Distribution and rate of disappearance of fluorene in pond ecosystems

Fluorene, an energy related polynuclear aromatic hydrocarbon, was applied to several experimental pond ecosystems to effect concentrations of 0.12, 0.5, 2.0, 5.0, and 10.0 mg/L. Water, benthic sediment, and rooted macrophytes were monitored for fluorene residues for 56 days after application. Most of the fluorene at concentrations greater than its water solubility appeared to sublime from the surface of the ponds. The rate of disappearance of fluorene from the water decreased as the application rate increased. This reduction was linked to high concentrations and a flux of fluorene from benthic sediments, macrophytes, and pond surfaces to water columns. Several parameters of photosynthetic primary production were statistically linked to the accelerated disappearance of fluorene from the water.     

Climate and human impact on lowland lake sedimentation in Central Coastal California: the record from c. 650 ad to the present

The limnological record of human impact on catchment land cover and on lake sedimentation during the historical period has been established for Pinto Lake in Central Coastal California. In addition, the sedimentary record of the ‘pre-impact’ condition preserves evidence of a climatic control on the nature of lake sedimentation. Chronological marker horizons have been determined using pollen data in combination with the documented land-use history and introductions of exotic species. Further chronological data have been determined using ¹⁴C and ¹³⁷Cs. The impact of Mexican and Euro-American immigrants and their ‘imported’ land-use practices is clearly reflected in an order of magnitude increase in the rate of lake sedimentation to c. 9 kg m⁻² year⁻¹ (c. 2 cm year⁻¹) between 1770 and 1850. Here, the occurrence of exotic plant species indicates disturbance as early as c. 1769–1797, whilst redwood deforestation between 1844 and 1860 represents the most significant human impact. Changes in the nature of sedimentation prior to this reveal a high degree of sensitivity to changes in precipitation where subtle decreases in lake level and the supply of runoff-derived mineral matter have resulted in two periods of organic lake sedimentation c. 650–900 and 1275–1750. Set against this background condition of high sensitivity, the dramatic impacts of Euro-American settlement are unsurprising. An erratum to this article can be found at     

Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin,Nevada1

Carroll, Rosemary W.H., Greg Pohll, David McGraw, Chris Garner, Anna Knust, Doug Boyle, Tim Minor, Scott Bassett, and Karl Pohlmann, 2010. Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin, Nevada. Journal of the American Water Resources Association (JAWRA) 46(3):554-573. DOI: 10.1111/j.1752-1688.2010.00434.x Abstract: An integrated surface water and groundwater model of Mason Valley, Nevada is constructed to replicate the movement of water throughout the different components of the demand side of water resources in the Walker River system. The Mason Valley groundwater surface water model (MVGSM) couples the river/drain network with agricultural demand areas and the groundwater system using MODFLOW, MODFLOW’s streamflow routing package, as well as a surface water linking algorithm developed for the project. The MVGSM is capable of simulating complex feedback mechanisms between the groundwater and surface water system that is not dependent on linearity among the related variables. The spatial scale captures important hydrologic components while the monthly stress periods allow for seasonal evaluation. A simulation spanning an 11-year record shows the methodology is robust under diverse climatic conditions. The basin-wide modeling approach predicts a river system generally gaining during the summer irrigation period but losing during winter months and extended periods of drought. River losses to the groundwater system approach 25% of the river’s annual budget. Reducing diversions to hydrologic response units will increase river flows exiting the model domain, but also has the potential to increase losses from the river to groundwater storage.     

Evaluation of Kraft Process Pollution Abatement Strategies by Time Series Analysis of Makeup Records

A historical record of monthly chemical makeups for a North American pulp mill has been analyzed by time series methods. The analysis yields estimates for the reduction in sulfur makeup resulting from each of three separate pollution abatement moves: black liquor oxidation, blow heat recovery, and cooking liquor sulfidity reduction. Further analysis yields estimates of sulfurous emissions and of the substantially lower emissions which could have been achieved if sulfidity management had been incorporated in the program.     

Bibliometric investigation of the integration of animal personality in conservation contexts

Consistent individual differences in behavior, commonly termed animal personality, are a widespread phenomenon across taxa that have important consequences for fitness, natural selection, and trophic interactions. Animal personality research may prove useful in several conservation contexts, but which contexts remains to be determined. We conducted a structured literature review of 654 studies identified by combining search terms for animal personality and various conservation subfields. We scored the relevance of personality and conservation issues for each study to identify which studies meaningfully integrated the 2 fields as opposed to surface-level connections or vague allusions. We found a taxonomic bias toward mammals (29% of all studies). Very few amphibian or reptile studies applied personality research to conservation issues (6% each). Climate change (21%), invasive species (15%), and captive breeding and reintroduction (13%) were the most abundant conservation subfields that occurred in our search, though a substantial proportion of these papers weakly integrated conservation and animal personality (climate change 54%, invasive species 51%, captive breeding and reintroduction 40%). Based on our results, we recommend that researchers strive for consistent and broadly applicable terminology when describing consistent behavioral differences to minimize confusion and improve the searchability of research. We identify several gaps in the literature that appear to be promising and fruitful avenues for future research, such as disease transmission as a function of sociability or exploration as a driver of space use in protected areas. Practitioners can begin informing future conservation efforts with knowledge gained from animal personality research.     

The limits to risk aversion: Part 2: The permission point and worked examples

Part 2 extends the analysis to show that it is possible to find the “permission point”, the value of (the coefficient of relative) risk-aversion, at which decisions to sanction environmental protection are most likely to be made. The mathematical model describes the process by which the decision maker varies his risk-aversion over a range of feasible values to find the risk-aversion that will give him the greatest desire to invest in the protection system under consideration. If he can find such a risk-aversion before losing discrimination (because the system is too expensive, given its performance), he will adopt it as his “permission point” and decide in favour of the expenditure. The permission point is, of course, bounded above by the point of indiscriminate decision. A maximum Risk Multiplier calculated at the point of indiscriminate decision may be applied to the protection expenditure at monetary break-even to give the maximum, rational outlay on protection. Moreover, it is possible to model how the average UK adult should take decisions on protection to maximise his utility. Different situations will call for different values of risk-aversion, which may explain why economists have come up with differing estimates of this parameter in the past. However, a central, average risk-aversion may be calculated for the average UK adult as 0.85, which is within 4% of the value, 0.82, found from the newly reported method based on a trade-off between income and future free time, and is consistent with several recent economic estimates. Worked examples assess how much an organisation should spend on a protection scheme to prevent accidents with very large environmental consequences.     

Flexible reproductive strategies in the squid Loligo forbesi

Body size at sexual maturity, egg-size distributions, and potential reproductive output have been estimated for female and male squid, Loligo forbesi Steenstrup, off the west coast of Scotland. Two size modes at maturity were found in both sexes, but separation into size cohorts was more pronounced in males (180 and 350 mm mantle length, ML). Preliminary ageing studies based on statolith ring-counts suggest that these size modes are not due to different age groups at breeding. Females have a single size mode of mature eggs in the proximal oviduct, but may have at least two size modes of eggs within the ovary. This finding is interpreted as evidence of batch-spawning in this squid. There was a weak relationship between total egg numbers (range 1000 to 16000) and body size (range 196 to 318 mm ML) and between mature egg size and body size. Males showed a strong positive relationship between spermatophore length and body length but a weak relationship between total number of spermatophores and body size. The results are discussed in the context of flexibility of breeding strategies in the loliginids and variety of life-cycle patterns.