EVALUATING THE PERSISTENCE OF RESIDENTIAL WATER CONSERVATION: A 1992–1997 PANEL STUDY OF A WATER UTILITY PROGRAM IN DELAWARE1

This study systematically evaluates residential consumer responses to a utility conservation initiative based on an econometric analysis of a sample of 510 households served by Artesian Water Company, Inc. (New Castle County of Delaware). Using a panel study approach covering the period from 1992 to 1997, this study shows that Artesian's water conservation program has had statistically significant and persistent impacts on residential water consumption.     

The Park Made of Oil: Towards a Historical Political Ecology of the Kenneth Hahn State Recreation Area

Within the park-deprived inner-city landscapes of Los Angeles, an unprecedented change is underway. Long considered to be the epitome of anti-nature, Los Angeles is witnessing a boom in park development and ecological restoration. Derelict, blighted and contaminated inner-city brownfield sites are being converted to greenspaces, nature parks and wildlife refuges. Indeed, Los Angeles has been the recent recipient of hitherto unimaginable political and fiscal support to ameliorate the dearth of parks in its neglected urban core. This paper situates the current round of park development within its historical context, by focusing on a very particular local site—the Kenneth Hahn State Recreation Area. Applying the theoretical lens of political ecology, the authors trace some of the political, economic, ecological and institutional factors from the late 1920s onwards, which engendered the creation of a park atop an oilfield. In so doing, the authors deepen the understanding of how local greenspace allocation, poverty, race and political power are oftentimes complexly entangled. Precursor to a much larger project currently in the planning and development stages, the creation of the Kenneth Hahn State Recreation Area reveals some of the ways that the Southern California oil industry has shaped nature spaces in Los Angeles.     

Silver accumulation by fungi

32 species of wild mushrooms were analysed by neutron activation for their silver and eight other trace element contents (Ag, Au, As, Cd, Cs, Cu, Hg, Se, Zn). In all 9 samples of 6 species of Agaricus, high silver concentrations of 10 to 133 ug.g^?1 (dry weight), median 30 ug.g^?1, were found. Puffballs also contained more silver than other species, and also the edible boletus; i.e. those species known to accumulate Hg and Cd. Gold levels tended to be higher where silver was higher, and resembled concentrations in green plants growing on gold mineralisation. Some fungi can accumulate up to 150 ug.g^?1 of caesium.     

ON‐FARM WATER CONSERVATION PRACTICES IN SOUTHERN ALBERTA1

ABSTRACT: In southern Alberta, as elsewhere, pressures on limited water supplies are increasing. Not surprisingly, a great deal of attention has been focused on irrigated agriculture, which accounts for the largest share of water consumed in the region. In order to meet broadly accepted water conservation goals, some commentators have suggested that irrigation water use should be metered and that irrigators should be charged based on the amount of water used. An alternative proposal would have water management authorities rely upon the perceived adaptability of irrigators. This paper offers a perspective on the willingness of irrigators to conserve water. Based on a survey of 183 irrigation farmers conducted over the summer and early fall of 1998, we found that irrigators are generally aware of the need to conserve water and soil moisture, and that a variety of water conserving strategies were being employed. Water saving technologies specific to irrigation agriculture were less widely adopted. The findings suggest that there is considerable potential to reduce the amount of water consumed by the irrigation sector through increased efficiency, but that change will be limited if current economic circumstances and institutional arrangements persist.     

Maternal provisioning for larvae and larval provisioning for juveniles in the toxopneustid sea urchin <Emphasis Type="Italic">Tripneustes gratilla</Emphasis>

Lipid and protein biochemistry of eggs (84 μm in diameter), embryos and early larvae of the tropical echinoid Tripneustes gratilla (Linnaeus 1758) were quantified to determine how maternal provisions are used to fuel development of the echinopluteus. The eggs contained a mean of 30.82 ng lipid and 87.32 ng protein. Energetic lipids were the major lipid component (55.52% of total lipid) with the major class being triglyceride (TG: mean 15.9 ng, 51.58% of total). Structural lipid was dominated by phospholipid (PL: mean 11.18 ng, 36.26% of total). Early embryogenesis was not a major drain on egg energetic lipid and protein. Development of the functional feeding larva used ca. 50% of initial egg energetic lipid and most of this was TG. Maternal TG was still present in the 8-day echinoplutei and it was estimated that this energetic lipid would be depleted in unfed larvae by day 10. There was no change in PL. In a separate experiment lipid biochemistry of rudiment stage larvae and early developing juveniles were quantified to determine how lipids are used during metamorphosis. Fed larvae accumulated lipid (mean 275.49 ng) with TG and PL being the major energetic and structural lipids, respectively. Larval lipid stores were not appreciably depleted by metamorphosis and so were available for the early benthic stage juvenile. Juveniles started their benthic existence with 314 ng total lipid (TG: mean 46.84 ng, 14.9% of total, PL: mean 137.51 ng, 43.67% of total). Nile Red histochemistry and histology showed that the stomach serves as a nutrient storage organ and, that lipid stores accrued by larvae sustain developing juveniles for up to 4 days post settlement. Triglyceride supported both non-feeding stages of development and the prefeeding larval and perimetamorphic benthic stage. In this first study of lipid stores in settlement stage echinoderm larvae, we show that T. gratilla larvae sequester the same major energetic lipid (TG) to support the early juvenile that the female parent provided them to fuel early development.     

Flow injection analysis of trace chromium (VI) in drinking water with a liquid waveguide capillary cell and spectrophotometric detection

Hexavalent chromium (Cr(VI)) is an acknowledged hazardous material in drinking waters. As such, effective monitoring and assessment of the risks posed by Cr(VI) are important analytical objectives for both human health and environmental science. However, because of the lack of highly sensitive, rapid, and simple procedures, a relatively limited number of studies have been carried out in this field. Here we report a simple and sensitive analytical procedure of flow injection analysis (FIA) for sub-nanomolar Cr(VI) in drinking water samples with a liquid core waveguide capillary cell (LWCC). The procedure is based on a highly selective reaction between 1, 5-diphenylcarbazide and Cr(VI) under acidic conditions. The optimized experimental parameters included reagent concentrations, injection volume, length of mixing coil, and flow rate. Measurements at 540 nm, and a 650-nm reference wavelength, produced a 0.12-nM detection limit. Relative standard deviations for 1, 2, and 10 nM samples were 5.6, 3.6, and 0.72 % (n?=?9), and the analysis time was <2 min sample^?1. The effects of salinity and interfering ions, especially Fe(III), were evaluated. Using the FIA-LWCC method, different sources of bottled waters and tap waters were examined. The Cr(VI) concentrations of the bottled waters ranged from the detection limit to ～20 nM, and tap waters collected from the same community supply had Cr(VI) concentration around 14 nM.     

The alarm call system of wild black-fronted titi monkeys, <Emphasis Type="Italic">Callicebus nigrifrons</Emphasis>

Upon encountering predators, many animals produce specific vocalisations that alert others and sometimes dissuade the predators from hunting. Callicebus monkeys are known for their large vocal repertoire, but little is known about the function and meaning of most call types. We recorded a large number of natural predator responses from five different groups of black-fronted titi monkeys in their Atlantic forest habitat in South Eastern Brazil. When detecting predatory threats, adult group members responded with call sequences that initially consisted of two brief, high-pitched calls with distinct frequency contours. Call A was mainly given to raptors but also to predatory capuchin monkeys and other threats within the canopy, while call B was given to predatory or non-predatory disturbances on the ground. In later parts of the sequences, we also recorded a high-pitched unmodulated call C and various low-pitched loud calls. Results therefore suggest that calls A and B provide listeners with rapid and reliable information about the general classes of danger experienced by the caller, while obtaining more specific information through other call types and combinations and behavioural responses. We discuss these findings in relation to current evolutionary theory of primate communication.     

Fertilization in a suite of coastal marine invertebrates from SE Australia is robust to near-future ocean warming and acidification

Climate change driven ocean acidification and hypercapnia may have a negative impact on fertilization in marine organisms because of the narcotic effect these stressors exert on sperm. In contrast, warmer, less viscous water may have a positive influence on sperm swimming speed and so ocean warming may enhance fertilization. To address questions on future vulnerabilities we examined the interactive effects of near-future ocean warming and ocean acidification/hypercapnia on fertilization in intertidal and shallow subtidal echinoids (Heliocidaris erythrogramma, H. tuberculata, Tripneustes gratilla, Centrostephanus rodgersii), an asteroid (Patiriella regularis) and an abalone (Haliotis coccoradiata). Batches of eggs from multiple females were fertilized by sperm from multiple males in all combinations of three temperature and three \textpH/P_\textCO2 {\text{pH}}/P_{{{\text{CO}}_{2} }} treatments. Experiments were placed in the setting of projected near-future conditions for southeast Australia, an ocean change hot spot. There was no significant effect of warming and acidification on the percentage of fertilization. These results indicate that fertilization in these species is robust to temperature and \textpH/P_\textCO2 {\text{pH}}/P_{{{\text{CO}}_{2} }} fluctuation. This may reflect adaptation to the marked fluctuation in temperature and pH that characterises their shallow water coastal habitats. Efforts to identify potential impacts of ocean change to the life histories of coastal marine invertebrates are best to focus on more vulnerable embryonic and larval stages because of their long time in the water column where seawater chemistry and temperature have a major impact on development.     

Thermal tolerance of early development in tropical and temperate sea urchins: inferences for the tropicalization of eastern Australia

The thermal envelope of development to the larval stage of two echinoids from eastern Australia was characterized to determine whether they fill their potential latitudinal ranges as indicated by tolerance limits. The tropical sand dollar, Arachnoides placenta, a species that is not known to have shifted its range, was investigated in Townsville, northern Australia (19°20′S, 146°77′E), during its autumn spawning season (May 2012). The subtropical/temperate sea urchin, Centrostephanus rodgersii, a species that has undergone poleward range expansion, was investigated in Sydney, southern Australia (33°58′S, 151°14′E), during its winter spawning season (August 2012). The thermal tolerance of development was determined in embryos and larvae reared at twelve temperatures. For A. placenta, the ambient water temperature near Townsville and experimental control were 24 °C and treatments ranged from 14 to 37 °C. For C. rodgersii, ambient Sydney water temperature and experimental control were 17 °C, and the treatment range was 9–31 °C. A. placenta had a broader developmental thermal envelope (14 °C range 17–31 °C) than C. rodgersii (9 °C range 13–22 °C). Both species developed successfully at temperatures well below ambient, suggesting that cooler water is not a barrier to poleward migration for either species. Both species presently live near the upper thermal limits for larval development, and future ocean warming could lead to contractions of their northern range limits. This study provides insights into the factors influencing the realized and potential distribution of planktonic life stages and changes to adult distribution in response to global change.