A moving target—incorporating knowledge of the spatial ecology of fish into the assessment and management of freshwater fish populations

Freshwater fish move vertically and horizontally through the aquatic landscape for a variety of reasons, such as to find and exploit patchy resources or to locate essential habitats (e.g., for spawning). Inherent challenges exist with the assessment of fish populations because they are moving targets. We submit that quantifying and describing the spatial ecology of fish and their habitat is an important component of freshwater fishery assessment and management. With a growing number of tools available for studying the spatial ecology of fishes (e.g., telemetry, population genetics, hydroacoustics, otolith microchemistry, stable isotope analysis), new knowledge can now be generated and incorporated into biological assessment and fishery management. For example, knowing when, where, and how to deploy assessment gears is essential to inform, refine, or calibrate assessment protocols. Such information is also useful for quantifying or avoiding bycatch of imperiled species. Knowledge of habitat connectivity and usage can identify critically important migration corridors and habitats and can be used to improve our understanding of variables that influence spatial structuring of fish populations. Similarly, demographic processes are partly driven by the behavior of fish and mediated by environmental drivers. Information on these processes is critical to the development and application of realistic population dynamics models. Collectively, biological assessment, when informed by knowledge of spatial ecology, can provide managers with the ability to understand how and when fish and their habitats may be exposed to different threats. Naturally, this knowledge helps to better evaluate or develop strategies to protect the long-term viability of fishery production. Failure to understand the spatial ecology of fishes and to incorporate spatiotemporal data can bias population assessments and forecasts and potentially lead to ineffective or counterproductive management actions.     

Optical and thermal characteristics of carbonaceous aerosols measured at an urban site in Gwangju,Korea, in the winter of 2011

Carbonaceous components (organic carbon [OC] and elemental carbon [EC]) and optical properties (light absorption and scattering) of fine particulate matter (aerodynamic diameter <2.5 μm; PM_2.5) were simultaneously measured at an urban site in Gwangju, Korea, during the winter of 2011. OC was further classified into OC1, OC2, OC3, and OC4, based on a temperature protocol using a Sunset OC/EC analyzer. The average OC and EC concentrations were 5.0 ± 2.5 and 1.7 ± 0.9 μg C m^?3, respectively. The average single-scattering albedo (SSA) at a wavelength of 550 nm was 0.58 ± 0.11, suggesting that the aerosols observed in the winter of 2011 had a local warming effect in this area. During the whole sampling period, “stagnant PM” and “long-range transport PM” events were identified. The light absorption coefficient (b_abs) was higher during the stagnant PM event than during the long-range transport PM event due to the existence of abundant light-absorbing OC during the stagnant PM event. In particular, the OC2 and OC3 concentrations were higher during the stagnant PM event than those during the long-range transport event, suggesting that OC2 and OC3 might be more related to the light-absorbing OC. The light scattering coefficient (b_scat) was similar between the events. On average, the mass absorption efficiency attributed to EC (σ_EC) was 9.6 m² g^?1, whereas the efficiency attributed to OC (σ_OC) was 1.8 m² g^?1 at λ = 550 nm. Furthermore, the σ_EC is comparable among the PM event days, but the σ_OC for the stagnant PM event was significantly higher than that for the long-range transport PM event (1.7 vs. 0.5).

Implications: Optical and thermal properties of carbonaceous aerosol were measured at Gwangju, and carbonaceous aerosol concentration and optical property varied between “stagnant PM” and “long-range transport PM” events. More abundant light absorbing OC was observed during the stagnant PM event.     

Gender differences in public office workers’ satisfaction,subjective symptoms and musculoskeletal complaints in workplace and office environments

This study investigates differences between male and female public office workers’ satisfaction levels, sick building syndrome (SBS) symptoms and musculoskeletal disorder (MSD) complaints in workplace and office environments. Questionnaire surveys were performed in 30 offices from 15 public institutions. Male and female workers of the same age were coupled and selected from each office, gathering a total of 120 male and 120 female subjects. The results show that differences exist between genders in noise and lighting satisfaction levels, SBS-related symptoms (eye, nose, skin) and MSD complaints of hand/wrist/finger, while there is no difference in overall satisfaction level of office environments. The study also suggests that office design for public office workers should take into account gender differences in preventing MSDs and also SBS. The findings of this study are expected to serve as basic data for designing effective public office environments.     

Ultrasound pretreatment of filamentous algal biomass for enhanced biogas production

The filamentous alga Hydrodictyon reticulatum harvested from a bench-scale wastewater treatment pond was used to evaluate biogas production after ultrasound pretreatment. The effects of ultrasound pretreatment at a range of 10–5000 J/mL were tested with harvested H. reticulatum. Cell disruption by ultrasound was successful and showed a higher degree of disintegration at a higher applied energy. The range of 10–5000 J/mL ultrasound was able to disintegrated H. reticulatum and the soluble COD was increased from 250 mg/L to 1000 mg/L at 2500 J/mL. The disintegrated algal biomass was digested for biogas production in batch experiments. Both cumulative gas generation and volatile solids reduction data were obtained during the digestion. Cell disintegration due to ultrasound pretreatment increased the specific biogas production and degradation rates. Using the ultrasound approach, the specific methane production at a dose of 40 J/mL increased up to 384 mL/g-VS fed that was 2.3 times higher than the untreated sample. For disintegrated samples, the volatile solids reduction was greater with increased energy input, and the degradation increased slightly to 67% at a dose of 50 J/mL. The results also indicate that disintegration of the algal cells is the essential step for efficient anaerobic digestion of algal biomass.     

Biodegradation characteristics of organic matters in swine carcasses under different initial operating conditions of simulated anaerobic lysimeter

This study was aimed to investigate the biodegradation characteristics of organic matters in swine carcasses. The lysimeters were simulated with different initial operating conditions: 30 % volumetric moisture content and no sludge addition for lysimeter A (control), 30 % volumetric moisture content and anaerobic sludge addition for lysimeter B, and 40 % volumetric moisture content and anaerobic sludge addition for lysimeter C. The degradation efficiency (18.4 %) of lysimeter B was higher than that (15.2 %) of lysimeter A due to anaerobic sludge addition. Lysimeter B showed higher CH₄ yield (15.6 L/kg VS) and CH₄ production rate (0.41 L/kg VS days) compared to lysimeter A by 31 % and 14 %, respectively. In addition, the degradation efficiency improved from 18.4 % (lysimeter B) to 26.3 % (lysimeter C) by increasing volumetric moisture content. The CH₄ yield (22.9 L/kg VS) and CH₄ production rate (0.68 L/kg VS days) of lysimeter C were higher than those of lysimeter B, respectively. Total organic carbon (TOC) removed in lysimeter C was converted to leachate (20.3 %) and gas (6.0 %), whose values were higher than those of lysimeter A and B. These results demonstrated that the proper control of initial operating conditions could accelerate the anaerobic degradation of organic matters in swine carcasses.     

<Emphasis Type="Italic">Synechococcus</Emphasis> production and grazing loss rates in nearshore tropical waters

Temporal variation of Synechococcus, its production (μ) and grazing loss (g) rates were studied for 2 years at nearshore stations, i.e. Port Dickson and Port Klang along the Straits of Malacca. Synechococcus abundance at Port Dickson (0.3–2.3 × 10⁵ cell ml^?1) was always higher than at Port Klang (0.3–7.1 × 10⁴ cell ml^?1) (p < 0.001). μ ranged up to 0.98 day^?1 (0.51 ± 0.29 day^?1), while g ranged from 0.02 to 0.31 day^?1 (0.15 ± 0.07 day^?1) at Port Klang. At Port Dickson, μ and g averaged 0.47 ± 0.13 day^?1 (0.29–0.82 day^?1) and 0.31 ± 0.14 day^?1 (0.13–0.63 day^?1), respectively. Synechococcus abundance did not correlate with temperature (p > 0.25), but nutrient and light availability were important factors for their distribution. The relationship was modelled as log Synechococcus = 0.37Secchi ? 0.01DIN + 4.52 where light availability (as Secchi disc depth) was a more important determinant. From a two-factorial experiment, nutrients were not significant for Synechococcus growth as in situ nutrient concentrations exceeded the threshold for saturated growth. However, light availability was important and elevated Synechococcus growth rates especially at Port Dickson (F = 5.94, p < 0.05). As for grazing loss rates, they were independent of either nutrients or light intensity (p > 0.30). In nearshore tropical waters, an estimated 69 % of Synechococcus production could be grazed.     

Immobilization of fungal laccase onto a nonionic surfactant-modified clay material: application to PAH degradation

Nonionic surfactant-modified clay is a useful absorbent material that effectively removes hydrophobic organic compounds from soil/groundwater. We developed a novel material by applying an immobilized fungal laccase onto nonionic surfactant-modified clay. Low-water-solubility polycyclic aromatic hydrocarbons (PAHs) (naphthalene/phenanthrene) were degraded in the presence of this bioactive material. PAH degradation by free laccase was higher than degradation by immobilized laccase when the surfactant concentration was allowed to form micelles. PAH degradation by immobilized laccase on TX-100-modified clay was higher than on Brij35-modified clay. Strong laccase degradation of PAH can be maintained by adding surfactant monomers or micelles. The physical adsorption of nonionic surfactants onto clay plays an important role in PAH degradation by laccase, which can be explained by the structure and molecular interactions of the surfactant with the clay and enzyme. A system where laccase is immobilized onto TX-100-monomer-modified clay is a good candidate bioactive material for in situ PAHs bioremediation.     

Income and distance-decay effects on willingness to pay estimated by the contingent valuation method

This study suggests a methodology for enhancing accuracy in evaluating amenity by the contingent valuation method when household's willingness to pay (WTP) is dependent to its income and the distance between a respondent's residence and the location of a target facility. Using a linear city model, this study demonstrates the influences of income and distance-decay effects on WTP. Simulations are performed to check the validity of the model, as well as to predict consequences when income and distance-decay effects are not properly treated. Finally, the suggested methodology is applied to two real cases. The estimation results from a structural model show that the calculated total benefit varies largely when income and distance-decay effects exist and are ignored. Also, an ad hoc model generates significantly different estimates from the utility difference model this study adopted. The difference in estimates suggests that the total benefit has to be estimated by a structural model.     

The comparison of fossil carbon fraction and greenhouse gas emissions through an analysis of exhaust gases from urban solid waste incineration facilities

In this study, in order to understand accurate calculation of greenhouse gas emissions of urban solid waste incineration facilities, which are major waste incineration facilities, and problems likely to occur at this time, emissions were calculated by classifying calculation methods into 3 types. For the comparison of calculation methods, the waste characteristics ratio, dry substance content by waste characteristics, carbon content in dry substance, and ¹²C content were analyzed; and in particular, CO₂ concentration in incineration gases and ¹²C content were analyzed together. In this study, 3 types of calculation methods were made through the assay value, and by using each calculation method, emissions of urban solid waste incineration facilities were calculated then compared. As a result of comparison, with Calculation Method A, which used the default value as presented in the IPCC guidelines, greenhouse gas emissions were calculated for the urban solid waste incineration facilities A and B at 244.43 ton CO₂/day and 322.09 ton CO₂/day, respectively. Hence, it showed a lot of difference from Calculation Methods B and C, which used the assay value of this study. It is determined that this was because the default value as presented in IPCC, as the world average value, could not reflect the characteristics of urban solid waste incineration facilities. Calculation Method B indicated 163.31 ton CO₂/day and 230.34 ton CO₂/day respectively for the urban solid waste incineration facilities A and B; also, Calculation Method C indicated 151.79 ton CO₂/day and 218.99 ton CO₂/day, respectively.

Implications: This study intends to compare greenhouse gas emissions calculated using ¹²C content default value provided by the IPCC (Intergovernmental Panel on Climate Change) with greenhouse gas emissions calculated using ¹²C content and waste assay value that can reflect the characteristics of the target urban solid waste incineration facilities. Also, the concentration and ¹²C content were calculated by directly collecting incineration gases of the target urban solid waste incineration facilities, and greenhouse gas emissions of the target urban solid waste incineration facilities through this survey were compared with greenhouse gas emissions, which used the previously calculated assay value of solid waste.     

Reservoir‐host amplification of disease impact in an endangered amphibian

Emerging wildlife pathogens are an increasing threat to biodiversity. One of the most serious wildlife diseases is chytridiomycosis, caused by the fungal pathogen, Batrachochytrium dendrobatidis (Bd), which has been documented in over 500 amphibian species. Amphibians vary greatly in their susceptibility to Bd; some species tolerate infection, whereas others experience rapid mortality. Reservoir hosts—species that carry infection while maintaining high abundance but are rarely killed by disease—can increase extinction risk in highly susceptible, sympatric species. However, whether reservoir hosts amplify Bd in declining amphibian species has not been examined. We investigated the role of reservoir hosts in the decline of the threatened northern corroboree frog (Pseudophryne pengilleyi) in an amphibian community in southeastern Australia. In the laboratory, we characterized the response of a potential reservoir host, the (nondeclining) common eastern froglet (Crinia signifera), to Bd infection. In the field, we conducted frog abundance surveys and Bd sampling for both P. pengilleyi and C. signifera. We built multinomial logistic regression models to test whether Crinia signifera and environmental factors were associated with P. pengilleyi decline. C. signifera was a reservoir host for Bd. In the laboratory, many individuals maintained intense infections (>1000 zoospore equivalents) over 12 weeks without mortality, and 79% of individuals sampled in the wild also carried infections. The presence of C. signifera at a site was strongly associated with increased Bd prevalence in sympatric P. pengilleyi. Consistent with disease amplification by a reservoir host, P. pengilleyi declined at sites with high C. signifera abundance. Our results suggest that when reservoir hosts are present, population declines of susceptible species may continue long after the initial emergence of Bd, highlighting an urgent need to assess extinction risk in remnant populations of other declined amphibian species.