Precopulatory guarding-time of the male amphipod Eogammarus oclairi: effect of population structure

This study shows that population structure affects guarding time in the amphipod Eogammarus oclairi Bousfield. In the laboratory, mean guarding time depended on the male weight-frequency distribution, operational sex ratio, and male density. It was longer when the male population encompassed a broad range of weights than when the weight distribution was narrower; however, guarding time did not differ when the population's weight distribution was narrow and composed of either small or large males. Mean guarding time varied between a few hours when the operational sex ratio (male:female) was 1:3 to>7 d when the sex ratio was 2:1. It was also affected by male density, increasing as male density increased. The results suggest that the stimulus to guard depends on the intensity of male-male competition.     

Mineral Soil and Solution Responses to Experimental N and S Enrichment at the Bear Brook Watershed in Maine (BBWM)

Buried mineral soil-bags and natural solutions were studied as indicators of forest ecosystem response to elevated N and S inputs at the Bear Brook Watershed in Maine (BBWM). The BBWM is the site of a paired watershed manipulation experiment in a northern New England forested ecosystem. The study includes two small (10 ha each) catchments dominated by northern hardwood forests with red spruce in the upper elevations. Treatments consist of (NH4)2SO4 applied to the West Bear watershed six times per year, increasing N and S deposition 3× and 2× above ambient values, respectively. Buried mineral soil-bag changes over time reflected both the native soil environment and the treatments. Most of the treatment effects on mineral soils were evident as higher inorganic S found in the treated watershed soils. Adsorbed SO4 in the buried mineral soil-bags increased by approximately 40% under softwood stands and 50% under hardwood stands over the study period. Hardwood soil solutions responded with significant increases in NO3 and SO4 concentrations that resulted in accelerated cation leaching, primarily Ca and Al. Few differences that could be attributed to treatments were evident in soil solutions under softwoods. No treatment effects were evident in throughfall and stemflow chemistry.     

Linkages of P and Al Export at High Discharge at the Bear Brook Watershed in Maine

Phosphorus chemistry in streams was evaluated at the paired watershed study at the Bear Brook Watershed, Maine. The West Bear catchment has been treated bimonthly since 1989 with 1,800 eq (NH4)2SO4 ha-1 yr-1. East Bear was the untreated reference watershed. During 1993, concentration of total phosphorus (P) in weekly samples from East and West Bear Brook ranged from 0 to 15 g L-1. The median values were 2 and 4 g L-1 for East and West Bear, respectively. During a high discharge event in January of 1995, the concentration of dissolved P remained relatively constant ( 3 g L-1) as pH decreased from 5.63 to 5.08 and from 5.14 to 4.75 in East and West Bear, respectively. The concentration of total P increased to ca. 60 g L-1 during the rising limb of the hydrograph in West Bear, four times the value in East Bear, total P then declined rapidly as discharge remained high followed by an increase. Dissolved Al increased in both streams during the episodic acidification. West Bear, the more acidic, had concentrations of dissolved Al four times those of East Bear (maximum of 1.1 mg L-1 versus 0.25 mg L-1). Acid-soluble particulate Al increased to 0.2 and 4.2 mg L-1 for East and West Bear, respectively, in parallel to total P (but was 102 greater than total P) and then declined in parallel to total P while discharge remained high. Total P, dissolved P, and particulate Al did not relate to pH. Total P and particulate Al and Fe were strongly correlated. Concurrently, base cations remained relatively constant or decreased slightly. Particulate acid-soluble Al exceeded particulate acid-soluble base cations. We hypothesize that the particulate P was occluded in, or adsorbed on, acid-soluble particulate Al(OH)3. This Al(OH)3. This Al(OH)3 precipitates as emerging acidic groundwater degasses CO2 and pH rises. The export of Al and P is greater from the treated watershed because the induced acidification is translocating more Al from soils to the stream. Most of the export of P is related to acid-soluble Al particulate material.     

The Bear Brook Watershed, Maine (BBWM), USA

The Bear Brook Watershed Manipulation project in Maine is a paired calibrated watershed study funded by the U. S. EPA. The research program is evaluating whole ecosystem response to elevated inputs of acidifying chemicals. The project consists of a 2.5 year calibration period (1987-1989), nine years of chemical additions of (NH4)2SO4 (15N- and 34S-enriched for several years) to West Bear watershed (1989-1998), followed by a recovery period. The other watershed, East Bear, serves as a reference. Dosing is in six equal treatments/yr of 1800 eq SO4 and NH4/ha/yr, a 200% increase over 1988 loading (wet plus dry) for SO4 and 300% for N (wet NO3 + NH4). The experimental and reference watersheds are forested with mixed hard- and softwoods, and have thin acidic soils, areas of 10.2 and 10.7 ha, and relief of 210 m. Thin till of variable composition is underlain by metasedimentary pelitic rocks and calc-silicate gneiss intruded by granite dikes and sills. For the period 1987-1995, precipitation averaged 1.4 m/yr, had a mean pH of 4.5, with SO4, NO3, and NH4 concentrations of 26, 14, and 7 eq/L, respectively. The nearly perrenial streams draining each watershed have discharges ranging from 0 (East Bear stops flowing for one to two months per year) to 150 L/sec. Prior to manipulation, East Bear and West Bear had a volume weighted annual mean pH of approximately 5.4, alkalinity = 0 to 4 eq/L, total base cations = 184 eq/L (sea-salt corrected = 118 eq/L), and SO4 = 100 to 111 eq/L. Nitrate ranged from 0 to 30 eq/L with an annual mean of 6 to 25 eq/L; dissolved organic carbon (DOC) ranged from 1 to 7 mg/L but was typically less than 3. Episodic acidification occurred at high discharge and was caused by dilution of cations, slightly increased DOC, significantly higher NO3, and the sea-salt effect. Depressions in pH were accompanied by increases in inorganic Al. The West Bear catchment responded to the chemical additions with increased export of base cations, Al, SO4, NO3, and decreased pH, ANC, and DOC. Silica remained relatively constant. Neutralization of the acidifying chemicals occurred dominantly by cation desorption and mobilization of Al.     

Acidification Trends and the Evolution of Neutralization Mechanisms through Time at the Bear Brook Watershed in Maine (BBWM), U.S.A.

The paired catchment study at the forested Bear Brook Watershed in Maine (BBWM) U.S.A. documents interactions among short- to long-term processes of acidification. In 1987–1989, runoff from the two catchments was nearly identical in quality and quantity. Ammonium sulfate has been added bi-monthly since 1989 to the West Bear catchment at 1800 eq ha^-1 a^-1; the East Bear reference catchment is responding to ambient conditions. Initially, the two catchments had nearly identical chemistry (e.g., Ca²⁺, Mg²⁺, SO₄ ^2-, and alkalinity ≈82, 32, 100, and 5 μeq L^-1, respectively). The manipulated catchment responded initially with increased export of base cations, lower pH and alkalinity, and increased dissolved Al,NO₃ ^- and SO₄ ^2-. Dissolved organic carbon and Si have remained relatively constant. After 7 yr of treatment, the chemical response of runoff switched to declining base cations, with the other analytes continuing their trends; the exports of dissolved and particulate Al, Fe, and P increased substantially as base cations declined. The reference catchment has slowly acidified under ambient conditions, caused by the base cation supply decreasing faster than the decrease of SO₄ ², as pollution abates. Export of Al, Fe and, P is mimicking that of the manipulated watershed, but is lower in magnitude and lags in time. Probable increasing SO₄ ^2- adsorption caused by acidification has moderated the longer-term trends of acidification of both watersheds. The trends of decreasing base cations were interrupted by the effects of several short-term events, including severe ice storm damage to the canopy, unusual snow pack conditions, snow melt and rain storms, and episodic input of marine aerosols. These episodic events alter alkalinity by5 to 15 μeq L^-1 and make it more difficult to determine recovery from pollution abatement.     

Mercury and Organochlorine Contamination in Brown Trout (Salmo Trutta) and Arctic Charr (Salvelinus Alpinus) from High Mountain Lakes in Europe and the Svalbard Archipelago

High concentration of Hg, less volatile PCB congeners and p,p-DDE in Arctic charr from an arctic lake was mainly causedby biomagnification in the food chain where cannibalism was thedriving force. We suggest that low sediment fluxes of Hg, low net production of methyl mercury, and short food chains excludingpiscivory explain the low levels of Hg in the invertebrate feeding fish population in five European high mountain lakes.Concentrations of less volatile PCB congeners in insectivorous fish populations from the European high mountain lakes were mainly influenced by fish age and atmospheric deposition, indicated by the sediment inventory. Atmospheric deposition influenced by local sources may explain the higher concentrationsof pesticides (p,p-DDT, p,p-DDE and -HCH) observedin fish from the Pyrenees compared to the other sites. Theconcentrations of Hg and organochlorines did not exceedthe guidelines for fish consumption, except for Hg levelsin the oldest fish from the arctic lake.     

Brown trout as a sentinel organism for organic pollution in the field using catalytic and immunochemical assays of cytochrome P-450 1A

The measurement in some living organisms of adequate biomarkers (e.g. cytochrome P-450) to assess the organic pollution in freshwater ecosystems is well established. However, the sensitivity of this approach depends on the analytical measurement method employed and on the chosen living organism for the biomonitoring. Three analytical methods were compared for measuring cytochrome P-450 1A levels in wild brown trout (Salmo trutta): a catalytic one, based on measurement of the ethoxyresorufin-O-deethylase (EROD) activity, and two immunochemical methods, namely, enzyme-linked immunosorbent assay (ELISA) and western blotting. The P-450 1A levels in those animals from a river located in an industrialized area (Trubia River, Northern Spain) and also from individuals living in a low-contamination reference area have been studied. Significant differences (Mann-Whitney U-test, P < 0.01) between rivers were found (ELISA and EROD assays), with the values for Trubia river being similar to those observed in laboratory experiments with well known P-450 1A inducers. However, no significant differences were observed in terms of sex and age. Western blot analysis confirmed the presence of a single band of 56 kDa (corresponding with P-450 1 A protein) in microsomes of fish caught in the Trubia river. On the other hand, and associated with the chemical analysis of PAHs in the waters of both rivers by SPME-GC-MS, high levels of naphthalene (P-450 1A inducer) in the contaminated river were found. In brief, a wide difference between basal levels and P-450 1A induction levels could be detected in trout living in natural field conditions using both EROD activity assay and immunochemical methods. Therefore, brown trout could constitute a good sentinel organism to biomonitor the exposure to PAHs in rivers using P-450 1A measurements.     

Tapping the leakages: Methane losses, mitigation options and policy issues for Russian long distance gas transmission pipelines

The Russian natural gas industry is the world's largest producer and transporter of natural gas. This paper aims to characterize the methane emissions from Russian natural gas transmission operations, to explain projects to reduce these emissions, and to characterize the role of emissions reduction within the context of current GHG policy. It draws on the most recent independent measurements at all parts of the Russian long distance transport system made by the Wuppertal Institute in 2003 and combines these results with the findings from the US Natural Gas STAR Program on GHG mitigation options and economics.With this background the paper concludes that the methane emissions from the Russian natural gas long distance network are approximately 0.6% of the natural gas delivered. Mitigating these emissions can create new revenue streams for the operator in the form of reduced costs, increased gas throughput and sales, and earned carbon credits. Specific emissions sources that have cost-effective mitigation solutions are also opportunities for outside investment for the Joint Implementation Kyoto Protocol flexibility mechanism or other carbon markets.     

Ecotoxicological evaluation of pig slurry

Swine sewage could be source of nutrients and pollutants. This work estimates the environmental risk in nine samples from different farm treatment systems based on the evaluation of their effects in Daphnia magna acute test, and on the assessment of Cu, Zn and ammonia as main contributors. NH3 and Cu were responsible for LC50 results (1-5% of dilution). Organic compounds were quantified through several extraction methods (SPMDs, SPE and solvent extraction). A more exhaustive extraction was performed in an additional sample, which showed indole and phenol recoveries much higher than the previous ones. This method also includes PCBs (430 ppb) and fatty acids (approximately =150 ppm) quantification.     

Reverse positional orientation in a neotropical orb-web spider, <Emphasis Type="Italic">Verrucosa arenata</Emphasis>

Most orb-web spiders face downwards in the web. A downward orientation has been proposed to be the optimal strategy because spiders run faster downwards and thus can catch prey quicker. Consequently, orb-web spiders also extend their web in the lower part, leading to top-down web asymmetry. Since the majority of orb-web spiders face downwards, it has been difficult to test the effect of orientation on prey capture and web asymmetry. In this study, we explored the influence of reverse orientation on foraging efficiency and web asymmetry in Verrucosa arenata, a neotropical orb-web spider that faces upwards in the web. We show that reverse orientation does not imply reverse web asymmetry in this species. V. arenata spiders captured more prey in the lower part of the web but more prey per area on the upper part. The average running speeds of spiders did not differ between upward and downward running, but heavier spiders took longer to capture prey while running upwards. We discuss these findings in the context of foraging efficiency and web asymmetry.