Spatial contrasts of seasonal and intraflock broiler litter trace gas emissions, physical and chemical properties

Comprehensive mitigation strategies for gaseous emissions from broiler operations requires knowledge of the litters' physical and chemical properties, gas evolution, bird effects, as well as broiler house management and structure. This research estimated broiler litter surface fluxes for ammonia (NH3), nitrous oxide (N2O), and carbon dioxide (CO2). Ancillary measurements of litter temperature, litter total N, ammonium (NH4+), total C content, moisture, and pH were also made. Grid sampling was imposed over the floor area of two commercial broiler houses at the beginning (Day 1), middle (Day 23), and end (Day 43) of a winter and subsequent summer flock housed on reused pine shavings litter. The grid was composed of 36 points, three locations across the width, and 12 locations down the length of the houses. To observe feeder and waterer (F/W) influences on the parameters, eight additional sample locations were added in a crisscross pattern among these automated supply lines. Color variograms illustrate the nature of parameter changes within each flock and between seasons. Overall trends for the NH3, N2O, and CO2 gas fluxes indicate an increase in magnitude with bird age during a flock for both summer and winter, but flux estimates were reduced in areas where compacted litter (i.e., caked litter or cake) formed at the end of the flocks (at F/W locations and in the fan area). End of flock gas fluxes were estimated at 1040 mg NH3 m(-2) h(-1), 20 mg N2O m(-2) h(-1), and 24,200 mg CO2 m(-2) h(-1) in winter; and 843 mg NH3 m(-2) h(-1), 18 mg N2O m(-2) h(-1)), and 27,200 mg CO2 m(-2) h(-1) in summer. The results of intensive sample efforts during winter and summer flocks, reported visually using contour plots, offer a resource to the poultry industry and researchers for creating new management strategies for improving production and controlling gas evolution. Particularly, efforts could focus on designing housing systems that minimize extremes in litter compaction. The extremes are undesirable with more friable litter prone to greater gas evolution and more compacted litter providing a slippery, disease-sustaining surface.     

An evaluation of two diffusion culture techniques for estimating phytoplankton growth rates In situ

In comparative tests, acrylic diffusion chambers (voltume=42 ml) with polycarbonate filter membranes (1 m pore diameter) consistently supported higher cell yields and faster growth rates of summer phytoplankton populations and species from Narragansett Bay than did dialysis bags (volume=50 ml, 0.24–0.48 nm pore diameter) or bottle cultures (with or without added nutrients). Stirring of diffusion chambers or dialysis bags had less effect on growth responses than did the choice of the containment membrane. Exchange measurements showed the polycarbonate filters (0.49 ml cm^-2 h^-1) to be five times more permeable than dialysis membranes (0.09 ml cm^-2 h^-1) per unit area. The mean of measured half-life times for water in diffusion chambers was less than one hour while comparable half-life times for dialysis bags were approximately 3 h. Diatoms from the <10 m size fraction had higher growth rates than assemblages of microflagellates and non-motile ultraplankton. Stirring of diffusion chambers did not adversly effect the growth of microflagellates or non-motile ultraplankton. Growth responses in diffusion chambers moored in situ were generally similar to those measured in diffusion chambers incubated in outdoor tanks connected to a running seawater system.     

Bigamy and mate choice in the biparental cichlid fish Cichlasoma nigrofasciatum

Summary Sixty percent of C. nigrofasciatum males showed bigamous behaviour when held in small, outdoor ponds at an adult sex ratio of 5 males to 10 females. No male held more than two pair bonds simultaneously. Bigamy had reproductive benefits; bigamous males, on average, fathered more broods that survived well into the free-swimming fry stage than did monogamous males. In ponds where adult size varied, no positive correlations were found, for either sex, between adult size and frequency of spawning or success of broodrearing, despite predictions that larger size would confer reproductive benefits on both sexes. A significant positive correlation was found between the sizes of mated individuals in the pond where both sexes varied in size. On theoretical grounds this relationship is likely to be more strongly influenced by female than by male choice of spawning partner.     

Growth rates of summer nanoplankton (<10 μm) populations in lower Narragansett Bay,Rhode Island,USA

Growth rates of summer (June–September) phytoplankton assemblages and constituent species were measured in 30 diffusion culture experiments. Size-fractionated (<10 m) phytoplankton assemblages were incubated in situ or under simulated in-situ conditions in outdoor tanks connected to a running seawater system. Doubling rates of important species and groups (such as microflagellates) were compared to community biomass doubling rates estimated from ¹⁴C uptake and changes in chlorophyll a concentrations. Division rates of dominant diatom species generally equalled or exceeded community biomass doubling rates, while those of flagellates and non-motile ultraplankters were slower. Maximum division rates of sixteen common diatom species exceeded 2.1 divisions d^-1, while nine had maximum division rates in excess of 3 d^-1. Mean division rates of 12 diatom species exceeded 1 d^-1. Maximum division rates of flagellated species, uncharacterized microflagellates and non-motile ultraplankton assemblages were 2.1, 1.5 and 1.4 d^-1, respectively. Microflagellate and non-motile ultraplankton assemblage doubling rates were less than 0.5 d^-1 in over half of all growth experiments.     

A statistical evaluation of the geogenic controls on indoor radon concentrations and radon risk

ANOVA is used to show that approximately 25% of the total variation of indoor radon concentrations in England and Wales can be explained by the mapped bedrock and superficial geology. The proportion of the total variation explained by geology is higher (up to 37%) in areas where there is strong contrast between the radon potential of sedimentary geological units and lower (14%) where the influence of confounding geological controls, such as uranium mineralisation, cut across mapped geological boundaries. When indoor radon measurements are grouped by geology and 1-km squares of the national grid, the cumulative percentage of the variation between and within mapped geological units is shown to be 34-40%. The proportion of the variation that can be attributed to mapped geological units increases with the level of detail of the digital geological data. This study confirms the importance of radon maps that show the variation of indoor radon concentrations both between and within mapped geological boundaries.     

Degradation of the insecticide fensulfothion by a mixed culture of soil microorganisms

Abstract

Fensulfothion was incubated in nutrient media with a mixed culture of soil microorganisms obtained from sandy loam. The half life of fensulfothion in both inoculated samples and sterile controls was about 16 wk. There was some conversion to fensulfothion sulfone (16% at 6 wk) in inoculated samples, but not in the controls. Traces of fensulfothion sulfide were found in both inoculated samples (<3%) and controls (<2%) . When 1% ethanol was added to the inoculated nutrient mixture the fensulfothion disappeared rapidly (t_½>～1_½> wk) with 32% conversion at 20 wk to fensulfothion sulfide.     

The Pollution Prevention Act of 1990: A Policy Whose Time Has Come or Symbolic Legislation?

/ In 1990, the United States officially entered the era of pollution prevention with passage of the Pollution Prevention Act. This paper analyzes EPA's implementation of the Pollution Prevention Act from its passage in 1990 to the present. It examines the barriers EPA must overcome if it is to effectively integrate pollution prevention into its existing regulatory structure, including impediments created by statutory and organizational structure, the existing relationship between EPA and the groups it regulates, the fragmented implementation scheme of national environmental regulation, the balancing of conflicting demands advanced by powerful interests, industry's economic and technical concerns, and institutional inertia. It also examines issues such as industry commitment, the limits of prevention, and measurement concerns. The findings suggest that EPA's efforts at shifting to a pollution prevention regulatory ethic that holds primacy over pollution control are mixed. Its organizational structure, statutory authority, and incentives system still reflect a single-medium pollution control focus, appropriations for pollution prevention programs and activities are paltry compared to traditional pollution control programs, and participation in the program is voluntary. Yet, the findings also point to some promising programs that are working to institutionalize a pollution prevention regulatory ethic, and many states appear very committed to the concept.KEY WORDS: Pollution prevention; Source reduction; Pollution control; Alternative regulatory design; Barriers to implementation     

Assessing the aerobic biodegradability of 14 hydrocarbons in two soils using a simple microcosm/respiration method.

The aerobic biodegradability of 14 hydrocarbons in two soils was determined using a simple microcosm/respirometric method based on oxygen consumption. Biodegradability was assessed indirectly by measuring the depletion of oxygen over time in the headspace of microcosms containing soil and test chemicals. The microcosms consisted of small glass vials fitted with valves that allowed headspace gas samples to be collected, essentially resulting in a sealed system. Respiration data from control microcosms were obtained from identically treated microcosms with no test chemical. Control data were necessarily included in all calculations of percent of theoretical oxygen demand (%ThOD) for any given test chemical. Two experiments were performed to verify this simple biodegradation test method. First, an experiment was performed in which disappearance of n-tetradecane from the microcosms was measured directly by standard soil extraction and analytical techniques while simultaneously performing this simple respirometric method based on %ThOD with the same test chemical. Second, the method was compared to a well-established radiochemical technique using 14C-phenanthrene. Results of both comparisons showed that the method is both accurate and reliable. The consistent manner with which the data were produced in two different soils show that the method is also very reproducible. The method described here provides a simple and inexpensive method for determining the aerobic biodegradability of organic compounds in soils.     

Congo Basin peatlands: threats and conservation priorities

Mitigation and Adaptation Strategies for Global Change - The recent publication of the first spatially explicit map of peatlands in the Cuvette Centrale, central Congo Basin, reveals it to be the...