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Registros recuperados: 9
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Assessment of nitrogen flows into the Cuban landscape OceanDocs
Baisre, J. A..
The alteration of the nitrogen (N) cycle by human activities is widespread and has often resulted in increased flows of nitrogen to the marine environment. In this paper we have attempted to know the changes of N fluxes in Cuba by quantifying the N inputs to the landscape from (1) fertilizer applications, (2) atmospheric deposition, (3) biological nitrogen fixation and (4) net import of food and feeds. N-inputs to the country progressively increased until the end of the 20th century, reaching a peak during the 80s when low cost fertilizer imported from the former Soviet Union led to heavy rates of application. This rapid growth represented more than a 5-fold increase with respect to pristine values; higher than the two-fold global increase of anthropogenic...
Tipo: Journal Contribution Palavras-chave: Nitrogen; Nitrogen cycle; Atmospheric deposition; Fertilizers.
Ano: 2006 URL: http://hdl.handle.net/1834/5111
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ATMOSPHERIC N DEPOSITION IN CENTRAL AND SOUTHERN CHILE: AN OVERVIEW Gayana Botánica
Godoy,Roberto; Paulino,Leandro; Oyarzún,Carlos; Boeckx,Pascal.
Temperate forests in Chile are not yet affected by elevated nitrogen (N) deposition. However, anthropogenic activities such as transport, industry and agriculture have been increasing in central and southern Chile. These activities can substantially alter the atmospheric N load and subsequently N deposition. Nitrogen deposition data for central and southern Chile are scares and scattered. In order to assess trends of N deposition a good knowledge of past and current N depositions is however essential. This study presents an overview of the existing N deposition data in Chile. In central Chile, dry deposition has been estimated at 0.8 kg NO3--N ha-1 yr-1 and 1.0 kg NH4+-N ha-1 yr-1, giving a total of 1.8 kg N ha-1 yr-1 and wet deposition was 0.4 kg NO3--N...
Tipo: Journal article Palavras-chave: Atmospheric deposition; Central and southern Chile; Mineral N; Organic N.
Ano: 2003 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100008
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Atmospherically-promoted photosynthetic activity in a well-mixed ecosystem: Significance of wet deposition events of nitrogen compounds ArchiMer
Boulart, C; Flament, Pierre; Gentilhomme, V; Deboudt, K; Migon, C; Lizon, F; Schapira, M; Lefebvre, Alain.
Wet atmospheric deposition of dissolved N, P and Si species is studied in well-mixed coastal ecosystem to evaluate its potential to stimulate photosynthetic activities in nutrient-depleted conditions. Our results show that, during spring, seawater is greatly depleted in major nutrients: Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP) and Silicic acid (Si), in parallel with an increase of phytoplanktonic biomass. In spring (March-May) and summer (June-September), wet atmospheric deposition is the predominant source (> 60%, relative to riverine contribution) for nitrates and ammonium inputs to this N-limited coastal ecosystem. During winter (October-February), riverine inputs of DIN predominate (> 80%) and are annually the most...
Tipo: Text Palavras-chave: Strait of Dover; Nutrient cycles; River plumes; Atmospheric deposition; Coastal zone; Primary production.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-2007.pdf
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COMPARISON OF DRY DEPOSITION AND CANOPY EXCHANGE OF BASE CATIONS IN TEMPERATE HARDWOOD FORESTS IN FLANDERS AND CHILE Gayana Botánica
Staelens,Jeroen; Schrijver,An De; Oyarzún,Carlos; Lust,Noël.
Bulk precipitation, throughfall and stemflow of base cations Na+, K+, Mg2+ and Ca2+ were measured in two deciduous beech forests, located in regions with different air pollution characteristics and strongly differing in soil acidity and soil base saturation. The contribution of dry deposition and canopy leaching to net throughfall flux was estimated using Na+ as a tracer ion. The input of base cations via bulk precipitation was not significantly different between Nothofagus obliqua (Mirb.) Bl. in southern Chile and Fagus sylvatica L. in Flanders. However, net throughfall input of Ca2+ and Mg2+ to the forest floor was significantly higher in Chile than in Flanders. Potassium fluxes were similar in both studied stands. Dry deposition of Ca2+ was higher in...
Tipo: Journal article Palavras-chave: Atmospheric deposition; Base cations; Fagaceae; Forest canopy; Throughfall.
Ano: 2003 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432003000100003
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Dry deposition of nitrogen to passive samplers in grassland and forest canopies in the Central depression of southern Chile Gayana Botánica
Godoy,Roberto; Haneke,Jörgen; Staelens,Jeroen; Oyarzún,Carlos; Paulino,Leandro; Barrientos,Mónica.
The growth of intensive livestock farming in the central depression of southern Chile (40° S) during the last century has resulted in elevated emissions of inorganic nitrogen (N) compounds into the atmosphere, particularly of NH3. Consequently, atmospheric N has been deposited to lakes, vegetation, and soil. Much attention has been paid to wet N deposition in southern Chile, while almost nothing is known about dry N deposition in this region. Our aim is to use an exploratory approach with SAM (Standard Air Monitoring) filters to investigate the potential contribution of the dry N deposition to the total N deposition in the central depression of southern Chile. Furthermore, the relationship between micro-climatological patterns and dry deposition was...
Tipo: Journal article Palavras-chave: Atmospheric deposition; Nitrogen; Nothofagus obliqua forest; Pinus radiata plantation; Surrogate surface.
Ano: 2005 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432005000200006
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Impact of atmospheric deposition of anthropogenic and natural trace metals on Northwestern Mediterranean surface waters: A box model assessment ArchiMer
Heimbuerger, Lars-eric; Migon, Christophe; Cossa, Daniel.
Under stratified oligotrophic conditions (May November), the surface mixed layer of the Northwestern Mediterranean constitutes a homogeneous water volume of 10-30 m depth. In other respects, the mean residence time of Ligurian surface waters (0-200 m) is 102 days. It is therefore possible to quantify the extent to which atmospheric deposition of trace metals affects surface waters. On the basis of literature data on anthropogenic and natural trace metals, we demonstrate that the ratios between total seawater labile atmospheric deposition during 102 days (Delta c) and dissolved TM concentrations in Ligurian surface waters (c) illustrate the impact of atmospheric deposition on surface seawater (Delta c/c). High ratios indicate surface TM enrichments, while...
Tipo: Text Palavras-chave: Atmospheric deposition; Trace metal pollution; Box model; Northwestern Mediterranean; Impact evaluation; Environmental antipollution policies.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00057/16786/14308.pdf
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NITROGEN FLUXES IN THROUGHFALL AND LITTERFALL IN TWO NOTHOFAGUS FORESTS IN SOUTHERN CHILE Gayana Botánica
Staelens,Jeroen; Godoy,Roberto; Oyarzún,Carlos; Thibo,Karen; Verheyen,Kris.
Nitrogen return by leaf litterfall was compared with atmospheric nitrogen deposition for two deciduous Nothofagus stands in southern Chile, located in areas with contrasting land use. The litterfall return of nitrogen in a Nothofagus alpina (Poepp. et Endl.) Oerst. stand at San Pablo de Tregua, in the Cordillera de los Andes, was similar to the litterfall return in a Nothofagus obliqua (Mirb.) Oerst. stand at Paillaco, in the Central Depression. In contrast, the net throughfall and stemflow deposition differed significantly between the two stands. At San Pablo de Tregua, the annual bulk deposition of NH4+ and NO3- was significantly higher than the throughfall and stemflow deposition reaching the forest floor. This demonstrates an uptake of inorganic...
Tipo: Journal article Palavras-chave: Ammonium; Atmospheric deposition; Canopy interactions; Nitrate; Nutrient cycling; Amonio; Ciclos de nutrientes; Depositación atmosférica; Interacciones del dosel; Nitrato.
Ano: 2005 URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-66432005000200002
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Total mercury in the water column near the shelf edge of the European continental margin ArchiMer
Cossa, Daniel; Cotte Krief, Marie-hélène; Mason, Robert P.; Bretaudeau-sanjuan, Jane.
The purpose of this paper is to investigate the distribution and the relative importance of processes that affect mercury distribution in the water column at the shelf edge of the Celtic Sea, on the western European continental margin. The water column, down to 4500 m, was sampled during two cruises, one in winter 1994 and the other in June 1995, on eight stations. Total mercury concentrations ranged from 0.29 to 9.37 pM with the extreme values in the first 200 m. The highly variable concentrations in the surface layers are attributed to intense atmospheric-sea water exchange processes. The low concentrations encountered in the shelf water prelude any significant influence of continental waters in this area. In the mixed layer, biological uptake and...
Tipo: Text Palavras-chave: Regeneration; Atmospheric deposition; Deep profile; Upwelling; Atlantic ocean; Celtic Sea; Shelf break; Continental margin; Mercury.
Ano: 2004 URL: https://archimer.ifremer.fr/doc/2004/publication-660.pdf
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Trace element and isotope deposition across the air-sea interface: progress and research needs ArchiMer
Baker, A. R.; Landing, W. M.; Bucciarelli, E.; Cheize, Marie; Fietz, S.; Hayes, C. T.; Kadko, D.; Morton, P. L.; Rogan, N.; Sarthou, G.; Shelley, R. U.; Shi, Z.; Shiller, A.; Van Hulten, M. M. P..
The importance of the atmospheric deposition of biologically essential trace elements, especially iron, is widely recognized, as are the difficulties of accurately quantifying the rates of trace element wet and dry deposition and their fractional solubility. This paper summarizes some of the recent progress in this field, particularly that driven by the GEOTRACES, and other, international research programmes. The utility and limitations of models used to estimate atmospheric deposition flux, for example, from the surface ocean distribution of tracers such as dissolved aluminium, are discussed and a relatively new technique for quantifying atmospheric deposition using the short-lived radionuclide beryllium-7 is highlighted. It is proposed that this field...
Tipo: Text Palavras-chave: Air-sea exchange; Atmospheric deposition; Trace element solubility; Biogeochemical impacts; Mineral dust; Anthropogenic aerosols.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00369/48045/48131.pdf
Registros recuperados: 9
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