Variability in dissolved organic matter fluorescence and reduced sulfur concentration in coastal marine and estuarine environments   总被引：1，自引：0，他引：1  

Sarah G.S. DePalmaW. Ray Arnold  James C. McGeerD. George Dixon  D. Scott Smith 《Applied Geochemistry》2011,26(3):394-404

Fluorescence characterization of dissolved organic matter (DOM) and measurements of Cr-reducible sulfide (CRS) are presented for 72 coastal marine and estuarine water samples obtained from the USA and Canada. Each sample is identified according to source: terrigenous, autochthonous, wastewater or mixed. Fluorescence data are resolved into contributions from humic, fulvic, tyrosine and tryptophan-like fluorophores. Humic and fulvic-like fluorophores correlate well with dissolved organic C (DOC) (r² = 0.73 and 0.71, respectively) but tyrosine and tryptophan-like fluorophores show no correlation with DOC. Quality factors are identified by normalization of fluorescence contributions to DOC. Humic and fulvic components show no statistical differences between sources but the amino acid-like fluorescence quality factors show significant variations between source, with highest values for autochthonous sources (0.07 ± 0.01 arbitrary fluorescence units per mg of C) versus low values (0.015 ± 0.005) for terrigenous source waters. CRS concentrations are highly variable from 0.07 ± 0.01 to 7703 ± 98 nM and do no correlate with DOC except when terrigenous source waters (n = 13) are separated out from the total sample set (r² = 0.55). There is an open question in the literature; does DOC source matter in terms of protective effects towards metal toxicity? Here is shown that DOC molecular-level quality does vary and that this variation is mostly in terms of the contributions of amino acids to total fluorescence.  相似文献   

Seasonal,Diel, and Landscape Effects on Resource Partitioning between Juvenile Chinook Salmon (<Emphasis Type="Italic">Oncorhynchus tshawytscha</Emphasis>) and Threespine Stickleback (<Emphasis Type="Italic">Gasterosteus aculeatus</Emphasis>) in the Columbia River Estuary     

Sarah Anne Spilseth  Charles A. Simenstad 《Estuaries and Coasts》2011,34(1):159-171

The objective of this study was to determine if exploitative competition between between juvenile Chinook salmon (Oncorhynchus tshawytscha) and threespine stickleback (Gasterosteus aculeatus) reduces the foraging opportunity of juvenile Chinook salmon in tidal channels of the Columbia River estuary. We sampled Chinook salmon and stickleback diets monthly and over a diel cycle in spatially distinct emergent marshes of the Columbia River estuary. Diets of the two fish species did not differ among marsh systems, but both fish species exhibited diel and seasonal differences in diet composition. Diet overlap between the two fish species was greatest in March and June. Exploitative competition was unlikely based on a comparison between consumption rates and estimated invertebrate production.  相似文献   

Google Earth and Google Fusion Tables in support of time-critical collaboration: Mapping the deepwater horizon oil spill with the AVIRIS airborne spectrometer   总被引：1，自引：0，他引：1  

Eliza S. Bradley  Dar A. Roberts  Philip E. Dennison  Robert O. Green  Michael Eastwood  Sarah R. Lundeen  Ian B. McCubbin  Ira Leifer 《Earth Science Informatics》2011,4(4):169-179

Web interfaces have made remote sensing image resources more accessible and interactive. However, many web-based and Digital Earth opportunities for remote sensing have not yet been fully explored and could greatly facilitate scientific collaboration. In many cases, these resources can augment traditional proprietary software packages, which can have limited flexibility, spatiotemporal controls, and data synthesis abilities. In this paper, we discuss how web services and Google Earth were used for time-critical geovisualizations of the NASA Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Deepwater Horizon oil spill imaging campaign. In particular, we describe how (1) AVIRIS Google Earth products were used to visualize the spatial and temporal characteristics of the campaign’s image acquisitions, critically needed for flight planning, (2) the Google Fusion Table cloud-based service was applied to create a highly-interactive image archive and mapping display, and (3) the Google Fusion Table API was utilized to create a flexible PHP-based interface for metadata creation and as the basis for an interactive data catalog. Although there are other possible software and programming approaches to these activities, we highlight freely-accessible and flexible solutions and bring attention to the newly introduced Google Fusion Tables as a collaborative scientific platform.  相似文献   

Characterization on arsenic sorption and mobility of the sediments of Chia-Nan Plain, where Blackfoot disease occurred   总被引：1，自引：1，他引：0  

Zhaohui Li  Hanlie Hong  Jiin-Shuh Jean  Andria J. Koski  Chia-Chuan Liu  Selim Reza  Jeffrey J. Randolph  Stephan R. Kurdas  Jonathan H. Friend  Sarah J. Antinucci 《Environmental Earth Sciences》2011,64(3):823-831

Higher levels of arsenic in the aquifers of Chia-Nan Plain in southwestern Taiwan were attributed to the cause of Blackfoot disease in the area half a century ago. Although extensive studies were conducted on the occurrence, speciation, mobility, and transport of arsenic in the region, the relationship between arsenic adsorption by different aquifer materials and the concentration and speciation of arsenic in these aquifers was poorly delineated. This study focused on characterization of sediments in the region, as well as determination of relations between arsenic adsorption and other geochemical and clay mineralogical properties of the sediments. The arsenic adsorption capacity was positively related to the clay minerals, Fe, and Mn contents in the sediments. The higher arsenic adsorption capacity of the sediments served as a sink for the arsenic during its transport from the central mountains to the coast and as a source for its release under reduced environment and in the presence of humic substances.  相似文献   

Dissolved and particulate organic carbon in hydrothermal plumes from the East Pacific Rise, 9°50′N     

Sarah A. Bennett  Peter J. StathamDarryl R.H. Green  Nadine Le BrisJill M. McDermott  Florencia PradoOlivier J. Rouxel  Karen Von Damm  Christopher R. German 《Deep Sea Research Part I: Oceanographic Research Papers》2011,58(9):922-931

Chemoautotrophic production in seafloor hydrothermal systems has the potential to provide an important source of organic carbon that is exported to the surrounding deep-ocean. While hydrothermal plumes may export carbon, entrained from chimney walls and biologically rich diffuse flow areas, away from sites of venting they also have the potential to provide an environment for in-situ carbon fixation. In this study, we have followed the fate of dissolved and particulate organic carbon (DOC and POC) as it is dispersed through and settles beneath a hydrothermal plume system at 9°50′N on the East Pacific Rise. Concentrations of both DOC and POC are elevated in buoyant plume samples that were collected directly above sites of active venting using both DSV Alvin and a CTD-rosette. Similar levels of POC enrichment are also observed in the dispersing non-buoyant plume, ∼500 m downstream from the vent-site. Further, sediment-trap samples collected beneath the same dispersing plume system, show evidence for a close coupling between organic carbon and Fe oxyhydroxide fluxes. We propose, therefore, a process that concentrates POC into hydrothermal plumes as they disperse through the deep-ocean. This is most probably the result of some combination of preferential adsorption of organic carbon onto Fe-oxyhydroxides and/or microbial activity that preferentially concentrates organic carbon in association with Fe-oxyhydroxides (e.g. through the microbial oxidation of Fe(II) and Fe sulfides). This potential for biological production and consumption within hydrothermal plumes highlights the importance of a multidisciplinary approach to understanding the role of the carbon cycle in deep-sea hydrothermal systems as well as the role that hydrothermal systems may play in regulating global deep-ocean carbon budgets.  相似文献   

Distributed deformation in the subducting lithosphere at Tonga     

Sarah Nothard  John Haines  James Jackson  Bill Holt 《Geophysical Journal International》1996,127(2):328-338

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Globalized Agriculture. Political Choice By R. Le Heron.     

Sarah Whatmore 《New Zealand geographer》1995,51(2):60a-61

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Using climate finance to advance climate justice: the politics and practice of channelling resources to the local level     

Sarah Colenbrander  David Dodman  Diana Mitlin 《Climate Policy》2018,18(7):902-915

Adaptation finance is primarily allocated to multilateral entities and national governments, rather than local organizations. This means that the social, political and economic processes that create and sustain inequalities within a country will be the same processes that determine how adaptation finance is used. Using an urban lens, we consider the obstacles currently faced by local governments and local civil society groups in accessing adaptation finance, and show that these are a function of systemic power imbalances between levels of government, and between government and vulnerable communities. We argue that even relatively small amounts of adaptation finance could have a catalytic effect on the capacities and impacts of local organizations, contributing to greater levels of both distributive and procedural justice. We analyse different financial intermediaries and planning systems that could be used to make disbursements from multilateral climate funds fairer and more effective. This could potentially create political opportunities both to respond to direct climate threats and to address underlying drivers of vulnerability, such as marginalization and exclusion. In this way, channelling adaptation finance to the local level could deliver more just processes and outcomes.

Key policy insights

1. More multilateral climate funds should establish direct access modalities, and introduce ‘fit-for-purpose’ accreditation procedures and approval processes. Those that have already established such enabling frameworks should prioritize providing readiness support to local organizations, and incentivize state and citizen collaboration in adaptation projects.

2. National governments should consider clearly enshrining the rights and responsibilities of local authorities in National Adaptation Plans, and help them to collect the information, build the capacities and acquire the resources needed to plan and implement adaptation measures. National governments should further encourage local authorities to adopt participatory planning, budgeting, monitoring and evaluation procedures to encourage citizen participation.

3. Local civil society groups should identify or establish collective entities that can seek accreditation with multilateral funds and then disburse money to their members. Collaboration between groups can facilitate up-scaling through replication (particularly where peer-to-peer learning is embedded in the network) and reduce the transaction costs associated with myriad small projects.

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Impact of climate change on potential evapotranspiration under a historical and future climate scenario in the Huang-Huai-Hai Plain,China     

Liu  Qin  Yan  Changrong  Ju  Hui  Garré  Sarah 《Theoretical and Applied Climatology》2018,132(1-2):387-401

Theoretical and Applied Climatology - Climate change is widely accepted to be one of the most critical problems faced by the Huang-Huai-Hai Plain (3H Plain), which is a region in which there is an...  相似文献   

Characteristics of southern California atmospheric rivers     

Harris  Sarah M.  Carvalho  Leila M. V. 《Theoretical and Applied Climatology》2018,132(3-4):965-981

Theoretical and Applied Climatology - Atmospheric rivers (ARs) are channels of high water vapor flux that transport moisture from low to higher latitudes on synoptic timescales. In areas of...  相似文献