Reduced planktotrophy in larvae of <Emphasis Type="Italic">Clypeaster</Emphasis><Emphasis Type="Italic">rosaceus</Emphasis> (Echinodermata,Echiniodea)

Phylogenetic analyses have demonstrated that nonfeeding larvae have evolved from feeding larvae many times among marine invertebrates. In light of this observation, it is surprising that an intermediate strategy, a larva that can feed but is provisioned with enough energy to metamorphose without acquiring exogenous food (i.e., facultative planktotrophy), is rare. A hypothesis for the lack of facultative planktotrophic species among marine invertebrates is that the transition from feeding to nonfeeding is rapid due to this intermediate stage being evolutionarily unstable. Evidence that would support this hypothesis is if species with facultative planktotrophy have reduced food assimilation when compared with obligate planktotrophs. We studied a species with facultative planktotrophic larvae, Clypeaster rosaceus, that is very near the boundary between facultative and obligatory planktotrophy, to answer two questions: (1) does feeding during the larval stage result in energy gains in larval or juvenile stages and (2) if not, are larvae capable of assimilating exogenous food at all. Our measurements of energetics in larval and juvenile stages show that C. rosaceus larvae accumulate very little if any energy when fed, but stable isotope data indicate that larvae are able to assimilate some food. Our results are consistent with similar studies on facultative planktotrophic larvae suggesting poor food assimilation and rapid loss of larval feeding after a population evolves the ability to reach metamorphosis without feeding (lecithotrophy).     

Effects of Cd and Zn waterborne exposure on the uptake and depuration of 57Co, 110mAg and 134Cs by the Asiatic clam (Corbicula fluminea) and the zebra mussel (Dreissena polymorpha)--whole organism study

Groups of zebra mussels (Dreissena polymorpha) and asiatic clams (Corbicula fluminea) were exposed to cadmium and zinc with the aim of studying the effect of these metals on the 57Co, 110Ag and 134Cs uptake and depuration by these freshwater bivalves. In the presence of zinc, the 57Co concentration factor for the whole organism of the two species was halved, notably because of a decrease of the uptake parameter. Conversely, Zinc and the Cd + Zn mixture increased the 110mAg uptake process by clams and mussels. The two metals also increased the depuration of this radionuclide in mussels, whereas this phenomenon was only observed in clams exposed to cadmium. In comparison with 57Co and 110mAg, the 134Cs bioconcentration was 5-10 times lower in D. polymorpha and not detected in C. fluminea. This weak contamination by this radionuclide resulted from a lower uptake and a higher depuration parameters.     

A greenhouse gas emissions inventory for Pennsylvania

The Pennsylvania greenhouse gas (GHG) emissions inventory presented in this paper provides detailed estimates of emissions and their sources for the six major categories of GHGs. The inventory was compiled using the current U.S. Environment Protection Agency methodology, which applies emissions factors to socioeconomic data, such as fossil energy use, vehicle miles traveled, and industrial production. The paper also contains an assessment of the methodology and suggestions for improving accounting with respect to process, sectoral, and geographic considerations. The study found that Pennsylvania emitted 77.4 million metric tons carbon equivalent of GHGs in 1990 and that this total increased by 3% to 79.8 million metric tons carbon equivalent by 1999. Despite this increase, however, the state's percentage contribution to the United States total declined during the decade. Pennsylvania's carbon dioxide (CO2) emissions from fossil fuels represented 92.4% of 1990 totals and declined to 90.5% in 1999. Electricity generation was the largest single source of CO2 emissions, being responsible for 38% of fossil fuel CO2 emissions in 1990 and 40% of the total in 1999. Transportation emissions accounted for the largest increases in emissions between 1990 and 1999, whereas industrial emissions accounted for the largest decrease. The overall trend indicates that Pennsylvania has been able to weaken the relationship between GHG emissions and economic growth.     

Effects of additives on solidification of API separator sludge

API separator sludge was solidified with various combinations of binders and absorbent soil additives. The binders utilized were Type I Portland Cement, Type C Flyash, and a 1:1 combination of the two. The soil additives used were bentonite, diatomite, Fuller's earth, and two brands of chemically altered bentonites, or organoclays. The effectiveness of the solidification materials was based on their effect on the physical and leaching characteristics of the sludge.It was determined the Portland cement and combination binders provided the sludge with adequate physical and strength characteristics. It was also determined the affinity of each additive for water had an important influence on the physical characteristics of the solidified sludge. The results of the leaching procedure indicated the binders alone reduced the leachability of organic constituents from the sludge by 1/5 to 1/10. It appeared the use of the additives with the binders may have further reduced the leachability of constituents from sludge, with the incorporation of the organoclay additives further reducing leachability by up to 1/2. Also, it appeared the absorbing capacity of the additives was directly related to their ability to reduce the leachability of organic constituents from the sludge.     

Natural capital in ecology and economics: an overview

The Brundtland Commission report, Our Common Future, defined sustainable development as development that meets the needs of the present without compromising the ability of futuregenerations to meet their own needs. Although the idea of sustainable development has been widely accepted, it has proveddifficult to identify and implement policies and practices thatpromote sustainable economic growth. Some economists, environmental scientists and policy analysts believe that they can transform the consensus about sustainability into manageablepractices. They propose to accomplish this feat with a set of new ideas about the relationships between the economy and theenvironment offered under the banner of 'natural capital'. An ideal account of natural capital would be one or more standard measures or models that would allow the direct comparison of environmental goods, like forests, fresh water and clean air, with economic goods, like money, capital and productivity. By bringing economic science and environmental science to an objective common ground, a natural capital model has the potentialto provide a concrete means of comparing the economic and ecological costs and benefits of particular policies and programmes. This paper offers a survey and analysis of several new contributions to the formation of the natural capital concept from economists, ecologists, policy analysts, biometricians, foresters and a philosopher. The paper concludes that existingmicroeconomic theory may be 'ungreenable', if it is not reformulated. While macroeconomic approaches to natural capitalhave been more successful, they share the limitation that ecosystems and species are valued solely in monetary terms. These problems are taken to suggest that the development of a successful natural capital model may require economic theory tobe recast to include non-monetary social preferences and values.     

A new market instrument for sustainable economic and environmental development

The regenerative capacity of ecosystems provides a regulatory basis for sustainable economic growth and development. A natural valuation of an ecosystem's services will arise in a market for developmental rights in the ecosystem using a unit of tradable 'right': E-Scrip. The amount of e-scrip needed for a development may be set by Environmental Assessment. The capacity of the ecosystem to regenerate with developmental pressure may be represented by an independent trader or Factor Proxy for the Environment who provides e-scrip to the market.     

Thermochemical treatment of sewage sludge ashes for phosphorus recovery

Phosphorus (P) is an essential element for all living organisms and cannot be replaced. Municipal sewage sludge is a carrier of phosphorus, but also contains organic pollutants and heavy metals. A two-step thermal treatment is suggested, including mono-incineration of sewage sludge and subsequent thermochemical treatment of the ashes. Organic pollutants are completely destroyed by mono-incineration. The resulting sewage sludge ashes contain P, but also heavy metals. P in the ashes exhibits low bioavailability, a disadvantage in farming. Therefore, in a second thermochemical step, P is transferred into mineral phases available for plants, and heavy metals are removed as well. The thermochemical treatment was investigated in a laboratory-scale rotary furnace by treating seven different sewage sludge ashes under systematic variation of operational parameters. Heavy metal removal and the increase of the P-bioavailability were the focus of the investigation. The present experimental study shows that these objectives have been achieved with the proposed process. The P-bioavailability was significantly increased due to the formation of new mineral phases such as chlorapatite, farringtonite and stanfieldite during thermochemical treatment.     

Selecting objectively defined reference sites for stream bioassessment programs

Our study develops and demonstrates an objective method for selecting reference sites for the assessment of ecological condition in freshwater ecosystems. The method uses widely available GIS data to group potential sites based on their natural environments. It then establishes the degree and types of human activities each site is exposed to prior to scoring the sites in each group by the relative amount of human activity present. Finally, the sites in each group with the least amount of human activity are categorized as reference sites, with the boundary between reference and test sites defined to maximize the distinctiveness of the two categories with respect to human activity. Application of this technique for the purpose of identifying headwater reference basins in rural areas of southwestern Ontario resulted in the classification of basins into six natural groups based on the dominant texture of the surface geology. Development of a human activity gradient indicated that basins varied according to the amount of exposure to agricultural activities with most basins having at least moderate exposure. Establishment of the reference test boundary indicated that the selected reference basins exhibited substantively lower extents of agricultural activity than test sites for most groups. Because this method uses only widely available GIS data, it enables rapid and cost-effective identification of candidate reference sites, even for large, remote, and understudied regions.