Egg mass and shell thickness in dippers Cinclus cinclus in relation to stream acidity in Wales and Scotland

The shell thickness and mass of eggs of the dipper (Cinclus cinclus) collected on streams of different pH in Wales and Scotland were measured. The aluminium, phosphorus and calcium content of their invertebrate prey were also measured. In a regression analysis, significant at p<0.05, stream pH accounted for up to 7% of the variance in shell thickness, with shells decreasing by 2.5% of the overall mean with each unit of pH decline. In the Welsh sample, differences in shell thickness due to pH were small compared with differences between years across all sites. In data pooled between Scotland and Wales, pH accounted for 17% of the variance in egg mass, but a greater proportion (25%) in Scottish eggs alone. Aluminium concentrations in invertebrates showed no relationship with stream pH, but calcium levels in two insect orders increased significantly with pH. Calcium rich prey, such as Gammarus, were found only in circumneutral streams. The importance of calcium in the diet of dippers before and during egg formation is discussed. No evidence that aluminium in prey adversely affected dipper eggs was found.     

Metal accumulation by wood-decaying fungi

Metal concentrations (Na, K, Rb, Mg, Ca, Sr, Mn, Fe, Cu, Zn, Cd, Al, and Pb) in the sporophores of ten wood-decaying macromycete species were related to concentrations in the wood substrates. Manganese, Sr, Ca, and Pb were usually excluded by the fungi, K, Rb, and, to a lower degree, Cd, Fe, Zn, Cu, Mg and Na, were accumulated. Accumulation ratios are compared with similar ratios for soil and litter inhabiting species previously studied.     

Analysis of organic and inorganic species on the surface of atmospheric aerosol using time-of-flight secondary ion mass spectrometry (TOF-SIMS)

This work explores the utility of time-of-flight static secondary-ion mass spectrometry (TOF-SIMS) for the analysis of the surface organic layer on individual atmospheric aerosol particles. The surface sensitivity and minimal fragmentation available with TOF-SIMS suggest that it can be a powerful tool for the examination of the organic and inorganic species on the surface of individual particles. Cascade impactors were used to collect aerosol from summer 2000 Montana forest fires, winter snowmobile samples in Yellowstone National Park, Hawaiian lava and sea salt, from an Asian Dust event reaching Salt Lake City, Utah in April 2001 and from Salt Lake Valley summer urban aerosol. TOF-SIMS analysis and multivariate statistical techniques combined gave chemical and morphological information about the particles. Surfaces of the aerosol from forest fires, snowmobile exhaust, and sea salt were all dominated by aliphatic hydrocarbons and their amphiphilic derivatives. Each source showed a different organic chemical signature. The extent and composition of the organics layer which typically covers the surface of atmospheric particles are expected to effect all of the surface related aerosol properties such as health effects, the ability of the particle to activate and form cloud droplets, and the aggregation of particles as well as reactions between the particle and gas phase species.     

Gametogenic periodicity in the chemosynthetic cold-seep mussel “<Emphasis Type="Italic">Bathymodiolus” childressi</Emphasis>

The gametogenic periodicity of the cold seep mussel “Bathymodiolus” childressi was analysed from a time series of samples from depths of ∼ 650 m surrounding the Brine Pool cold seep on the continental slope of the northern Gulf of Mexico. Occasional samples were retrieved from Bush Hill and GC 234 for comparison. At the Brine Pool, both females and males showed strong reproductive periodicity with the initiation of gametogenesis from December to March, followed by a period of gamete growth or proliferation and spawning from October to February. Gametogenesis was synchronized at all three sites. Gametogenic periodicity appears to be correlated with surface production that peaks during the winter months. Downward flux of detritus during this period may provide food for the planktotrophic larvae and also supplementary nutrition for the adult, which has chemosynthetic bacterial symbionts but is also capable of filter feeding. Individuals in all three populations carried parasites and these were especially common at Bush Hill and GC234, where it is suggested they have a major impact on reproductive output.     

Preliminary results from the first national in situ gamma spectrometry survey of the United Kingdom

In situ gamma spectrometry was introduced as part of a national soil and herbage pollution survey of the United Kingdom (UK) in 2002, to evaluate its potential for complimenting or even replacing the conventional soil sampling approach in environmental monitoring. A total of 128 points were measured across the whole of the UK on a 50-km grid, including 11 calibration sites, encompassing a complete spectrum of soil types, geology and depositional environments. Good comparisons are demonstrated between in situ and soil sample derived estimates of environmental radioactivity from spatially matched sampling plans. Air kerma results and the contributions to air kerma rate are also presented and compared with calibrated conventional single parameter GM based instruments. The preliminary results are presented here and show that in situ gamma spectrometry provides a rapid and robust approach, providing spatially integrated estimates for environmental monitoring purposes.     

Variations between winter and summer in the toxicity of copper to a population of the mysid Praunus flexuosus

 Copper toxicity was tested on a coastal population of the mysid Praunus flexuosus (Müller) from Southampton Water (Southern England) under winter and summer conditions. Ten-day toxicity tests were performed on the different life-cycle stages (female, male and juvenile) present in winter (December/February) and summer (August). The individuals were in winter or summer physiological condition and were exposed to seawater to which 0, 5, 25, 75 and 200 μg l⁻¹ copper was added. There were significantly different copper toxicity effects in winter and summer. In winter mortality was ≤ 1% at all levels of copper exposure, while in summer identical exposure levels caused mortality of up to 93%. The 96 h LC₅₀ was 30.8 μg l⁻¹ copper added in the summer. In winter, the low mortality prevented calculation of LC₅₀. There were differences in responses to copper between the life-cycle stages. Juveniles were more sensitive than adults, and were severely affected within 24 h. Females were more affected than males at lower doses and shorter exposure times. Received: 28 April 1999 / Accepted: 22 June 2000     

Gametogenesis, spawning behavior, and early development in the “iceworm”Hesiocaeca methanicola (Polychaeta: Hesionidae) from methane hydrates in the Gulf of Mexico

Gametogenesis, spawning behavior, and early development have been described in the methane-seep polychaete Hesiocaecamethanicola Desbruyères and Toulmond, 1998, the first documentation of the reproductive biology of any cold-seep polychaete species. The worms were collected at the Green Canyon site in the Gulf of Mexico (27°44.77N; 91°13.33W) in August 1997. The gonads are situated in the neuropodia in association with an intraepithelial capillary system. Oogenesis is intraovarian, with oocytes remaining in the ovary until late vitellogenesis when they are released into the coelom for final growth and differentiation. Vitellogenesis involves both autosynthetic and heterosynthetic processes and, along with ovarian structure, suggests a relatively slow process of egg formation. Sperm differentiation is intertesticular until early spermiogenesis, when spermatid tetrads complete development in the coelom. The mature spermatozoon is an ect-aquasperm consisting of a tapering, digitate acrosome, a spherical nucleus, a midpiece containing from six to eight mitochondria and glycogen stores, and two centrioles associated with the flagellum. Both sexes undergo broadcast spawning, but the males spawn exclusively through the anus, a behavior previously unknown in polychaetes. Artificial fertilization resulted in spiral cleavage and development to the trochophore stage. Oocyte size-frequency analysis of adult females indicates a wide range of oocyte sizes and vitellogenic stages, suggesting that asynchronous gametogenesis occurs. Received: 13 July 2000 / Accepted: 29 November 2000     

An In Situ Bioreactor for the Treatment of Petroleum Hydrocarbons in Groundwater

Two pilot tests of an aerobic in situ bioreactor (ISBR) have been conducted at field sites contaminated with petroleum hydrocarbons. The two sites differed with respect to hydrocarbon concentrations. At one site, concentrations were low but persistent, and at the other site concentrations were high enough to be inhibitory to biodegradation. The ISBR unit is designed to enhance biodegradation of hydrocarbons by stimulating indigenous microorganisms. This approach builds on existing Bio‐Sep^® bead technology, which provides a matrix that can be rapidly colonized by the active members of the microbial community and serves to concentrate indigenous degraders. Oxygen and nutrients are delivered to the bioreactor to maintain conditions favorable for growth and reproduction, and contaminated groundwater is treated as it is circulated through the bed of Bio‐Sep^® beads. Groundwater moving through the system also transports degraders released from Bio‐Sep^® beads away from the bioreactor, potentially increasing biodegradation rates throughout the aquifer. Groundwater sampling, Bio‐Traps, and molecular biological tools were used to assess ISBR performance during the two pilot tests. Groundwater monitoring indicated that contaminant concentrations decreased at both sites, and the microbial data suggested that these decreases were due to degradation by indigenous microorganisms rather than dilution or dispersion mechanisms. Taken together, these lines of evidence showed that the ISBR system effectively increased the number and activity of indigenous microbial degraders and enhanced bioremediation at the test sites. © 2013 Wiley Periodicals, Inc.     

Communities and change in the anthropocene: understanding social-ecological vulnerability and planning adaptations to multiple interacting exposures

The majority of vulnerability and adaptation scholarship, policies and programs focus exclusively on climate change or global environmental change. Yet, individuals, communities and sectors experience a broad array of multi-scalar and multi-temporal, social, political, economic and environmental changes to which they are vulnerable and must adapt. While extensive theoretical—and increasingly empirical—work suggests the need to explore multiple exposures, a clear conceptual framework which would facilitate analysis of vulnerability and adaptation to multiple interacting socioeconomic and biophysical changes is lacking. This review and synthesis paper aims to fill this gap through presenting a conceptual framework for integrating multiple exposures into vulnerability analysis and adaptation planning. To support applications of the framework and facilitate assessments and comparative analyses of community vulnerability, we develop a comprehensive typology of drivers and exposures experienced by coastal communities. Our results reveal essential elements of a pragmatic approach for local-scale vulnerability analysis and for planning appropriate adaptations within the context of multiple interacting exposures. We also identify methodologies for characterizing exposures and impacts, exploring interactions and identifying and prioritizing responses. This review focuses on coastal communities; however, we believe the framework, typology and approach will be useful for understanding vulnerability and planning adaptation to multiple exposures in various social-ecological contexts.     

Instream sensor results suggest soil–plant processes produce three distinct seasonal patterns of nitrate concentrations in the Ohio River Basin

The Ohio River Basin (ORB) is responsible for 35% of total nitrate loading to the Gulf of Mexico yet controls on nitrate timing require investigation. We used a set of submersible ultraviolet nitrate analyzers located at 13 stations across the ORB to examine nitrate loading and seasonality. Observed nitrate concentrations ranged from 0.3 to 2.8 mg L⁻¹ N in the Ohio River's mainstem. The Ohio River experiences a greater than fivefold increase in annual nitrate load from the upper basin to the river's junction with the Mississippi River (74–415 Gg year⁻¹). The nitrate load increase corresponds with the greater drainage area, a 50% increase in average annual nitrate concentration, and a shift in land cover across the drainage area from 5% cropland in the upper basin to 19% cropland at the Ohio River's junction with the Mississippi River. Time-series decomposition of nitrate concentration and nitrate load showed peaks centered in January and June for 85% of subbasin-year combinations and nitrate lows in summer and fall. Seasonal patterns of the terrestrial system, including winter dormancy, spring planting, and summer and fall growing-harvest seasons, are suggested to control nitrate timing in the Ohio River as opposed to controls by river discharge and internal cycling. The dormant season from December to March carries 51% of the ORB's nitrate load, and nitrate delivery is high across all subbasins analyzed, regardless of land cover. This season is characterized by soil nitrate leaching likely from mineralization of soil organic matter and release of legacy nitrogen. Nitrate experiences fast transit to the river owing to the ORB's mature karst geology in the south and tile drainage in the northwest. The planting season from April to June carries 26% of the ORB's nitrate and is a period of fertilizer delivery from upland corn and soybean agriculture to streams. The harvest season from July to November carries 22% of the ORB's nitrate and is a time of nitrate retention on the landscape. We discuss nutrient management in the ORB including fertilizer efficiency, cover crops, and nitrate retention using constructed measures.