Can traditional harvesting methods for cockles be accommodated in a Special Area of Conservation?     

McLaughlin  Emma; Portig  Alex; Johnson  Mark P. 《ICES Journal of Marine Science》2007,64(2):309-317

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Change in carbon flux (1960–2015) of the Red River (Vietnam)     

Thi Phuong Quynh Le  Nhu Da Le  Viet Nga Dao  Emma Rochelle-Newall  Thi Mai Huong Nguyen  Cyril Marchand  Thi Thuy Duong  Thi Xuan Binh Phung 《Environmental Earth Sciences》2018,77(18):658

Global riverine carbon concentrations and fluxes have been impacted by climate and human-induced changes for many decades. This paper aims to reconstruct the longterm carbon concentrations and carbon fluxes of the Red River, a system under the coupled pressures of environmental change and human activity. Based on (1) the relationships between particulate and dissolved organic carbon (POC, DOC) or dissolved inorganic carbon (DIC), and suspended sediments (TSS) or river water discharge and on (2) the available detailed historical records of river discharge and TSS concentration, the variations of the Red River carbon concentration and flux were estimated for the period 1960–2015. The results show that total carbon flux of the Red River averaged 2555?±?639 kton C year^?1. DIC fluxes dominated total carbon fluxes, representing 64% of total, reflecting a strong weathering process from carbonate rocks in the upstream basin. Total carbon fluxes significantly decreased from 2816 kton C year^?1 during the 1960s to 1372 kton C year^?1 during the 2010s and showed clear seasonal and spatial variations. Organic carbon flux decreased in both quantity and proportion of the total carbon flux from 40.9% in 1960s to 14.9% in 2010s, reflecting the important impact of dam impoundment. DIC flux was also reduced over this period potentially as a consequence of carbonate precipitation in the irrigated, agricultural land and the reduction of the Red River water discharge toward the sea. These decreases in TSS and carbon fluxes are probably partially responsible for different negatives impacts observed in the coastal zone.  相似文献   

Spatial variability of recent macroscopic charcoal deposition in a small montane lake and implications for reconstruction of watershed-scale fire regimes     

Colin J. Courtney Mustaphi  Emma L. Davis  Joelle T. Perreault  Michael F. J. Pisaric 《Journal of Paleolimnology》2015,54(1):71-86

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Sun,sea, sand and tsunami: examining disaster vulnerability in the tourism community of Khao Lak,Thailand   总被引：2，自引：0，他引：2  

Emma Calgaro  Kate Lloyd 《Singapore journal of tropical geography》2008,29(3):288-306

The impact of the 2004 Indian Ocean tsunami on coastal tourism communities highlights the vulnerability of tourism destinations to external shocks. Based on fieldwork conducted in Thailand in the wake of this disaster, this paper addresses one fundamental question: what sociopolitical and environmental conditions contributed to the vulnerability of the affected tourism community of Khao Lak in the southern Phang Nga Province. We argue that an understanding of the root causes of destination vulnerability is vital not only for the successful implementation of regional recovery plans, but also for building long‐term resilience against future shocks. In the absence of an appropriate tourism vulnerability framework, this paper analyzes Khao Lak's vulnerability through an innovative theoretical framework comprised of the sustainability vulnerability framework, relational scale and place. The findings reveal that Khao Lak's vulnerability is shaped by 13 interlinked factors. These are the complex outcomes of social norms and developmental and dynamic governance processes driven by the competing agendas and scaled actions of key government and industry stakeholders. The identification and understanding of the drivers of Khao Lak's vulnerability and a strong vulnerability framework have significant implications for the wider tourism community. First, the empirical findings provide tourism communities with a blueprint for understanding the foundations of their vulnerability to external shocks. Second, the tourism vulnerability framework presented here provides destination communities and government stakeholders with an analytical tool through which to analyze their unique sociopolitical conditions. Together, these empirical and theoretical contributions bring us closer to securing sustainable livelihood futures for tourism dependent communities.  相似文献   

Uncoupled viral and bacterial distributions in coral reef waters of Tuamotu Archipelago (French Polynesia)     

Bouvy M  Combe M  Bettarel Y  Dupuy C  Rochelle-Newall E  Charpy L 《Marine pollution bulletin》2012,65(10-12):506-515

This study examined the distribution of virioplankton and bacterioplankton in two coral reef systems (Ahe and Takaroa atolls) in the Tuamotu Archipelago, in comparison with the surrounding oligotrophic ocean. Mean concentrations of 4.8×10(5) and 6.2×10(5)cellsml(-1) for bacteria and 8.1×10(6) and 4.3×10(6)VLP(virus-like particle) ml(-1) were recorded in Ahe and Takaroa lagoons, respectively. Chlorophyll-a concentrations and dissolved organic matter were higher in Ahe whereas (3)H thymidine incorporation rates were higher in Takaroa. First data on lytic and lysogenic strategies of phages in coral reef environments were discussed in this paper. The fraction of visibly infected cells by viruses was negligible regardless of the lagoon station (mean=0.15%). However, the fraction of lysogenic cells ranged between 2.5% and 88.9%. Our results suggest that the distribution patterns of virioplankton are apparently not coupled to the spatial dynamics of the bacterioplankton communities.  相似文献   

The Krafla fissure swarm, Iceland, and its formation by rifting events     

ásta Rut Hjartardóttir  Páll Einarsson  Emma Bramham  Tim J. Wright 《Bulletin of Volcanology》2012,74(9):2139-2153

Fissure swarms at divergent plate boundaries are activated in rifting events, during which intense fracturing occurs in the fissure swarm accompanied by intrusion of magma to form dikes that sometimes lead to eruptions. To study the evolution of fissure swarms and the behaviour of rifting events, detailed mapping was carried out on fractures and eruptive fissures within the Krafla fissure swarm (KFS). Fracture densities of dated lava flows ranging from 10,000?years bp to ~30?years old were studied, and the fracture pattern was compared with data on the historical Myvatn rifting episode (1724–1729) and the instrumentally recorded Krafla rifting episode (1975–1984). Additionally, the interaction of transform faults and fissure swarms was studied by analysing the influence of the Húsavík transform faults on the KFS. During the historical rifting episodes, eruptions on the fissure swarm occurred within ~7?km from the Krafla central volcano, although faults and fractures were formed or activated at up to 60–70?km distance. This is consistent with earlier rifting patterns, as Holocene eruptive fissures within the KFS are most common closer to the central volcano. Most fractures within the central Krafla caldera are parallel to the overall orientation of the fissure swarm. This suggests that the regional stress field is governing in the Krafla central volcano, while the local stress field of the volcano is generally weak. A sudden widening of the graben in the northern KFS and a local maximum of fracture density at the junction of the KFS and the extrapolation of the Húsavík transform fault zone indicates possible buried continuation of the Húsavík transform fault zone which extends to the KFS. Eruptive fissures are found farther away from the Krafla central volcano in the southern KFS than in the northern KFS. This is either due to an additional magma source in the southern KFS (the Heiearsporeur volcanic system) or caused by the Húsavík transform faults, transferring some of the plate extension in the northern part. Fracture density within particular lava flow fields increases with field age, indicating that repeated rifting events have occurred in the fissure swarm during the last 10,000?years bp. The fracture density in the KFS is also generally higher closer to the Krafla central volcano than at the ends of the fissure swarm. This suggests that rifting events are more common in the parts of the fissure swarm closer to the Krafla central volcano.  相似文献   

Lithology and hydrocarbon mapping from multicomponent seismic data     

Hüseyin Özdemir  Kevin Flanagan  Emma Tyler 《Geophysical Prospecting》2010,58(2):297-306

Elastic rock properties can be estimated from prestack seismic data using amplitude variation with offset analysis. P‐wave, S‐wave and density ‘reflectivities’, or contrasts, can be inverted from angle‐band stacks. The ‘reflectivities’ are then inverted to absolute acoustic impedance, shear impedance and density. These rock properties can be used to map reservoir parameters through all stages of field development and production. When P‐wave contrast is small, or gas clouds obscure reservoir zones, multicomponent ocean‐bottom recording of converted‐waves (P to S or Ps) data provides reliable mapping of reservoir boundaries. Angle‐band stacks of multicomponent P‐wave (Pz) and Ps data can also be inverted jointly. In this paper Aki‐Richards equations are used without simplifications to invert angle‐band stacks to ‘reflectivities’. This enables the use of reflection seismic data beyond 30° of incident angles compared to the conventional amplitude variation with offset analysis. It, in turn, provides better shear impedance and density estimates. An important input to amplitude variation with offset analysis is the V_s/V_p ratio. Conventional methods use a constant or a time‐varying V_s/V_p model. Here, a time‐ and space‐varying model is used during the computation of the ‘reflectivities’. The V_s/V_p model is generated using well log data and picked horizons. For multicomponent data applications, the latter model can also be generated from processing V_s/V_p models and available well data. Reservoir rock properties such as λρ, μρ, Poisson's ratio and bulk modulus can be computed from acoustic impedance, shear impedance and density for pore fill and lithology identification. λ and μ are the Lamé constants and ρ is density. These estimations can also be used for a more efficient log property mapping. V_p/V_s ratio or Poisson's ratio, λρ and weighted stacks, such as the one computed from λρ and λ/μ, are good gas/oil and oil/water contact indicators, i.e., pore fill indicators, while μρ mainly indicates lithology. μρ is also affected by pressure changes. Results from a multicomponent data set are used to illustrate mapping of gas, oil and water saturation and lithology in a Tertiary sand/shale setting. Whilst initial log crossplot analysis suggested that pore fill discrimination may be possible, the inversion was not successful in revealing fluid effects. However, rock properties computed from acoustic impedance, shear impedance and density estimates provided good lithology indicators; pore fill identification was less successful. Neural network analysis using computed rock properties provided good indication of sand/shale distribution away from the existing wells and complemented the results depicted from individual rock property inversions.  相似文献   

Entanglements of marine mammals and seabirds in central California and the north-west coast of the United States 2001-2005     

Emma Moore  Shannon Lyday  Kate Litle  Hannah Nevins  Joe Mortenson  Melanie Piazza  Derek Lee  Sarah Allen 《Marine pollution bulletin》2009,58(7):1045-1051

Entanglement records for seabirds and marine mammals were investigated for the period 2001-2005. The entanglement records were extracted from databases maintained by seven organizations operating along the west coast of the United States of America. Their programmes included beach monitoring surveys, rescue and rehabilitation and regional pinniped censuses. Records of 454 entanglements were documented in live animals and in carcasses for 31 bird species and nine marine mammal species. The most frequently entangled species were Common Murres, Western Gulls and California sea lions. The entanglement materials identified were primarily fishing related. Entanglements were recorded every year suggesting that although the incidence level differs annually, entanglement is a persistent problem. It is recommended that each programme records details in standardized categories to determine entanglement material sources. Numbers of entanglements observed during these surveys are likely to be a conservative view of the actual entanglement rate taking place at sea.  相似文献   

Evidence for glaciation in the Northern Hemisphere back to 44 Ma from ice-rafted debris in the Greenland Sea     

Aradhna K. Tripati  Robert A. Eagle  Andrew Morton  Julian A. Dowdeswell  Katie L. Atkinson  Yannick Bahé  Caroline F. Dawber  Emma Khadun  Ruth M.H. Shaw  Oliver Shorttle  Lavaniya Thanabalasundaram 《Earth and Planetary Science Letters》2008,265(1-2):112-122

The widely accepted age estimate for the onset of glaciation in the Northern Hemisphere ranges between 2 and 15 million years ago (Ma). However, recent studies indicate the date for glacial onset may be significantly older. We report the presence of ice-rafted debris (IRD) in ～ 44 to 30 Ma sediments from the Greenland Sea, evidence for glaciation in the North Atlantic during the Middle Eocene to Early Oligocene. Detailed sedimentological evidence indicates that glaciers extended to sea level in the region, allowing icebergs to be produced. IRD may have been sourced from tidewater glaciers, small ice caps, and/or a continental ice sheet.  相似文献   

Exobiological prospecting     

Emma Newton  Howell G M Edwards  David Wynn-Williams  Julian A Hiscox 《Astronomy& Geophysics》2000,41(5):5.28-5.31

Emma Newton , Howell G M Edwards , David Wynn-Williams and Julian A Hiscox review the combination of biology, geology and physics necessary to search for life off Earth.  相似文献