Pyrolysis GC-MS as a rapid screening tool for determination of peat-forming plant composition in cores from ombrotrophic peat

Peat cores provide decadal to centennial records of climatic and environmental change, including evidence for human/environment interaction. Existing palaeoenvironmental proxies (macrofossils, pollen, humification, testate amoebae, lipid composition) require multiple laboratory preparation steps and may be subject to differential preservation that can limit production of a continuous time series. The potential for pyrolysis gas-chromatography-mass-spectrometry (Py-GC-MS) to be applied to bulk peat samples is investigated here. The only preparatory step required was freeze drying. Analysis of a range of important peat-forming plants demonstrates that Sphagnum moss species are unique in containing the pyrolysis product of sphagnum acid, 4-isopropenylphenol. In contrast, non-Sphagnum species are rich in lignin pyrolysis products, which are absent from Sphagnum. The presence of these pyrolysis markers is reflected in bulk peat composition and tested here using archives from Bolton Fell Moss and Butterburn Flow (UK), Kontolanrahka (Finland) and Bissendorfer Moor (Germany). A ratio between 4-isopropenylphenol and two lignin pyrolysis products is proposed as a proxy for total Sphagnum input to peat archives and shows potential for use as a rapid screening tool for characterising bulk peat composition before more intensive analysis.     

Analysis of multiple enteric viral targets as sewage markers in coral reefs

Water and coral mucus samples were collected from throughout the Florida Keys National Marine Sanctuary and the Dry Tortugas for three years and were analyzed for human enteric viruses (enteroviruses, noroviruses, hepatitis A virus and adenoviruses) as conservative markers of human sewage using molecular methods. Of the 100 coral and water samples collected, 40 contained genetic material from one or more human enteric viruses. DNA-based adenoviruses were detected widely, in 37.8% of samples and at 91% of stations, including ‘pristine’ reefs in the Dry Tortugas; however, the detection rate was 12% for the RNA-based enteroviruses and noroviruses (hepatitis A virus was never detected). The disparity between the prevalence of RNA- and DNA-based viruses suggests the need for additional work to determine the utility of adenovirus as marker of human sewage.     

A GIS‐based variable source area hydrology model

Effective control of nonpoint source pollution from contaminants transported by runoff requires information about the source areas of surface runoff. Variable source hydrology is widely recognized by hydrologists, yet few methods exist for identifying the saturated areas that generate most runoff in humid regions. The Soil Moisture Routing model is a daily water balance model that simulates the hydrology for watersheds with shallow sloping soils. The model combines elevation, soil, and land use data within the geographic information system GRASS, and predicts the spatial distribution of soil moisture, evapotranspiration, saturation‐excess overland flow (i.e., surface runoff), and interflow throughout a watershed. The model was applied to a 170 hectare watershed in the Catskills region of New York State and observed stream flow hydrographs and soil moisture measurements were compared to model predictions. Stream flow prediction during non‐winter periods generally agreed with measured flow resulting in an average r² of 0·73, a standard error of 0·01 m³/s, and an average Nash‐Sutcliffe efficiency R² of 0·62. Soil moisture predictions showed trends similar to observations with errors on the order of the standard error of measurements. The model results were most accurate for non‐winter conditions. The model is currently used for making management decisions for reducing non‐point source pollution from manure spread fields in the Catskill watersheds which supply New York City's drinking water. Copyright © 1999 John Wiley & Sons, Ltd.     

Flow Adjustments Across Sea-Surface Temperature Changes

The adjustment of airflow across sea-surface temperature changes is examinedusing aircraft eddy-correlation data. Major features of the observed flow adjustmentare not included in the theory of internal boundary layers. However, the data samplesize and coverage are not sufficient to accurately quantify the additional influences.With flow from warm water over cooler water, substantial turbulence intermittentlydevelops above the newly formed surface inversion layer. The corresponding,spatially-averaged, downward momentum flux is stronger than that close to the surface.With stably stratified flow over modest increases of sea-surface temperature, areduction of stratification can trigger episodic shear generation of turbulence. Inthese cases, the primary role of increasing surface temperature in the downwinddirection is to induce shear generation of turbulence. With larger increases ofsurface temperature, upward heat flux generates turbulence, warms the air and generates a significant horizontal gradient of hydrostatic pressure. This contributionto the pressure field appears to strongly modify the flow. Major inadequacies inexisting data and future needs are noted.     

Estimated supply of RED credits 2011–2035

Previous attempts to estimate the supply of greenhouse gas emission reductions from reduced emissions from deforestation (RED) have generally failed to incorporate policy developments, country-specific abilities and political willingness to supply offsets for developed countries’ emissions. To address this, we estimate policy-appropriate projections of creditable emission reductions from RED. Two global forest carbon models are used to examine major assumptions affecting the generation of credits. The results show that the estimated feasible supply of RED credits is significantly below the biophysical mitigation potential from deforestation. A literature review identified an annual RED emission reduction potential between 1.6 and 4.3 Gt CO₂e. Feasible RED supply estimates applying the OSIRIS model were 1.74 Gt CO₂e annually between 2011 and 2020, with a cumulative supply of 17.4 Gt CO₂e under an ‘own-efforts’ scenario. Estimates from the Forest Carbon Index were very low at $5/t CO₂e with 8 million tonne CO₂e annually, rising to 1.8 Gt CO₂e at $20/t CO₂e. Cumulative abatement between 2011 and 2020 was 9 billion Gt CO₂e ($20/t CO₂e). These volumes were lower, sometimes dramatically, at prices of $5/t CO₂e suggesting a non-linear supply of credits in relation to price at a low payment level. For policy makers, the results suggest that inclusion of RED in a climate framework increases abatement potential, although significant constraints are imposed by political and technical issues.     

Distributed and integrated response of a geographic information system‐based hydrologic model in the eastern Palouse region,Idaho

Verification of distributed hydrologic models is rare owing to the lack of spatially detailed field measurements and a common mismatch between the scale at which soil hydraulic properties are measured and the scale of a single modelling unit. In this study, two of the most commonly calibrated parameters, i.e. soil depth and the vertical distribution of lateral saturated hydraulic conductivity K_s, were eliminated by a spatially detailed soil characterization and results of a hillslope‐scale field experiment. The soil moisture routing (SMR) model, a geographic information system‐based hydrologic model, was modified to represent the dominant hydrologic processes for the Palouse region of northern Idaho. Modifications included K_s as a double exponential function of depth in a single soil layer, a snow accumulation and melt algorithm, and a simple relationship between storage and perched water depth (PWD) using the drainable porosity. The model was applied to a 2 ha catchment without calibration to measured data. Distributed responses were compared with observed PWD over a 3‐year period on a 10 m × 15 m grid. Integrated responses were compared with observed surface runoff at the catchment outlet. The modified SMR model simulated the PWD fluctuations remarkably well, especially considering the shallow soils in this catchment: a 0·20 m error in PWD is equivalent to only a 1·6% error in predicted soil moisture content. Simulations also captured PWD fluctuations during a year with high spatial variability of snow accumulation and snowmelt rates at upslope, mid‐slope, and toe slope positions with errors as low as 0·09 m, 0·12 m, and 0·12 m respectively. Errors in distributed and integrated model simulations were attributed mostly to misrepresentation of rain events and snowmelt timing problems. In one location in the catchment, simulated PWD was consistently greater than observed PWD, indicating a localized recharge zone, which was not identified by the soil morphological survey. Copyright © 2006 John Wiley & Sons, Ltd.     

Uneven development of the sustainable city: shifting capital in Portland,Oregon

Portland, Oregon, is renowned as a paradigmatic “sustainable city.” Yet, despite popular conceptions of the city as a progressive ecotopia and the accolades of planners seeking to emulate its innovations, Portland’s sustainability successes are inequitably distributed. Drawing on census data, popular media, newspaper archives, city planning documents, and secondary source histories, we attempt to elucidate the structural origins of Portland’s “uneven development,” exploring how and why the urban core of this paragon of sustainability has become more White and affluent while its outer eastside has become more diverse and poor. We explain how a “sustainability fix”—in this case, green investment in the city’s core—ultimately contributed to the demarcation of racialized poverty along 82nd Avenue, a major north–south arterial marking the boundary of East Portland. Our account of structural processes taking place at multiple scales contributes to a growing body of literature on eco-gentrification and displacement and inner-ring suburban change while empirically demonstrating how Portland’s advances in sustainability have come at the cost of East Portland’s devaluation. Our “30,000 foot” perspective reveals systemic patterns that might then guide more fine-grained analyses of particular political-socio-cultural processes, while providing cautionary insights into current efforts to extend the city’s sustainability initiatives using the same green development model.     

Implications for U.S. Trade and Nonindigenous Species Risk Resulting from Increased Economic Integration of the Asia-Pacific Region

This work investigates how potential changes in trade patterns resulting from increased economic integration in the Asia-Pacific region may affect the risk for nonindigenous species spread to the United States. We construct an invasion risk index utilizing the results from a global economic modeling framework in tandem with data for climate similarities between trade partners. The index is based on risk of introduction, determined by changes in trade, and risk of establishment, given by terrestrial and marine climate similarities between countries. The results indicate that Japan may be the riskiest trade partner for the United States in the Asia-Pacific region from a nonindigenous species perspective. This is driven by large expected changes in trade and high environmental similarity between the two countries. This research provides the basis of a risk assessment prediction system to examine the effects of changes in trade on nonindigenous species risk, an important, novel contribution to the trade policy literature.     

Sediment flux in a small gravel-bed stream: Response to channel remediation works

Abstract:  Sediment transfers in a short reach of the Kiwitea Stream, near Fielding, lower North Island, New Zealand, are assessed using morphological budgeting based on repeat digital elevation model (DEM) differencing. Field data were acquired using high-precision GPS in October 2004, May and November 2005. Two interpolation methods to construct DEMs were compared. Universal kriging and Triangulation with Linear Interpolation produced consistent results and mean errors of between 4 and 14 mm. DEM error increases where relief changes rapidly. Sediment transfers are derived only from the low-relief active channel and indicate a rapidly changing environment. Remediation works following 2004 flood impacts have reduced bank erosion. A highly mobile bed renders the channel system sensitive to small and frequent flood events.