Changes in character of organics in the receiving environment of effluent from a sulphite pulp mill

Purpose

The characteristics of organics in sulphite pulp mill effluent and in the receiving environment of effluent discharge were investigated to assess the basis for the persistence or attenuation of colour.

Methods

Characterization of organics was conducted through determination of SUVA, specific colour, and molecular weight distribution of organics using high performance size exclusion chromatography and by solid-state ¹³?C cross polarization (CP) NMR. The characteristics of organics from mill wastewater before and after secondary aerobic treatment, followed by lime treatment and from the receiving environment, an enclosed brackish lake were compared. Changes in the character of organics in lake water over a period of 14?years were studied in the context of changes in mill processing and climate impacts.

Results

High colour in mill effluent and in receiving waters correlated with high SUVA and specific colour levels, high molecular weight range and aromatic content. Conversely, lake waters with low colour had UV absorbing compounds of much lower molecular weight range and low relative abundance of aromatic compounds. Attenuation of colour and changes in the character of organics in the receiving environment coincided with increased concentrations of metal cations.

Conclusions

These increased concentrations appear to be due to the effects of climate change, lake management and their presence in mill effluent, with subsequent discharge to the lake. Attenuation of colour was found to be predominantly through removal of high molecular weight aromatic compounds where the removal processes could be through adsorption and co-precipitation with divalent metals, as well as through dilution processes.     

The Costa Rican Experience with Market Instruments to Mitigate Climate Change and Conserve Biodiversity

Two decades of developing relevant legal and institutional regimes for the sustainable and nondestructive use of natural resources have framed Costa Rica's pioneer approach to mitigate climate change and conserve its rich biological diversity. This policy framework provides an appropriate context for the actual and proposed development of market instruments designed to attract capital investments for carbon sequestration and biodiversity conservation, and allows the establishment of mechanisms to use those funds to compensate owners for the environmental services provided by their land. As a developing economy. Costa Rica is striving to internalize the benefits from the environmental services it offers, as a cornerstone of its sustainable development strategy.     

Dioxins in human milk and smoking of mothers

BACKGROUND: The relation between the levels of dioxins in human breast milk and the smoking habits of the mothers is controversial. To clarify this relationship, we analyzed data from the human milk survey in Japan. METHODS: The human milk survey has been conducted in Japan since 1997. Healthy pregnant women aged 20-39 years were recruited and 50 ml of breast milk was collected from them at 30 days after delivery. PCDDs, PCDFs, and dioxin-like PCBs were measured by using GC/MS. The smoking habits of the mothers were established by interviewing them soon after delivery and were classified into four categories: current smokers, ever smokers who quit smoking at the pregnancy, ever smokers who quit smoking before the pregnancy, and never smokers. The levels of dioxins in breast milk were compared in the four categories of smoking among 853 primiparas. In addition, we analyzed the association between dioxin levels and passive smoking among never smokers. The geometric means of the dioxin concentrations were calculated in order to compare the differences between dioxins. RESULTS: The geometric means of dioxin-like PCBs in milk of never smokers was the highest (9.2 pg TEQ/g fat); followed by ever smokers who quit smoking before the pregnancy, ever smokers who quit smoking at the pregnancy, and current smokers (7.5, 7.2, and 6.6 pg TEQ/g fat, respectively). The differences between these levels were statistically significant (ANOVA, p<0.001). No significant difference was observed between the level of dioxins in milk from never smokers subjected to passive smoking status and those who had not experienced passive smoking. CONCLUSION: The levels of dioxin-like PCBs in human milk were negatively related to the smoking habits of mothers.     

Effects of learning and adaptation on population viability

Cultural adaptation is one means by which conservationists may help populations adapt to threats. A learned behavior may protect an individual from a threat, and the behavior can be transmitted horizontally (within generations) and vertically (between generations), rapidly conferring population-level protection. Although possible in theory, it remains unclear whether such manipulations work in a conservation setting; what conditions are required for them to work; and how they might affect the evolutionary process. We examined models in which a population can adapt through both genetic and cultural mechanisms. Our work was motivated by the invasion of highly toxic cane toads (Rhinella marina) across northern Australia and the resultant declines of endangered northern quolls (Dasyurus hallucatus), which attack and are fatally poisoned by the toxic toads. We examined whether a novel management strategy in which wild quolls are trained to avoid toads can reduce extinction probability. We used a simulation model tailored to quoll life history. Within simulations, individuals were trained and a continuous evolving trait determined innate tendency to attack toads. We applied this model in a population viability setting. The strategy reduced extinction probability only when heritability of innate aversion was low (<20%) and when trained mothers trained >70% of their young to avoid toads. When these conditions were met, genetic adaptation was slower, but rapid cultural adaptation kept the population extant while genetic adaptation was completed. To gain insight into the evolutionary dynamics (in which we saw a transitory peak in cultural adaptation over time), we also developed a simple analytical model of evolutionary dynamics. This model showed that the strength of natural selection declined as the cultural transmission rate increased and that adaptation proceeded only when the rate of cultural transmission was below a critical value determined by the relative levels of protection conferred by genetic versus cultural mechanisms. Together, our models showed that cultural adaptation can play a powerful role in preventing extinction, but that rates of cultural transmission need to be high for this to occur.     

Historical area and shoreline change of reef islands around Tarawa Atoll, Kiribati

Low-lying reef islands on atolls appear to be threatened by impacts of observed and anticipated sea-level rise. This study examines changes in shoreline position on the majority of reef islands on Tarawa Atoll, the capital of Kiribati. It investigates short-term reef-island area and shoreline change over 30 years determined by comparing 1968 and 1998 aerial photography using geographical information systems. Reef islands have substantially increased in size, gaining about 450 ha, driven largely by reclamations on urban South Tarawa, accounting for 360 ha (~80 % of the net change). Widespread erosion and high average accretion rates appear to be related to disjointed reclamations. In rural North Tarawa, most reef islands show stability, with localised changes in areas such as embayments, sand spits and beaches adjacent to, or facing, inter-island channels. Shoreline changes in North Tarawa are largely influenced by natural factors, whereas those in South Tarawa are predominantly affected by human factors and seasonal variability associated with El Niño—Southern Oscillation (ENSO). However, serious concerns are raised for the future of South Tarawa reef islands, as evidence shows that widespread erosion along the ocean and lagoon shorelines is primarily due to human activities and further encroachment onto the active beach will disrupt longshore sediment transport, increasing erosion and susceptibility of the reef islands to anticipated sea-level rise. Appropriate adaptation measures, such as incorporating coastal processes and seasonal variability associated with ENSO when designing coastal structures and developing appropriate management plans, are required, including prohibiting beach mining practices near settlements.     

The influence of ants on host plant selection by Jalmenus evagoras,a myrmecophilous lycaenid butterfly

Summary (1) Females of the myrmecophilous lycaenid butterfly, Jalmenus evagoras are far more likely to lay eggs on plants that contain their attendant ants, Iridomyrmex sp. 25 than on plants without ants, although the clutch sizes of individual egg masses laid in either situation is the same. (2) Ovipositing females respond to the presence or absence of ants before they alight on a potential food plant. Once they have landed, they are equally likely to ley eggs whether or not they encounter ants. (3) Ovipositing females prefer to lay eggs on plants that contain ant tended homopterans than on plants that contain only a few foraging ants. The presence of ant tended homopterans can act as a strong stimulus to induce females to lay eggs on plant species that differ from their original host species. (4) Ant dependent oviposition behavior has been described or suggested in 46 species of lycaenid and one riodinid. In general, the more dependent a species is upon ants for either food or protection, the more likely it is to use ants as cues in oviposition. Prominent characteristics of lycaenids that have ant dependent oviposition are described and discussed. (5) Myrmecophilous lycaenids that may use ants as cues in oviposition feed on a significantly wider range of plants than non-myrmecophilous lycaenids. Possible reasons for this pattern and its ecological significance are discussed.     

Temporal and spatial variability in water quality of wetlands in the Minneapolis/St. Paul,MN metropolitan area: Implications for monitoring strategies and designs

Temporal and spatial variability in wetland water-quality variables were examined for twenty-one wetlands in the Minneapolis/St. Paul metropolitan area and eighteen wetlands in adjacent Wright County. Wetland water quality was significantly affected by contact with the sediment (surface water vs. groundwater), season, degree of hydrologic isolation, wetland class, and predominant land-use in the surrounding watershed (p<0.05). Between years, only nitrate and particulate nitrogen concentrations varied significantly in Wright County wetland surface waters. For eight water-quality variables, the power of a paired before-and-after comparison design was greater than the power of a completely randomized design. The reverse was true for four other water-quality variables. The power of statistical tests for different classes of water-quality variables could be ranked according to the predominant factors influencing these: climate factors>edaphic factors>detritivory>land-use factors>biotic-redox or other multiple factors.For two wetlands sampled intensively, soluble reactive phosphate and total dissolved phosphorus were the most spatially variable (c.v.=76–249%), while temperature, color, dissolved organic carbon, and DO were least variable (c.v.=6–43%). Geostatistical analyses demonstrated that the average distance across which water-quality variables were spatially correlated (variogram range) was 61–112% of the mean radius of each wetland. Within the shallower of the two wetlands, nitrogen speciation was explained as a function of dissolved oxygen, while deeper marsh water-quality variables were explained as a function of water depth or distance from the wetland edge. Compositing water-quality samples produced unbiased estimates of individual sample means for all water quality variables examined except for ammonium.     

Genotypic differences in brood rearing in honey bee colonies: context-specific?

Summary Three experiments were performed to determine whether brood care in honey bee colonies is influenced by colony genetic structure and by social context. In experiment 1, there were significant genotypic biases in the relative likelihood of rearing queens or workers, based on observations of individually labeled workers of known age belonging to two visually distinguishable subfamilies. In experiment 2, no genotypic biases in the relative likelihood of rearing drones or workers was detected, in the same colonies that were used in experiment 1. In experiment 3, there again were significant genotypic differences in the likelihood of rearing queens or workers, based on electrophoretic analyses of workers from a set of colonies with allozyme subfamily markers. There also was an overall significant trend for colonies to show greater subfamily differences in queen rearing when the queens were sisters (half- and super-sisters) rather than unrelated, but these differences were not consistent from trial to trial for some colonies. Results of experiments 1 and 3 demonstrate genotypic differences in queen rearing, which has been reported previously based on more limited behavioral observations. Results from all three experiments suggest that genotypic differences in brood care are influenced by social context and may be more pronounced when workers have a theoretical opportunity to practice nepotism. Finally, we failed to detect persistent interindividual differences in bees from either subfamily in the tendency to rear queen brood, using two different statistical tests. This indicates that the probability of queen rearing was influenced by genotypic differences but not by the effect of prior queen-rearing experience. These results suggest that subfamilies within a colony can specialize on a particular task, such as queen rearing, without individual workers performing that task for extended periods of time.