Flexible foraging strategies in a diving seabird with high flight cost

How central-place foragers change search strategy in response to environmental conditions is poorly known. Foragers may vary the total distance travelled and how far they range from the central place in response to variation in the distribution of their prey. One potential reason as to why they would extend the length of their foraging trip and its distance from the colony would be to increase prey quality or quantity, despite incurring higher transit costs. To test this trade-off hypothesis in a species with high flight costs, we recorded the foraging behaviour of razorbills (Alca torca) using state-of-the-art techniques that log both individual horizontal (flight activity) and vertical (dive activity) movements. We show that the distance that razorbills travelled to foraging locations increased with sea-surface temperature, which may relate to higher prey quality or quantity. This relation is supported by an indirect index of patch quality, based on dive profiles, which also increased with travel distance from the colony. Furthermore, we show that this index was highest during the daily peak in diving activity, around midday. Taken together, these results suggest that razorbills are capable of adjusting their search strategies sensitively in response to proximate environmental cues.     

A distributed approach to accounting for carbon in wood products

With an evolving political environment of commitments to limit emissions of greenhouse gases, and of markets to trade in emissions permits, there is growing scientific, political, and economic need to accurately evaluate carbon (C) stocks and flows—especially those related to human activities. One component of the global carbon cycle that has been contentious is the stock of carbon that is physically held in harvested wood products. The carbon stored in wood products has been sometimes overlooked, but the amount of carbon contained in wood products is not trivial, it is increasing with time, and it is significant to some Parties. This paper is concerned with accurate treatment of harvested wood products in inventories of CO₂ emissions to the atmosphere. The methodologies outlined demonstrate a flexible way to expand current methods beyond the assumption of a simple, first-order decay to include the use of more accurate and detailed data while retaining the simplicity of simple formulas. The paper demonstrates that a more accurate representation of decay time can have significant economic implications in a system where emissions are taxed or emissions permits are traded. The method can be easily applied using only data on annual production of wood products and two parameters to characterize their expected lifetime. These methods are not specific to wood products but can be applied to long-lived, carbon-containing products from sources other than wood, e.g. long-lived petrochemical products. A single unifying approach that is both simple and flexible has the potential to be both more accurate in its results, more efficient in its implementation, and economically important to some Parties.     

Swarm cognition in honey bees

We synthesize findings from neuroscience, psychology, and behavioral biology to show that some key features of cognition in the neuron-based brains of vertebrates are also present in the insect-based swarm of honey bees. We present our ideas in the context of the cognitive task of nest-site selection by honey bee swarms. After reviewing the mechanisms of distributed evidence gathering and processing that are the basis of decision making in bee swarms, we point out numerous similarities in the functional organization of vertebrate brains and honey bee swarms. These include the existence of interconnected subunits, parallel processing of information, a spatially distributed memory, layered processing of information, lateral inhibition, and mechanisms of focusing attention on critical stimuli. We also review the performance of simulated swarms in standard psychological tests of decision making: tests of discrimination ability and assessments of distractor effects.     

ASSESSING INSTREAM FLOWS AND RESERVOIR OPERATIONS ON AN EASTERN IDAHO RWER1

ABSTRACT: A methodology for assessing reservoir management was applied to the historical conflict between winter fish and wildilife flows below Island Park Reservoir on Henrys Fork of the Snake River and the fulfillment of storage water rights. The methodology consists of (1) identifying impacts of flow regulation, (2) quantifying relationships among variables affecting physical reservoir fill, and (3) assessing effects of these discharges on the fulfillment of water rights in the context of a larger system of interrelated reservoirs. Winter (storage season) flows are critical to management of fish and wildlife populations below Island Park Dam, but flow regulation has resulted in decreased winter discharge. Allowable winter flows are a function of inflow, length of storage season, reservoir content at the start of storage season, and potential for downstream capture of excess storage season water discharged at Island Park. Modeling results indicate that winter flows in the range of those recommended for fish and wildlife management are attainable during average years but not during years when initial reservoir content is low. The methodology was successful in quantifying information useful to decision makers in a variety of agencies and disciplines and could be applied to solve water management problems on other regulated river systems.     

Bioaccessibility of lead sequestered to corundum and ferrihydrite in a simulated gastrointestinal system

Lead (Pb) sorption onto oxide surfaces in soils may strongly influence the risk posed from incidental ingestion of Pb-contaminated soil. Lead was sorbed to model oxide minerals of corundum (alpha-Al(2)O(3)) and ferrihydrite (Fe(5)HO(8).4H(2)O). The Pb-sorbed minerals were placed in a simulated gastrointestinal tract (in vitro) to simulate ingestion of Pb-contaminated soil. The changes in Pb speciation were determined using extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectroscopy (XANES). Both corundum (sorption maximum of 2.13 g kg(-1)) and ferrihydrite (sorption maximum of 38.6 g kg(-1)) have been shown to sorb Pb, with ferrihydrite having a very high affinity for Pb. The gastric bioaccessible Pb for corundum was >85% for corundum when the concentration of Pb was >200 mg kg(-1). Bioaccessible Pb was not detectable at 4. However, much of the sorbed Pb will become bioaccessible under gastric conditions (pH 1.5-2.5) if this soil is ingested. Caution should be used before using these materials to remediate a soil where soil ingestion is an important exposure pathway.     

Mineralisation of target hydrocarbons in three contaminated soils from former refinery facilities

This study investigated the microbial degradation of ¹⁴C-labelled hexadecane, octacosane, phenanthrene and pyrene and considered how degradation might be optimised in three genuinely hydrocarbon-contaminated soils from former petroleum refinery sites. Hydrocarbon mineralisation by the indigenous microbial community was monitored over 23 d. Hydrocarbon mineralisation enhancement by nutrient amendment (biostimulation), hydrocarbon degrader addition (bioaugmentation) and combined nutrient and degrader amendment, was also explored. The ability of indigenous soil microflora to mineralise ¹⁴C-target hydrocarbons was appreciable; ≥16% mineralised in all soils. Generally, addition of nutrients or degraders increased the rates and extents of mineralisation of ¹⁴C-hydrocarbons. However, the addition of nutrients and degraders in combination had a negative effect upon ¹⁴C-octacosane mineralisation and resulted in lower extents of mineralisation in the three soils. In general, the rates and extents of mineralisation will be dependent upon treatment type, nature of the contamination and adaptation of the ingenious microbial community.     

Influence of hydroxypropyl-β-cyclodextrin on the biodegradation of C-phenanthrene and C-hexadecane in soil

Soil was spiked with [9-¹⁴C]phenanthrene and [1-¹⁴C]hexadecane at 50 mg kg⁻¹ and aged for 1, 25, 50, 100 and 250 d. At each time point, the microcosms were amended with aqueous solutions of cyclodextrin (HP-β-CD) at a range of concentrations (0-40 mM). Mineralisation assays and aqueous HP-β-CD extractions were performed to assess the effect of the amendments on microbial degradation. The results showed that amendments had no significant impact on the microbial degradation of either of the ¹⁴C-contaminants. Further, HP-β-CD extractions were correlated with the mineralisation of the target chemicals in each of the soil conditions. It was found that the HP-β-CD extraction was able to predict mineralisation in soils which had not been amended with cyclodextrin; however, in the soils containing the HP-β-CD, there was no predictive relationship. Under the conditions of this study, the introduction of HP-β-CD into soils did not enhance the biodegradation of the organic contaminants.     

APCA Financial Statements for 1975-1976

Abstract

A wind tunnel study was completed to determine the effects the presence of a parapet and raised intake configurations have on the dilution of a pollutant between a rooftop stack and building intake. This study was the first to address the effects of building parapets and varying intake configurations. A study of this kind is desirable because it is common practice for architects to attempt to hide stacks with the use of a parapet in order to make industrial buildings more aesthetically pleasing. This is done with no thought to the effect it may have on the intended function of the stacks, which is dispersing gases away from the building to avoid contamination of ventilation air.

Three parapet configurations (no parapet and two different parapet heights) and two intake configurations (flush and raised) were investigated. The relative effects of the parapets and the raised intake configurations were also compared and contrasted for five stack heights, two stack locations, and four intake locations.

The parapets were found to produce a cavity zone that extends above the building's roof by as much as two times the physical height of the parapet; increasing stack height had little effect on dispersion until the stack extended beyond this cavity region. The independent use of the parapets and raised intake configuration decreased the number of dilutions occurring between stack and intake when compared to the no parapet and flush intake configurations in all cases. Also substantiated in this study is the widely accepted view that the effect of the parapet addition is to decrease the effective stack height by the parapet height itself.

The results of this investigation were then compared to existing wind tunnel-derived empirical models. The models tested were not able to predict the effects of varying stack height and of varying the relative distance between stack and intake on the dilution of a pollutant between stack and intake under the tested configurations.     

Linking chemical extraction to microbial degradation of 14C-hexadecane in soil

Chemical extractions have been shown to measure the biodegradable fraction of aromatic contaminants in soil; however, there is little research on the chemical prediction of aliphatic hydrocarbon degradation. The aim of this study was to investigate the potential for cyclodextrin extractions to predict hexadecane biodegradation in soil. Soils were amended with 10 or 100 mg kg⁻¹ of a model alkane n-hexadecane and 100 Bq g⁻¹¹⁴C-n-hexadecane. Correlations between the extents of mineralisation and extractions of the ¹⁴C-contaminant were determined. Solvent shake extractions and aqueous CaCl₂ extractions were poor predictors of hexadecane bioaccessibility. However, the novel HP-α-CD shake extraction showed close correlation (r² = 0.90, n = 36, p < 0.05) to the mineralisation data. This novel extraction technique has the potential to be used to assess the biodegradable aliphatic hydrocarbon fraction in contaminated soils.