Settlement of larval blacklip abalone, Haliotis rubra, in response to green and red macroalgae

Surfaces from the habitat of adult Haliotis rubra were tested as inducers of larval settlement to determine the cues that larvae may respond to in the field. Settlement was high on the green algal species Ulva australis and Ulva compressa (Chlorophyta), the articulated coralline algae Amphiroa anceps and Corallina officinalis, and encrusting coralline algae (Rhodophyta). Biofilmed abiotic surfaces such as rocks, sand and shells did not induce settlement. Ulvella lens was also included as a control. Treatment of U. australis, A. anceps and C. officinalis with antibiotics to reduce bacterial films on the surface did not reduce the settlement response of H. rubra larvae. Similarly, treatment of these species and encrusting coralline algae with germanium dioxide to reduce diatom growth did not significantly reduce larval settlement. These results suggest that macroalgae, particularly green algal species, may play an important role in the recruitment of H. rubra larvae in the field and can be used to induce larval settlement in hatchery culture.     

Power and Sample Size Calculations for Linear Hypotheses Associated with Mixtures of Many Components using Fixed-Ratio Ray Designs

Response surface methodology, often supported by factorial designs, is the classical experimental approach that is widely accepted for detecting and characterizing interactions among chemicals in a mixture. In an effort to reduce the experimental effort as the number of compounds under study is increased, ray designs have been proposed to study combinations of chemicals. When interest is restricted to relevant mixing ratios, we are only interested in making inference along the specific rays of interest, as opposed to methods which use designs that require more experimental effort to support the estimation of a response surface over a broader experimental region. Methods have been developed for the test of additivity along multiple fixed-ratio rays. Of primary importance is the detection of interactions with reasonable power. The objective of this paper is to address power and sample size issues related to the hypothesis of no interaction.     

UK electricity requirements and the environmental and economic aspects of the development of the combined cycle power station

In the space of three to four years, gas has changed from being a premium fuel, not to be utilized in power stations, to virtually the only fuel being considered for future electricity generation in the UK. This paper reviews the growth in the use of gas for electricity generation within the UK, with particular regard to the adoption of the gas-fired combined cycle power station. The environmental, economic and strategic issues associated with the proposed development of approximately 27 GW of new gas-fired plant are analysed and the resulting effects on existing base load power plant within the UK are considered.Dr James W.S. Longhurst is Director of the Atmospheric Research and Information Centre, ARIC, at Manchester Metropolitan University He is an environmental scientist who has specialized in the air quality impacts of transport and energy. He holds a BSc, MSc and PhD in Environmental Science from, Plymouth Polytechnic, Aston University and Birmingham University, respectively. He has written numerous papers, consultancy reports, books and technical reports since 1986.Jane Bantock joined ARIC in 1992 with a degree in Environmental Studies from Manchester Polytechnic. She jointly manages ARIC's information and education programmes. Her research interests include the inter-relationship of UK energy policy and emission control in the electricity generating sector, the subject of her part time PhD, and urban air quality issues.     

Humic complexes of diethyl phthalate: molecular modelling of the sorption process

The sorption mechanisms and complex formation between humic acid (HA) and a successively increasing number of diethyl phthalate (DEP) molecules have been studied theoretically using molecular mechanics, the number (n) of DEP molecules being varied from 1 to 30. The energy components of the single HA x nDEP complexes have been used as explanatory variables in a principal component analysis for exploring the presence of similarities/dissimilarities in the energetic properties of the individual xenobiotic complexes. The sorption can be explained in terms of a two-step mechanism. Absorption takes place as long as the host humic acid structure offers (a) enough internal docking space and (b) favorable interactions (energy release) with the guest molecule. This takes place for up to 7 DEP molecules. Further increase in the number to 30 DEP molecules will, due to the lack of free available internal voids, lead to surface controlled adsorption. The two-step sorption process apparently results in (a) a linear increase in energy gain by DEP bonds, and similarly (b) a constant incremental rise in molecular properties of the complexes such as volume and surface area. Three outstanding observations emerge: (1) Structural features at the atomic level (nanochemistry), such as partial atomic charges and high aromaticity of the humic acid, are observed to be dominating the intermolecular interactions in the complexes at the specific sorption sites. (2) Torsional relief and favorable changes in bonding energy also prevail for the growing complex. The latter indicates both the structural flexibility of the HA host and the stabilizing effect of DEP on the complex, by filling of the voids within the HA molecule. (3) The intermolecular forces are described mainly by hydrogen bonds (electrostatic energy) and interactions between dipole-dipole, such as carboxylic functions and uncharged moieties such as aromatic rings (van der Waals energy).     

Duck Populations as Indicators of Landscape Condition in the Prairie Pothole Region

The Prairie Pothole Region of the northern GreatPlains is an important region for waterfowl production becauseof the abundance of shallow wetlands. The ecologicalsignificance of the region and impacts from intensiveagriculture prompted the U.S. Environmental Protection Agency to select it as one ofthe first areas for developing and evaluating ecologicalindicators of wetland condition. We examined hypothesizedrelations between indicators of landscape and wetlandconditions and waterfowl abundance on 45 40 km² study sites in North Dakota for1995–1996. Landscape condition was defined a priori as the ratio of cropland area to total upland area surroundingwetlands. Measures of waterfowl abundance included estimatednumbers of breeding pairs (by species and total numbers) and , a species-specific correction factor which effectively adjusts breedingpair estimates for annual or area-related differences in pondsize. Landscape indicators and waterfowl measures varied among regions. Results indicated that most areas in the Coteau region are ofmuch higher quality for ducks than those in the Drift Plain,and areas in the Red River Valley are of the poorest qualityfor ducks. Regression models demonstrated the impact ofagricultural development on breeding duck populations in the PrairiePothole Region. The most consistent landscape indicators ofwaterfowl abundance were percent of cropland and grassland. Models were inconsistent among years and species. Thepotential biotic indicators of landscape and wetland condition examined here wouldbe appropriate for temporal trend analyses, but because ofinherent geographic variability would not be appropriate forsingle-year geographic trend analyses without more extensiveevaluations to improve explanatory models.     

Can progress in reducing alcohol-impaired driving fatalities be resumed? Results of a workshop sponsored by the Transportation Research Board,Alcohol, Other Drugs,and Transportation Committee (ANB50)

Objective: Despite successes in the 1980s and early 1990s, progress in reducing impaired driving fatalities in the United States has stagnated in recent years. Since 1997, the percentage of drivers involved in fatal crashes with illegal blood alcohol concentration (BAC) levels has remained at approximately 20 to 22%. Many experts believe that public complacency, competing social and public health issues, and the lack of political fortitude have all contributed to this stagnation. The number of alcohol-related crashes, injuries, and fatalities is still unacceptable, and most are preventable. The public needs to be aware that the problem presented by drinking drivers has not been solved. Political leaders need guidance on which measures will affect the problem, and stakeholders need to be motivated once again to implement effective strategies.

Methods: The National Academy of Sciences (NAS) Transportation Research Board (TRB), Alcohol, Other Drugs, and Transportation Committee (ANB50) sponsored a workshop held at the NAS facility in Woods Hole, Massachusetts, on August 24–25, 2015, to discuss the lack of progress in reducing impaired driving and to make recommendations for future progress. A total of 26 experts in research and policy related to alcohol-impaired driving participated in the workshop. The workshop began by examining the static situation in the rate of alcohol-impaired driving fatal crashes to determine what factors may be inhibiting further progress. The workshop then discussed 8 effective strategies that have not been fully implemented in the United States. Workshop participants (16 of the 26) rated their top 3 strategies.

Results: 3 strategies received the most support: 1. Impose administrative sanctions for drivers with BACs = 0.05 to 0.08 g/dL.

2. Require alcohol ignition interlocks for all alcohol-impaired driving offenders.

3. Increase the frequency of sobriety checkpoints, including enacting legislation to allow them in the 11 states that currently prohibit them.

5 other important strategies included the following: (1) increase alcohol taxes to raise the price and reduce alcohol consumption; (2) reengage the public and raise the priority of impaired driving; (3) lower the illegal per se BAC limit to 0.05 for a criminal offense; (4) develop and implement in-vehicle alcohol detection systems; and (5) expand the use of screening and brief interventions in medical facilities.

Conclusions: Each of these strategies is proven to be effective, yet all are substantially underutilized. Each is used in some jurisdictions in the United States or Canada, but none is used extensively. Any one of the 3 strategies implemented on a widespread basis would decrease impaired driving crashes, injuries, and fatalities. Based on the research, all 3 together would have a substantial impact on the problem.     

An Integrated Approach to Reservoir Management: The Williston Reservoir Case Study

/ The management of industrial reservoirs for hydroelectric energy can cause severe impacts to surrounding communities. This study examines the generation of dust along the northern foreshore zones of Williston Reservoir in northern British Columbia. The dust is generated in the spring when the reservoir levels are low and impacts a relocated First Nations' village (Tsay Keh) at the north end of the reservoir. Data were gathered to provide an overview of the physical conditions that contribute to the dust problem, including a social survey, soil analysis, and vegetation inventory. The study provides a scoping method to assess a large-scale and complex problem with respect to dust management along a large reservoir. Methods for dust control include short- and long-term solutions that integrate the use of native vegetation along the foreshore zones of the reservoir.     

Fitness benefits of size-dependent diet switching in a marine herbivore

Although diet is one of the most important parameters affecting the fitness of terrestrial and marine herbivores, host plant choice and subsequent fitness on that host are not always correlated. This study investigated the effect of diet on fitness of the sea urchin Holopneustes purpurascens, which show an ontogenetic change in host plant use subsequent to recruitment. To test whether fitness on host plant mirrored host plant choice, small and large individuals were collected from both hosts and fed either host plant (Ecklonia radiata or Delisea pulchra). Small urchins survived better than large individuals. Those fed E. radiata produced fewer test lesions, grew faster and were more fecund than those fed D. pulchra, irrespective of size. This pattern was enhanced when the host plant the urchin previously inhabited was assessed. Our results show that diet is driving the previously recorded ontogenetic change in host plant use associated with increasing size in H. purpurascens, where medium-sized individuals switch from D. pulchra to E. radiata.     

Moderate seawater acidification does not elicit long-term metabolic depression in the blue mussel Mytilus edulis

Marine organisms are exposed to increasingly acidic oceans, as a result of equilibration of surface ocean water with rising atmospheric CO₂ concentrations. In this study, we examined the physiological response of Mytilus edulis from the Baltic Sea, grown for 2 months at 4 seawater pCO₂ levels (39, 113, 243 and 405 Pa/385, 1,120, 2,400 and 4,000 μatm). Shell and somatic growth, calcification, oxygen consumption and \textNH₄ ⁺ {\text{NH}}_{4}^{ + } excretion rates were measured in order to test the hypothesis whether exposure to elevated seawater pCO₂ is causally related to metabolic depression. During the experimental period, mussel shell mass and shell-free dry mass (SFDM) increased at least by a factor of two and three, respectively. However, shell length and shell mass growth decreased linearly with increasing pCO₂ by 6–20 and 10–34%, while SFDM growth was not significantly affected by hypercapnia. We observed a parabolic change in routine metabolic rates with increasing pCO₂ and the highest rates (+60%) at 243 Pa. \textNH₄ ⁺ {\text{NH}}_{4}^{ + } excretion rose linearly with increasing pCO₂. Decreased O:N ratios at the highest seawater pCO₂ indicate enhanced protein metabolism which may contribute to intracellular pH regulation. We suggest that reduced shell growth under severe acidification is not caused by (global) metabolic depression but is potentially due to synergistic effects of increased cellular energy demand and nitrogen loss.