The development of alum rates to enhance the remediation of phosphorus in fluvial systems following manure spills

Following the remediation of animal manure spills that reach surface waters, contaminated streambed sediments are often left in place and become a source for internal phosphorus (P) loading within the stream in subsequent flow. The objective of this study was to develop treatment rates and combinations of alum and CaCO(3) to mitigate P from contaminated sediments of different particle size distributions following a manure spill. Sediment specific alum and CaCO(3) treatment rates were developed based upon the resultant alum treatment ranges established for each sediment type. Clay loam sediments required 54% more alum to mitigate P desorption relative to sediments that contain at least 60% sand. Amending sediments with the highest rates of alum/alum + CaCO(3), resulted in a 98-100% reduction in P desorption and a similar water column pH for all sediments types. Observations from this study demonstrated the effectiveness of alum/alum + CaCO(3) to increase P retention in sediments following a manure spill.     

The biodiversity challenge: Expanded hot-spots analysis

Summary This paper aims to throw light on the mass extinction that is overtaking Earth's species. Using an analytic methodology developed for an earlier partial assessment, it focuses on a series of hot-spot areas, these being areas that (a) feature exceptional concentrations of species with high levels of endemism, and (b) face exceptional threats of destruction. The paper identifies another eight such areas, four of them in tropical forests and four in Mediterranean-type zones. The analysis reveals that the four tropical-forest areas contain at least 2,835 endemic plant species in 18,700 km², or 1.1 percent of Earth's plant species in 0.013 percent of Earth's land surface; and that the four Mediterranean-type areas contain 12,720 endemic plan: species in 435,700 km², or 5.1 percent of Earth's plant species in 0.3 percent of the Earth's land surface. Taken together, these eight hot-spot areas contain 15,555 endemic plant species in 454,400 km², or 6.2 percent of Earth's plant species in 0.3 percent of Earth's land surface. This is to be compared with the earlier hot-spots analysis of 10 tropical-forest areas, with 34,400 endemic plant species in 292,000 km², or 13.8 percent of Earth's plant species in 0.2 percent of Earth's land surface.Taking all 18 hot-spot areas together, we find they support 49,955 endemic plant species, or 20 percent of Earth's plant species, in 746,400 km², or 0.5 percent of Earth's land surface. This means that one fifth of Earth's plant species are confined to half of one percent of the Earth's land surface — and they occur in habitats that are mostly threatened with imminent destruction.By concentrating on these hot-spot areas where needs are greatest and where the pay-off from safeguard measures would be greatest, conservationists can engage in a more systematised response to the challenge of large scale impending extinctions.Dr Norman Myers is a consultant in environment and development, a member of this journal's Advisory Board, and a regular contributor to the journal. He is a Senior Fellow of World Wildlife Fund — US. This paper enlarges on an important theme developed by Dr Myers in a contribution which appeared inThe Environmentalist,8(3), 187–208. The research for this paper has been supported by the MacArthur Foundation, Chicago, USA.     

Incorporating behaviour into simple models of dispersal using the biological control agent Dicyphus hesperus

We explored the utility of incorporating easily measured, biologically realistic movement rules into simple models of dispersal. We depart from traditional random walk models by designing an individual-based simulation model where we decompose animal movement into three separate processes: emigration, between-patch movement, and immigration behaviour. These processes were quantified using experiments on the omnivorous insect Dicyphus hesperus moving through a tomato greenhouse. We compare the predictions of the individual-based model, along with a series of biased random walk models, against an independent experimental release of D. hesperus. We find that in this system, the short-term dispersal of these insects is described well by our individual-based model, but can also be described by a 2D grid-based biased random walk model when mortality is accounted for.     

Simulated Impacts of Three Decadal Climate Variability Phenomena on Water Yields in the Missouri River Basin1

Mehta, Vikram M., Norman J. Rosenberg, and Katherin Mendoza, 2011. Simulated Impacts of Three Decadal Climate Variability Phenomena on Water Yields in the Missouri River Basin. Journal of the American Water Resources Association (JAWRA) 47(1):126‐135. DOI: 10.1111/j.1752‐1688.2010.00496.x Abstract: The Missouri River Basin (MRB) is the largest river basin in the United States (U.S.), and is one of the most important crop and livestock‐producing regions in the world. In a previous study of associations between decadal climate variability (DCV) phenomena and hydro‐meteorological (HM) variability in the MRB, it was found that positive and negative phases of the Pacific Decadal Oscillation (PDO), the tropical Atlantic sea‐surface temperature gradient variability (TAG), and the west Pacific warm pool (WPWP) temperature variability were significantly associated with decadal variability in precipitation and 2‐meter air temperature in the MRB, with combinations of various phases of these DCV phenomena associated with drought, flood, or neutral HM conditions. Here, we report on a methodology developed and applied to assess whether the aforementioned DCVs directly affect the hydrology of the MRB. The Hydrologic Unit Model of the U.S. (HUMUS) was used to simulate water yields in response to realistic values of the PDO, TAG, and WPWP at 75 widely distributed, eight‐digit hydrologic unit areas within the MRB. HUMUS driven by HM anomalies in both the positive and negative phases of the PDO and TAG resulted in major impacts on water yields, as much as ±20% of average water yield in some locations. Impacts of the WPWP were smaller. The combined and cumulative effects of these DCV phenomena on the MRB HM and water availability can be dramatic with important consequences for the MRB.     

Removing color and chlorinated organics from pulp mill bleach plant effluents by use of flyash

Color and chemical oxygen demand (COD) in bleach plant effluents are of concern. Acidified flyash can effectively remove both color and COD from caustic bleach plant effluents. Equally effective, but quicker and easier, is to acidify the effluent to approximately pH 1 and use untreated flyash. Based on maximum color removal, the required contact time is short, about 10 min, and the optimum ash dosage is that amount which raises the pH of the final effluent to about 5. Sufficient color removal is obtained to easily meet Maine's color regulations. Preliminary tests on samples of deionized water spiked with two arochlors of PCB showed high removal efficiency.The major cost of implementing and operating the cleanup procedure will be the cost of the required acid. This might be minimized by using some of the acidic (chlorine) effluent to lower the pH of the caustic effluent. This will, however, lead to less color reduction, and an unknown effect on the COD.