INVENTORY OF THE VATICAN METEORITE COLLECTION     

Rosamaria Salvatori  Adriana Maras  Elbert A. King 《Meteoritics & planetary science》1984,19(3):161-172

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The Hydrologic Importance of Small- and Medium-Sized Dams: Examples from Texas     

Anne Chin  Laura R. Laurencio  Adriana E. Martinez 《The Professional geographer》2013,65(2):238-251

Studies of the effects of dams have emphasized large and very large dams; less well understood are the impacts caused by smaller dams. Using Texas as an example area, this article highlights the role of small- and medium-sized dams in affecting the surface hydrology of river systems. Analysis of data from the National Inventory of Dams (NID) in a geographic information system showed that small and medium dams comprise about 97 percent of the dams registered in Texas. A small-or medium-sized dam is found approximately every 100 km² of area and about 120 km of river length. Different from large dams, which affect water storage the most, the major impact of these smaller dams is fragmentation of river landscapes. Analysis of data for dams extracted from digital orthoquads and for water bodies from the National Hydrography Dataset indicates that the extent of river fragmentation is likely greater than that suggested by data from the NID, because the NID underrepresents the smaller dams. Such extent of river fragmentation can degrade stream habitats and pose barriers to the migration of aquatic species and transport of sediment. Because small and medium dams are largely built for fire protection and stock ponds, mitigating the impacts associated with these dams likely involves working with the private individuals who own them.  相似文献   

The role of near-surface cavities in the carbon dioxide cycle of karst areas: evidence from the Carburangeli Cave Natural Reserve (Italy)   总被引：2，自引：1，他引：1  

Paolo Madonia  Adriana Bellanca  Rosario Di Pietro  Laura Mirabello 《Environmental Earth Sciences》2012,67(8):2423-2439

Hydrological, chemical and meteorological data collected during the years 2006–2007 at Carburangeli Cave (Italy) have provided new insights on the near-surface cycle of carbon dioxide, particularly concerning the role played by fractures and karst conduits. Carbon dioxide is trapped in the underground atmosphere essentially when its temperature is lower than the outer one. By contrast, convective air circulation disperses all the excess CO₂ in the external environment when the thermal differential is inverted. The network of fractures and karst conduits then works, in the vadose zone, as a re-circulator of CO₂ from the soil to the atmosphere. The total amount of CO₂ fixed in the underground is controlled, during the wet season, by the amount of infiltrating waters, which act as the main carrier of CO₂ in the subsoil. By contrast, during the dry season, gravitational drainage is responsible for the accumulation of carbon dioxide in the underground voids. The quantitative balance demonstrated that the degassed CO₂ amounts are one order of magnitude higher than the dissolved CO₂. In light of this, if the near-surface outgassing processes are not taken into account, CO₂ budgets may be affected by significant errors.  相似文献   

Polychaetes as environmental indicators revisited   总被引：1，自引：0，他引：1  

Giangrande A  Licciano M  Musco L 《Marine pollution bulletin》2005,50(11):1153-1162

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Daily Milan Temperature and Pressure Series (1763–1998): Completing and Homogenising the Data     

Maurizio Maugeri  Letizia Buffoni  Barbara Delmonte  Adriana Fassina 《Climatic change》2002,53(1-3):119-149

Daily meteorological observations have been made at the Brera astronomical observatory in Milan since 1763. Even if the data have always been collected at this observatory, the Milan series are far from being homogeneous as several changes were made to instruments, station location and observation methods. Within this context, the purpose of the paper is to discuss data homogenisation. Homogenisation is based both on objective information extracted from the station history (direct methodology) and on some statistical estimates (indirect methodology). Homogenisation by indirect methodology is mainly performed by comparison with other series whereas, if no other homogeneous series are available, it is based on the hypothesis that some statistics, such as the daily temperature range or the day to day variability, have no significant trends within some selected periods. Besides homogenisation also the completion of the series is discussed. Theresulting series are complete and homogenised daily minimum, mean and maximum temperatures and complete and homogenised daily mean pressures. They all cover the period 1763–1998.  相似文献   

Charophyta: their use in paleolimnology   总被引：1，自引：0，他引：1  

Adriana García 《Journal of Paleolimnology》1994,10(1):43-52

Charophyta are common algae in limnic waters from many regions and are an interesting group from an evolutionary point-of-view, as they are believed to be related to the Chlorophyceae and land plants. Paleontological-botanical systematics are discussed, taking into consideration some new advances. Charophytes live in all types of inland waters and are sensitive to ecological change, and so they are very useful paleolimnological markers. Gaps concerning gyrogonite morphology in extant taxa and their responses to different environmental conditions must be described. This paper discusses data concerning ecological factors affecting the distribution of Argentinian Charophyta (principally distributed between 30°S and 40°S), gyrogonite morphology related to different ecological conditions, and the way that Charophyta can modify the environment.This is the fifth in a series of papers published in this issue on Paleolimnology in Southern South America. Dr C. A. Fernández served as guest editor for these papers.  相似文献   

The coastal ocean off Oregon from 1961 to 2000: is there evidence of climate change or only of Los Niños?     

Robert L. Smith  Adriana Huyer  Jane Fleischbein 《Progress in Oceanography》2001,49(1-4)

A zonal hydrographic section along 44.65°N, from the coast of Oregon to 300 km offshore, was occupied regularly (at least seasonally) from 1961 to 1971 and then sporadically until recently. Regular monitoring of this section to 160 km offshore resumed in July 1997 as part of the GLOBEC Long Term Observational Program; the recent data provide observations in Oregon coastal waters of El Niño 1997–98 and La Niña conditions that followed. The complete seasonal data from the decade 1961–1971 provide a basis for comparison with the recent temperature and salinity sections, steric height profiles, geostrophic velocity, and water mass characteristics. These data, and sporadic observations in intervening years, allow us to compare conditions during several ENSO events with the recent event and to search for evidence of climate change. The PFEL Coastal Upwelling Index, sea level from the University of Hawaii Sea Level Center, the Multivariate ENSO Index (MEI), the Pacific Decadal Oscillation (PDO), and outflow from the Columbia River are used to distinguish local and remote causes of variability in physical oceanographic conditions off Oregon. The sequence of El Niño/La Niña/El Niño in 1963–66, during a cool phase of PDO, provides a comparison to El Niño/La Niña of 1997–2000. El Niño in 1982–83 and 1997–98, during a warm phase of PDO, caused the largest oceanographic anomalies in the 40 years. The comparison indicates warming of the coastal ocean off Oregon and suggests a modulation of ENSO effects by PDO. Such modulation would mask evidence for secular climate change in our 40-year oceanographic data series.  相似文献   

Life Cycle,Growth and Secondary Production in a Brackish-Water Population of the Polychaete Notomastus latericeus (Capitellidae) in the Mediterranean Sea     

Adriana Giangrande  Simonetta Fraschetti 《Marine Ecology》1993,14(4):313-327

Abstract. Three years of observations on a population of Notomastus latericeus Sars from Acquatina lagoon (Lecce, Italy) are reported. The population dynamics, life cycle, and reproduction were investigated in order to explain periodic density variations of this species. Some physical parameters of the water column were measured and sediment analyses were performed to characterize the environment. Secondary production was also estimated as part of a functional study of the benthic system in the Acquatina lagoon. The species is opportunistic; its density is apparently correlated to variation in salinity, but its presence in the lagoon is dependent on recruitment success and competition with other polychaete species.  相似文献   

Hierarchical procedure for creating local typologies for riparian zone research and management based on biophysical features     

Adriana C. Flores-Díaz  Roger Guevara Hernández  Manuel E. Mendoza  Rosario Langrave  Alexander Quevedo  Manuel Maass 《自然地理学》2018,39(2):118-139

Riparian systems have been included as a key component in ecosystem management because of their role in buffering the impact of land-use activities on fluvial systems. Riparian knowledge can be enhanced with a typology that reflects the multiple relationships occurring throughout the landscape. We propose a hierarchical procedure based on biophysical aspects for building local to regional typologies for guiding research and management, using the Cuitzmala River Basin as a case study. The variables involved were obtained from geospatial databases, water balances, and topographic profiles. The levels and variables are context (altitude, geoform [mountains/hills/plains], and runoff coefficient), structure (stream order, longitudinal slope, hydroperiod, and segment length), and microstructure (lateral slope, bankfull width, and length-to-width ratio). We consider humidity and functional gradient along the basin to identify groups of streams and fluvial networks. Inside each network, we described structural and microstructural features associated with riparian functions, linking them with management decisions. Therefore, the proposed hierarchical procedure can help in making riparian heterogeneity visible, focusing research and management goals, and allowing the recognition of a spatial dimension of the processes being studied.  相似文献   

Late pleistocene and holocene loess deposits of the Southeastern Buenos Aires province,Argentina     

Marcelo Zarate  Adriana Blasi Dr. 《GeoJournal》1991,24(2):211-220

The Late Pleistocene and Holocene loess deposits of the SE Buenos Aires province are composed of four allostratigraphic units that represent four episodes of loess deposition. The first and the second episodes occurred in Late Pleistocene times. The second episode was followed by a soil forming interval (Early Holocene to Mid-Holocene times). The third episode took place at about 5000 yr BP, after the Holocene sea-level maximum when marine regression began. The fourth episode constitutes a historical event of only local significance.Loess shows a fairly constant granulometric and mineralogical composition. The modal fraction consists of very fine sand and coarse silt (3 to 5 phi). They are classified as sandy silts or silty sands. Three grain-size subpopulations are differentiated: coarse, medium and fine. The medium-size subpopulation, which is the most important, consists of most of the very fine sand and coarse silt. It is thought to be transported by modified saltation and short-term suspension during local dust-storms.The mineralogical composition of loess consists of a volcaniclastic assemblage derived mainly from reworked pyroclastic deposits, primary tephras and volcaniclastic sediments. The source area of these materials was located in the lower Colorado river valley about 400 km SW of the studied area. There was also a direct supply by volcanic ash falls.  相似文献