Measuring mucus thickness in reef corals using a technique devised for vertebrate applications

A method previously used to measure thickness of the surface mucus layer (SML) of the mammalian gastrointestinal tract has been applied to the SML of reef corals. It involves manual measurement of mucus thickness using a micromanipulator and fine glass needle (micropipette) and is non-destructive to the coral, meaning that repeated measurements can be taken. A measurable mucus layer was recorded in all cases in the study, which comprised 450 individual thickness measurements from four coral species. Mucus thickness ranged from 145 to 700 μm. Thus, whatever dynamic processes control mucus synthesis, secretion to the tissue surface and subsequent release into the water column, a continuous mucosal barrier is maintained. A change in SML thickness was recorded as a response to aerial exposure during the natural tidal cycle and to solar exposure-induced bleaching, although the response due to bleaching varied between two studied species. The technique is rapid, cost-effective and a simple means of assessing coral SML thickness, a variable that shows significant variation in relation to environmental conditions and is likely to be an important health indicator in these organisms.     

A preliminary analysis of aortic injuries in lateral impacts

Injuries to the aorta are among the more serious injuries that result from vehicle impacts, and often may be fatal. This article examines the incidence of aortic injuries in the United States and United Kingdom by using two international databases of real-world crashes. The main outcome of interest was the level of risk associated with each principal direction of force for drivers and front-seat passengers with respect to sustaining aortic injuries. The results indicate that the risk of sustaining an injury to the aorta is greater for near-side crashes than for far-side crashes. Further it is apparent that, given a near-side crash, the risk of an aortic injury is greater on the left side of the body (and left side of the vehicle) than on the right. It also was found that the delta-V of crashes where occupants sustained an injury to the aorta was considerably higher than crashes where occupants did not sustain aortic injuries. It is speculated that the anatomical asymmetry of the thorax might play a role in the differences seen in injury risk associated with different impact directions. The results presented in this article could be of use to both the emergency physician treating patients involved in motor vehicle collisions as well as the engineer involved in occupant design countermeasures. Limitations and further planned research are discussed.     

Testing soils and cornstalks to evaluate nitrogen management on the watershed scale

High nitrate (NO3-N) concentrations in Iowa rivers have been linked to areas of intensive row crop production, but they have not been experimentally linked to specific management practices used during row crop production. This study demonstrates how the late-spring test for soil NO3-N and the end-of-season test for cornstalk NO3-N can be used to measure N sufficiency levels across many fields and how the results can be used to evaluate management practices within a watershed. More than 3200 soil and cornstalk samples were collected over a 12-yr period from fields planted to corn (Zea mays L.) and already fertilized by farmers using their normal practices. Results showed that early-season rainfall and associated N losses were major factors affecting N concentrations in soils and cornstalks. Evidence for NO3-N movement from fields to rivers was provided by an inverse relationship between annual means for NO3-N concentrations in soils and rivers. Because these losses can be avoided by delaying N applications, the practice of applying N several weeks or months before plants grow was linked to inefficient use of fertilizer and manure N by crops. Results of the study demonstrate how aggregate analyses of soil and cornstalk samples collected across many farms and years make it possible to identify the major factors affecting N management outcomes and, therefore, N management practices that are likely to produce the best outcomes within a watershed or region. This approach seems to have unique potential to interrelate the management practices of farmers, the efficiency of N fertilization, and NO3-N concentrations in rivers.     

Partitioning and availability of uranium and nickel in contaminated riparian sediments

The effects of iron oxides and organic matter on the partitioning and chemical lability of U and Ni were examined for contaminated riparian sediments from the U.S. Department of Energy's Savannah River Site. In sequential extractions of four sediments that ranged from 12.7 to 82.2 g kg(-1) in organic carbon, U was found almost exclusively in moderately labile fractions (93% in acid-soluble + organically bound). Nickel was distributed across all operationally defined fractions, including substantial amounts in the very labile fractions (4-15% in water-soluble + exchangeable), noncrystalline and crystalline iron oxides (38-49%), and in the nonlabile residual fraction (25-34%). Aqueous U concentrations in 1:1 sediment-water extracts were highly correlated to dissolved organic carbon (DOC) (R2 = 0.96; p < 0.0001) and ranged from 29 to 410 microg L(-1). Aqueous concentrations of Ni exceeded U by two to three orders of magnitude (124-2227 microg L(-1)) but were not correlated with DOC (R2 = 0.04; p = 0.53). Partitioning and solubility trends suggest that Ni availability is controlled primarily by iron-oxide phases, whereas U availability is dominated by naturally occurring organic carbon. Discrete mineral phases were also identified as nonlabile reservoirs of anthropogenic metals. In spite of comparably high sediment concentrations, Ni appears to be significantly more available than U in riparian sediments and therefore warrants greater consideration in terms of environmental consequences (i.e., transport, biological uptake, and toxicity).     

Plutonium solubility in sediment pore waters

Using in situ porous cup samplers, dissolved Pu concentrations have been measured over a year in the pore waters from two contrasting sites in the valley of the River Esk, North West England. In saltmarsh sediments, dissolved Pu represents approximately 1 part in 10(6) of the total inventory. The Pu concentration in solution is in the range 1.1-3.5 mBq l-1, varying by a factor of 3 in the course of the year. Most of the changes in dissolved Pu coincide with changes in dissolved Fe and Mn concentrations, with Pu being low in the summer months when Fe and Mn are high. Nevertheless, there are a number of factors which make it unclear as to whether these patterns might be related to seasonal redox changes in the saltmarsh. At the highly organic, reducing reedbed site, the proportion of Pu in solution is typically around 1 part in 10(3), proportionately much higher than in the saltmarsh, giving concentrations ranging between 9.0 and 28.5 mBq l-1, and are apparently maintained by complexation to dissolved organic matter. There is no obvious seasonal pattern at the reedbed site nor is there any relation to any of the dissolved species measured (Fe, Mn, Na, DOC).     

Farm tourism in England's peak national park

Summary The careful integration of tourism/leisure activities with agriculture is proving of increasing economic value to farming communities whilst providing also the means to safeguard and conserve rural environments and landscapes. The recognition of this value is reflected in the number of grants available in Europe to assist and encourage farmers to diversify their farming activities to embrace tourism and leisure. This paper describes a number of schemes which have been promoted in the Peak National Park (UK) to encourage farmers to attempt such diversification. Their value in conserving a valuable and valued landscape is discussed.Haydon Morris was until recently Senior Planner at the Peak National Park, and is currently Development Manager for the Cumbria Tourist Board. He may be contacted at the Board's Offices; Ashleigh, Windermere, LA23 2AQ, UK.Dr Michael Romeril is Conservation Officer for the Island of Jersey. His address is; Planning Office, South Hill, St. Helier, Jersey, G.B.     

Effect of Chlorination on the Gill Lipids of the Mussel Mytilus edulis (L)

Experiments are described which involve the chlorination of standard solutions of lipids and populations of the mussel, Mytilus edulis (L). The object was to test the hypothesis that chlorine will bind to unsaturated lipids. Evidence is presented that chlorine and aqueous chlorinated species rapidly and readily form addition compounds with unsaturated lipids in vivo as well as in vitro. The relevance of these findings to possible environmental effects of chlorination is discussed.     

Daily mortality in the Philadelphia metropolitan area and size-classified particulate matter

Time-series of daily mortality data from May 1992 to September 1995 for various portions of the seven-county Philadelphia, PA, metropolitan area were analyzed in relation to weather and a variety of ambient air quality parameters. The air quality data included measurements of size-classified PM, SO4(2-), and H+ that had been collected by the Harvard School of Public Health, as well as routine air pollution monitoring data. Because the various pollutants of interest were measured at different locations within the metropolitan area, it was necessary to test for spatial sensitivity by comparing results for different combinations of locations. Estimates are presented for single pollutants and for multiple-pollutant models, including gaseous pollutants and mutually exclusive components of PM (PM2.5 and coarse particles, SO4(2-) and non-SO4(2-) portions of total suspended particulate [TSP] and PM10), measured on the day of death and the previous day. We concluded that associations between air quality and mortality were not limited to data collected in the same part of the metropolitan area; that is, mortality for one part may be associated with air quality data from another, not necessarily neighboring, part. Significant associations were found for a wide variety of gaseous and particulate pollutants, especially for peak O3. Using joint regressions on peak O3 with various other pollutants, we found that the combined responses were insensitive to the specific other pollutant selected. We saw no systematic differences according to particle size or chemistry. In general, the associations between daily mortality and air pollution depended on the pollutant or the PM metric, the type of collection filter used, and the location of sampling. Although peak O3 seemed to exhibit the most consistent mortality responses, this finding should be confirmed by analyzing separate seasons and other time periods.     

Energy recovery from solid waste fuels using advanced gasification technology

Since the mid-1980s, TPS Termiska Processer AB has been working on the development of an atmospheric-pressure gasification process. A major aim at the start of this work was the generation of fuel gas from indigenous fuels to Sweden (i.e. biomass). As the economic climate changed and awareness of the damage to the environment caused by the use of fossil fuels in power generation equipment increased, the aim of the development work at TPS was changed to applying the process to heat and power generation from feedstocks such as biomass and solid wastes. Compared with modern waste incineration with heat recovery, the gasification process will permit an increase in electricity output of up to 50%. The gasification process being developed is based on an atmospheric-pressure circulating fluidised bed gasifier coupled to a tar-cracking vessel. The gas produced from this process is then cooled and cleaned in conventional equipment. The energy-rich gas produced is clean enough to be fired in a gas boiler (and, in the longer term, in an engine or gas turbine) without requiring extensive flue gas cleaning, as is normally required in conventional waste incineration plants. Producing clean fuel gas in this manner, which facilitates the use of efficient gas-fired boilers, means that overall plant electrical efficiencies of close to 30% can be achieved. TPS has performed a considerable amount of pilot plant testing on waste fuels in their gasification/gas cleaning pilot plant in Sweden. Two gasifiers of TPS design have been in operation in Grève-in-Chianti, Italy since 1992. This plant processes 200 tonnes of RDF (refuse-derived fuel) per day. It is planned that the complete TPS gasification process (including the complete fuel gas cleaning system) be demonstrated in several gas turbine-based biomass-fuelled power generating plants in different parts of the world. It is the aim of TPS to prove, at commercial scale, the technical feasibility and economic advantages of the gasification process when it is applied to solid waste fuels. This aim shall be achieved, in the short-term, by employing the cold clean product gas in a gas boiler and, in the longer-term, by firing the gas in engines and gas turbines. A study for a 90 MWth waste-fuelled co-generation plant in Sweden has shown that, already today, gasification of solid waste can compete economically with conventional incineration technologies.     

Niagara region farmers' markets: local food systems and sustainability considerations

This article presents the findings of a survey of farmers' markets customers in the Niagara region of Ontario, Canada. The recent growth of farmers' markets in North America and the association of these markets with local food systems development provoke examination to gain insights into consumer motivations for patronizing these markets, and to then reflect on their potential role within locally oriented and sustainable food production systems. The survey carried out on customers of three Niagara region farmers' markets corroborates previous studies that noted that socioeconomic and cultural factors such as the importance of food freshness, support of local farmers and the local farm economy, and social interaction—embeddedness—are key expressions of people's support and interest in farmers' markets. This work serves to heighten our understanding of consumer attitudes toward direct marketing via farmers' markets, yields useful speculation about these markets and their roles in sustainable local food systems progress, and also raises critical questions about such customer patronage and associated farmers' markets potential in local food system development.