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81.
This paper presents the results of a 2008 citation-analysis study that was undertaken for the 1995 FAO Code of Conduct for Responsible Fisheries and its associated instruments. The overall objective of this study was to contribute towards a strategy for improved dissemination, awareness raising and communication about the Code and its implementation. For each citation, additional information was collected to identify patterns by year, topic, author affiliation or type of literature. Results support previously suggested anecdotal patterns, in particular related to the diversity of publishing outlets and the high proportion of fisheries information published as grey literature. The results also point to areas of concern for long-term preservation and dissemination of fisheries information. 相似文献
82.
Diana Zúñiga M. Mar Flexas Anna Sanchez-Vidal Johan Coenjaerts Antoni Calafat Gabriel Jordà Jordi García-Orellana Joan Puigdefàbregas Miquel Canals Manuel Espino Francesc Sardà Joan B. Company 《Progress in Oceanography》2009,82(4):239-251
Within the framework of the multidisciplinary RECS project and with the aim of describing the particle flux transfer from the continental shelf to the deep basin, an array of five mooring lines equipped with a total of five pairs of PPS3/3 sequential-sampling sediment traps and RCM-7/8 current meters were deployed 30 m above the bottom from March 2003 to March 2004 inside and outside the Blanes Canyon. One mooring line was located in the upper canyon at 600 m depth, one in the canyon axis at 1700 m depth and other two close to the canyon walls at 900 m depth. A fifth mooring line was deployed in the continental open slope at 1500 m water depth.The highest near-bottom downward particle flux (14.50 g m−2 d−1) was recorded at the trap located in the upper canyon (M1), where continental inputs associated with the presence of the Tordera River are most relevant. On the other hand, the downward fluxes (4.35 g m−2 d−1) in the canyon axis (M2) were of the same order as those found in the western flank (M3) of the canyon. Both values were clearly higher than the value (1.95 g m−2 d−1) recorded at the eastern canyon wall (M4). The open slope (M5) mass flux (5.42 mg m−2 d−1) recorded by the sediment trap located outside the canyon system was three orders of magnitude lower than the other values registered by the inner canyon stations. The relevance of our data is that it explains how the transport pathway in the canyon occurs through its western flank, where a more active and persistent current toward the open ocean was recorded over the entire year of the experiment.Off-shelf sediment transport along the canyon axis showed clear differences during the period of the study, with some important events leading to strong intensifications of the current coupled with large transport of particle fluxes to the deepest parts of the canyon. Such events are primarily related to increases in river discharge and the occurrence of strong storms and cascading events during the winter.In summary, in this study it is shown that the dynamics of the water masses and the currents in the study area convert the sharp western flank of the Blanes Canyon in a more active region that favors erosion processes than the eastern flank, which has a smoother topography and where the absence of erosional conditions yields to steadier sedimentary processes. 相似文献
83.
The regulation and expression of biological rhythms with respect to sex and ontogeny in deep-water benthic decapod crustaceans constitutes an exciting field in marine biology that is far from understood. Liocarcinus depurator , Munida intermedia and Munida tenuimana are ecologically key crustacean decapod species of the Atlantic and Mediterranean shelves and slopes, and their activity rhythms in the field are poorly known. Our aim was to measure the behavioural rhythms of these species, while at the same time defining their type of displacement ( i.e. endobenthic, nektobenthic or benthopelagic). Whether gender and ontogeny modulate the rhythmic behaviour of these decapods is unknown, and we sought to clarify this issue. A temporally scheduled series of trawl hauls and light intensity measures was performed on the western Mediterranean shelf (100–110 m depth) and slope (400–430 m), close to the autumn equinox and the summer solstice. The sex and the size of animals in the catches were analysed. Catch patterns were evaluated through waveform and periodogram analyses. Liocarcinus depurator was captured at night on the shelf, whereas on the slope, animals displayed peaks both in the middle of the day and night. Size-related differences (but no gender differences) were found in its rhythmic behaviour, possibly due to intra-specific competition ( e.g. fighting) between juveniles and adults. Munida intermedia were weakly diurnal in October and both diurnal and nocturnal in June. Munida tenuimana presented no discernible rhythmicity in October, but was nocturnal in June. Both species showed no evident sex or size modulation of their behaviour. Data were interpreted assuming that all tested species present an endobenthic behaviour ( i.e. animals emerge from the substrate during the active phase of their behavioural cycle). 相似文献
84.
Eva Ramirez-Llodra Joan Baptista Company Francisco Sardà & Guiomar Rotllant 《Marine Ecology》2010,31(1):167-182
The composition and structure of megabenthic communities in the Blanes canyon and adjacent open margin (Northwestern Mediterranean) were studied. The aim was to assess the effect of the canyon and commercial fishing intensity on the community composition and structure of benthic megafauna by (i) describing the megabenthic community composition, (ii) quantifying faunal abundance and biomass and (iii) describing community structure with MDS analyses and biodiversity indices. The results are compared between three sites (canyon head, canyon wall and open margin) located between 435 m and 700 m. Samples were collected using a commercial bottom trawl between April 2003 and March 2004. These sites are exploited by the local fishing fleet that targets the rose shrimp Aristeus antennatus . A total of 131 megabenthic species were identified from the three sites, with fishes and decapod crustaceans being the most speciose, most abundant and of higher biomass. The species richness, abundance and biomass of non-crustacean invertebrates were low. There were no significant differences in total abundance and biomass between the three sites. However, community structure analysis suggests that the open margin community is significantly different from the canyon head and canyon wall, with a lower species richness, lower diversity and lower evenness. The open margin community also reflects a higher degree of disturbance compared to the two canyon habitats. The results indicate that there is a canyon effect on the community structure of benthic megafauna, but this may be modulated by differing fishing pressure, which adds an additional factor to margin heterogeneity. 相似文献
85.
This paper examines the impacts of climate variability upon the regional hydrological regimes of the Yellow River in China. Results indicate that the average annual precipitation is 494·8 mm in La Niña years and only 408·8 mm in El Niño years. The difference is 86·0 mm, or 18·8% over the long-term average. The stream-flows in the La Niña years are higher than that in El Niño years: 9·2% at the Lan-Zhou station, 9·5% for Tou-Dao-Guai station, 11·8% for Long-Men, 17·6% for San-Men-Xia, 19·2% at the Hua-Yuan-Hou station, and 22·0% at the Li-Jin station. Both precipitation and stream-flow responses show temporal and spatial patterns. The relationship among the stream-flow, precipitation, and temperature, which was obtained by ArcGIS Geostatistical Analyst based on observed data, indicates stream-flow is sensitive to both precipitation and temperature. For small precipitation increases (less than 13%), the stream-flow percentage change is less than the precipitation change for the Yellow River. The results of this paper can be used as a reference for watershed water resources planning and management to maintain the healthy life and proper function of the river. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
86.
87.
88.
Melanie Louise Inez Witt Stephen Skrabal Robert Kieber Joan Willey 《Journal of Atmospheric Chemistry》2007,58(2):89-109
Significant quenching of fluorescence by Cu in rainwater samples from southeastern North Carolina demonstrates that chromophoric
dissolved organic matter (CDOM) is an effective ligand for Cu in rainwater. A strong inverse correlation between the decrease
in fluorescence upon Cu addition and CDOM abundance suggests the presence of excess binding sites for Cu in high CDOM samples.
Electroanalytical studies indicate that CDOM extracted from C18 cartridges formed Cu complexes with concentrations and conditional stability constants similar to ligands found in ambient
rainwater. When authentic rainwater samples were photolyzed with simulated sunlight both photoproduction and photodestruction
of ligands were observed, suggesting the photochemical response of Cu-complexing ligands in rainwater is the result of two
competing reactions. The rate of CDOM photobleaching was directly related to changes in strong ligands (KCuL ∼ 1015) whereas weaker ligands (KCuL < 1013) were not correlated, suggesting the photolabile CDOM resides in the strong ligand class. A photolysis study comparing filtered
and unfiltered rainwater samples indicated that Cu-complexing ligands adsorbed onto or otherwise associated with particles
are photodegraded much more rapidly than dissolved ligands. Photolysis with UV radiation appears to be most effective at engendering
changes in Cu ligands, however a significant photochemical response was also observed when samples were exposed to photosynthetically
active radiation with wavelengths greater than 400 nm. Results from this study demonstrate that complexation of Cu by CDOM
has important ramifications for controlling both the speciation of the metal and the reactivity of CDOM in rainwater. 相似文献
89.
Freshwater fraction and tidal prism models are simple methods for estimating the turnover time of estuarine water. The freshwater
fraction method prominently features flushing by freshwater inflow and has sometimes been criticized because it appears not
to include flushing by seawater, but this is accounted for implicitly because the average estuary salinity used in the calculation
reflects all the processes that bring seawater into the estuary, including gravitational circulation and tidal processes.
The model relies on measurable salinity differences among water masses and so must be used for estuaries with substantial
freshwater inflow. Tidal prism models are based on flushing by flood tide inflow and ignore seawater inflow due to gravitational
circulation. These models should only be applied to estuaries with weak or nonexistent gravitational circulation, which are
generally those with little freshwater inflow. Using a framework that is less ambioguous and more directly applicable to the
estimation of turnover times than those used previously, this paper critically examines the application of tidal prism models
in well-mixed estuaries with complete tidal exchange, partial ebb return, or incomplete flood mixing and in partially mixed
estuaries. Problems with self-consistency in earlier versions of these models also apply to the budgeting procedure used by
the LOICZ (Land-Ocean Interactions in the Coastal Zone) program. Although freshwater fraction and tidal prism models are different
approaches to estimating turnover times in systems with very different characteristics, consistent derivation shows that these
models have much in common with each other and that they yield equivalent values that can be used to make comparisons across
systems. 相似文献
90.
Joan Vorpahl 《Solar physics》1973,29(2):447-460
I examined two multiple impulsive events in May 1969 and compared their impulsive Hex, hard X-ray and microwave components to the observed type III emission. No good correlation was observed between meter intensity and the degree of simultaneous H outflow although almost every type III burst had some associated H activity. Correspondingly, an inverse relationship existed between X-ray and type III emission, i.e., a strong meter burst accompanied weak hard X-radiation. This, along with the fact that sufficient energetic electrons were normally present to produce the X-rays, implies that the trajectory, rather than electron spectrum or supply, determines whether type III noise is observed during an impulsive event. 相似文献