO₂ and SO₂, the diurnal and vertical redistributions of emissions play essential roles, while the day-of-week variation is less important. When all incorporated, WRF-Chem best simulates observations of surface NO₂ and SO₂ concentrations, while using the default emissions produces the worst result. The sensitivity is especially large over major cities and industrial areas, where surface NO₂ and SO₂ concentrations are reduced by respectively 3–7 and 6–12 ppbv when using the scaled emissions. The incorporation of all the three redistributions of emissions simulates surface O₃ concentrations higher by 4–8 ppbv at night and 2–4 ppbv in daytime over broad areas of northern, eastern and central China. To this sensitivity, the diurnal redistribution contributes more than the other two.     

Dealing with disjunct concentration measurements in eddy covariance applications: A comparison of available approaches

Using proton transfer reaction mass spectrometry equipped with a quadrupol mass analyser to quantify the biosphere-atmosphere exchange of volatile organic compounds (VOC), concentrations of different VOC are measured sequentially. Depending on how many VOC species are targeted and their respective integration times, each VOC is measured at repeat rates on the order of a few seconds. This represents an order of magnitude longer sample interval compared to the standard eddy covariance (EC) method (5–20 Hz sampling rates). Here we simulate the effect of disjunct sampling on EC flux estimates by decreasing the time resolution of CO₂ and H₂O concentrations measured at 20 Hz above a temperate mountain grassland in the Austrian Alps. Fluxes for one month are calculated with the standard EC method and compared to fluxes calculated based on the disjunct data (1, 3 and 5 s sampling rates) using the following approaches: i) imputation of missing concentrations based on the nearest neighbouring samples (iDEC_nn), ii) imputation by linear interpolation (iDEC_li), and iii) virtual disjunct EC (vDEC), i.e. flux calculation based solely on the disjunct concentrations. It is shown that the two imputation methods result in additional low-pass filtering, longer lag times (as determined with the maximum cross-correlation method) and a flux loss of 3–30% as compared to the standard EC method. A novel procedure, based on a transfer function approach, which specifically corrects for the effect of data treatment, was developed, resulting in improved correspondence (to within 2%). The vDEC method yields fluxes which approximate the true (20 Hz) fluxes to within 3–7% and it is this approach we recommend because it involves no additional empirical corrections. The only drawback of the vDEC method is the noisy nature of the cross-correlations, which poses problems with lag determination – practical approaches to overcome this limitation are discussed.     

Hands on explosives: Safety testing of protective measures

Several attempts have been made to test the suitability of protective measures for the handling of explosives. We investigated the suitability of safety gloves and a combined safety helmet and face shield. In the presented studies, three different experimental setups were used to simulate the effects of an explosion of a primary explosive in a glass flask on the glove or helmet protected body. Depending on the experimental setup, the fragment effects were evaluated and compared. Furthermore, the fragment distribution of an explosion inside a glass flask was investigated. The explosion of 1 g of lead azide in a 10 mL flask yielded approximately 14,000 glass fragments. However, most of the shards were accelerated down- and side-wards and only few upwards. Holding a flask on its neck (instead of its bottom) is therefore a simple but effective way of diminishing the risk of injury, when handling explosives. The safety helmet/face shield performed very well, by shielding the face from all fragments. Furthermore, it could be proven that DIN and EN standard testing procedures for gloves are unsuitable to simulate the effects of a respective explosion.In this article, the progress in the development of realistic testing procedures for the testing of gloves for the protection against fragmentation effects of glassware in situations involving explosions is reported and the results and methods of previous tests are summarized.     

A Cyclone for Size-Selective Sampling of Ambient Air

A cyclone with a 47 mm after-filter has been developed for ambient air size-selective monitoring. It has been extensively evaluated with laboratory-generated aerosol. Variation of the pressure drop and 50% cut point with flow rate show that the cyclone operates in a single flow regime with a vortex in the outlet flow. The particle size cutoff curve is comparable in sharpness to a cascade impactor and is the same for solid or liquid particles. At 21.7 L/min, D ₅₀ is 2.5μm and at 15.4 L/min, D ₅₀ is 3.5 μm. Collection efficiency data for flow rates from 8 to 27 L/min fit a universal curve when plotted vs. the normalized particle diameter, (D-D ₅₀)/D ₅₀ Reentrainment of previously deposited particles is less than 1 % of the loading per day. In field tests the cyclone has proved to be a very satisfactory size-selective sampler.     

The BIOTA Biodiversity Observatories in Africa—a standardized framework for large-scale environmental monitoring

The international, interdisciplinary biodiversity research project BIOTA AFRICA initiated a standardized biodiversity monitoring network along climatic gradients across the African continent. Due to an identified lack of adequate monitoring designs, BIOTA AFRICA developed and implemented the standardized BIOTA Biodiversity Observatories, that meet the following criteria (a) enable long-term monitoring of biodiversity, potential driving factors, and relevant indicators with adequate spatial and temporal resolution, (b) facilitate comparability of data generated within different ecosystems, (c) allow integration of many disciplines, (d) allow spatial up-scaling, and (e) be applicable within a network approach. A BIOTA Observatory encompasses an area of 1?km² and is subdivided into 100 1-ha plots. For meeting the needs of sampling of different organism groups, the hectare plot is again subdivided into standardized subplots, whose sizes follow a geometric series. To allow for different sampling intensities but at the same time to characterize the whole square kilometer, the number of hectare plots to be sampled depends on the requirements of the respective discipline. A hierarchical ranking of the hectare plots ensures that all disciplines monitor as many hectare plots jointly as possible. The BIOTA Observatory design assures repeated, multidisciplinary standardized inventories of biodiversity and its environmental drivers, including options for spatial up- and downscaling and different sampling intensities. BIOTA Observatories have been installed along climatic and landscape gradients in Morocco, West Africa, and southern Africa. In regions with varying land use, several BIOTA Observatories are situated close to each other to analyze management effects.     

Integral assessment of estrogenic potentials in sediment-associated samples

Background, aim, and scope  The enzyme-linked receptor assay (ELRA) detects estrogenic and anti-estrogenic effects at the molecular level of receptor binding and is a useful tool for the integrative assessment of ecotoxicological potentials caused by hormonally active agents (HAA) and endocrine disrupting compounds (EDC). The main advantage of the ELRA is its high sample throughput and its robustness against cytotoxicity and microbial contamination. After a methodological adaptation to salinity of the ELRA, according to the first part of this study, which increased its salinity tolerance and sensitivity for 17-β-estradiol, the optimised ELRA was used to investigate 13 native sediments characterised by different levels of salinity and chemical contamination. The applicability of the ELRA for routine analysis in environmental assessment was evaluated. Salinity is often a critical factor for bioassays in ecotoxicological sediment assessment. Therefore, salinity of the samples was additionally adjusted to different levels to characterise its influence on elution and binding processes of receptor-binding substances. Materials and methods  The ELRA was carried out with the human estrogen receptor α (ER) in a 96-well microplate format using the experimental setup known from the competitive immunoassay based on ligand–protein interaction. It is an important improvement that a physiologically relevant receptor was used as a linking protein instead of an antibody. The microplates were coated with a 17-β-estradiol-BSA conjugate, and dilution series of estradiol and of native sediment samples were added and incubated with the ER. After a washing step, a biotinylated mouse anti-ER antibody was added to each well. Receptor binding to estradiol, agonistic and antagonistic receptor binding, were determined by a streptavidin-POD-biotin complex with subsequent measurement of the peroxidase activity at the wavelength of 450 nm using a commercial ELISA multiplate reader. The sediment elutriates and pore water samples of sediments were tested in a dilution series to evaluate at which dilution step the receptor-binding potential ends. In the elution process (see Section 2.1 to 2.2), a method was developed to adjust the salinity to the levels of the reference testings, which offers an appropriate option to adjust the salinity in both directions. Statistical evaluation was made with a combination of the Mann–Whitney U test and the pT-method. Results  This part of the study characterised the environmental factor ‘salinity’ for prospective applications of the ELRA. Using reference substances such as 17-β-estradiol, the ELRA showed sigmoid concentration-effect relations over a broad range from 0.05 μg/l to 100 μg/l under physiological conditions. After methodological optimisation, both sensitivity and tolerance of the assay against salinity could be significantly raised, and the ELRA became applicable under salinity conditions up to concentrations of 20.5‰. The mean relative inter-test error (n = 3) was around 11% with reference substances and below 5% for single sediments elutriates in three replicates each. For sediment testings, the pore water and different salinity-adjusted elutriates of 13 sediments were used. A clear differentiation of the receptor-binding potential could be reached by application of the pT-method. Thereby, pT-values from one to six could be assigned to the sediments, and the deviation caused by the different salinity conditions was one pT-value. The mean standard deviation in the salinity adaptation procedure of the elutriates was below 5%. Discussion  Although the ELRA has already been used for assessments of wastewater, sludge and soil, its applicability for samples to different salinity levels has not been investigated so far. Even if the ELRA is not as sensitive as the E-screen or the YES-assay, with regard to reference substances like 17-β-estradiol, it is a very useful tool for pre-screening, because it is able to integrate both estrogenic as well as anti-estrogenic receptor-binding effects. According to the results of sediment testing, and given the integrative power to detect different directions of effects, the ELRA shows sufficient sensitivity and salinity tolerance to discriminate receptor-binding potentials in environmental samples. Conclusions  The optimised ELRA assay is a fast, cost-effective, reliable and highly reproducible tool that can be used for high-throughput screening in a microplate format in detecting both estrogenic and anti-estrogenic effects. Additionally, the ELRA is robust against microbial contaminations, and is not susceptible towards cytotoxic interferences like the common cell-culture methods. The general applicability and sufficient sensitivity of the ELRA was shown in freshwater environments. Marine and brackish samples can be measured up to salinity levels of 20.5‰. Recommendations and perspectives  In view of the proven sensitivity, functionality and the fastness of the ELRA, it is recommendable to standardise the test method. At the moment, no adequate in vitro test procedure exists which is standardised to DIN or ISO levels. The E-screen and the yeast estrogen/androgen screens (YES/YAS) sometimes underlie strong cytotoxic effects, as reported in the first part of this study. Further development of an ELRA assay using human androgen receptors appears to be very promising to gain information about androgenic and anti-androgenic effects, too. This would offer a possibility to use the ELRA as a fast and reliable pre-screening tool for the detection of endocrine potentials, thus minimising time and cost-expensive animal experiments.