Small-business demise and recovery after Katrina: rate of survival and demise

Post-disaster research is often plagued by displacement of subjects, loss of infrastructure, and the disruption of communication. Economic losses and business disruptions caused by a disaster tend to affect small businesses on a greater scale. With the majority of small businesses being operated out of a home, the inability to recover affects both economic and overall well-being of the business and the family. Specifically for small businesses, post-disaster research is important because it leads to increased preparedness and survival strategies for the sector and reduced economic vulnerabilities in owner-controlled areas. Historically, most of what is known about preparation, response, and recovery of small businesses from natural disasters is based on businesses that have recovered. However, there exists a need for understanding recovery also from the perspective of those that tried, but failed to recover. Grounded in a pragmatic approach, this study presents a methodology for tracking demised small businesses after Hurricane Katrina. Supported by empirical evidence, solutions to the problems of timing, generalizability, and access are presented, providing a systematic methodology for successfully studying small businesses after a disaster event. Rate of survival and demise data are presented, providing more useful numbers than prior estimates. Locating demised and recovered small businesses efficiently is the first step in understanding how business owners prepare, react, adjust, and strive to recover from disaster-driven events. A solution to this challenging issue of access makes the study of demised small businesses possible.     

An experimental study of bromine behaviour in water-saturated silicic melts

To assess the effect of the melt composition on bromine concentrations in magmas, we have investigated bromide solubility for water-saturated, iron-free silicic melts with variable Na+K/Al and Si/Al molar ratios (albite, haplogranite, rhyolite, and pantellerite). The experiments were performed in rapid quench cold-seal autoclaves over a range of pressure (1, 1.5, and 2 kbar) and temperature (900, 1000, and 1080 °C) with run durations from 5 to 7 days. A series of natural volcanic glasses and melt inclusions hosted in magmatic minerals were analysed together with the synthetic glasses by PIXE (proton-induced X-ray emission). The Br concentrations range from 5360 to 7850 ppm for albite, from 2800 to 3900 ppm for haplogranite, from 4300 to 5900 ppm for rhyolite, and from 9745 to 11,250 ppm for pantellerite. Br concentrations are negatively correlated with pressure in H₂O-saturated silicic melts and vary with (Na+K)/Al molar ratio with a minimum value at the ratio close to unity. Br behaves similarly to chlorine for all of these melt compositions. The bromide solubility is similar in albitic and rhyolitic melts, which implies that D^f/m is nearly the same for both compositions and is applicable for natural rhyolites as suggested in our previous study (Bureau et al., 2000). This means that the volcanic Br contribution to the atmosphere may be significant. In natural obsidian samples and MI hosted in quartz, olivine, and leucite, the Br concentration varies from < 3 to 28 ppm, with the highest concentrations in pantelleritic melts. We attribute the low Br concentrations of natural melts to a low initial abundance of this halogen in the Earth mantle. However, because Br behaves as an incompatible element before water exsolution, our results imply that magmas could contain much more dissolved Br before eruption and water degassing than the few ppm usually measured in volcanic rocks. Br behaviour during magma crystallisation is controlled by its partitioning into the H₂O-rich fluid phase when this occurs. In addition, its potential high solubility in silicate melts makes it a very sensitive chemical tracer of magma contamination by seawater and Br-rich material. This infers that the investigation of Br behaviour in subduction-zone samples may help for a better understanding of volatiles cycling between the Earth reservoirs.     

Influence of the circumglobal wave-train on European summer precipitation

We investigate European summer (July–August) precipitation variability and its global teleconnections using the NCEP/NCAR reanalysis data (1950–2010) and a historical Coupled Model Intercomparison Project climate simulation (1901–2005) carried out using the ECHAM6/MPIOM climate model. A wavelike pattern is found in the upper tropospheric levels (200 hPa) similar to the summer circumglobal wave train (CGT) extending from the North Pacific to the Eurasian region. The positive phase of the CGT is associated with upper level anomalous low (high) pressure over western (eastern) Europe. It is further associated with a dipole-like precipitation pattern over Europe entailing significantly enhanced (reduced) precipitation over the western (eastern) region. The anomalous circulation features and associated summer precipitation pattern over Europe inverts for the negative CGT phase. Accordingly, the global teleconnection pattern of a precipitation index summarizing summer precipitation over Western Europe entails an upper level signature which consists of a CGT-like wave pattern extending from the North Pacific to Eurasia. The imprint of the CGT on European summer precipitation is distinct from that of the summer North Atlantic Oscillation, despite the two modes of variability bear strong similarities in their upper level atmospheric pattern over Western Europe. The analysis of simulated CGT features and of its climatic implications for the European region substantiates the existence of the CGT-European summer precipitation connection. The summer CGT in the mid-latitude therefore adds to the list of the modes of large-scale atmospheric variability significantly influencing European summer precipitation variability.     

Trace metal dynamics in the water column and pore waters in a temperate tidal system: response to the fate of algae-derived organic matter

Tidal and seasonal behaviour of the redox-sensitive trace metals Mn, Fe, Mo, U, and V have been investigated in the open-water column and shallow pore waters of the backbarrier tidal flats of the island of Spiekeroog (Southern North Sea) in 2002 and 2007. The purpose was to study the response of trace metal cycles on algae blooms, which are assumed to cause significant changes in the redox state of the entire ecosystem. Trace metal data were complemented by measurements of nutrients and enumeration of algae cells in 2007. Generally, Mn and V show a tidal cyclicity in the water column with maximum values during low tide which is most pronounced in summer due to elevated microbial activity in the sediments. Mo and U behave almost conservatively throughout the year with slightly increasing levels towards high tide. Exceptions are observed for both metals after summer algae blooms. Thus, the seasonal behaviour of the trace metals appear to be significantly influenced by productivity in the water column as the occurrence of algae blooms is associated with an intense release of organic matter (e.g. transparent exopolymer particles, TEP) thereby forming larger organic-rich aggregates. Along with elevated temperatures in summer, the deposition of such aggregates favours microbial activity within the surface sediments and release of DOC, nutrients and trace metals (Mn, Mo and V) during the degradation of the aggregates. Additionally, pronounced reducing conditions lead to the reduction of Mn(IV)-oxides and Fe(III)-(oxihydr)oxides, thereby releasing formerly scavenged compounds as V and phosphate. Therefore, pore-water profiles show significant enrichments in trace metals especially from July to September. Finally, the trace metals are released to the open water column via draining pore waters (esp. Mo, Mn, and V) and/or fixed in the sediment as sulphides (Fe, Mo) and bound to organic matter (U). Non-conservative behaviour of Mo in oxygenated seawater, first observed in the investigation area by Dellwig et al. (Geochim Cosmochim Acta 71:2745–2761, 2007a), was shown to be a recurrent phenomenon which is closely coupled to bacterial activity after the breakdown of algae blooms. In addition to the postulated fixation of Mo in oxygen-depleted micro-zones of the aggregates or by freshly formed organic matter, a direct removal of Mo from the water column by reduced sediment surfaces may also play an important role.     

A freshwater species wintering in a brackish environment: Habitat selection and diet of Slavonian grebes in the southern Baltic Sea

After the breeding season, Slavonian grebes (Podiceps auritus) leave their freshwater breeding habitats and migrate to wintering grounds in marine or brackish waters. The most important wintering area in northwestern Europe is located in the southern Baltic Sea, with the largest concentrations in the offshore area of the Pommeranian Bight. Analysis of ship-based surveys revealed that the habitat selection of Slavonian grebes in this brackish area is significantly influenced by water depth and bottom sediment type. The grebes prefer shallow waters of 4–14 m depth and occur only over sandy sediments. While the diving depths of endothermic animals is limited due to energetic constraints and thermoregulation, sediment type is regarded to be a proxy for food choice. The diet of Slavonian grebes in the Pomeranian Bight consists mainly of demersal gobies (Gobiidae) that frequently occur over sandy bottom substrates.     

Orogen‐scale drainage network evolution and response to erodibility changes: insights from numerical experiments

The continuous feedbacks among tectonics, surface processes, and climate are reflected in the distribution of catchments on active mountain ranges. Previous studies have shown a regularity of valley spacing across mountain ranges worldwide, but the origin of this geomorphological feature is currently not well known. In this work, we use a landscape evolution model to investigate the process of fluvial network organization and the evolution of regular ridge‐and‐valley patterns on simulated mountain ranges. In particular, we investigate the behavior of such patterns when subjected to a perturbation in landscape processes from a previous steady state, resulting from a sudden variation in the pattern of bedrock erodibility, from homogeneous to a gradient. We analyze the time evolution of the mean ratio λ' between the linear spacing of adjacent valleys and the half width of the mountain range. We show how a valley spacing ratio of ~0.5 is first achieved at steady state under uniform bedrock erodibility. After applying the gradient of bedrock erodibility across the landscape, we observe that λ' first increases and then decreases to a new steady‐state value that is smaller than the original value. A detailed analysis of the simulations, through observations of surface ‘snapshots’ at repeated time intervals, allows to gain some insight into the mechanisms governing this fluvial network reorganization process, driven by the migration of the main divide toward the side characterized by lower bedrock erodibility. On both sides of the range the new steady‐state valley spacing is obtained through mechanisms of catchment reorganization and competition between adjacent fluvial networks. In particular, catchment reorganization is characterized by the growth of smaller catchments between shrinking larger catchments on the side with lower erodibility, and the growth of larger catchments on the side with higher erodibility. Copyright © 2014 John Wiley & Sons, Ltd.     

Microtopographical and hydrophysical controls on subsurface flow and solute transport: A continuous solute release experiment in a subarctic bog

Resource extraction and transportation activities in subarctic Canada can result in the unintentional release of contaminants into the surrounding peatlands. In the event of a release, a thorough understanding of solute transport within the saturated zone is necessary to predict plume fate and the potential impacts on peatland ecosystems. To better characterize contaminant transport in these systems, approximately 13,000 L/day of sodium chloride tracer (200 mg/L) was released into a bog in the James Bay Lowland. The tracer was pumped into a fully penetrating well (1.5 m) between July 5 and August 18, 2015. Horizontal and vertical plume development was measured via in situ specific conductance and water table depth from an adaptive monitoring network. Over the spill period, the bulk of the plume travelled a lateral distance of 100 m in the direction of the slight regional groundwater and topographical slope. The plume shape was irregular and followed the hollows, indicating preferential flow paths due to the site microtopography. Saturated transport of the tracer occurred primarily at ~25 cm below ground surface (bgs), and at a discontinuous high hydraulic conductivity layer ~125 cm bgs due to a complex and heterogeneous vertical hydraulic conductivity profile. Plume measurement was confounded by a large amount of precipitation (233 mm over the study period) that temporarily diluted the tracer in the highly conductive upper peat layer. Longitudinal solute advection can be approximated using local water table information (i.e., depth and gradient); microtopography; and meteorological conditions. Vertical distribution of solute within the peat profile is far more complex due to the heterogeneous subsurface; characterization would be aided by a detailed understanding of the site‐specific peat profile; the degree of decomposition; and the type of contaminant (e.g., reactive/nonreactive). The results of this research highlight the difficulty of tracking a contaminant spill in bogs and provide a benchmark for the characterization of the short‐term fate of a plume in these complex systems.     

Total Earth Pressure Cells for Measuring Loads in a Municipal Solid Waste Landfill

Commercially available hydraulic total overburden pressure cells were installed in the sand drainage layer of a municipal solid waste landfill and monitored for a period of 3,110 days. Both overburden pressure and temperature were measured in the landfill as it was filled with compacted waste. Topographic surveys of the landfill were periodically conducted to measure the height of waste above the pressure cells and to determine the landfill volume for indirect unit weight estimation. The average ratio of measured to theoretically-predicted overburden pressure was 0.6, indicating that on average the pressure cells underestimated the load. The overburden pressure measured near the toe of the landfill was greater than that predicted by the unit weight of landfilled material, while most of the overburden pressure measurements further inside the landfill were less than predicted. Several possible causes for this phenomenon are discussed, including the uneven distribution of forces resulting from the heterogeneous nature of the waste and cover soil. The earth pressure cells were capable of detecting the placement of individual waste lifts.