Electronic Trends in Environmental Reporting and Recordkeeping

EPA is developing a Cross‐Media Electronic Reporting and Record‐Keeping Rule. © 2001 John Wiley & Sons, Inc.     

Generalised linear modelling of fecundity at length in southern rock lobsters, <Emphasis Type="Italic">Jasus edwardsii</Emphasis>

Accurate fecundity estimates are central to population modelling of reproductive status and egg production in a fishery. Southern rock lobster (Jasus edwardsii) fisheries are managed with the consideration of performance measures based on the level of current egg production relative to the unfished stock. Egg production is a function of the size at the onset of maturity, the size structure of the stock, and the fecundity at length of lobsters. Fecundity at length of the Tasmania stock of J. edwardsii has not been reported previously and was estimated from seven sites around Tasmania. Data were analysed by classical linear regression and also generalised linear models (GLM) with gamma and Poisson distributions. GLM with a gamma distribution produced the best fit and did not require a correction factor to generate a model on the linear scale. Individual fecundity ranged from 43,918 to 660,156 and could be predicted from carapace length according to the equation F = −1.707 + 2.969 (log length). The coefficient of length approximated three, implying the fecundity at length relationship is cuboidal. Despite the spatial heterogeneity in reproductive parameters in this fishery, the inclusion of spatial information and egg development stage into the analysis only explained an additional 1% of the variance in fecundity. Thus, it appears valid to apply the relationship across the fishery without spatial separation.     

Positive association between social and extra-pair mating in a polygynous songbird, the dickcissel (Spiza americana)

In polygynous species, males appear to gain additional offspring by pairing with multiple females simultaneously. However, this may not be true if some females copulate outside of the social pair bond. Polygynous males could experience lower paternity because of trade-offs among gaining multiple social mates, guarding fertility with these mates, and pursuing extra-pair matings. Alternatively, polygynous males could simultaneously gain extra social mates and have high paternity, either because of female preferences or because of male competitive attributes. We tested four predictions stemming from these hypotheses in a facultatively polygynous songbird, the dickcissel (Spiza americana). Unlike most previous studies, we found that males with higher social mating success (harem size) also tended to have higher within-pair paternity and that the number of extra-pair young a male sired increased significantly with his social mating success. Females that paired with mated males were not more likely to produce extra-pair young. In contrast, extra-pair paternity was significantly lower in the nests of females whose nesting activity overlapped that of another female on the same territory. This pattern of mating was robust to differences in breeding density. Indeed, breeding density had no effect on either extra-pair mating or on the association between polygyny and paternity. Finally, nest survival increased with harem size. This result, combined with the positive association between polygyny and paternity, contributed to significantly higher realized reproductive success by polygynous male dickcissels.     

The spatial distribution of ammonia emitted from seabirds and its contribution to atmospheric nitrogen deposition in the UK

Simple bioenergetics models were used to derive annual nitrogen excretion rates of each seabird species occurring at colonies in the UK. These were combined with population distribution data and an estimated fraction of nitrogen volatilized to estimate the spatial distribution of NH₃ emissions from seabird colonies at a 1 km resolution. The effect of these emissions on atmospheric NH₃ concentrations and nitrogen deposition in the UK was assessed using the FRAME atmospheric chemistry and transport model. The total emission of NH₃ from the UK seabird colonies is estimated at 2.7 kt yr^–1. Emissions from seabirds are largely concentrated in remote parts of Britain, where agricultural and other anthropogenic emissions are minimal. Although seabirds account for less than 1% of total UK NH₃ emissions (370 kt yr^–1), their occurrence in remote areas and frequently large colony sizes results in seabirds providing a major fraction of the atmospheric nitrogen deposition for many remote ecosystems.     

The setting of standards for agricultural nitrogen emissions: a case study of the Delphi technique

The Delphi technique is a means of aggregating the judgement of a panel of experts in order to improve the quality of decision-making. This paper provides a case study of the technique by undertaking a three-round Delphi study to determine a package of best available techniques to reduce nitrogen emissions from a poultry unit under the Integrated Pollution Prevention and Control Directive (IPPC). Forms of nitrogen addressed included ammonia (NH3), nitrous oxide (N2O) nitrogen oxides (NOx), dusts and nitrate (NO3-), with the study providing a means to prioritise the pollution concerns on different spatial scales. The priority pollutant issues were the contribution of NH3 to eutrophication, the global cooling effect of NH4+ aerosol, the role of NH4+ as a vector for atmospheric transport of NOx and SO2, the contribution of N2O to global warming, and NO3- leaching. Reduced nitrogen (NHx) was rated as a priority on all scales, while N2O and NO3- were rated as priorities only on global and local scales, respectively. The study indicated the need for abatement techniques at each stage of poultry rearing and waste management, with particular attention to reduce NH3 emissions, reflecting the priority pollutant concerns. Measures identified by the panel include maintenance of dry litter, low emission removal of litter from housing and storage of litter under cover. Once the litter has left the farm, this should either be used as a biofuel for electricity generation or rapidly incorporated into agricultural soils. The amounts and timing of manure application should be tuned to crop needs. Uncertainties in the Delphi technique limit its suitability as a stand-alone decision making tool. However, the Delphi technique proved useful in identifying priority pollutant issues, areas of agreement, disagreement and where information is lacking. This demonstrates its use when dealing with the complex issues of prioritising pollution issues and abatement approaches.     

Uranium(VL) interactions with OPC/PFA grout

The sorption of uranium on to Ordinary Portland Cement (OPC)/Pulverized Fuel Ash (PFA, fly ash) grout material has been investigated with respect to time, pH, grout:uranium ratio and the chemical composition of the supporting solution. The information obtained is of relevance to the disposal of low-level nuclear waste. The grout material has been chemically characterised and is negatively charged above pH 2.3. At the uranium concentrations studied (2 microM) all uranyl hydroxide aqueous species are expected to be monomeric, rather than polymeric. Uranium(VI) sorption on to the grout material has been explained in terms of inner sphere complexation binding by means of hydroxide bridge formation between the uranium and grout surface. It is also proposed that oligomeric uranyl species are formed across the grout surface, perhaps stabilising the repulsive effects of the negatively charged grout surface and anionic uranyl hydroxide species. Thermodynamic modelling has been used to explain the sorption variation versus solution pH and identifies potential binding mechanisms.     

Deposition monitoring networks: what monitoring is required to give reasonable estimates of ammonia/ammonium?

Deposition is one of the main loss terms for ammonia and ammonium from the atmosphere. It is also the input for ecosystems that can lead to drastic changes and effects. Deposition networks are needed to evaluate the need and the effect of policies to reduce nitrogen emissions, but also for studying deposition parameters and for developing deposition models. As with ambient concentrations of ammonia, deposition, especially dry deposition, varies strongly in space and in time. Furthermore, the bi-directional surface-atmosphere exchange of ammonia makes the combination of ambient concentration measurements with inferential models inadequate. Developing deposition monitoring networks with reasonable accuracy and representativeness is therefore not straightforward. In Europe several projects have addressed deposition monitoring. From these results it is concluded that a monitoring strategy should consist of a network with a limited amount of super sites combined with a larger number of sites where low cost methods are applied, together with models for generalisation.