Social vulnerability in the context of bushfire risk at the urban-bush interface in Sydney: a case study of the Blue Mountains and Ku-ring-gai local council areas     

Daminda Solangaarachchi  Amy L. Griffin  Michael D. Doherty 《Natural Hazards》2012,64(2):1873-1898

In the recent past, Australia has experienced several catastrophic hazard events and the frequency and intensity of such events is expected to increase in the future. Natural hazards can rarely be fully prevented, yet their losses can be minimized if the necessary preparedness and mitigation actions are taken before an event occurs. Identification of vulnerable groups is an important first step in any preparedness and emergency management planning process. Social vulnerability refers to population characteristics that influence the capacity of a community to prepare for, respond to and recover from disasters. Factors that contribute to social vulnerability are often hidden and difficult to capture. This study analyzes the relative levels of social vulnerability of communities at the urban?Cbush interface in the Blue Mountains and Ku-ring-gai local council areas in New South Wales (NSW), Australia. We tested whether a standardized social vulnerability index could be developed using a pre-existing set of indicators. We created an exploratory principle component analysis model using Australian Bureau of Statistics 2006 census data at the Census Collection District (CCD) level. We identified variables contributing to social vulnerability and used the component scores to develop a social vulnerability index. Finally, the social vulnerability index was mapped at the CCD level. Our results indicate that both contributors to and the level of social vulnerability differ between and within communities. In other words, they are spatially variable. They show different spatial patterns across the areas, which provides useful information for identifying communities that are most likely to experience negative disaster impacts due to their socio-demographic characteristics.  相似文献   

Stratified convection with multiple states     

J. A. Whitehead 《Ocean Modelling》2000,2(3-4)

A simplified box model of the cooling of a salt-stratified ocean is analyzed analytically and numerically. A large isothermal basin of salt water has a layer of fresh water at the surface. Beside this is a small basin, cooled from above and connected to the large basin by horizontal tubes at the top, middle and bottom. For small cooling rate, fresh water enters the small basin, is cooled and leaves through the middle tube. For greater cooling rate, the fresh water leaves the small basin through the middle and bottom tube. If the top tube is smaller than the deeper tubes and the fresh water layer is sufficiently shallow, flow in the middle tube reverses at a critical cooling rate. In this case, a mixture of salt and fresh water is cooled and leaves the bottom tube. Increased cooling produces much greater flow rate; consequentially temperature increases rather than decreases in the small basin. A relaxation heat flow condition results in multiple equilibria. One of the stable modes has fresh surface water descending in the small basin and flowing out through the middle and bottom tube. The other has a greater rate of flow of both fresh and salty water (through the middle tube) into the basin with the flow of mixed salty water out of the bottom tube. Implications for deep convection in the ocean are discussed.  相似文献   

Fisheries mismanagement     

O'Leary BC  Smart JC  Neale FC  Hawkins JP  Newman S  Milman AC  Roberts CM 《Marine pollution bulletin》2011,62(12):2642-2648

We analysed the extent to which European politicians have adhered to scientific recommendations on annual total allowable catches (TACs) from 1987 to 2011, covering most of the period of the Common Fisheries Policy (CFP). For the 11 stocks examined, TACs were set higher than scientific recommendations in 68% of decisions. Politically-adjusted TACs averaged 33% above scientifically recommended levels. There was no evidence that the 2002 reform of the CFP improved decision-making, as was claimed at the time. We modelled the effects of such politically-driven decision-making on stock sustainability. Our results suggest that political adjustment of scientific recommendations dramatically increases the probability of a stock collapsing within 40 years.In 2012 European fisheries policy will undergo a once-a-decade reform. Ten years ago radical reforms were promised but the changes failed to improve sustainability. It is likely that the 2012 reform will be similarly ineffective unless decision-making is changed so that catch allocations are based on science rather than politics.  相似文献   

Phytoplankton abundance and contributions to suspended particulate matter in the Ohio,Upper Mississippi and Missouri Rivers     

Paul A. Bukaveckas  Amy MacDonald  Anthony Aufdenkampe  John H. Chick  John E. Havel  Richard Schultz  Ted R. Angradi  David W. Bolgrien  Terri M. Jicha  Debra Taylor 《Aquatic Sciences - Research Across Boundaries》2011,73(3):419-436

Main channel habitats of the Ohio, Missouri, and Upper Mississippi Rivers were surveyed during the summers of 2004, 2005 and 2006 using a probability-based sampling design to characterize inter-annual and inter-river variation in suspended chlorophyll a (CHLa) and related variables. Large (fivefold) differences in CHLa were observed with highest concentrations in the Upper Mississippi (32.3 ± 1.8 μg L⁻¹), intermediate values in the Missouri (19.7 ± 1.1 μg L⁻¹) and lowest concentrations in the Ohio (6.8 ± 0.5 μg L⁻¹). Inter-annual variation was small in comparison to inter-river differences suggesting that basin-specific factors exert greater control over river-wide CHLa than regional-scale processes influencing climate and discharge. The rivers were characterized by variable but generally low light conditions as indicated by depth-averaged underwater irradiance <4 E m⁻² day⁻¹ and high ratios of channel depth to euphotic depth (>3). Despite poor light conditions, regression analyses revealed that TP was the best single predictor of CHLa (R ² = 0.40), though models incorporating both light and TP performed better (R ² = 0.60). Light and nutrient conditions varied widely within rivers and were inversely related, suggesting that riverine phytoplankton may experience shifts in resource limitation during transport. Inferred grazing and sedimentation losses were large yet CHLa concentrations did not decline downriver indicating that growth and loss processes were closely coupled. The contribution by algae to suspended particulate organic matter in these rivers (mean = 41%) was similar to that of lakes (39%) but lower relative to reservoirs (61%).  相似文献   

Sulfide Oxidation across Diffuse Flow Zones of Hydrothermal Vents     

Amy Gartman  Mustafa Y��cel  Andrew S. Madison  David W. Chu  Shufen Ma  Christopher P. Janzen  Erin L. Becker  Roxanne A. Beinart  Peter R. Girguis  George W. Luther III 《Aquatic Geochemistry》2011,17(4-5):583-601

The sulfide (H₂S/HS^?) that is emitted from hydrothermal vents begins to oxidize abiotically with oxygen upon contact with ambient bottom water, but the reaction kinetics are slow. Here, using in situ voltammetry, we report detection of the intermediate sulfur oxidation products polysulfides [ $ {\text{S}}_{\text{x}}^{2 - } $ ] and thiosulfate [ $ {\text{S}}_{ 2} {\text{O}}_{ 3}^{ 2- } $ ], along with contextual data on sulfide, oxygen, and temperature. At Lau Basin in 2006, thiosulfate was identified in less than one percent of approximately 10,500 scans and no polysulfides were detected. Only five percent of 11,000 voltammetric scans taken at four vent sites at Lau Basin in May 2009 show either thiosulfate or polysulfides. These in situ data indicate that abiotic sulfide oxidation does not readily occur as H₂S contacts oxic bottom waters. Calculated abiotic potential sulfide oxidation rates are <10^?3 ??M/min and are consistent with slow oxidation and the observed lack of sulfur oxidation intermediates. It is known that the thermodynamics for the first electron transfer step for sulfide and oxygen during sulfide oxidation in these systems are unfavorable, and that the kinetics for two electron transfers are not rapid. Here, we suggest that different metal catalyzed and/or biotic reaction pathways can readily produce sulfur oxidation intermediates. Via shipboard high-pressure incubation experiments, we show that snails with chemosynthetic endosymbionts do release polysulfides and may be responsible for our field observations of polysulfides.  相似文献   

Interannual variability in vertical export in the Ross Sea: Magnitude, composition, and environmental correlates     

Walker O. Smith Jr  Amy R. Shields  Jennifer C. Dreyer  Vernon Asper 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(2):147-159

The vertical flux of particulate matter from the surface of the Ross Sea, Antarctica, has been suggested as being large, with substantial seasonal and spatial variations. We conducted a study in which vertical flux was quantified using sediment traps deployed at 200 m and compared to estimates calculated from one-dimensional budgets of nutrients (nitrogen and silicon). Estimates of flux were collected at two locations in the southern Ross Sea from late December to early February during four years: 2001-2002, 2003-2004, 2004-2005, and 2005-2006. Phytoplankton biomass and vertical flux varied substantially seasonally and spatially between the two sites, and among years. The greatest flux was observed in 2001-2002, with a short-term maximum organic carbon flux of 3.13 mmol m⁻² d⁻¹, and the summer mean organic carbon flux equal to 0.93 mmol m⁻² d⁻¹. In contrast, the mean carbon flux at the same site in 2003-2004 was over an order of magnitude less, averaging 0.19 mmol m⁻² d⁻¹, despite the fact that productivity in that year was substantially greater. In 2005-206 the contribution of fecal pellets to flux was smallest among all years, and the pellet contribution ranged from <1 to more than 50% of organic flux. As the moorings also had surface layer fluorometers, the relationship between surface biomass and sediment trap flux was compared. Temporal lags between surface fluorescence and flux at 200 m maxima in 2003-2004 and 2004-2005 ranged from two to six days; however, in 2005-2006 the temporal offset between biomass and flux was much longer, ranging from 11 to 27 days, suggesting that fecal pellet production appeared to increase the coupling between flux and surface production. Estimates of export from the upper 200 m based on one-dimensional nutrient budgets were greater than those recorded by the sediment traps. Nutrient budgets also indicated that siliceous production averaged ca. 40% of the total annual production. The variations observed in the flux of biogenic matter to depth in the Ross Sea are large, appear to reflect different forcing among years, and at present are not adequately understood. However, such variability needs to be both understood and represented in biogeochemical models to accurately assess and predict the effects of climate change on biogeochemical cycles.  相似文献   

Analysis of photosynthetic picoeukaryote community structure along an extended Ellett Line transect in the northern North Atlantic reveals a dominance of novel prymnesiophyte and prasinophyte phylotypes     

Amy R. Kirkham  Ludwig E. Jardillier  Ross HollandMikhail V. Zubkov  Dave J. Scanlan 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(7):733-744

Photosynthetic picoeukaryotes (PPEs) of a size <3 ??m can contribute significantly to primary production. Here, PPE community structure was analysed along an extended Ellett Line transect, an area in the North Atlantic well studied by physical oceanographers but largely neglected in the field of microalgal ecology. Distribution patterns of specific PPE classes were determined using dot-blot hybridization analysis, while the taxonomic composition of specific PPE classes was revealed by phylogenetic analysis of plastid 16S rRNA gene sequences. In addition, we performed fluorescent in situ hybridization (FISH) analysis of seawater samples collected along the transect to provide a PCR-independent survey of class level PPE distribution patterns. We found the PPE community was dominated by members of the Prymnesiophyceae, Prasinophyceae and Mamiellophyceae. Interestingly, phylogenetic analysis revealed several novel Prymnesiophyceae and Prasinophyceae phylotypes (with only 85-96% identity to neighbouring sequences) within lineages for which cultured counterparts are unknown.  相似文献   

Influence of Two Tropical Storms on the Residual Flow in a Subtropical Tidal Inlet     

Amy F. Waterhouse  Bilge Tutak  Arnoldo Valle-Levinson  Y. Peter Sheng 《Estuaries and Coasts》2013,36(5):1037-1053

The mechanisms responsible for the modulation of laterally sheared non-tidal (residual) exchange flow in a subtropical inlet, with special emphasis on tropical storm influence, are studied using a combination of current velocity profiles and hydrographic and meteorological data. The mouth of the inlet, St. Augustine Inlet in northeast Florida, is characterized by a 15-m-deep channel flanked by shoals (<6 m deep). Residual flows across the inlet mouth were laterally sheared with inflow in the channel and outflow over the shoals. This pattern persisted during four separate semi-diurnal tidal cycle surveys effected over 3 years. During spring tides, residual exchange flows intensified relative to neap tides. Residual inflow in the channel only reversed immediately after tropical storms because of their extreme winds and major temporal changes in water level. After the residual flow reversed in the channel, along-channel baroclinicity drove gravitational circulation that persisted for 4.5 days and was enhanced by offshore winds. A depth-averaged along-basin momentum budget highlighted the importance of bottom friction to help balance the barotropic pressure gradient. The rest of the momentum budget was likely provided by advective terms. During and after tropical storms, accelerations from wind stress and baroclinic pressure gradients also became influential in the along-basin momentum budget.  相似文献   

Transmission of kinematic information in dense granular systems: local and nonlocal network sensing     

David M. Walker  Antoinette Tordesillas  Amy L. Rechenmacher 《Acta Geotechnica》2013,8(5):547-560

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Mesozoic Deposystems and Evolution of the Qamdo Basin, Eastern Tibet     

SHANG Fei  Amy WEISLOGEL 《《地质学报》英文版》2013,87(Z1):582-582

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