Anion and cation leaching or desorption from activated carbons from municipal sludge and poultry manure as affected by pH.

The conversion of municipal sludge and poultry manure to activated carbon results in a significant ash fraction that contains several different anions and cations. The objectives of this study were to determine whether the select ions are released or leached from virgin carbon into the sorption medium at different pH values. Activated carbon was placed in solutions of pH 1, 5, or 7, and the leaching of six cations (cadmium, chromium, copper, nickel, lead, and zinc) and two anions (arsenate and selenate) was recorded. Considerable quantities of zinc and copper were removed at pH 1 from all carbon sources. However, the amounts leached at pH 5 and 7 were small or undetectable. Our results indicate that leaching or desorption from carbons made from municipal sludge or poultry manure is pH-dependent and occurs readily under highly acidic conditions but minimally under pH conditions typically seen in contaminated water or wastewater.     

Responses to projected changes in climate and UV-B at the species level

Environmental manipulation experiments showed that species respond individualistically to each environmental-change variable. The greatest responses of plants were generally to nutrient, particularly nitrogen, addition. Summer warming experiments showed that woody plant responses were dominant and that mosses and lichens became less abundant. Responses to warming were controlled by moisture availability and snow cover. Many invertebrates increased population growth in response to summer warming, as long as desiccation was not induced. CO2 and UV-B enrichment experiments showed that plant and animal responses were small. However, some microorganisms and species of fungi were sensitive to increased UV-B and some intensive mutagenic actions could, perhaps, lead to unexpected epidemic outbreaks. Tundra soil heating, CO2 enrichment and amendment with mineral nutrients generally accelerated microbial activity. Algae are likely to dominate cyanobacteria in milder climates. Expected increases in winter freeze-thaw cycles leading to ice-crust formation are likely to severely reduce winter survival rate and disrupt the population dynamics of many terrestrial animals. A deeper snow cover is likely to restrict access to winter pastures by reindeer/caribou and their ability to flee from predators while any earlier onset of the snow-free period is likely to stimulate increased plant growth. Initial species responses to climate change might occur at the sub-species level: an Arctic plant or animal species with high genetic/racial diversity has proved an ability to adapt to different environmental conditions in the past and is likely to do so also in the future. Indigenous knowledge, air photographs, satellite images and monitoring show that changes in the distributions of some species are already occurring: Arctic vegetation is becoming more shrubby and more productive, there have been recent changes in the ranges of caribou, and "new" species of insects and birds previously associated with areas south of the treeline have been recorded. In contrast, almost all Arctic breeding bird species are declining and models predict further quite dramatic reductions of the populations of tundra birds due to warming. Species-climate response surface models predict potential future ranges of current Arctic species that are often markedly reduced and displaced northwards in response to warming. In contrast, invertebrates and microorganisms are very likely to quickly expand their ranges northwards into the Arctic.     

Variability in host plant chemistry: behavioural responses and life-history parameters of the Colorado potato beetle (Leptinotarsa decemlineata)

Summary. Many studies investigating effects of plant chemicals on herbivore performance have reported contradictory results, perhaps because of possible interaction between different chemicals. Also, a herbivore’s performance is not necessarily consistent with its food or oviposition preference. Our aim was to investigate simultaneously antibiosis (larval growth and survival) and antixenosis (oviposition and feeding preferences) responses in herbivore to three plant chemicals, of which one is expected to have positive and two are expected to have negative effects. Antibiosis was measured by correlating the nitrogen and glycoalkaloid levels in host plants to the survival and adult size of Leptinotarsa decemlineata, by rearing larvae on whole plants of three potato varieties. Although host plants differed in their glycoalkaloid levels, survival rate and adult body size did not differ among beetles reared on different potato varieties. This suggests that beetles are quite robust for differences in both foliar α-chaconine and foliar α-solanine content. However, differences in antixenosis were found although they could not be directly predicted from the leaf chemistry. Females preferred to lay their eggs on the variety with high α-solanine content (Nevsky) towards which males showed a tendency to feeding preference. Overall, our results confirm that beetles are well adapted to the chemical defences of potato plants as potato varieties did not significantly affect beetle performance, but differences in oviposition preference may still result in major differences in the amount of damage inflicted on plants in the fields.     

Sex-role reversal in willow tit nest defence

Summary The roles of sexes in the nest defence behavior of monogamous willow tit (Parus montanus) were studied near Oulu, northern Finland, in 1988–1990. The relative roles of the sexes changed during the breeding cycle: females defended their nests more vigorously before hatching and males defended more after hatching. This sexual asymmetry was studied by means of the cost/benefit model of optimal parental investment (PI). Because of the monogamous breeding system, sexual differences in future benefits were not a likely explanation for the asymmetry. This was also supported by preliminary results of DNA-fingerprinting analyses. Behavioral observations — sex-role reversal, high correlation between the mates, and equal variations in male and female behavior — indicated the same. In the beginning of the breeding cycle, higher female defence was related to renesting potential. The extra costs of renesting are considerably higher for females than for males, and therefore, females appeared to benefit more than males in keeping the first clutch alive while renesting was still possible. Such a female strategy was possible in this northern population, since the time for renesting was rather short and never lasted beyond the hatching of the first nests. After this point, the male can only invest in the present clutch. By the end of the breeding cycle, increased defence of the nest by males may be a consequence of males being larger and/or in better condition than females. Therefore, in the latter half of the breeding cycle, the sexual differences in nest defence did not indicate any sexual difference in PI. The asynchronous arrival of the parents at the nest also affected individual responses, indicating that defending the nest is a dynamic process.     

Fetal granulocytes in maternal venous blood detected by in situ hybridization

Fetal male cells from maternal venous blood were detected by a non-radioactive in situ hybridization method using the biotinylated Y-specific DNA probe pY431. The hybridizations were performed on Ficoll-Paque-isolated nucleated blood cells obtained from 11 pregnant women in the seventh to 31st week of gestation. A Y-specific signal was detected in both granulocytes and lymphocyte-like cells in seven of the 11 women studied. These women gave birth to boys. In one of the four remaining cases, a Y-specific signal was detected in the lymphocyte-like cells but not in the granulocytes. This woman gave birth to a girl. The other three women had no cells with a Y-specific signal and all three gave birth to girls. Altogether, 83 500 nucleated cells were analysed. One hundred and three cells showed a Y-specific signal. Of these Y-specific cells, 62 per cent were granulocytes and 38 per cent lymphocyte-like cells. Our results suggest that fetomaternal transfer of granulocytes is common and that it occurs as early as in the seventh week of gestation. None of the ten non-pregnant female control samples showed positive cells with the Y-chromosome-specific probe; approximately 97 per cent of the cells from the five adult male controls showed a Y-specific signal. Our results indicate that in situ hybridization using a Y-specific DNA probe performed on granulocytes in maternal blood can be used for fetal male sex determination.     

Season- and herbivore-dependent competition and facilitation in a semiarid savanna

Empirical and theoretical evidence suggests that facilitation between plants, when it occurs, is more likely during periods of abiotic stress, while competition predominates under more moderate conditions. Therefore, one might expect the relative importance of competition vs. facilitation to vary seasonally in ecosystems characterized by pronounced dry (abiotically stressful) and wet (benign) seasons. Herbivory also varies seasonally and can affect the net outcome of plant-plant interactions, but the interactive effects of seasonality and herbivory on the competition-facilitation balance are not known. I experimentally manipulated neighboring plants and herbivory during wet and dry periods for two species of grass: Cynodon plectostachyus and Pennisetum stramineum, in the semiarid Laikipia District of Kenya. These experiments indicate that Pennisetum was competitively dominant during the wet season and that it responded negatively to grazing, especially during the dry season. Cynodon showed more complex season- and herbivore-dependent responses. Cynodon experienced facilitation that was simultaneously dependent on presence of herbivores and on dry season. During the wet season Cynodon experienced net competition. These results illustrate how herbivory and seasonality can interact in complex ways to shift species-species competition-facilitation balance. Additionally, because Cynodon and Pennisetum are key players in a local successional process, these results indicate that herbivory can affect the direction and pace of succession.     

Aging and demographic plasticity in response to experimental age structures in honeybees (<Emphasis Type="Italic">Apis mellifera</Emphasis> L)

Honeybee colonies are highly integrated functional units characterized by a pronounced division of labor. Division of labor among workers is mainly age-based, with younger individuals focusing on in-hive tasks and older workers performing the more hazardous foraging activities. Thus, experimental disruption of the age composition of the worker hive population is expected to have profound consequences for colony function. Adaptive demography theory predicts that the natural hive age composition represents a colony-level adaptation and thus results in optimal hive performance. Alternatively, the hive age composition may be an epiphenomenon, resulting from individual life history optimization. We addressed these predictions by comparing individual worker longevity and brood production in hives that were composed of a single-age cohort, two distinct age cohorts, and hives that had a continuous, natural age distribution. Four experimental replicates showed that colonies with a natural age composition did not consistently have a higher life expectancy and/or brood production than the single-cohort or double-cohort hives. Instead, a complex interplay of age structure, environmental conditions, colony size, brood production, and individual mortality emerged. A general tradeoff between worker life expectancy and colony productivity was apparent, and the transition from in-hive tasks to foraging was the most significant predictor of worker lifespan irrespective of the colony age structure. We conclude that the natural age structure of honeybee hives is not a colony-level adaptation. Furthermore, our results show that honeybees exhibit pronounced demographic plasticity in addition to behavioral plasticity to react to demographic disturbances of their societies.     

Perceived and measured levels of environmental pollution: interdisciplinary research in the subarctic lowlands of northeast European Russia

Using interdisciplinary field research in the Usa Basin, northeast European Russia, we compared local inhabitants' perception of environmental problems with chemical and remote-sensing signatures of environmental pollution and their local impacts. Extensive coal mining since the 1930s around Inta and Vorkuta has left a legacy of pollution, detected by measuring snowpack, topsoil, and lichen chemistry, together with remote-sensing techniques and analysis of lake water and sediments. Vorkuta and its environs suffered the worst impacts, with significant metal loading and alkalization in lakes and topsoils, elevated metals and cations in terricolous (reindeer) lichens, and changes in vegetation communities. Although the coal industry has declined recently, the area boasts a booming oil and gas industry, based around Usinsk. Local perceptions and concerns of environmental pollution and protection were higher in Usinsk, as a result of increased awareness after a major oil spill in 1994, compared with Vorkuta's inhabitants, who perceived air pollution as the primary environmental threat. Our studies indicate that the principal sources of atmospheric emissions and local deposition within 25 to 40 km of Vorkuta were coal combustion from power and heating plants, coal mines, and a cement factory. Local people evaluated air pollution from direct observations and personal experiences, such as discoloration of snow and respiratory problems, whereas scientific knowledge played a minor role in shaping these perceptions.