Fault‐controlled fluid flow inferred from hydrothermal vents imaged in 3D seismic reflection data,offshore NW Australia          下载免费PDF全文

Craig Magee  Oliver B. Duffy  Kirsty Purnell  Rebecca E. Bell  Christopher A.‐L. Jackson  Matthew T. Reeve 《Basin Research》2016,28(3):299-318

Fluid migration pathways in the subsurface are heavily influenced by pre‐existing faults. Although studies of active fluid‐escape structures can provide insights into the relationships between faults and fluid flow, they cannot fully constrain the geometry of and controls on the contemporaneous subsurface fluid flow pathways. We use 3D seismic reflection data from offshore NW Australia to map 121 ancient hydrothermal vents, likely related to magmatic activity, and a normal fault array considered to form fluid pathways. The buried vents consist of craters up to 264 m deep, which host a mound of disaggregated sedimentary material up to 518 m thick. There is a correlation between vent alignment and underlying fault traces. Seismic‐stratigraphic observations and fault kinematic analyses reveal that the vents were emplaced on an intra‐Tithonian seabed in response to the explosive release of fluids hosted within the fault array. We speculate that during the Late Jurassic the convex‐upwards morphology of the upper tip‐lines of individual faults acted to channelize ascending fluids and control where fluid expulsion and vent formation occurred. This contribution highlights the usefulness of 3D seismic reflection data to constraining normal fault‐controlled subsurface fluid flow.  相似文献   

Tips and tricks in designing management procedures   总被引：2，自引：2，他引：2  

Rademeyer  Rebecca A.; Plaganyi  Eva E.; Butterworth  Doug S. 《ICES Journal of Marine Science》2007,64(4):618-625

  相似文献   

Ecosystem management bioindicators: the ECOMAN project--a multi-biomarker approach to ecosystem management     

Galloway TS  Brown RJ  Browne MA  Dissanayake A  Lowe D  Jones MB  Depledge MH 《Marine environmental research》2004,58(2-5):233-237

The ECOMAN project was initiated from an awareness of the complexity of the functioning of coastal marine systems and the clear need for more pragmatic environmental assessment techniques linking environmental degradation with its causes. The aim of the project is to develop a suite of easy to use, cost effective and environmentally valid biological responses (biomarkers) to assess the general health of coastal systems, including estuaries. To achieve this aim, various sublethal endpoints are being measured and evaluated from a range of common coastal organisms showing different feeding types (filter feeding, grazing and predation) and habitat requirements (estuary and rocky shore) and at different levels of biological response (cellular, physiological and behavioural). This holistic integrated approach is essential to identify the full impact of chemical contamination on organisms, and enables the sensitivity of organisms to be ranked and key sentinel species for specific habitats to be identified.  相似文献   

Ecosystem management bioindicators: the ECOMAN project – a multi-biomarker approach to ecosystem management     

Tamara S. Galloway  Rebecca J. Brown  Mark A. Browne  Awantha Dissanayake  David Lowe  Malcolm B. Jones  Michael H. Depledge 《Marine environmental research》2004,58(2-5):233

The ECOMAN project was initiated from an awareness of the complexity of the functioning of coastal marine systems and the clear need for more pragmatic environmental assessment techniques linking environmental degradation with its causes. The aim of the project is to develop a suite of easy to use, cost effective and environmentally valid biological responses (biomarkers) to assess the general health of coastal systems, including estuaries. To achieve this aim, various sublethal endpoints are being measured and evaluated from a range of common coastal organisms showing different feeding types (filter feeding, grazing and predation) and habitat requirements (estuary and rocky shore) and at different levels of biological response (cellular, physiological and behavioural). This holistic integrated approach is essential to identify the full impact of chemical contamination on organisms, and enables the sensitivity of organisms to be ranked and key sentinel species for specific habitats to be identified.  相似文献   

Lateral water flux in the unsaturated zone: A mechanism for the formation of spatial soil heterogeneity in a headwater catchment          下载免费PDF全文

John P. Gannon  Kevin J. McGuire  Scott W. Bailey  Rebecca R. Bourgault  Donald S. Ross 《水文研究》2017,31(20):3568-3579

Measurements of soil water potential and water table fluctuations suggest that morphologically distinct soils in a headwater catchment at the Hubbard Brook Experimental Forest in New Hampshire formed as a result of variations in saturated and unsaturated hydrologic fluxes in the mineral soil. Previous work showed that each group of these soils had distinct water table fluctuations in response to precipitation; however, observed variations in soil morphology also occurred above the maximum height of observed saturation. Variations in unsaturated fluxes have been hypothesized to explain differences in soil horizon thickness and presence/absence of specific horizons but have not been explicitly investigated. We examined tensiometer and shallow groundwater well records to identify differences in unsaturated water fluxes among podzols that show distinct morphological and chemical differences. The lack of vertical hydraulic gradients at the study sites suggests that lateral unsaturated flow occurs in several of the soil units. We propose that the variations in soil horizon thickness and presence/absence observed at the site are due in part to slope‐parallel water flux in the unsaturated portion of the solum. In addition, unsaturated flow may be involved in the translocation of spodic material that primes those areas to contribute water with distinct chemistry to the stream network and represents a potential source/sink of organometallic compounds in the landscape.  相似文献   

Effects of instream processes,discharge, and land cover on nitrogen export from southern Appalachian Mountain catchments     

Jackson R. Webster  Rebecca M. Stewart  Jennifer D. Knoepp  C. Rhett Jackson 《水文研究》2019,33(2):283-304

Catchments with minimal disturbance usually have low dissolved inorganic nitrogen (DIN) export, but disturbances and anthropogenic inputs result in elevated DIN concentration and export and eutrophication of downstream ecosystems. We studied streams in the southern Appalachian Mountains, USA, an area dominated by hardwood deciduous forest but with areas of valley agriculture and increasing residential development. We collected weekly grab samples and storm samples from nine small catchments and three river sites. Most discharge occurred at baseflow, with baseflow indices ranging from 69% to 95%. We identified three seasonal patterns of baseflow DIN concentration. Streams in mostly forested catchments had low DIN with bimodal peaks, and summer peaks were greater than winter peaks. Streams with more agriculture and development also had bimodal peaks; however, winter peaks were the highest. In streams draining catchments with more residential development, DIN concentration had a single peak, greatest in winter and lowest in summer. Three methods for estimating DIN export produced consistent results. Annual DIN export ranged from less than 200 g ha^?1 year^?1 for the less disturbed catchments to over 2,000 g ha^?1 year^?1 in the catchments with the least forest area. Land cover was a strong predictor of DIN concentration but less significant for predicting DIN export. The two forested reference catchments appeared supply limited, the most residential catchment appeared transport limited, and export for the other catchments was significantly related to discharge. In all streams, baseflow DIN export exceeded stormflow export. Morphological and climatological variation among watersheds created complexities unexplainable by land cover. Nevertheless, regression models developed using land cover data from the small catchments reasonably predicted concentration and export for receiving rivers. Our results illustrate the complexity of mechanisms involved in DIN export in a region with a mosaic of climate, geology, topography, soils, vegetation, and past and present land use.  相似文献   

Fixing marine governance in Fiji? The new scalar narrative of ecosystem-based management     

Leila Sievanen  Rebecca L. Gruby  Lisa M. Campbell 《Global Environmental Change》2013,23(1):206-216

Although there is widespread concern over degrading marine environments, there is debate within the global marine conservation agenda about the nature of the problem and appropriate solutions. At the center of this debate lie questions about the appropriate scale at which to plan and implement marine resource management. In the late 1990s, Fiji became recognized as one of the most successful examples of community-based marine resource management in the world. Recently, there has been a move to manage human–environment interactions at larger “natural” scales. We draw from the political ecology and “politics of scale” literatures, and a critical realist understanding of nature and politics, to explain the emergence of large-scale management and conservation in Fiji. We contribute to a “political ecology of scale” by developing the concept of a scalar narrative to show how social and ecological scales are reworked in the development of an ecosystem-based approach to marine management in Fiji. In doing so, we consider implications of the struggle to define the appropriate scale of marine management, which is closely bound to debates about the role of science and local participation. Our findings suggest that the struggle to define the scale at which marine management should be planned and implemented is inseparable from the struggle over who should define, inform, and conduct the governance process. We aim to clarify marine policy debates as policy actors worldwide move forward to implement ecosystem-based management, increase marine protected area coverage, and pursue sustainable development.  相似文献   

Spatiotemporal development of physical,chemical, and biological characteristics of stormwater plumes in Santa Monica Bay,California (USA)     

Alina A. Corcoran  Kristen M. Reifel  Burton H. Jones  Rebecca F. Shipe 《Journal of Sea Research》2010,63(2):129-142

This study characterized stormwater plume development and associated phytoplankton dynamics in a coastal marine ecosystem through shipboard monitoring. We focused on plumes within Santa Monica Bay, California (USA), a coastal system that is subject to rapid pulses of untreated runoff from the urbanized watershed of Los Angeles during the winter rainy season. The physical, chemical, and biological signatures of stormwater plumes were tracked over time after each of 4 precipitation events ranging in magnitude from 1.5 cm to 9 cm. Low salinity surface plumes persisted in Santa Monica Bay for at least 2 to 5 days over spatial scales of up to 15 km. This is consistent with a 6-day residence time for surface water plume parcels, which was estimated from a drifter trajectory in the bay. Shipboard sampling and salinity measurements in the surf zone showed that plumes often persisted even longer nearshore. Plume waters were generally characterized by higher concentrations of dissolved nitrogen, colored dissolved organic matter, and higher light attenuation than non-plume waters. The magnitude of the effect of stormwater runoff on phytoplankton dynamics was dependent on the size of each storm and subsequent residence time of runoff within the bay. Rain events led to increases in primary productivity, phytoplankton biomass, and specifically, increases in diatom biomass, as measured by concentrations of biogenic silica.  相似文献   

Evaluating the Process and Outcomes of Collaborative Conservation: Tools,Techniques, and Strategies     

Rebecca E. W. Thomas  Arren Mendezona Allegretti 《社会与自然资源》2020,33(4):433-441

Abstract

Collaborative conservation has been touted as a viable option for addressing contentious natural resource stewardship issues in a way that represents the diverse voices impacted by, and involved in, conservation decisions. Engaging meaningfully in collaborative conservation involves overcoming a unique set of challenges while also realizing opportunities. In this special issue, we use the term collaborative conservation evaluation to encompass research and evaluation related to collaborative governance and collaborative natural resource management projects, programs, or decision-making processes that leverage a participatory approach, involve multiple stakeholders, and incorporate a range of contemporary evaluation approaches. Here, we provide a series of articles and tools intended to highlight different approaches to evaluation that utilize a variety of methodologies adapted for different contexts. We intend for these articles to spark further conversation and inspire future directions in evaluating collaborative conservation for researchers and practitioners.  相似文献   

Developing building-damage scales for lahars: application to Merapi volcano,Indonesia     

Susanna F. Jenkins  Jeremy C. Phillips  Rebecca Price  Kate Feloy  Peter J. Baxter  Danang Sri Hadmoko  Edouard de Bélizal 《Bulletin of Volcanology》2015,77(9):1-17

  相似文献