Metabolism provides a basis for using first principles of physics, chemistry, and biology to link the biology of individual organisms to the ecology of populations, communities, and ecosystems. Metabolic rate, the rate at which organisms take up, transform, and expend energy and materials, is the most fundamental biological rate. We have developed a quantitative theory for how metabolic rate varies with body size and temperature. Metabolic theory predicts how metabolic rate, by setting the rates of resource uptake from the environment and resource allocation to survival, growth, and reproduction, controls ecological processes at all levels of organization from individuals to the biosphere. Examples include: (1) life history attributes, including devel- opment rate, mortality rate, age at maturity, life span, and population growth rate; (2) population interactions, including carrying capacity, rates of competition and predation, and patterns of species diversity; and (3) ecosystem processes, including rates of biomass production and respiration and patterns of trophic dynamics. Data compiled from the ecological literature strongly support the theoretical predictions. Even- tually, metabolic theory may provide a conceptual foundation for much of ecology, just as genetic theory provides a foundation for much of evolutionary biology.

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Toward a metabolic theory of ecology

NOTE The report of the Committee without its annexes appears as Official Records of the General Assembly, Sixty-third Session, Supplement No. 46. The designations employed and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The country names used in this document are, in most cases, those that were in use at the time the data were collected or the text prepared. In other cases, however, the names have been updated, where this was possible and appropriate, to reflect political changes. Scientific Annexes Annex A. Medical radiation exposures Annex B. Exposures of the public and workers from various sources of radiation INTROdUCTION 1. In the course of the research and development for and the application of atomic energy and nuclear technologies, a number of radiation accidents have occurred. Some of these accidents have resulted in significant health effects and occasionally in fatal outcomes. The application of technologies that make use of radiation is increasingly widespread around the world. Millions of people have occupations related to the use of radiation, and hundreds of millions of individuals benefit from these uses. Facilities using intense radiation sources for energy production and for purposes such as radiotherapy, sterilization of products, preservation of foodstuffs and gamma radiography require special care in the design and operation of equipment to avoid radiation injury to workers or to the public. Experience has shown that such technology is generally used safely, but on occasion controls have been circumvented and serious radiation accidents have ensued. 2. Reviews of radiation exposures from accidents have been presented in previous UNSCEAR reports. The last report containing an exclusive chapter on exposures from accidents was the UNSCEAR 1993 Report [U6]. 3. This annex is aimed at providing a sound basis for conclusions regarding the number of significant radiation accidents that have occurred, the corresponding levels of radiation exposures and numbers of deaths and injuries, and the general trends for various practices. Its conclusions are to be seen in the context of the Committee's overall evaluations of the levels and effects of exposure to ionizing radiation. 4. The Committee's evaluations of public, occupational and medical diagnostic exposures are mostly concerned with chronic exposures of …

sources and effects of ionizing radiation

Traditionally, measurement of the acute toxicity of pesticides to beneficial arthropods has relied largely on the determination of an acute median lethal dose or concentration. However, the estimated lethal dose during acute toxicity tests may only be a partial measure of the deleterious effects. In addition to direct mortality induced by pesticides, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. An increasing number of studies and methods related to the identification and characterization of these effects have been published in the past 15 years. Review of sublethal effects reported in published literature, taking into account recent data, has revealed new insights into the sublethal effects of pesticides including effects on learning performance, behavior, and neurophysiology. We characterize the different types of sublethal effects on beneficial arthropods, focusing mainly on honey bees and natural enemies, and we describe the methods used in these studies. Finally, we discuss the potential for developing experimental approaches that take into account these sublethal effects in integrated pest management and the possibility of integrating their evaluation in pesticide registration procedures.

The Sublethal Effects of Pesticides on Beneficial Arthropods

Antifouling technology—past, present and future steps towards efficient and environmentally friendly antifouling coatings

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

Substantial efforts have been devoted to developing and applying biomarkers for use in ecotoxicology. These efforts have resulted partly from a desire for early warning indicators that respond before measurable effects on individuals and populations occur and partly as an aid to identifying the causes of observed population- and community-level effects. Whereas older biomarkers focused on measures of organism physiology or biochemistry, advances in molecular biology are extending the biomarker philosophy to the level of the genes (i.e., ecotoxicogenomics). However, the extent to which biomarkers are able to provide unambiguous and ecologically relevant indicators of exposure to or effects of toxicants remains highly controversial. In the present paper, we briefly discuss the application of biomarkers in ecotoxicology and ecological risk assessment, and we provide examples of how they have been applied. We conclude that although biomarkers can be helpful for gaining insight regarding the mechanisms causing observed effects of chemicals on whole-organism performance and may, in some cases, provide useful indicators of exposure, individual biomarker responses should not be expected to provide useful predictions of relevant ecological effects—and probably not even predictions of whole-organism effects. Suites of biomarkers are only likely to provide increased predictability if they can be used in a comprehensive mechanistic model that integrates them into a measure of fitness. Until this can be achieved, biomarkers may be useful for hypothesis generation in carefully controlled experiments. However, because the aims of environmental monitoring and ecological risk assessment are to detect and/or predict adverse chemical impacts on populations, communities, and ecosystems, we should be focusing our efforts on improving methods to do this directly. This will involve developing and testing models of appropriate complexity that can describe real-world systems at multiple scales.

The use and misuse of biomarkers in ecotoxicology.

In this paper we consider the relationships between effects of toxicants on population growth rate (r) and the individual-level traits (survival and reproduction) contributing to it by examining population dynamics theory and by reviewing the experimental work that has been carried out in this context. There was no consistent pattern in terms of which individual-level traits were most or least sensitive to toxicant exposure, and it is therefore impractical to select traits for ecotoxicological testing on this basis. Although percent changes in several of the individual-level traits showed significant overall correlations with percent changes in r, changes in any single trait could explain no more than about one-half of the percent change in r. Our conclusion is that r is a better measure of responses to toxicants than are individual-level effects, because it integrates potentially complex interactions among life-history traits and provides a more relevant measure of ecological impact.

Is the per capita rate of increase a good measure of population‐level effects in ecotoxicology?

We revisit the assumptions associated with the derivation and application of species sensitivity distributions (SSDs). Our questions are (1) Do SSDs clarify or obscure the setting of ecological effects thresholds for risk assessment? and (2) Do SSDs reduce or introduce uncertainty into risk assessment? Our conclusions are that if we could determine a community sensitivity distribution, this would provide a better estimate of an ecologically relevant effects threshold and therefore be an improvement for risk assessment. However, the distributions generated are typically based on haphazard collections of species and endpoints and by adjusting these to reflect more realistic trophic structures we show that effects thresholds can be shifted but in a direction and to an extent that is not predictable. Despite claims that the SSD approach uses all available data to assess effects, we demonstrate that in certain frequently used applications only a small fraction of the species going into the SSD determine the ef...

Species Sensitivity Distributions Revisited: A Critical Appraisal

Preface and acknowledgements. Answers to some important questions. Decision-making in ecotoxicology: science and society meet. Measuring ecotoxicological effects on populations, communities and ecosystems. Room for improvement. Integrated ecotoxicolgy: linking fate and effect within a biological hierarchy. Ecotoxicology: past, present and future. References. Tables. List of figure captions. Figures.

Ecotoxicology in Theory and Practice

1. This paper approaches the phenomenon of hormesis (i.e. stimulatory effects occurring in response to low levels of exposure to agents that are harmful at high levels of exposure) from an evolutionary perspective and addresses three questions related to its occurrence and consequences: (1) Is the occurrence of hormesis to be expected on the basis of evolutionary arguments? (2) Considering selection as a driving force in the evolution of hormesis, is it likely that certain aspects of organism performance have a greater tendency than others to exhibit hormesis? (3) What are the practical implications of hormesis for ecological risk assessment?



2. Several hypotheses are presented to explain the observations of hormesis, and a literature review is used to assess the evidence for hormesis of various fitness-related traits.



3. To avoid statistical artefacts, it is essential that the underlying distribution of traits that appear to show hormesis be examined, particularly as many of them may be expected to deviate from normality.



4. The occurrence of hormesis of individual life-history traits can be explained as an evolutionary adaptation that acts to maintain fitness in a changing environment.



5. As a result of energetic trade-offs among life-history traits, not all traits are likely to exhibit hormesis simultaneously, and therefore overall fitness is not likely to be enhanced at low levels of exposure to toxic agents. Because toxic agents affect different traits in different directions and to different degrees, interpreting the ecological consequences of hormesis of any single trait is not possible without examining it in relation to overall effects on fitness.

Valery E. Forbes

Papers

The use and misuse of biomarkers in ecotoxicology.

Is the per capita rate of increase a good measure of population‐level effects in ecotoxicology?

Species Sensitivity Distributions Revisited: A Critical Appraisal

Ecotoxicology in Theory and Practice

Is hormesis an evolutionary expectation