Controls on coarse wood decay in temperate tree species: birth of the LOGLIFE experiment

Dead wood provides a huge terrestrial carbon stock and a habitat to wide-ranging organisms during its decay. Our brief review highlights that, in order to understand environmental change impacts on these functions, we need to quantify the contributions of different interacting biotic and abiotic drivers to wood decomposition. LOGLIFE is a new long-term 'common-garden' experiment to disentangle the effects of species' wood traits and site-related environmental drivers on wood decomposition dynamics and its associated diversity of microbial and invertebrate communities. This experiment is firmly rooted in pioneering experiments under the directorship of Terry Callaghan at Abisko Research Station, Sweden. LOGLIFE features two contrasting forest sites in the Netherlands, each hosting a similar set of coarse logs and branches of 10 tree species. LOGLIFE welcomes other researchers to test further questions concerning coarse wood decay that will also help to optimise forest management in view of carbon sequestration and biodiversity conservation.     

Cytogenetic analysis of 1375 amniotic fluid specimens from pregnancies with gestational age less than 14 weeks

Our laboratory has received 1375 early amniotic fluid (EA) specimens during the past 5-year period for cytogenetics analysis. The gestational ages of the EA specimens were less than 14 weeks as estimated by ultrasound. The average volume of specimen received was 16 ml. Specimens were typically received in two collection tubes and cultured in Chang A and in supplemented MEM media using the in situ technique. Of the 1375 EA specimens received, 1356 were successfully cultured and yielded results. Abnormal results were found in 67 (4.9 per cent) of the cases. Nineteen specimens (1.4 per cent) failed to yield a result. The mean turn-around time (TAT) for all EA specimens was 8.28 days. In 1991, the average TAT for the EA specimens was 8.00 days compared with a TAT of 6.59 days for all specimens received over 14 weeks gestational age. The number of EA specimens received has increased from 1.5 per month in 1986 to 57 per month in 1991. In summary, our experience with EA specimens for cytogenetic analysis has demonstrated that the success rate is 98.6 per cent and that an increasing number of obstetricians are performing early amniocentesis as they seek to provide their patients with earlier results and an alternative to chorionic villus sampling.     

A review of the health impacts of barium from natural and anthropogenic exposure

There is an increasing public awareness of the relatively new and expanded industrial barium uses which are potential sources of human exposure (e.g., a shale gas development that causes an increased awareness of environmental exposures to barium). However, absorption of barium in exposed humans and a full spectrum of its health effects, especially among chronically exposed to moderate and low doses of barium populations, remain unclear. We suggest a systematic literature review (from 1875 to 2014) on environmental distribution of barium, its bioaccumulation, and potential and proven health impacts (in animal models and humans) to provide the information that can be used for optimization of future experimental and epidemiological studies and developing of mitigative and preventive strategies to minimize negative health effects in exposed populations. The potential health effects of barium exposure are largely based on animal studies, while epidemiological data for humans, specifically for chronic low-level exposures, are sparse. The reported health effects include cardiovascular and kidney diseases, metabolic, neurological, and mental disorders. Age, race, dietary patterns, behavioral risks (e.g., smoking), use of medications (those that interfere with absorbed barium in human organism), and specific physiological status (e.g., pregnancy) can modify barium effects on human health. Identifying, evaluating, and predicting the health effects of chronic low-level and moderate-level barium exposures in humans is challenging: Future research is needed to develop an understanding of barium bioaccumulation in order to mitigate its potential health impacts in various exposured populations. Further, while occupationally exposed at-risk populations exist, it is also important to identify potentially vulnerable subgroups among non-occupationally exposed populations (e.g., elderly, pregnant women, children) who are at higher risk of barium exposure from drinking water and food.     

Diel vertical movements of adult male dolphinfish (Coryphaena hippurus) in the western central Atlantic as determined by use of pop-up satellite archival transmitters

The vertical movements of six adult male dolphinfish (Coryphaena hippurus) (95–120 cm estimated fork length), caught using standard sportfishing methods, were investigated using high-rate single-point pop-up satellite archival transmitters from 2005 to 2011 in the western central Atlantic. Data revealed a diel activity pattern within the mixed surface layer with dives below the thermocline suggesting temperature is not a barrier to vertical movements for short periods of time. Dolphinfish were tracked for periods of 4.96–30.24 day (Σ = 83.37 day), reaching depths >200 m, and in temperatures ranging from 16.20 to 30.87 °C. The six tags allowed comprehensive vertical movement analyses by time of day, duration at depth, and based on vertical movement patterns. The longest (>60 min), deepest (>30 m), and most extensive vertical movement patterns occurred during night rather than day, with the most time spent near the surface during the day. Dolphinfish spent 66 % of their time in the surface layer (0–9.9 m) and only one individual spent 8 % of the monitoring period diving >8 °C from the maximum surface temperatures recorded while tracked. Two tags were analyzed based on lunar phase and revealed contrasting relationships between vertical movements during new and full phases. Our results suggest dolphinfish vertically shift between surface and at-depth feeding strategies to exploit aggregating epipelagic and mesopelagic prey items leading to predictable diel vertical movements.     

Cytoskeletal elements in the bacterium Mycoplasma pneumoniae

Mycoplasma pneumoniae is a pathogenic eubacterium lacking a cell wall. Three decades ago, a "rod", an intracellular cytoskeletal structure, was discovered that was assumed to define and stabilize the elongated cell shape. Later, by treatment with detergent, a "Triton shell" (i.e. a fraction of detergent-insoluble cell material) could be obtained, believed to contain additional cytoskeletal elements. Now, by application of a modified Triton X-100 treatment, we are able to demonstrate that M. pneumoniae possesses a cytoskeleton consisting of a blade-like rod and a peripheral lining located close to the inner face of the cytoplasmic membrane, exhibiting features of a highly regular network. Attached "stalks" may support the cytoplasmic membrane. The rod was connected to the cell periphery by "spokes" and showed a defined ultrastructure. Its proximal end was found to be attached to a wheel-like complex. Fibrils extended from the proximal end of the rod into the cytoplasm.     

Quantifying water savings from willow removal in Australian streams

Willows (Salix Spp.), while not endemic to Australia, form dense stands in many stream locations. Australia has been experiencing a long-term drought and potential water extraction by willows is considered a significant problem, although little global scientific evidence exists to support such concerns. The extent of willow occupation in Australian streams has been deemed large enough to warrant investigation of their evapotranspiration rates and quantification of potential water savings from willow removal. Willows situated in-stream (permanent water) and on stream banks (semi-permanent water) were monitored over three summers from August 2005 to May 2008 employing heat pulse velocity sap flux sensors and field measurement of water balance components. A comparative study of native riparian River Red Gum trees was also undertaken. Differences in transpiration flux rates between willows with permanent and semi-permanent access to water were substantial, with peak transpiration of 15.2 mm day(-1) and 2.3 mm day(-1) respectively. Water balance calculations over the three year period indicate that an average potential net water saving of 5.5 ML year(-1)ha(-1) of crown projected area is achievable by removal of in-stream willows with permanent access to water. On stream banks, replacement of willows with native riparian vegetation will have no net impact on site water balances. Results also indicate that under the influence of natural environmental events such as drought, heat stress and willow sawfly infestation, evapotranspiration rates from in-stream willows remain greater than that from open water. These results will have important implications in environmental management of willows and in future water resource allocation and planning in Australia.     

Physical, chemical, and mineralogical characteristics of a reservoir sediment delta (Lake Powell, U.S.A.) and implications for water quality during low water level

Lake Powell is a large reservoir in Utah and Arizona that has experienced large changes in water level during a recent drought. As a first step in assessing the connection between hydrologic and chemical changes at Lake Powell, we characterized the particle size and solid-phase bulk concentrations for 31 elements and 25 minerals in sediment from the inflow region and some shoreline locations by using laser diffractometry, X-ray fluorescence, elemental analysis, and X-ray diffraction Our results are consistent with previous results that show a negative correlation between particle size and concentrations of most elements and most minerals other than quartz and some feldspars. In our samples, however, solid-phase iron, rather than particle size or organic carbon, is the best predictor variable for the solid-phase concentrations of elements and minerals. Sediment characteristics vary on a scale of tens of kilometers, with fine sediment that is enriched in trace elementsnearer to the dam. These trends allow formulation of an algorithm for determining a water-level threshold below which sediment resuspension may alter water chemistry in a generic reservoir with a long and narrow sediment delta.     

Effects of watershed configuration and composition on downstream lake water quality

We evaluated the relationships between landscape characteristics and lake water quality in receiving waters by regressing four water quality responses on landscape variables that were measured for whole watersheds and three different buffer distances (30, 60, and 120 m). Classical percolation theory was used to conceptualize nutrient pathways and to explain nonlinear responses. The response variables were total nitrogen (TN), total phosphorus (TP), chlorophyll-a (Chl-a), and Secchi transparency (SD). Landscape data were obtained from satellite image-derived maps of 130 watersheds in Iowa using geographic information systems software. We developed regression models with a stepwise protocol selecting the optimal number of significant explanatory variables. Configuration variables such as contagion, the cohesion of cropland and urban land, and the aggregation index of forest were very important and more important than variables assessing landscape composition (e.g., percentage farmland). Whole watershed models predicted between 15 and 67% of the variability in TN, TP, Chl-a, and SD. Proximity-explicit data offered only slightly improved statistical power over land cover data derived from the entire watershed for variables TN, Chl-a. and SD, but not for TP.     

Effect of uranium(VI) speciation on simultaneous microbial reduction of uranium(VI) and iron(III)

Uranium is a pollutant of concern to both human and ecosystem health. Uranium's redox state often dictates whether it will reside in the aqueous or solid phase and thus plays an integral role in the mobility of uranium within the environment. In anaerobic environments, the more oxidized and mobile form of uranium (UO2(2+) and associated species) may be reduced, directly or indirectly, by microorganisms to U(IV) with subsequent precipitation of UO. However, various factors within soils and sediments, such as U(VI) speciation and the presence of competitive electron acceptors, may limit biological reduction of U(VI). Here we examine simultaneous dissimilatory reduction of Fe(III) and U(VI) in batch systems containing dissolved uranyl acetate and ferrihydrite-coated sand. Varying amounts of calcium were added to induce changes in aqueous U(VI) speciation. The amount of uranium removed from solution during 100 h of incubation with S. putrefaciens was 77% in absence of Ca or ferrihydrite, but only 24% (with ferrihydrite) and 14% (without ferrihydrite) were removed for systems with 0.8 mM Ca. Dissimilatory reduction of Fe(III) and U(VI) proceed through different enzyme pathways within one type of organism. We quantified the rate coefficients for simultaneous dissimilatory reduction of Fe(III) and U(VI) in systems varying in Ca concecentration (0-0.8 mM). The mathematical construct, implemented with the reactive transport code MIN3P, reveals predominant factors controlling rates and extent of uranium reduction in complex geochemical systems.     

Worst case scenario study to assess the environmental impact of amine emissions from a CO2 capture plant

Use of amines is one of the leading technologies for post-combustion carbon dioxide capture from gas and coal-fired power plants. This study assesses the potential environmental impact of emissions to air that result from use of monoethanol amine (MEA) as an absorption solvent for the capture of carbon dioxide (CO₂). Depending on operation conditions and installed reduction technology, emissions of MEA to the air due to solvent volatility losses are expected to be in the range of 0.01–0.8 kg/tonne CO₂ captured. Literature data for human and environmental toxicity, together with atmospheric dispersion model calculations, were used to derive maximum tolerable emissions of amines from CO₂ capture. To reflect operating conditions with typical and with elevated emissions, we defined a scenario MEA-LOW, with emissions of 40 t/year MEA and 5 t/year diethyl amine (DEYA), and a scenario MEA-HIGH, with emissions of 80 t/year MEA and 15 t/year DEYA. Maximum MEA deposition fluxes would exceed toxicity limits for aquatic organisms by about a factor of 3–7 depending on the scenario. Due to the formation of nitrosamines and nitramines, the estimated emissions of DEYA are close to or exceed safety limits for drinking water and aquatic ecosystems. The “worst case” scenario approach to determine maximum tolerable emissions of MEA and other amines is in particular useful when both expected environmental loads and the toxic effects are associated with high uncertainties.