Schooling behaviour and environmental forcing in relation to anchoveta distribution: An analysis across multiple spatial scales   总被引：7，自引：4，他引：3  

Arnaud Bertrand  Franois Gerlotto  Sophie Bertrand  Mariano Gutirrez  Luis Alza  Andres Chipollini  Erich Díaz  Pepe Espinoza  Jesús Ledesma  Roberto Quesqun  Salvador Peraltilla  Francisco Chavez 《Progress in Oceanography》2008,79(2-4):264

The Peruvian anchovy or anchoveta (Engraulis ringens) supports the highest worldwide fishery landings and varies in space and time over many scales. Here we present the first comprehensive sub-mesocale study of anchoveta distribution in relation to the environment. During November 2004, we conducted a behavioural ecology survey off central Peru and used a series of observational and sampling tools including SST and CO₂ sensors, Niskin bottles, CTD probes, zooplankton sampling, stomach content analysis, echo-sounder, multibeam sonar, and bird observations. The sub-mesoscale survey areas were chosen from mesoscale acoustic surveys. A routine coast-wide (2000 km) acoustic survey performed just after the sub-mesoscale surveys, provided information at an even larger population scale. The availability of nearly concurrent sub-mesoscale, mesoscale and coast-wide information on anchoveta distribution allowed for a unique multi-scale synthesis. At the sub-mesoscale (100s m to km) physical processes (internal waves and frontogenesis) concentrated plankton into patches and determined anchoveta spatial distribution. At the mesoscale (10s km) location relative to the zone of active upwelling (and age of the upwelled water) and the depth of the oxycline had strong impacts on the anchoveta. Finally, over 100s km the size of the productive area, as defined by the upwelled cold coastal waters, was the determining factor. We propose a conceptual view of the relative importance of social behaviour and environmental (biotic and abiotic) processes on the spatial distribution of anchoveta. Our ecological space has two y-axis; one based on self-organization (social behaviour), and the other based on the environmental processes. At scales from the individual (10s cm), to the nucleus (m), social behaviour (e.g. the need to school) drives spatial organization. At scales larger than the school, environmental forces are the main driver of fish distribution. The conceptual ecosystem models presented in this paper may provide the final links needed to develop accurate forecasts of the spatial distribution of anchoveta over multiple scales.  相似文献   

X-Ray and optical observations of the X-ray source EX0020528+1454.8     

R. Hudec  W. Wenzel  W. Goetz  B. Valníček  R. Peřestý  G. A. Richter  G. Hacke  H. Huth  A. Mrkos  J. Tremko 《Astrophysics and Space Science》1987,131(1-2):697-700

We present preliminary results of the EXOSAT X-ray observations and quasisimultaneous and simultaneous optical photometry of the X-ray source EX0020528+1454.8=1E0205+149 found independently as an serendipitous source both with Einstein and EXOSAT satellites. The optical counterpart is a pair of dMe stars. Our results indicate that the object is variable both in X-rays and optical wavelenghts, and probably belongs to dMe flare stars.Paper presented at the IAU Colloquium No. 93 on Cataclysmic Variables. Recent Multi-Frequency Observations and Theoretical Developments, held at Dr. Remeis-Sternwarte Bamberg, F.R.G., 16–19 June, 1986.  相似文献   

The Gulf of California: Review of ecosystem status and sustainability challenges     

Salvador E. Lluch-Cota  Eugenio A. Aragón-Noriega  David Aurioles-Gamboa  Richard C. Brusca  Roberto Cortés-Altamirano  Alfonso Esquivel-Herrera  Michel E. Hendrickx  Hugo Herrera-Cervantes  Miguel Lavín  Daniel B. Lluch-Cota  Silvio G. Marinone  Sofia Ortega-García  Alejandro Parés-Sierra  Mauricio Ramírez-Rodríguez  Richard A. Schwartzlose  Arturo P. Sierra-Beltrán 《Progress in Oceanography》2007,73(1):1-26

The Gulf of California is unique because of its geographical location and conformation. It hosts diverse ecosystems and important fisheries that support industry and provide livelihood to coastal settlements. It is also the site of interests and problems, and an intense interaction among managers, producers, and conservationists. In this report, we scrutinize the abiotic (hydrography, climate, ocean circulation, and chemistry) and biotic (phyto- and zooplankton, fish, invertebrates, marine mammals, birds, and turtles) components of the marine ecosystem, and some particular aspects of climate variability, endemisms, harmful algal blooms, oxygen minimum layer, and pollution. We also review the current conditions and conflicts around the main fisheries (shrimp, small and large pelagic fishes, squid, artisanal and sportfishing), the most important human activity in the Gulf of California. We cover some aspects of management and conservation of fisheries, especially the claimed overexploitation of fish resources and the ecosystems, and review proposals for creating networks of marine protected areas. We conclude by identifying main needs for information and research, particularly the integration of data bases, the implementation of models and paleoreconstructions, establishment of monitoring programs, and the evaluation of fishing impacts and management actions.  相似文献   

New controversies on Columbus' “cosmographic” ideas     

M. Peñaloza  A. Marcos 《GeoJournal》1995,35(4):471-479

On the basis of modern works of a Spanish paleographer, a North American geographer and, a historian-sailor, also North American, respectively, we have reexamined some controversial aspects of the cosmographic ideas ascribed to the Columbus brothers (Christopher and Bartholomew), regarding the preparation of their first transoceanic voyage. First, we present a discussion of two versions of the translation and explanation of a part or phrase of one of the marginal notes or postils, written supposedly by one of them or both in Latin in their IMAGO MUNDI (d'Ailly, Pierre. Tract of Geography of century XV) copy that seriously questions the credibility of the Columbus brothers' knowledge of the cartography of that time. Secondly, we have analized three hypotheses attempting to explain the methods they could have used, to measure the length of a terrestrial degree either on the equator or on a meridian. We will show that these hypotheses are unacceptable due to the manipulation of the information by its authors and, because there is not enough historical evidence to demonstrate that Christopher Columbus or his brother made such geodesical measurements.  相似文献   

Seasonal deposition of authigenic calcite out of isotopic equilibrium with DIC and water,and implications for paleolimnological studies     

Apolinarska  Karina  Pleskot  Krzysztof  Pełechata  Aleksandra  Migdałek  Michał  Pełechaty  Mariusz 《Journal of Paleolimnology》2021,66(1):41-53

Journal of Paleolimnology - We conducted year-round, monthly monitoring of the stable isotope composition of DIC and water in hypereutrophic Lake Kierskie, western Poland, along with isotope...  相似文献   

Short-term effects of gamma ray bursts on oceanic photosynthesis     

Liuba Peñate  Osmel Martín  Rolando Cárdenas  Susana Agustí 《Astrophysics and Space Science》2010,330(2):211-217

We continue our previous work on the potential short-term influence of a gamma ray bursts on Earth’s biosphere, focusing on the only important short-term effect on life: the ultraviolet flash which occurs as a result of the retransmission of the γ radiation through the atmosphere. Thus, in this work we calculate the ultraviolet irradiances penetrating the first hundred meters of the water column, for Jerlov’s ocean water types I, II and III. Then we estimate the UV flash potential for photosynthesis inhibition in the whole photic zone, showing that it can be important in the first tens of meters of the water column.  相似文献   

Regional non-hazardous landfill site selection by integrating fuzzy logic, AHP and geographic information systems   总被引：4，自引：4，他引：0  

Katerina R. Donevska  Pece V. Gorsevski  Milorad Jovanovski  Igor Pe?evski 《Environmental Earth Sciences》2012,67(1):121-131

This study presents a geographic information systems-based multi-criteria site selection of non-hazardous regional landfill in Polog Region, Macedonia. The multi-criteria decision framework integrates legal requirements and physical constraints that relate to environmental and economic concerns and builds a hierarchy model for landfill suitability. The methodology is used for preliminary assessment of the most suitable landfill sites by combining fuzzy set theory and analytic hierarchy process (AHP). The fuzzy set theory is used to standardize criteria using different fuzzy membership functions while the AHP is used to establish the relative importance of the criteria. The AHP makes pairwise comparisons of relative importance between hierarchy elements grouped by environmental and economic decision criteria. The landfill suitability is achieved by applying weighted linear combination that uses a comparison matrix to aggregate different importance scenarios associated with environmental and economic objectives. The results from the study suggested that a least suitable landfill area of 1.0% from the total is generated when environmental and economic objectives are valued equally while a most suitable landfill area of 1.8% area is generated when the economic objective is valued higher. Such results are aimed for enhancement of regional landfill site selection in the country that is compliant with modern EU standards.  相似文献   

Cyclical salt efflorescence weathering: an invisible threat to the recovery of underground mine environment for tourist exploitation     

J. Matías Peñas Castejón  J. Francisco Maciá Sánchez  Mª Pilar Jiménez Medina  Mª Jesús Peñalver Martínez 《Environmental Earth Sciences》2014,72(6):1901-1913

Enhancing the value of an underground mine environment for tourist exploitation involves altering the physico-chemical balance of stone materials whose original mechanical properties guaranteed the structural stability of the site’s galleries and chambers. Humidity and temperature changes caused by the public exhibition of this kind of assets are the main causes of such disorders. After the intervention in the Agrupa-Vicenta mine in La Union (Spain) there were still runoff-water leaks into the mine. These water runoffs through the fault and schistosity planes of the enclosing rock mass give rise to salt precipitation over time. Adapting this mine and turning it into a museum have meant a decrease in relative indoors humidity and an increase in temperature. These variations have caused rocks, which were stable in the original conditions, to increase their rate of physico-chemical weathering due to the polycyclic supergene alteration of the metal sulfides they contain. The resulting release of sulfates into the solution and their subsequent precipitation as single and double salt efflorescence causes haloclasty, deteriorating the rock’s mechanical properties and diminishing the structural stability of the operation. This paper presents the results of characterizing the supergene mineral phases of salt efflorescence in the rock bed enclosing an underground sulfide mine value enhanced for tourist exploitation. Dangers for the structural stability of this type of architectural intervention, associated to the formation of efflorescences, are also identified; these efflorescences are caused by the weathering of rocks that make up its supporting structure.  相似文献   

Competition effects in cation binding to humic acid: Conditional affinity spectra for fixed total metal concentration conditions     

Calin David  Carlos Rey-Castro  Encarnació Companys  José Salvador  Joan Cecilia  Francesc Mas 《Geochimica et cosmochimica acta》2010,74(18):5216-18046

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Strömgren photometry and spectroscopy of the δ Scuti stars 7 Aql and 8 Aql     

L. Fox Machado  M. Alvarez  R. Michel  A. Moya  J.H. Peña  L. Parrao  A. Castro 《New Astronomy》2010,15(5):397-402

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