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181.
Global decline of marine resources has triggered a worldwide demand for changing the way ocean resources are managed. Ecosystem-based management approaches have emerged using marine protected areas (MPA) as the main tool. Several classifications of marine protected areas benefits have been made, but all have focused only on the benefits to humans, neglecting many important benefits accrued to nature. This paper presents a new comprehensive classification of MPA benefits that will provide scientists and managers with an inclusive framework to accurately identify and account for all possible benefits derived from MPAs. The paper also analyses the methods available for valuing these benefits. A total of 99 benefits were identified within nine main categories: fishery, non-fishery, management, education/research, cultural, process, ecosystem, population and species benefits. These categories are arranged in two main divisions (direct and indirect benefits), which, at the same time, fall within the realms of benefits to humans and to nature. 相似文献
182.
Melisa Daiana Fernández Severini Sandra Elizabeth BottéMónica Susana Hoffmeyer Jorge Eduardo Marcovecchio 《Estuarine, Coastal and Shelf Science》2009
Cadmium and copper in the dissolved and particulate phase and in zooplankton were determined in the Bahía Blanca estuary during six surveys from March to December 2005. Temperature, pH, salinity, dissolved oxygen, suspended particulate matter, particulate organic matter and chlorophyll-a were also considered. Dissolved Cd was below the detection limit (0.2 μg L−1) for almost the entire study period whereas Cu concentrations (0.5–2.4 μg L−1) indicated a continuous dissolved Cu input. Particulate Cd concentrations ranged from below the detection limit (<0.01) to 28.6 μg g−1 d.w. while particulate Cu ranged from below the detection limit (<0.04) to 53.5 μg g−1 d.w. Cd in mesozooplankton ranged from below the detection limit (<0.01) to 37.4 μg g−1 d.w. Some of the Cd levels were higher than those reported for other aquatic ecosystems. Cu in the mesozooplankton ranged from 1.3 to 89.3 μg g−1 d.w., values which were within the reported values or higher than other studies. The log of the partition coefficients (log (Kd)) of Cd was 0.04, while log (Kd) for Cu ranged from −0.39 to 2.79. These values were lower than both those calculated for other estuaries and the typical coefficients for marine environments. The log of the bioconcentration factor (log BCF) of Cd was 1.78, indicating that Cd concentration was higher in the zooplankton than in the dissolved phase. Log BCF of Cu ranged from 1.15 to 3. The logs of the biomagnification factors (log BMF) of Cd were low, with a range between −3.45 and 2.21 and those for Cu ranged from −0.1 to 3.35. Positive values indicate biomagnification while negative values indicate biodiminution. In general, no significant dissolved Cd concentration appeared to be present in the Bahía Blanca estuary and Cu values did not indicate a critical environmental status. The particulate phase seemed to be the major carrier for Cd and Cu and TPCu values were within the normal values for an anthropogenically stressed estuary but not for a strongly polluted system. This fraction was the most important metal source for the mesozooplankton. Moreover, the highest metal concentrations were in the mesozooplankton since most of the bioconcentration and biomagnification factors were positive, especially for Cu. 相似文献
183.
Andres H. Arias Carla V. Spetter Rubén H. Freije Jorge E. Marcovecchio 《Estuarine, Coastal and Shelf Science》2009
Polycyclic aromatic hydrocarbons (PAHs), one of the major groups of anthropogenic environmental pollutants, were firstly identified and measured in coastal waters, native mussels and fish of an industrialized South American estuary. 相似文献
184.
185.
Geoenvironmental site investigation using different techniques in a municipal solid waste disposal site in Brazil 总被引:3,自引:0,他引:3
Giulliana Mondelli Heraldo Luiz Giacheti Maria Eugênia Gimenez Boscov Vagner Roberto Elis Jorge Hamada 《Environmental Geology》2007,52(5):871-887
Different geoenvironmental site investigation techniques to assess contamination from a municipal solid waste disposal site
in Brazil are presented here. Superficial geophysical investigation (geoelectrical survey), resistivity piezocone penetration
tests (RCPTU), soil samples collected with direct-push samplers and water samples collected from monitoring wells were applied
in this study. The application of the geoelectrical method was indispensable to identify the presence and flow direction of
contamination plumes (leachate) as well as to indicate the most suitable locations for RCPTU tests and soil and water sampling.
Chemical analyses of groundwater samples contributed to a better understanding of the flow of the contaminated plume. The
piezocone presented some limitations for tropical soils, since the groundwater level is sometimes deeper than the layer which
is impenetrable to the cone, and the soil genesis and unsaturated conditions affect soil behavior. The combined interpretation
of geoelectrical measurements and soil and water samplings underpinned the interpretation of RCPTU tests. The interpretation
of all the test results indicates that the contamination plume has already overreached the landfill’s west-northwest borders.
Geoenvironmental laboratory test results suggest that contamination from the solid waste disposal site has been developing
gradually, indicating the need for continuous monitoring of the groundwater. 相似文献
186.
Arnoldo Valle-Levinson Nandita Sarkar Rosario Sanay Doris Soto Jorge León 《Estuaries and Coasts》2007,30(1):113-126
Underway current velocity profiles were combined with temperature and salinity profiles at fixed stations to describe tidal
and subtidal flow patterns in the middle of the northernmost Chilean fjord, Estuario Reloncaví. This is the first study involving
current velocity measurements in this fjord. Reloncaví fjord is 55 km long, 2 km wide, and on average is 170 m deep. Measurements
concentrated around a marked bend of the coastline, where an 8-km along-fjord transect was sampled during a semidiurnal tidal
cycle in March 2002 and a 2-km cross-fjord transect was occupied, also during a semidiurnal cycle, in May 2004. The fjord
hydrography showed a relatively thin (<5 m deep), continuously stratified, buoyant layer with stratification values >4 kg
m−3 per meter of depth. Below this thin layer, the water was relatively homogeneous. Semidiurnal tidal currents had low amplitudes
(<10 cm s−1) that allowed the persistence of a surface front throughout the tidal cycle. The front oscillated with a period of ca. 2.5
h and showed excursions of 2 km. The front oscillations could have been produced by a lateral seiche that corresponds to the
natural period of oscillation across the fjord. This front could have also caused large (2 h) phase lags in the semidiurnal
tidal currents, from one end of the transect to the other, within the buoyant layer. Tidal phases were relatively uniform
underneath this buoyant layer. Subtidal flows showed a 3-layer pattern consisting of a surface layer (8 m thick, of 5 cm s−1 surface outflow), an intermediate layer (70 m thick, of 3 cm s−1 net inflow), and a bottom layer (below 80 m depth, of 3 cm s−1 net outflow). The surface outflow and, to a certain extent, the inflow layer were related to the buoyant water interacting
with the ambient oceanic water. The inflowing layer and the bottom outflow were attributed to nonlinear effects associated
with a tidal wave that reflects at the fjord's head. The weak subtidal currents followed the morphology of the bend and caused
downwelling on the inside and upwelling on the outside part of the bend. 相似文献
187.
Lena Virgínia Soares Monteiro Jorge Silva Bettencourt Caetano Juliani Tolentino Flvio de Oliveira 《Gondwana Research》2007,11(3):362-381
The Vazante Group hosts the Vazante nonsulfide zinc deposit, which comprises high-grade zinc silicate ore (ZnSiO4), and late-diagenetic to epigenetic carbonate-hosted sulfide-rich zinc deposits (e.g. Morro Agudo, Fagundes, and Ambrósia). In the sulfide-rich deposits, hydrothermal alteration involving silicification and dolomitization was related with ground preparation of favorable zones for fluid migration (e.g. Fagundes) or with direct interaction with the metalliferous fluid (e.g. Ambrósia). At Vazante, hydrothermal alteration resulted in silicification and dolomite, siderite, jasper, hematite, and chlorite formation. These processes were accompanied by strong relative gains of SiO2, Fe2O3(T), Rb, Sb, V, U, and La, which are typically associated with the nonsulfide zinc mineralization. All sulfide-rich zinc ores in the district display a similar geochemical signature suggesting a common metal source from the underlying sedimentary sequences.Oxygen and carbon isotope compositions of hydrothermally altered rocks reveal a remarkable alteration halo at the Vazante deposit, which is not a notable feature in the sulfide-rich deposits. This pattern could be attributed to fluid mixing processes involving the metalliferous fluid and channelized meteoric water, which may control the precipitation of the Vazante nonsulfide ore. Sulfide deposition resulted from fluid–rock interaction processes and mixing between the ascending metalliferous fluids and sulfur-rich tectonic brines derived from reduced shale units. 相似文献
188.
The evolution with time of circular polarization (t) from solar bursts at 7 GHz presents, in the majority of cases, a polarization degree peak before the maximum flux time. The subsequent evolution of (t) is continuous and usually increasing. The changes could be caused by superimposed polarization effects, due to the fast emissive electrons (dominant in the first phase), and to the propagation effects caused by the coronal condensation where the event occurred (dominant in the second phase). In an approximate approach, (t) is connected to the movement of the source in the second phase, being qualitatively sound, but limited to the lack of knowledge on acceleration processes and on magnetic field topology in the active region where the flares take place. 相似文献
189.
Late-Glacial History of Lago Argentino, Argentina, and Age of the Puerto Bandera Moraines 总被引:1,自引:0,他引:1
In the west-central part of Lago Argentino, the Puerto Bandera moraines are clearly detached from longer, more prominent moraines of the last glaciation and from shorter and smaller Neoglacial moraines. Scientists have long speculated about the age of the Puerto Bandera moraines. Detailed geomorphologic studies in the western area of Lago Argentino, including stratigraphic profiles at Bahía del Quemado in the northern branch (Brazo Norte), indicate that the Puerto Bandera moraines were deposited by three pulses of ice. Each of the three pulses is represented by single moraine ridges and belts of tightly arranged ridges. The timing of the three glacier advances was established by radiocarbon dating, including data published by John Mercer. The oldest moraine system, formed during the Puerto Bandera I substade, was deposited ca. 13,000 14C yr B.P. Moraines of the Puerto Bandera II substade were deposited ca. 11,000 14C yr B.P. The youngest moraine system was deposited during a minor readvance, shortly before 10,390 C14 yr B.P., and thus appears to have occurred some time during the European Younger Dryas interval. After this third substade, the ice tongues retreated into the interior branches of Lago Argentino and have remained there since. Evidence found at Bahía del Quemado, together with data provided by other authors, attests to a significant climatic change by the middle Holocene, which we believe occurred during the Herminita advance, the first Holocene glacial readvance recognized within the area. 相似文献
190.
Global sensitivity analysis of hydrologic processes in major snow‐dominated mountainous river basins in Colorado 下载免费PDF全文
The performance of watershed models in simulating stream discharge depends on the adequate representation of important watershed processes. In snow‐dominated systems, snow, surface and subsurface hydrologic processes comprise a complex network of nonlinear interactions that influence the magnitude and timing of discharge. This study aims to identify critical processes and interactions that control discharge hydrographs in five major mountainous snow‐dominated river basins in Colorado, USA. A comprehensive watershed model (Soil and Water Assessment Tool) and a variance‐based global sensitivity analysis technique (Fourier Amplitude Sensitivity Test) were used in conjunction to identify critical models parameters and processes that they represent. Average monthly streamflow and streamflow root mean square error over a period of 20 years were used as two separate objective functions in this analysis. Examination of the sensitivity of monthly streamflow revealed the influence of parameters on flow volume, whereas the sensitivity of streamflow root mean square error also exposed the influence of parameters on the timing of the hydrographs. A stability analysis was performed to investigate the computational requirements for a robust sensitivity analysis. Results show that streamflow volume is mostly influenced by shallow subsurface processes, whereas interactions between groundwater and snow processes were the key in the timing of streamflows. A large majority of important parameters were common among all study watersheds, which underlies the prospect for regionalization of process‐based hydrologic modelling in headwater river basins in Colorado. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献