High resolution proton NMR spectroscopy of human amniotic fluid

Human amniotic fluid (HAF) is a dynamic system whose characteristics depend on continuous interchanges between fetal and maternal circulations. HAF reflects not only the environment of the fetus but may also provide information about fetal development or pathology. The concentration of HAF constituents varies with gestational age and pathological states. The number of the compounds currently implicated in fetal developmental pathology are relatively few. Currently used assay methods are not adequate to totally explain or predict the complex biochemistry of the fetus. The purpose of this work was to investigate HAF with NMR spectroscopy. In the present study HAF was obtained from 47 women undergoing routine amniocentesis. Cells were separated for karyological analysis and the supernatant was acid-extracted, lyophilized and re-suspended in D₂0 resulting in a concentration increase over native fluid. ¹H NMR spectra were obtained at 360 MHz and 60 MHz. Eighteen compounds including several amino acids, were identified using parallel reference and standard addition protocols. NMR spectroscopy detected compounds of known clinical importance including glucose, leucine, isoleucine, lactate and creatinine. In conclusion, we have demonstrated that a number of physiologically relevant compounds are readily observable in HAF using ¹H NMR spectroscopy. This technique can currently provide valuable information regarding HAF composition and has the potential of being used in vivo in the future.     

Effects of turbidity on calcification rate,protein concentration and the free amino acid pool of the coral Acropora cervicornis

Calcification rate in the coral Acropora cervicornis was reduced significantly when exposed for 24 h to 100-ppm kaolin, but was unchanged in corals exposed to 50-ppm kaolin. Calcification rate returned to control levels during a 48-h recovery period. Most free amino acids (FAA) in the FAA pool decreased significantly in corals exposed to 100-ppm kaolin, but were unchanged in corals exposed to 50-ppm kaolin. After a 48-h recovery period, the FAA pool remained considerably below control levels in the 100-ppm exposed corals and dropped below control levels in the 50-ppm exposed corals. Calcification rate dropped less and later during the exposure period in the growing tip than in sections further down the stalk. The reduction in FAA pool size was considerably larger in the growing tip than further down the stalk. Soluble protein concentration remained unchanged during both exposure and recovery. The data are consistent with the interpretation that turbidity not only causes a decrease in photosynthetic rate and the synthesis of small molecules, but also causes a large increase in the utilization of stored organic molecules for such metabolically costly processes as mucus production and sediment removal.     

Enrichment of <Superscript>15</Superscript>N/<Superscript>14</Superscript>N in wastewater-derived effluent varies with operational performance of treatment systems: implications for isotope monitoring in receiving environments

Stable nitrogen isotope ratios are routinely used to trace the dispersion and assimilation of wastewater-derived N in receiving environments, but few isotope studies have investigated wastewater treatment plants and ponds themselves. An improved understanding of N isotope compositions in effluent will help assess treatment plant processes and performance and will help trace sources of excess nutrients in receiving environments. Here, we assess N budgets and treatment processes in seven wastewater treatment plants and wastewater stabilisation ponds in northern Australia based on concentrations and isotope ratios of N in effluent. We show that δ¹⁵N values in effluent are linked to treatment type, effectiveness of conversion of ammonia and levels of gaseous N emissions. These relationships suggest that N isotope monitoring of wastewater treatment plants and ponds can provide an integrated assessment of treatment performance and gaseous N emissions on a pond- or plant-wide scale that is not readily available through other methods. Our findings further imply that monitoring N isotope ratios in receiving environments cannot be assumed to be universally effective as their sensitivity to uptake of wastewater-derived N will vary with the characteristics of individual treatment systems. Paradoxically, N isotope monitoring is less effective where treatment systems are functioning poorly and where monitoring needs are the greatest.     

Visiting a Climate-Influenced National Park: The Stability of Climate Change Perceptions

Understanding perceptions of global environmental issues, such as climate change, can help inform resource management, policy development, and communication with constituents. Although a considerable amount of research documents citizens’ perceptions of climate change, few have investigated how interactions with climate-impacted parks and protected areas influence these perceptions, and consequently elements of environmental management. Using a mixed methods Instrument Development Approach, the researchers examined the stability of park visitors’ (N = 429) climate change perceptions during a daylong interaction with climate-sensitive and influenced resources at Kenai Fjords National Park in Alaska. Results indicate that global-level beliefs about climate change remained relatively stable during a park experience, but perceptions about climate change at the park-level (e.g., impacts) appeared more malleable. Findings also revealed the type of park experience (terrestrial vs. marine) can influence the degree of change in visitors’ perceptions. Implications for communication, outreach, and park management are discussed.     

Effect of humic acid on water chemistry, bioavailability and toxicity of aluminium in the freshwater snail, Lymnaea stagnalis, at neutral pH

The influence of humic acid on the water chemistry of environmentally relevant concentrations of Al at neutral pH was studied, together with its effect on the bioavailability and toxicity of Al in Lymnaea stagnalis. Humic acid significantly reduced the loss of Al from the water and increased the fraction of filterable Al, although this was a relatively small fraction of total Al. Filterable Al concentration in the presence or absence of humic acid was independent of initial Al concentration. Humic acid only partly reduced toxicity, as observed by a reduction in behavioural suppression, and had no effect on the level of Al accumulated in tissues. These results suggest that humic acid maintains Al in a colloidal form that is bioavailable to L. stagnalis. However, these colloidal Al-humic acid species were less toxic since behavioural toxicity was reduced. Humic acid may play an important role in limiting the toxicity of Al to freshwater organisms.     

WATER QUALITY SAMPLING SCHEMES FOR VARIABLE FLOW CANALS AT REMOTE SITES1

ABSTRACT: Growing interest in water quality has resulted in the development of monitoring networks and intensive sampling for various constituents. Common purposes are regulatory, source and sink understanding, and trend observations. Water quality monitoring involves monitoring system design; sampling site instrumentation; and sampling, analysis, quality control, and assurance. Sampling is a process to gather information with the least cost and least error. Various water quality sampling schemes have been applied for different sampling objectives and time frames. In this study, a flow proportional composite sampling scheme is applied to variable flow remote canals where the flow rate is not known a priori. In this scheme, historical weekly flow data are analyzed to develop high flow and low flow sampling trigger volumes for auto‐samplers. The median flow is used to estimate low flow sampling trigger volume and the five percent exceedence probability flow is used for high flow sampling trigger volume. A computer simulation of high resolution sampling is used to demonstrate the comparative bias in load estimation and operational cost among four sampling schemes. Weekly flow proportional composite auto‐sampling resulted in the least bias in load estimation with competitive operational cost compared to daily grab, weekly grab sampling and time proportional auto‐sampling.     

Estimated effects of climate change on flood vulnerability of U.S. bridges

We assessed the potential impacts of increased river flooding from climate change on bridges in the continental United States. Daily precipitation statistics from four climate models and three greenhouse gas (GHG) emissions scenarios (A2, A1B, and B1) were used to capture a range of potential changes in climate. Using changes in maximum daily precipitation, we estimated changes to the peak flow rates for the 100-year return period for 2,097 watersheds. These estimates were then combined with information from the National Bridge Inventory database to estimate changes to bridge scour vulnerability. The results indicate that there may be significant potential risks to bridges in the United States from increased precipitation intensities. Approximately 129,000 bridges were found to be currently deficient. Tens of thousands to more than 100,000 bridges could be vulnerable to increased river flows. Results by region vary considerably. In general, more bridges in eastern areas are vulnerable than those in western areas. The highest GHG emissions scenarios result in the largest number of bridges being at risk. The costs of adapting vulnerable bridges to avoid increased damage associated with climate change vary from approximately $140 to $250 billion through the 21st century. If these costs were spread out evenly over the century, the annual costs would be several billion dollars. The costs of protecting the bridges against climate change risks could be reduced by approximately 30% if existing deficient bridges are improved with riprap.     

Alternative scenarios to meet the demands of sustainable waste management

This paper analyses different alternatives for solid waste management that can be implemented to enable the targets required by the European Landfill and Packaging and Packaging Waste Directives to be achieved in the Valencian Community, on the east coast of Spain. The methodology applied to evaluate the environmental performance of each alternative is Life Cycle Assessment (LCA). The analysis has been performed at two levels; first, the emissions accounted for in the inventory stage have been arranged into impact categories to obtain an indicator for each category; and secondly, the weighting of environmental data to a single unit has been applied. Despite quantitative differences between the results obtained with four alternative impact assessment methods, the same preference ranking has been established: scenarios with energy recovery (1v and 2v) achieve major improvements compared to baseline, with scenario 1v being better than 2v for all impact assessment methods except for the EPS'00 method, which obtains better results for scenario 2v. Sensitivity analysis has been used to test some of the assumptions used in the initial life cycle inventory model but none have a significant effect on the overall results. As a result, the best alternative to the existing waste management system can be identified.     

Tannin extracts abate ammonia emissions from simulated dairy barn floors

Feeding more tannin and less crude protein (CP) to dairy cows may have synergistic impacts on reducing NH emissions from dairy barns. Three trials using lab-scale ventilated chambers with concrete floors were conducted to determine the impacts on NH emission of tannin and CP feeding, tannin feeding on urease activity in feces, and tannin application directly to the barn floor. For Trial 1, mixtures of feces and urine from lactating Holstein dairy cows () fed four levels (g kg) of dietary tannin extract [a mixture from red quebracho () and chestnut () trees]: 0 tannin (0T), 4.5 (low tannin [LT]), 9.0 (medium tannin [MT]), and 18.0 (high tannin [HT]); each fed at two levels (g kg) of dietary CP: 155 low CP (LCP) and 168 high CP (HCP) were applied to chambers. For Trial 2, urea solution was added to feces obtained from cows fed 0T, MT, and HT at HCP. For Trial 3, tannin amounts equivalent to those fed at 0T, MT, and HT were applied directly to feces-urine mixtures from 0T-HCP. For all trials, NH emissions were measured 1, 3, 6, 12, 24, 36, and 48 h after treatment application. For Trial 1, reductions in NH emission due to tannin feeding were greatest when fed at LCP: The LCP-LT and LCP-HT treatments emitted 30.6% less NH than LCP-0T, and the HCP-LT and HCP-HT treatments emitted 16.3% less NH than HCP-0T. For Trial 2, feeding tannin decreased urease activity in feces, resulting in an 11.5% reduction in cumulative NH loss. For Trial 3, the application of tannin directly to simulated barn floors also apparently decreased urease activity, resulting in an average reduction in cumulative NH emissions of 19.0%. Larger-scale trails are required to ascertain the effectiveness of tannin extracts in abating NH loss from dairy barn floors.     

Exceptionally high levels of multiple mating in an army ant

Most species of social insects have singly mated queens, although there are notable exceptions. Competing hypotheses have been proposed to explain the evolution of high levels of multiple mating, but this issue is far from resolved. Here we use microsatellites to investigate mating frequency in the army ant Eciton burchellii and show that queens mate with an exceptionally large number of males, eclipsing all but one other social insect species for which data are available. In addition we present evidence that suggests that mating is serial, continuing throughout the lifetime of the queen. This is the first demonstration of serial mating among social hymenoptera. We propose that high paternity within colonies is most likely to have evolved to increase genetic diversity and to counter high pathogen and parasite loads.