OHP–APT 2002 gravity wave campaign: waves,turbulence and forecasts

In July 2002, a multi-sensor campaign was conducted in southern France to investigate the hypothesized connection between gravity waves and optical turbulence. A generalized scidar (GS) was mounted on the 1.93 m diameter telescope at l’Observatoire de Haute-Provence (OHP). The GS provides continuous profiles of optical turbulence with 300 m vertical resolution from telescope altitude up to 25 km. Thermosondes, which provide in situ measurement of optical turbulence by measuring temperature variance, were launched at the OHP site and at a site approximately 20 km west-northwest of OHP. Gravity wave activity was deduced from temperature and wind velocity measured by radiosondes, which are part of the thermosonde system. In this paper, gravity waves were analyzed using techniques for simple two-dimensional mountain waves, with only fair results. Mesoscale models were run at moderately high resolution for the period. The forecasts were analyzed for wave activity, and a post processor model was used to diagnose the optical turbulence. Mountain waves were evident in the forecast, but quantitative comparison showed the forecast to be inadequate in predicting wave strength. The forecast optical turbulence was in fair agreement with measurements with notable exceptions. This paper is declared a work of the U.S. Government and is not subject to copyright protection in the United States. The U.S. Government’s right to retain a non-exclusive, royalty-free license in and to any copyright is acknowledged. Presented at the Turbulence and Waves in Stably Stratified Atmospheric Shear Flows: Measurements, High Resolution Simulations and Numerical Prediction Challenges Conference, 13–15 September 2004, Lighthill Institute of Mathematical Sciences, University College London, London, UK.     

Corticosterone levels in relation to migratory readiness in red-eyed vireos (<Emphasis Type="Italic">Vireo olivaceus</Emphasis>)

We examined the relationship between plasma levels of corticosterone and the migratory activity and directional preference of red-eyed vireos during fall migration at the northern coast of the Gulf of Mexico. Corticosterone is thought to play a role in physiological and behavioural processes before, during, and after long-distance migratory flights. An increase in corticosterone at the onset of migratory flights can be expected in birds that are energetically prepared to migrate in a seasonally appropriate southerly direction. Red-eyed vireos ( Vireo olivaceus) were tested in orientation cages under clear twilight skies. Just prior to the orientation experiments, blood was sampled to assay baseline corticosterone levels. Average corticosterone level for all birds was 22.8 ng/ml. Red-eyed vireos with higher than average baseline levels of corticosterone were significantly more active in orientation cages compared to birds with lower levels of corticosterone. Moreover, birds with higher than average levels oriented in a southwesterly direction, which is consistent with a trans-Gulf flight, whereas individuals with levels below average showed a NNW mean direction. Although there was no significant difference in baseline levels of corticosterone between fat and lean birds, individual mass loss between capture and test was negatively correlated with corticosterone levels. Results from this study clearly demonstrate that corticosterone influences departure decisions and the choice of direction during migration.     

Habitat and reef-fish assemblages of banks in the Northwestern Hawaiian Islands

The moderately deep terraces and banks of the Northwestern Hawaiian Islands (NWHI) were surveyed to describe their habitat and reef-fish assemblages. These tracts of bottom at 30–40 m comprise more than 4,500 km² of the regions reef area. The habitat was found to be dominated by algal meadows (65% cover of exposed bottom), with infrequent relief features. Annual monitoring of select stations for 4 years at Necker Bank indicated that the relative difference in algal abundance between stations persisted from year to year (at least in summer). Temperature records from year-long deployments of archival thermistors in high-cover (>70%) and low-cover (<30%) algal biotopes were indistinguishable, providing no explanation of the algal differences between stations. At all banks, Microdictyon was the primary alga, averaging 1.22 kg/m². In spite of the extensive standing primary production, and a historical lack of fishing, bank reef-fish populations were impoverished. Mean densities, sizes, and biomass of trophic groups were considerably less than values reported for NWHI reef shallows. An overall mean biomass was estimated at 22.5 g/m², which is a fifth of that reported for shallow reefs of the region. Fish biomass of all trophic groups was associated with the few sources of relief available on the banks. Apex predators (sharks, jacks, and snappers), common on all surveys (with a mean of five per station), were proposed to constrain fish populations to sparse sources of relief resulting in a skewed size structure of the two primary fish trophic components. Sizes of lower-level carnivores were tightly correlated with sources of relief whereas the size of herbivores were not, indicating that herbivores more often venture out and risk the exposed algal meadows. These bank summits are a rare example of a near pristine reef system with high benthic primary productivity and low fish biomass, and are a stark contrast to shallower coral-reef ecosystems of the NWHI.Communicated by P.W. Sammarco, Chauvin     

The toxicity of aluminum to aquatic species in the US

In August 1988 the US Environmental Protection Agency (EPA) published an ambient water quality criteria document for the protection of aquatic organisms from the toxic effects of aluminum. The EPA water quality criteria were developed utilizing procedures described in theGuidelines for Deriving Numerical National Water Quality Criteria for the Protection of Aquatic Organisms and Their Uses, and after careful analysis of the latest toxicological information available to EPA on the adverse effects of aluminum on aquatic vertebrates, invertebrates and plants.The EPA criteria recommend that the four-day average concentration of aluminum not exceed 87 g L^–1 more than once every three years on the average when the ambient pH is between 6.5 and 9.0 to provide protection from chronic toxicity. The criteria also recommend that the one-hour average concentration of aluminum not exceed 750 g L^–1 more than once every three years on the average when the ambient pH is between 6.5 and 9.0 to provide protection from acute toxicity.Acute toxicity data for 20 species of freshwater aquatic organisms and chronic toxicity data for five species of freshwater aquatic organisms were utilized to develop the EPA water quality criteria. Striped bass and brook trout were observed to be the two most sensitive North American species to the toxic effects of aluminum. Aluminum toxicity was also observed to be increased at lower pH.     

Replacement of breeders and within-group conflict in the cooperatively breeding acorn woodpecker

Summary Breeding males or females were removed from groups of the cooperatively breeding acorn woodpecker to study (1) competition among individuals from different groups to fill the breeding vancancies, (2) conflict between parents and offspring within groups over replacement of the removed bird, and (3) conflict between parents and offspring for breeding status. Intense fights (power struggles) among nonbreeders from other groups to fill the breeding vacancies developed after the removals. In groups containing only helpers of the opposite sex as the removed bird, replacement was rapid, but in groups containing helpers of the same sex as the removed bird replacement was delayed substantially. In these latter groups parent-offspring conflict developed: helpers could not breed because their parent of the opposite sex was present, and they attacked potential replacements, while their remaining parent advertised for a new mate by calling. Once replacement had occurred, dominance interactions between parents and offspring and among siblings appeared to prevent some individuals from breeding. We conclude that the potential for competition among close kin is high in cooperative species because breeding opportunities are limited.     

Integration of Flow and Chemical Sensing for Guidance of Autonomous Marine Robots in Turbulent Flows

We explored the utility of odor-gated rheotaxis (OGR) with a biomimetic robot. OGR is a widely accepted biological plume-tracing strategy that uses mean flow and chemical detection for guidance. In experiments which contrasted the `classic' single-sensor formulation of the strategy against one which used two sensors and against another which combined the use of two sensors and memory of past stimulation patterns we quantified the relative advantages of each. The use of two, spatially separated, chemical sensors confers a significant advantage and still greater performance is obtained with rudimentary memory. The performance of the American lobster under the same turbulent dispersal regime leads us to conclude that significantly more effective plume tracing strategies remain to be discovered.     

Aggregation of Dynamic Systems and the Existence of a Regeneration Function

In environmental economics, complex ecosystems are often represented by low-dimensional models. The question of whether the results of these models can be applied to a more complex reality leads to the investigation of an aggregation problem in a nonlinear dynamic setting. We show that restrictive assumptions are needed for aggregation and that the low-dimensional model has to be linear. On the basis of these results, we argue that the aggregation of complex ecosystems is often oversimplifying and that substantial gains can be expected from the use of more complex models.     

The effect of limestone treatments on the rate of acid generation from pyritic mine gangue

Surface water enters the Haile Gold Mine, Lancaster County, South Carolina by means of a small stream and is ponded behind a dam and in an abandoned pit. This water is affected by acidic drainage. In spite of the large exposures of potentially acid producing pyritic rock, the flux of acid to the water is relatively low. Nevertheless, the resulting pH values of the mine water are low (around 3.5) due to negligible buffering capacity. In view of the observed low release of acidity, the potential for acid drainage abatement by limestone ameliorants appears feasible. This study investigated the effects of limestone treatment on acid generation rates of the Haile mine pyritic rocks through a series of leaching experiments. Below a critical alkalinity threshold value, solutions of dissolved limestone were found consistently to accelerate the rate of pyrite oxidation by varying degrees. The oxidation rates were further accelerated by admixing solid limestone with the pyritic rock. However, after a period of about a month, the pyrite oxidation rate of the admixed samples declined to a level lower than that of untreated pyrite. Leachates produced by the pyrite and limestone mixtures contained little if any iron. Further, in the mixtures, an alteration of the pyrite surface was apparent. The observed behaviour of the treated pyrite appears to be related to the immersion of the pyrite grains within a high alkalinity/high pH environment. The high pH increases the rate of oxidation of ferrous iron which results in a higher concentration of ferric iron at the pyrite surface. This, in turn, increases the rate of pyrite oxidation. Above a threshold alkalinity value, the precipitation of hydrous iron oxides at the pyrite surface eventually outpaces acid generation and coats the pyrite surface, retarding the rate of pyrite oxidation.     

REACh im praxistest

In October 2003, the EU Commission presented the proposal for a new Chemicals Regulation. In late autumn 2005, Parliament and Council were working on finding their position on the Commission’s proposal. From November 2004 to April 2005, a simulation was carried out at EU level aiming to test the workability of registration under REACh. Based on a strategic partnership, the European Chemical Industry Council together with other industry associations, the EU Commission and a number of Member States had launched this project. 53 manufacturers or users of chemicals and competent authorities of 13 EU Member States took part in the simulation: eight registration cases were dealt with in parallel. The participants had to conduct the registration of a substance (including preparatory work) and the dossier evaluation by the authorities. The simulation was performed in a ’free-flow mode’, which means, that the participants worked without any guidance on how to practically implement the duties and tasks as laid down in the draft regulation. In the final phase of the project, the three strategic parners worked towards a common understanding on potential workability problems and suitable options for solutions. This process resulted in a report including a set of agreed recommendations on 12 identified workability issues The recommendations are mostly related to the co-operation between registrants, the sharing of responsibilities and communication between manufactures and down-stream users as well as technical and scientific aspects of dossier compilation., In addition, the recommendations address the need to develop a common understanding across Europe regarding the role of authorities in evaluating the registration dossiers and developing suitable tools for the evaluation. In addition to the set of practical recommendations, SPORT has demonstrated that useful insights in the workability of a new piece of legislation can be gained from simulating the key processes in practise already during the legislative process. Such pilot trials could be seen as a contribution toBetter Regulation, one of the strategic goals of the EU Commission.