Groundwater biofilm dynamics grown in situ along a nutrient gradient

This paper describes the in situ response of groundwater biofilms in an alluvial gravel aquifer system on the Canterbury Plains, New Zealand. Biofilms were developed on aquifer gravel, encased in fine mesh bags and suspended in protective columns in monitoring wells for at least 20 weeks. Four sites were selected in the same groundwater system where previous analyses indicated a gradient of increasing nitrate down the hydraulic gradient from Sites 1 to 4. Measurements during the current study classified the groundwater as oligotrophic. Biofilm responses to the nutrient gradients were assessed using bioassays, with biomass determined using protein and cellular and nucleic acid staining and biofilm activity using enzyme assays for lipid, carbohydrate, phosphate metabolism, and cell viability. In general, biofilm activity decreased as nitrate levels increased from Sites 1 to 4, with the opposite relationship for carbon and phosphorus concentrations. These results showed that the groundwater system supported biofilm growth and that the upper catchment supported efficient and productive biofilms (high ratio of activity per unit biomass).     

Storm rainfall conditions for floods and debris flows from recently burned areas in southwestern Colorado and southern California

Debris flows generated during rain storms on recently burned areas have destroyed lives and property throughout the Western U.S. Field evidence indicate that unlike landslide-triggered debris flows, these events have no identifiable initiation source and can occur with little or no antecedent moisture. Using rain gage and response data from five fires in Colorado and southern California, we document the rainfall conditions that have triggered post-fire debris flows and develop empirical rainfall intensity–duration thresholds for the occurrence of debris flows and floods following wildfires in these settings. This information can provide guidance for warning systems and planning for emergency response in similar settings.Debris flows were produced from 25 recently burned basins in Colorado in response to 13 short-duration, high-intensity convective storms. Debris flows were triggered after as little as six to 10 min of storm rainfall. About 80% of the storms that generated debris flows lasted less than 3 h, with most of the rain falling in less than 1 h. The storms triggering debris flows ranged in average intensity between 1.0 and 32.0 mm/h, and had recurrence intervals of two years or less. Threshold rainfall conditions for floods and debris flows sufficiently large to pose threats to life and property from recently burned areas in south-central, and southwestern, Colorado are defined by: I = 6.5D^− 0.7 and I = 9.5D^− 0.7, respectively, where I = rainfall intensity (in mm/h) and D = duration (in hours).Debris flows were generated from 68 recently burned areas in southern California in response to long-duration frontal storms. The flows occurred after as little as two hours, and up to 16 h, of low-intensity (2–10 mm/h) rainfall. The storms lasted between 5.5 and 33 h, with average intensities between 1.3 and 20.4 mm/h, and had recurrence intervals of two years or less. Threshold rainfall conditions for life- and property-threatening floods and debris flows during the first winter season following fires in Ventura County, and in the San Bernardino, San Gabriel and San Jacinto Mountains of southern California are defined by I = 12.5D^−0.4, and I = 7.2D^−0.4, respectively. A threshold defined for flood and debris-flow conditions following a year of vegetative recovery and sediment removal for the San Bernardino, San Gabriel and San Jacinto Mountains of I = 14.0D^−0.5 is approximately 25 mm/h higher than that developed for the first year following fires.The thresholds defined here are significantly lower than most identified for unburned settings, perhaps because of the difference between extremely rapid, runoff-dominated processes acting in burned areas and longer-term, infiltration-dominated processes on unburned hillslopes.     

The last 500 year of sedimentation in Shkodra Lake (Albania/Montenegro): paleoenvironmental evolution and potential for paleoseismicity studies

Lake Shkodra (northern Albania, southern Montenegro) is a large (45 km length, 15 km width) and shallow (5 m mean depth) lake, developed on a mainly karstic carbonate substratum. Its recent sedimentary fill (mixed calcareous/siliciclastic clayey silts) was analysed through short gravity cores representing five centuries of environmental archive. A combination of high resolution texture analysis (particle size), magnetic susceptibility, carbon content, and radionuclide activity profiles (²¹⁰Pb, ¹³⁷Cs, ²⁴¹Am) permitted us to detect and date environmental changes, such as the Little Ice Age and the 1962–1963 catastrophic floods. Anthropogenic influences on the watershed, such as damming of the Drin River in the late 1970s, also appear to be recorded. Impacts of known strong earthquakes (1905, 1979), however, could not be clearly detected in the sediment record. The potential of the Shkodra lacustrine archive for paleoseismic investigations on long time intervals (such as Holocene) is discussed. This paper is a preliminary contribution to Shkodra Lake’s Holocene paleolimnology.     

Spectra® fishing twine entanglement of a bottlenose dolphin: A case study and experimental modeling

We report here the first documented case of a cetacean fatality from entanglement in recreational Spectra® fishing twine. Spectra® twine is a relatively new microfilament braided twine that is marketed to replace nylon monofilament twine in rod and reel fisheries. Following the case of this entangled bottlenose dolphin (Tursiops truncatus), we conducted tests with Spectra® and comparable monofilament twines on Tursiops tissue from stranded animals to compare the abrasion properties of the twines. We found that Spectra® twine was significantly more abrasive on bottlenose dolphin fluke tissue than a similar strength and diameter monofilament. With the same forces applied, the Spectra® twine cut deeper than the monofilament, exhibiting a linear relationship with force applied where the monofilament appeared to reach a maximum depth of penetration of approximately 2 mm. These tests may explain why this bottlenose dolphin was so severely debilitated from carrying a relatively light load of twine over a short period of time (20 days). Future public and corporate outreach will be essential to minimize the effect that this increasingly popular fishing twine will have on non-target species.     

The Qijurittuq site (IbGk-3), Eastern Hudson Bay: An IPY Interdisciplinary Study

Geografisk Tidsskrift—Danish Journal of Geography 110(2):227–243, 2010

An interdisciplinary study was conducted at Qijurittuq (IbGk-3), an archaeological site located on Drayton Island along the eastern shore of Hudson Bay, Nunavik. Local Inuit made important contributions to the research. High school students participated in the field school, and elders shared their traditional knowledge. The elders expressed an interest in the source of the wood used to construct Qijurittuq's semi-subterranean dwellings, and this inspired us to expand our research in that direction. This interdisciplinary study included a reconstruction of the geomorphological and environmental history of Drayton Island, wood provenance and dendrochronology studies, research on house architecture and settlement patterns, and a zooarchaeological analysis. This paper synthesizes the preliminary results of this interdisciplinary investigation within the context of climate change. We discuss the persistence of semi-subterranean dwellings in eastern Hudson Bay long after they had been abandoned elsewhere. At Qijurittuq, their abandonment corresponds with the end of Little Ice Age. However, at the same time, the development of more permanent contact with Euro-Canadians was having a strong impact upon Inuit culture.     

Disaster Declarations and Major Hazard Occurrences in the United States∗

This article examines the potential geographic inequities between major hazard events and U.S. presidential disaster declarations at the county level from 1965 through 2004. The previous literature suggests that the disaster declaration process is highly politicized and not necessarily based on need. We hypothesize that there is a spatial inequity between the receipt of disaster declarations and the distribution of major hazard events. The results indicate that the geographic distribution of disaster declarations is not totally explained by the spatial pattern of major hazard events. In some locales, state experience in submitting disaster requests and achieving success translates into more disaster declarations (holding everything else constant), providing further evidence of the political nature of the process.     

Developing the Commons: The Contradictions of Growth in Exurban Montana

Property development in exurban areas has the capacity to undermine the amenity values that undergird that development. Predicated on that contradiction, this research seeks to explain the emergence of local, informal, planning-based regulations in the traditionally antiregulatory context of rural Montana. Adopting both the insights of institutional common property theory and those of critical materialist analysis of economic growth, the work reconciles accounts of development as inherently ecologically self-destructive with those stressing creative development and adoption of rules for collective self-governance. Using a detailed case analysis of a Montana county undergoing rapid growth, it examines what drives localized land use regulation, what controls are enacted, and whether such controls are resisted or facilitated by development capital. Findings suggest that informal regulations seek to control externalities of development on valuable amenity commons and that they are adopted with the acceptance, if not encouragement, of the development community. These fragile instruments are vulnerable to opposition, however, highlighting problems of more general relevance: Growth depends on a deregulated development regime, which produces externalities that undermine the valorization of property. Localized regulatory planning regimes are therefore both a solution to contradictions inherent in growth and a potential source of future planning problems.     

Early Detection of Terrorism Outbreaks Using Prospective Space–Time Scan Statistics

Terrorism is a complex phenomenon with high uncertainty involving a myriad of dynamic known and unknown factors. It is and will remain a challenge to predict or detect terrorism outbreaks at an early stage. This research presents an alternative approach for modeling terrorism activity, one that monitors and detects space–time clusters of terrorist incidents using prospective space–time scan statistics. Such clusters provide indicators of potential outbreaks of terrorist incidents. To evaluate the effectiveness of the approach, we analyze the terrorist incidents in the Consortium for the Study of Terrorism and Responses to Terrorism's (START) Global Terrorism Database (GTD) from 1998 to 2004. Clusters of terrorist events are detected at each time stamp and life trajectories of these clusters are constructed based on their space–time relationship to each other. Through the life trajectories and trends of clusters, we demonstrate how space–time scan statistics detect terrorism outbreaks at an early stage.