Methanogenesis in monogastric animals

Studies of methanogenic bacteria present in monogastric animals are still scarce. Methanogens have been isolated from faeces of rat, horse, pig, monkey, baboon, rhinoceros, hippopotamus, giant panda, goose, turkey and chicken. The predominant methanogen in all except the chicken and turkey is species of Methanobrevibacterium. The chicken and turkey harbour species of Methanogenium. In pig the population of methanogenic bacteria is more than 30 times as dense in the distal colon as in the caecum. This finding is in agreement with the finding that the rate of methane production is much higher in the colon than in the ceacum. The amount of methane excreted clearly seems to depend on the amount of non-starch polysaccharide intake.The directly measured methane production rate in pigs is from 3.3 to 3.8 times lower than the amount expected from stoichiometric estimates. These data, together with data showing that only small net amounts of hydrogen and small amounts of methane are produced in the ceacum and proximal colon where the microbial activity is high, clearly indicate that hydrogen sinks other than methane production are involved in hydrogen removal in the hindgut of pigs and probably also in other monogastric animals.Methane production by monogastric animals is lower than methane production by ruminants. However, methane production by large herbivorous monogastric animals such as horses, mules and asses is substantial (up to 80 l per animal per day). Methane production by rodents and avians is low. In general, methane production by wild animals is lower than methane production by domestic animals. It is concluded that the contribution of monogastric animals to the global methane emission is negligible, as it only represent about 5% of the total methane emission by domestic and wild animals of 80 Tg per year.     

A Knowledge-Based Approach to the Assessment of Watershed Condition

The Ecosystem Management Decision Support (EMDS) system is an application framework for knowledge-based decision support of ecological assessments. EMDS integrates geographic information system and knowledge base system technologies to provide an analytical tool for environmental assessment and monitoring. The basic objective of EMDS is to improve the quality and completeness of environmental assessments and the efficiency with which they are performed. The USDA Forest Service and the U.S. Environmental Protection Agency have cooperatively developed an EMDS knowledge base for watershed condition assessment. Specifically, this knowledge base evaluates watershed processes, patterns, general effects of human activity, and fisheries habitat suitability. Such assessments are based on spatially explicit input data concerning current conditions and reference conditions which are subsequently interpreted by user-defined "fuzzy" membership functions. In this paper we describe basic components of our knowledge base for assessing watershed condition and illustrate its application within northern Idaho and northwestern Montana.     

Increased lipid accumulation but not reduced metabolism explains improved starvation tolerance in cold-acclimated arthropod predators

Predatory arthropods are used for biological control in greenhouses, but there is increasing interest to extend their use to the outdoor environment where temperatures are typically lower. Acclimation at low temperature increases the ability of ectotherms to cope with subsequent more extreme cold, but may involve costs or benefits to other performance traits. A recent study in mesostigmatid mites (Gaeolaelaps aculeifer) showed that starvation tolerance was improved following a period of cold exposure. However, the physiological mechanisms that underlie improved starvation tolerance following cold exposure were not investigated. To examine whether cold acclimation would also improve starvation tolerance in an insect, we repeated the starvation study in another arthropod predator, the pirate bug Orius majusculus, as well as in G. aculeifer. Before tests, the two species were acclimated at 10, 15, or 20 °C for 7 (G. aculeifer) or 16 (O. majusculus) days. We then analyzed the effects of thermal exposure on body composition, consumption, and basal metabolic rate in both species. Our results confirmed that exposure to low temperature improves starvation tolerance in these arthropod predators. Body composition analyses revealed that both species had accumulated larger lipid stores during exposure to colder temperature, which at least in part can explain the larger starvation tolerance following cold exposure. In contrast, consumption and basal metabolic rate were not changed by thermal acclimation. Our study indicates that predatory arthropods exposed to cold increase their physiological robustness and ability to endure environmental challenges, including low temperature and low prey availability.     

“Conflict over Risks in Food Production: A Challenge for Democracy”

When it comes to conflict over risk management priorities in food production, a number of observers, including myself, have called for some sort of public deliberation as a means of resolving the moral disagreements underlying such conflicts. This paper asks how, precisely, such deliberation might be facilitated. It is shown that representative democracy and the liberal regulation that most Western democracies adhere to place important constraints on public deliberation. The challenge is to find forums for public deliberation that can operate within these constraints while still making a constructive contribution.     

Does the nutrition profile of vitamins, fatty acids and microelements counteract the negative impact from organohalogen pollutants on bone mineral density in Greenland sledge dogs (Canis familiaris)?

There is a great need for understanding the impact from dietary OHCs (organohalogen compounds) on bone mineral composition - and thereby osteoporosis - in especially arctic wildlife such as polar bears (Ursus maritimus) as well as humans. For that purpose, we measured BMD (bone mineral density) by DXA scanning (g/cm(-2)) in 15 age and weight normalized sledge dog (Canis familiaris) bitches and their 26 pups divided into a control group (n=26) given 50-200 g/day clean pork (Suis scrofa) fat and a treated group (n=15) given 50-200 g/day OHC polluted minke whale (Balaenoptera acutorostrata) blubber as main lipid sources. The results showed that BMD increased significantly with age (linear regression: p<0.0001, r(2)=0.83, n=41) while no sex difference was found in the F-generation (two-way ANOVA: all p>0.3). No differences in BMD(femur) or BMD(vertebrae) between exposed and control individuals in the bitch generation were found (linear mixed effect model: both p>0.38). Likewise, no difference between exposed and control subadults and juveniles in the F-generation was found (two-way ANOVA: all p>0.33). Correlation analyses between BMD(femur), BMD(vertebrae) and groups of OHCs, respectively, did not show any statistically significant relationships nor a clear or decreasing trend (Pearson's: p: 0.07-0.78; r: -0.2-0.59; n: 10-18). As the groups were similar regarding genetics, age and sex are the only factors that can explain this observation. Either the pollutants did not have an impact on BMD using the present time frame and OHC concentrations (threshold levels not reached), or the difference in food composition (mainly vitamins and n3 fatty acids) conceal the potential OHC impact on BMD. Such information is important when evaluating the positive and negative health consequences from eating polluted marine species.     

Methodological complexities of product carbon footprinting: a sensitivity analysis of key variables in a developing country context

Product carbon footprinting schemes adopt different analytical methodologies. The calculations can also be affected by limited data availability and uncertainty surrounding the value of key variables. The combination of these factors reduces the validity of comparing carbon footprints between products and countries.We used data from sugar production in Zambia and Mauritius to test how variations in methodology affected the product carbon footprint (PCF). We calculated a PCF according to PAS 2050 and explored the sensitivity of the results to the variation of key variables.Results showed that land use change emissions can dominate PCFs. The largest potential impact came from assuming global worst case data for land use change emissions where a product's origin is unknown (+1900%). The issue of land use change can lead to high carbon footprints for products from developing countries where more natural vegetation is still being converted and data are most lacking. When land use change is not important, variables such as electricity emission factors, capital inputs and loss of soil carbon had significant impacts on the PCF.This analysis highlights the large effect of methodology on PCFs. These results are of particular concern for developing countries where data are scarce and the use of global worst case data may be prescribed. We recommend the development of more precise emission factors for tropical countries and bio-regions, and encourage the transparent use of PCF methodologies, where data sources, uncertainties and variability are explicitly noted.     

Review of greenhouse gas emissions from crop production systems and fertilizer management effects

Fertilizer nitrogen (N) use is expanding globally to satisfy food, fiber, and fuel demands of a growing world population. Fertilizer consumers are being asked to improve N use efficiency through better management in their fields, to protect water resources and to minimize greenhouse gas (GHG) emissions, while sustaining soil resources and providing a healthy economy. A review of the available science on the effects of N source, rate, timing, and placement, in combination with other cropping and tillage practices, on GHG emissions was conducted. Implementation of intensive crop management practices, using principles of ecological intensification to enhance efficient and effective nutrient uptake while achieving high yields, was identified as a principal way to achieve reductions in GHG emissions while meeting production demands. Many studies identified through the review involved measurements of GHG emissions over several weeks to a few months, which greatly limit the ability to accurately determine system-level management effects on net global warming potential. The current science indicates: (1) appropriate fertilizer N use helps increase biomass production necessary to help restore and maintain soil organic carbon (SOC) levels; (2) best management practices (BMPs) for fertilizer N play a large role in minimizing residual soil nitrate, which helps lower the risk of increased nitrous oxide (N₂O) emissions; (3) tillage practices that reduce soil disturbance and maintain crop residue on the soil surface can increase SOC levels, but usually only if crop productivity is maintained or increased; (4) differences among fertilizer N sources in N₂O emissions depend on site- and weather-specific conditions; and (5) intensive crop management systems do not necessarily increase GHG emissions per unit of crop or food production; they can help spare natural areas from conversion to cropland and allow conversion of selected lands to forests for GHG mitigation, while supplying the world's need for food, fiber, and biofuel. Transfer of the information to fertilizer dealers, crop advisers, farmers, and agricultural and environmental authorities should lead to increased implementation of fertilizer BMPs, and help to reduce confusion over the role of fertilizer N on cropping system emissions of GHGs. Gaps in scientific understanding were identified and will require the collaborative attention of agronomists, soil scientists, ecologists, and environmental authorities in serving the immediate and long-term interests of the human population.     

Bacterial antibiotic resistance levels in Danish farmland as a result of treatment with pig manure slurry

Resistance to tetracycline, macrolides and streptomycin was measured for a period of 8 months in soil bacteria obtained from farmland treated with pig manure slurry. This was done by spread plating bacteria on selective media (Luria Bertani (LB) medium supplemented with antibiotics). To account for seasonal variations in numbers of soil bacteria, ratios of resistant bacteria divided by total count on nonselective plates were calculated. Soil samples were collected from four different farms and from a control soil on a fifth farm. The control soil was not amended with animal manure. The occurrence of tetracycline-resistant bacteria was elevated after spread of pig manure slurry but declined throughout the sampling period to a level corresponding to the control soil. Higher load of pig manure slurry yielded higher occurrence of tetracycline resistance after spreading; however, the tetracycline resistance declined to normal occurrence defined by the tetracycline resistance occurrence in the control soil. Concentrations of tetracycline in soil and in pig manure slurry were measured using HPLC. No tetracycline exceeding the detection limit was found in soil samples. Manure slurry concentrations of tetracycline for three of the farms were 42, 81 and 698 microg/l, respectively. For streptomycin and macrolides, only minor variations in resistance levels were detected. Results obtained in this study thus indicate that tetracycline resistance levels in soil are temporarily influenced by the addition of pig manure slurry. The results indicate also that increased amount of pig manure slurry amendment may result in increased levels of tetracycline resistance in the soil.     

Status of Control of Motor Vehicle Emissions in California

The State of California, because of an acute air pollution problem has been forced to move ahead on a pioneer basis to control motor vehicle emissions. The Golden State’s program, as put into operation by the Motor Vehicle Pollution Control Board, is discussed in detail. Inspection-installation stations, enforcement and legal requirements relating to crankcase control devices and other facets of the program are presented. Of particular importance is the experience gained by the Board in requiring devices on all new vehicles registered in California and its used vehicle program, affecting vehicles back to the 1950 model year. Recent developments in exhaust control, anticipated installation requirements, and scheduling, as well as an indication of staff long-term planning is also outlined. California’s program is based on the principle that the motor vehicle must be controlled and that sewage no longer can be dumped into the air, if the public health is to be preserved.