Effects of brackish water incursions and diel phasing of tides on vertical excursions of the keystone predator Pisaster ochraceus

The physical factors that constrain the vertical foraging excursions of the keystone predator, the sea star Pisaster ochraceus, hold considerable interest because they indirectly shape the vivid patterns of zonation of rocky shore communities by impeding or enhancing the ability of P. ochraceus to traverse the intertidal zone. In this paper, we describe a study conducted in the Pacific Northwest of North America in which we examined, in the field and laboratory, the abiotic factors that can affect vertical excursions by P. ochraceus. Our field observations revealed that the extreme upward reach and average shore level height reached by P. ochraceus were significantly lower for daylight high tides than nocturnal high tides. Based on diver observations following a severe storm, it would also appear that these diurnal movements can be impeded by freshwater incursions into the intertidal zone; a regularly occurring event in the Pacific Northwest. As part of an experimental investigation into this phenomenon, we observed that sea stars maintained in tall cylindrical aquaria, without tidal flux, remained near the bottom during daylight and moved to the top of the column at night, suggesting that photoperiod alone can influence the cycle of vertical movement. Adding a freshwater layer to the aquaria restricted these vertical excursions. Our results suggest that on rocky coastlines susceptible to fresh water incursions, the suppression of foraging may be an important factor in the spatial and temporal variation in the intensity of predation. Furthermore, given the relative increase in frequency and intensity of freshwater incursions in the Pacific Northwest and the intolerance of P. ochraceus to lowered salinity, there is the long-term potential to significantly alter patterns of species zonation in this essential marine habitat.     

Sustainable Rainwater Catchment Systems for Micronesian Atoll Communities

Atoll island communities rely on rainwater catchment systems (RWCS) as a primary method of storing freshwater. However, stored freshwater can be depleted during times of drought, requiring importation of water to sustain community living. To maintain adequate water supply under future climatic conditions, the functioning of RWCS for atoll communities must be analyzed and optimal designs must be adopted. In this study, a quantitative analysis of stored daily water volumes is provided for atoll islands within the Federated States of Micronesia (FSM), with Nikahlap Island, Pakein Atoll, and a generic island in western FSM used as representative cases. Using a daily water balance model for the RWCS, baseline conditions are simulated for the 1997‐1999 time period, during which an intense El Niño‐induced drought occurred, and a sensitivity analysis is performed to quantify the influence of RWCS features on water system outputs, whereupon an optimal RWCS design using existing infrastructure is analyzed. Results indicate the strong influence of catchment area, system efficiency, and storage capacity on water volumes and the depletion of water during dry seasons and drought periods using current RWCS infrastructure. Adequate storage can be maintained during a major drought if unused RWCS features are employed and if minimal rationing is adopted. Study results provide water resource managers and government officials with valuable data for consideration in water security measures.     

Exposure estimates in assessing helath effects of air pollution

Air pollution has been associated with adverse health effects. Difficulties in interpreting studies of health effects of exposure to air pollution arise in estimating exposure. Until recently, studies of effects of air pollution have relied on pollution exposure measurements obtained from fixed location air pollution stations monitoring outside air (to evaluate compliance with air quality standards, rather than to examine population exposure). However, recent evidence suggests that there are substantial differences between air pollution levels measured at such sites and levels to which people are actually exposed, i.e. personal exposure. The present study examines effects of ambient urban air pollution on persons suffering from asthma, healthy non-asthmatic subjects and school children (in 2 Canadian cities, Toronto and Hamilton). Air pollution exposure is being assessed by data obtained from: (1) conventional abatement oriented fixed location air pollution monitoring stations, (2) an extensive population oriented network, (3) inside and (4) outside structures (homes and schools) as well as (5) personal air pollution samplers. The data indicate variability in these different estimates of exposure which have implications on health effects assessment.     

Leaching and sorption of neonicotinoid insecticides and fungicides from seed coatings

Seed coatings are a treatment used on a variety of crops to improve production and offer protection against pests and fungal outbreaks. The leaching of the active ingredients associated with the seed coatings and the sorption to soil was evaluated under laboratory conditions using commercially available corn and soybean seeds to study the fate and transport of these pesticides under controlled conditions. The active ingredients (AI) included one neonicotinoid insecticide (thiamethoxam) and five fungicides (azoxystrobin, fludioxonil, metalaxyl, sedaxane thiabendazole). An aqueous leaching experiment was conducted with treated corn and soybean seeds. Leaching potential was a function of solubility and seed type. The leaching of fludioxonil, was dependent on seed type with a shorter time to equilibrium on the corn compared to the soybean seeds. Sorption experiments with the treated seeds and a solution of the AIs were conducted using three different soil types. Sorption behavior was a function of soil organic matter as well as seed type. For most AIs, a negative relationship was observed between the aqueous concentration and the log K_oc. Sorption to all soils tested was limited for the hydrophilic pesticides thiamethoxam and metalaxyl. However, partitioning for the more hydrophobic fungicides was dependent on both seed type and soil properties. The mobility of fludioxonil in the sorption experiment varied by seed type indicating that the adjuvants associated with the seed coating could potentially play a role in the environmental fate of fludioxonil. This is the first study to assess, under laboratory conditions, the fate of pesticides associated with seed coatings using commercially available treated seeds. This information can be used to understand how alterations in agricultural practices (e.g., increasing use of seed treatments) can impact the exposure (concentration and duration) and potential effects of these chemicals to aquatic and terrestrial organisms.     

Key role for nuclear energy in global biodiversity conservation

Modern society uses massive amounts of energy. Usage rises as population and affluence increase, and energy production and use often have an impact on biodiversity or natural areas. To avoid a business‐as‐usual dependence on coal, oil, and gas over the coming decades, society must map out a future energy mix that incorporates alternative sources. This exercise can lead to radically different opinions on what a sustainable energy portfolio might entail, so an objective assessment of the relative costs and benefits of different energy sources is required. We evaluated the land use, emissions, climate, and cost implications of 3 published but divergent storylines for future energy production, none of which was optimal for all environmental and economic indicators. Using multicriteria decision‐making analysis, we ranked 7 major electricity‐generation sources (coal, gas, nuclear, biomass, hydro, wind, and solar) based on costs and benefits and tested the sensitivity of the rankings to biases stemming from contrasting philosophical ideals. Irrespective of weightings, nuclear and wind energy had the highest benefit‐to‐cost ratio. Although the environmental movement has historically rejected the nuclear energy option, new‐generation reactor technologies that fully recycle waste and incorporate passive safety systems might resolve their concerns and ought to be more widely understood. Because there is no perfect energy source however, conservation professionals ultimately need to take an evidence‐based approach to consider carefully the integrated effects of energy mixes on biodiversity conservation. Trade‐offs and compromises are inevitable and require advocating energy mixes that minimize net environmental damage. Society cannot afford to risk wholesale failure to address energy‐related biodiversity impacts because of preconceived notions and ideals.     

In situ measures of foraging success and prey encounter reveal marine habitat-dependent search strategies

Predators are thought to reduce travel speed and increase turning rate in areas where resources are relatively more abundant, a behavior termed "area-restricted search." However, evidence for this is rare, and few empirical data exist for large predators. Animals exhibiting foraging site fidelity could also be spatially aware of suitable feeding areas based on prior experience; changes in movement patterns might therefore arise from the anticipation of higher prey density. We tested the hypothesis that regions of area-restricted search were associated with a higher number of daily speed spikes (a proxy for potential prey encounter rate) and foraging success in southern elephant seals (Mirounga leonina), a species exhibiting both area-restricted searches and high interannual foraging site fidelity. We used onshore morphological measurements and diving data from archival tags deployed during winter foraging trips. Foraging success was inferred from in situ changes in relative lipid content derived from measured changes in buoyancy, and first-passage time analysis was used to identify area-restricted search behavior. Seals exhibited relatively direct southerly movement on average, with intensive search behavior predominantly located at the distal end of tracks. The probability of being in search mode was positively related to changes in relative lipid content; thus, intensively searched areas were associated with the highest foraging success. However, there was high foraging success during the outward transit even though seals moved through quickly without slowing down and increasing turning rate to exploit these areas. In addition, the probability of being in search mode was negatively related to the number of daily speed spikes. These results suggest that movement patterns represent a response to prior expectation of the location of predictable and profitable resources. Shelf habitat was 4-9 times more profitable than the other habitats, emphasizing the importance of the East Antarctic shelf for this and other predators in the region. We have provided rare empirical data with which to investigate the relationship between predator foraging strategy and prey encounter/ foraging success, underlining the importance of inferring the timing and spatial arrangement of successful food acquisition for interpreting foraging strategies correctly.     

Vitamin B12 als biologisch aktive Modellsubstanz

A critical review on corrinoid biochemistry and physiology is presented. This includes: chemical synthesis of biologically important organocorrinoids and the correlation between their structures and coenzymatic activity; forms, distribution and transport of physiologically active corrinoids; methylcobalamin- and adenosylcobalamin-dependent enzymatic reactions and their physiological functions; and steric course of the adenosylcobalamin-dependent enzymatic rearrangements. Special attention is paid to the mechanisms of adenosylcobalamin-dependent enzymatic reactions.     

Effects of human footprint and biophysical factors on the body-size structure of fished marine species

Marine fisheries in coastal ecosystems in many areas of the world have historically removed large-bodied individuals, potentially impairing ecosystem functioning and the long-term sustainability of fish populations. Reporting on size-based indicators that link to food-web structure can contribute to ecosystem-based management, but the application of these indicators over large (cross-ecosystem) geographical scales has been limited to either fisheries-dependent catch data or diver-based methods restricted to shallow waters (<20 m) that can misrepresent the abundance of large-bodied fished species. We obtained data on the body-size structure of 82 recreationally or commercially targeted marine demersal teleosts from 2904 deployments of baited remote underwater stereo-video (stereo-BRUV). Sampling was at up to 50 m depth and covered approximately 10,000 km of the continental shelf of Australia. Seascape relief, water depth, and human gravity (i.e., a proxy of human impacts) were the strongest predictors of the probability of occurrence of large fishes and the abundance of fishes above the minimum legal size of capture. No-take marine reserves had a positive effect on the abundance of fishes above legal size, although the effect varied across species groups. In contrast, sublegal fishes were best predicted by gradients in sea surface temperature (mean and variance). In areas of low human impact, large fishes were about three times more likely to be encountered and fishes of legal size were approximately five times more abundant. For conspicuous species groups with contrasting habitat, environmental, and biogeographic affinities, abundance of legal-size fishes typically declined as human impact increased. Our large-scale quantitative analyses highlight the combined importance of seascape complexity, regions with low human footprint, and no-take marine reserves in protecting large-bodied fishes across a broad range of species and ecosystem configurations.     

Miscanthus and switchgrass production in central Illinois: impacts on hydrology and inorganic nitrogen leaching

Biomass crops are being promoted as environmentally favorable alternatives to fossil fuels or ethanol production from maize (Zea mays L.), particularly across the Corn Belt of the United States. However, there are few if any empirical studies on inorganic N leaching losses from perennial grasses that are harvested on an annual basis, nor has there been empirical evaluation of the hydrologic consequences of perennial cropping systems. Here we report on the results of 4 yr of field measurements of soil moisture and inorganic N leaching from a conventional maize-soybean [Glycine max (L.) Merr.] system and two unfertilized perennial grasses harvested in winter for biomass: Miscanthus x giganteus and switchgrass (Panicum virgatum cv. Cave-in-Rock). All crops were grown on fertile Mollisols in east-central Illinois. Inorganic N leaching was measured with ion exchange resin lysimeters placed 50 cm below the soil surface. Maize--soybean nitrate leaching averaged 40.4 kg N ha(-1) yr(-1), whereas switchgrass and Miscanthus had values of 1.4 and 3.0 kg N ha(-1) yr(-1), respectively. Soil moisture monitoring (to a depth of 90 cm) indicated that both perennial grasses dried the soil out earlier in the growing season compared with maize-soybean. Later in the growing season, soil moisture under switchgrass tended to be greater than maize-soybean or Miscanthus, whereas the soil under Miscanthus was consistently drier than under maize--soybean. Water budget calculations indicated that evapotranspiration from Miscanthus was about 104 mm yr(-1) greater than under maize-soybean, which could reduce annual drainage water flows by 32% in central Illinois. Drainage water is a primary source of surface water flows in the region, and the impact ofextensive Miscanthus production on surface water supplies and aquatic ecosystems deserves further investigation.     

Metal Contamination of Sediments and Soils of Bayou Saint John: A Potential Health Impact to Local Fishermen?

This research examines the pattern of sediment contamination of an urban bayou of New Orleans (formerly a natural waterway) and the potential for human exposure from consumption of fish caught in the bayou. Sediments and soils of Bayou Saint John were evaluated for lead (Pb), zinc (Zn), and cadmium (Cd). Sediment cores were collected at bridges (n = 130) and sites between the bridges (n = 303) of the bayou. In addition, soil samples (n = 66) were collected along the banks of the bayou. Sediments below the bridges contain significantly more (p-value approximately 10(-7)) Pb and Zn (medians of 241 and 230 mg kg(-1), respectively) than bayou sediments located between bridges (medians of 64 and 77 mg kg(-1), respectively). Sediments below bridges of the upper reaches of the bayou contain significantly larger amounts of metals (p < 10(-14) for Pb and Zn and p approximately 10(-8) for Cd) (medians of 329, 383 and 1.5, respectively) than sediments below bridges in the lower reaches of the bayou (medians of 43, 31 and 0.5 for Pb, Zn and Cd, respectively). Likewise, medians for sediments located between bridges contain significantly (p < 10(-14)) higher quantities of Pb, Zn and Cd (170, 203 and 1.8 mg kg(-1), respectively) in the upper bayou than Pb, Zn, and Cd (48, 32, and 0.8 mg kg(-1), respectively) in the lower reaches of the bayou. The potential risk for human exposure may be magnified by the fact that fishing generally occurs from the numerous bridges that cross the bayou. Poor and minority people do most of the fishing. Most people (87%) indicated they ate fish they caught from the Bayou.