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Produção de óleo essencial e balanço nutricional em Corymbia citriodora adubado com lodo de esgoto em diferentes espaçamentos; PRODUCTION OF ESSENTIAL OIL AND NUTRIENT BUDGET IN Corymbia citriodora FERTILIZED WITH SEWAGE SLUDGE IN DIFFERENT SPACING

SILVA, Paulo Henrique Mueller da; POGGIANI, Fabio; STAPE, Jose Luiz; BRITO, Jose Otavio; MOREIRA, Rildo Moreira
Fonte: UNIV FEDERAL LAVRAS-UFLA Publicador: UNIV FEDERAL LAVRAS-UFLA
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
46.23%
The Corymbia citriodora is one of the most cultivated species in Brazil for wood and essential oil production. The oil is obtained by the leaves distillation and the yield is around 2%. For the sustainability of leaves extraction is necessary a good nutritional replacement, because the leaves contain a large quantity of nutrients. The sewage sludge application in Corymbia plantations is a way to apply organic fertilizer and is also a good alternative for the final disposal of this residue. In this context, the objective of this study was to evaluate the sewage sludge use as fertilizer for the essential oil production in two different Spacing. The experiment was constituted by 4 blocks and the treatments were: i) Close spacing (1m x 1m) with sewage sludge + K and B; ii) Close spacing with mineral fertilization: iii) Regular spacing (3m x 1m) with sewage sludge + K and B; and iv) Regular spacing with mineral fertilization. When the C. citriodora plots were 12, 18, 24 and 30 months old, leaves and branches biomass and also essential oil production were quantified. It was observed that the system of close planting totalized a higher biomass, 3.8 times more than the conventional system, providing 3 times more essential oil production (363 l ha(-1) at the close spacing and 116 l ha(-1) at the regular Spacing during 30 months). No difference was found in the leaves or oil production with the use of sewage sludge or mineral fertilizer any of spacing studied The use of sewage sludge as fertilizer for Corymbia citriodora plantations may be an interesting alternative. because it supplies large quantities of nutrients and ensures a positive budget of nutrients in the ecosystem.

Production and carbon allocation in a clonal Eucalyptus plantation with water and nutrient manipulations

STAPE, Jose Luiz; BINKLEY, Dart; RYAN, Michael G.
Fonte: ELSEVIER SCIENCE BV Publicador: ELSEVIER SCIENCE BV
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.05%
We examined resource limitations on growth and carbon allocation in a fast-growing, clonal plantation of Eucalyptus grandis x urophylla in Brazil by characterizing responses to annual rainfall, and response to irrigation and fertililization for 2 years. Productivity measures included gross primary production (GPP), total belowground carbon allocation (TBCA), bole growth, and net ecosystem production (NEP). Replicate plots within a single plantation were established at the midpoint of the rotation (end of year 3), with treatments of no additional fertilization or irrigation, heavy fertilization (to remove any nutrient limitation), irrigation (to remove any water limitation), and irrigation plus fertilization. Rainfall was unusually high in the first year (1769mm) of the experiment, and control plots had high rates of GPP (6.64 kg C m(-2) year(-1)), TBCA (2.14 kg C m(-2) year(-1)), and bole growth (1.81 kg C m(-2) year). Irrigation increased each of these rates by 15-17%. The second year of the experiment had average rainfall (1210 mm), and lower rainfall decreased production in control plots by 46% (GPP), 52% (TBCA), and 40% (bole growth). Fertilization treatments had neglible effects. The response to irrigation was much greater in the drier year...

Ciclagem de nutrientes via serapilheira em um fragmento ciliar do rio Urupá, Rondônia; Nutrient cycling via litterfall in a riparian forest of Urupá river, (Rondônia)

Cabianchi, Giovana Mendonça
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 11/06/2010 PT
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36.19%
Os objetivos deste estudo foram: estimar a produção e a decomposição de serapilheira, quantificar os macronutrientes, além de avaliar a estrutura da vegetação e a composição florística de uma floresta de várzea em uma região sob forte influência antrópica no sudoeste da Amazônia. O conhecimento destes processos é extremamente importante, uma vez que tais informações fornecem dados essenciais para estimar a produção líquida destes sistemas, sua ciclagem de nutrientes, além de auxiliar na recuperação de áreas degradadas através de planos de manejo adequados. As coletas de serapilheira foram realizadas quinzenalmente, durante o período de Setembro de 2005 a Agosto de 2007 e o experimento de decomposição foi realizado no período de um ano. O levantamento florístico e as medidas de estrutura florestal foram realizadas em campanha intensiva em Agosto de 2009. A produção média anual de serapilheira foi de 12,7 t ha-1, com elevado grau de sazonalidade, apresentando maior produção durante os meses mais secos do ano. A produção para as frações obedeceu à seguinte ordem: folhas >> galhos > miscelânea. O retorno médio anual de carbono via serapilheira foi de 5,4 t ha-1. Em termos de proporção, existem quase duas vezes mais carbono sendo depositado no período seco do que no chuvoso. A devolução média anual de N foi de 199...

Fluxo de nutrientes em um fragmento de mata ciliar no estado de Rondônia, Brasil; Nutrient fluxes on a riparian forest fragment in the Rondônia State, Brazil

Leite, Nei Kavaguichi
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 29/11/2011 PT
Relevância na Pesquisa
46.3%
Para identificar a importância ecológica das matas ciliares é essencial conhecer a interação entre sua hidrologia e ciclagem de nutrientes. Isto se torna ainda mais crucial diante das crescentes transformações na paisagem causadas pelo homem, que têm promovido forte antropização destas formações florestais. O estudo foi conduzido em uma floresta ribeirinha sazonalmente alagada na região sudoeste da Amazônia entre os anos de 2005 e 2007. Foram medidas as principais vias hidrológicas: chuva, precipitação interna, escoamento pelo tronco, escoamento superficial, solução do solo e água subterrânea, além do rio Urupá. Em todas foram realizadas análises químicas para determinação das concentrações de C, N e macronutrientes (cátions/ânions). A mata ciliar apresenta solos ácidos, bem estruturados, pobres em nutrientes e com um eficiente mecanismo de retenção nas camadas superficiais, associado à distribuição da matéria orgânica, absorção por raízes finas ou retenção pelos complexos de troca do solo. Os estoques de nutrientes no solo estão dentro da faixa de valores observada em outros estudos na Amazônia, apresentando baixa fertilidade. A região estudada apresenta altos índices pluviométricos (em torno de 2125 mm)...

Phosphorus and potassium budget in the soil-plant system in crop rotations under no-till

Rosolem, C. A.; Calonego, J. C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 127-133
ENG
Relevância na Pesquisa
36.16%
Soil management and crop rotations can affect P and K budget in soil, decreasing losses, and increasing fertilizer use efficiency. The P and K budget in the soil-plant system at depths up to 60. cm was studied for different soil managements and crop rotations under no-till for three years in Botucatu, São Paulo, Brazil. The investigated crop rotations were: triticale (X Triticosecale) and sunflower (Helianthus annuus) cropped in autumn-winter; pearl millet (Pennisetum glaucum), forage sorghum (Sorghum bicolor), and Sunn hemp (Crotalaria juncea) were grown in the spring, as well as an additional treatment with chiseling followed by a fallow period; and soybean (Glycini max, L., Merril) was cropped in the summer. Each year triticale and sunflower were grown in plots and pearl millet, forage sorghum, Sunn hemp and of chisel/fallow in sub-plots. The triticale/millet rotation led to the largest decrease in available P within the 0-0.60. m layer of the soil profile and the largest K increase within the 0-0.05. m layer. Potassium mobility in the soil profile and the increases in the available K content in the 0.40-0.60. m layer were independent of the management system. Crop rotations with or without chiseling are not effective in preventing soil P losses. There is considerable K leaching below 0.60. m...

The LOICZ biogeochemical budget approach applied to Ria Formosa lagoon, - Algarve, South Portugal

Jian Su
Fonte: Universidade do Algarve Publicador: Universidade do Algarve
Tipo: Dissertação de Mestrado
Publicado em //2007 ENG
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36.32%
Dissertação mest., Gestão da Água e da Costa, Universidade do Algarve, 2007; The Ria Formosa lagoon is a mesotidal lagoon located in the south coast of Portugal. A single-box, single-layer LOICZ model was applied to data in 1987 and 1999 to estimate the biogeochemical budget of the Ria Formosa lagoon. Water exchange time in the lagoon was estimated to be about 2 days. Both the fluxes of DIP and DIN were negative, indicating that the system acts as sink of both DIP and DIN. Stoichiometric calculations assumed nutrient ratios in both Redfield proportions (C:N:P=106:16:1) and in proportions appropriate for macroalgae (C:N:P=335:35:1). Overall, the lagoon can be consider as “autotrophic”, with a net ecosystem metabolism (p-r) 8.4 mmol C m-2 d-1 considering Redfield ratio. Nitrification dominated over nitrogen fixation since it was positive in both cases. The Ria Formosa lagoon is sensitive to the tide. The water and nutrient budget in the lagoon has strong seasonal variation, especially the dry and rainy seasons. According to the standards of EEA, the Ria Formosa lagoon is between oligotrophic and mesotrophic.

The influence of castanhão reservoir on nutrient and suspended matter transport during rainy season in the ephemeral Jaguaribe river (CE, Brazil)

Molisani,MM.; Becker,H.; Barroso,HS.; Hijo,CAG.; Monte,TM.; Vasconcellos,GH.; Lacerda,LD.
Fonte: Instituto Internacional de Ecologia Publicador: Instituto Internacional de Ecologia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2013 EN
Relevância na Pesquisa
46.19%
Measurements of nutrient and suspended matter concentrations and loads entering and leaving the Castanhão reservoir during the rainy season were carried out to assess the influence of this large reservoir on land-sea fluvial transport in the ephemeral Jaguaribe river basin. Spatial variation indicated statistically significant attenuation of concentrations only for total phosphorous and suspended matter across the reservoir. Strong retention of nutrients and suspended matter loads by the reservoir was observed with average trapping efficiency of 89% for dissolved silicon, 98% of soluble reactive phosphorus, 71% for ammonium, 87% for total nitrogen, 98% for total phosphorus and 97% for suspended matter compared to the reservoir inflow. The dam operational procedure defined by the ephemeral conditions of the river reduced water releases compared to reservoir inflow and induced strong retention of nutrient and suspended matter loads within the reservoir when fluvial transfer occurs in this semiarid watershed.

Nutrient flux and budget in the Ebro estuary

Falco, Silvia Giaccaglia; Niencheski, Luis Felipe Hax; Rodilla, Miguel; Gil, Inma Romero; R??o, Jimena Gonz??lez del; Sierra, Joan Pau; M??sso, C??sar
Fonte: Universidade Federal do Rio Grande Publicador: Universidade Federal do Rio Grande
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.31%
The Ebro river flows to the Mediterranean coast of Spain. During its final stretch, the Ebro behaves ina similar way to a highly stratified estuary. This paper describes the transport of nutrients to the Ebro estuary, evaluates the general movement of nutrients in the estuarine region, using a mass balance approach, and estimates the amounts of nutrients discharged to the coastal environment. Given the strong saline stratification, this study only includes the surface layer that contains the continental freshwater. The annual nutrient budget for the Ebro estuary shows a net excess for nitrogen and phosphorus, while silicate almost attains equilibrium between addition and removal. There are several reasons for gains in nitrogen and phosphorous: a contribution of dissolved and particulate compounds in the freshwater (some of which are mineralized); a lower uptake of phytoplankton indicated by chlorophyll reduction in the estuary; an entrainment of the nutrient-rich upper part of the salt wedge; and, to a lesser extent, the impact of wastewater and agricultural water use. The biggest load discharged into the Mediterranean Sea by the Ebro is nitrogen, followed by silicate with over 10 000 tons of each deposited annually. Phosphorus is discharged at relatively low concentrations and with an annual load of about 200 t yr_1.

A tidal creek water budget: Estimation of groundwater discharge and overland flow using hydrologic modeling in the Southern Everglades

Michot, Béatrice; Meselhe, Ehab A.; Rivera-Monroy, Victor H.; Coronado-Molina, Carlos; Twilley, Robert R.
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
26.42%
Taylor Slough is one of the natural freshwater contributors to Florida Bay through a network of microtidal creeks crossing the Everglades Mangrove Ecotone Region (EMER). The EMER ecological function is critical since it mediates freshwater and nutrient inputs and controls the water quality in Eastern Florida Bay. Furthermore, this region is vulnerable to changing hydrodynamics and nutrient loadings as a result of upstream freshwater management practices proposed by the Comprehensive Everglades Restoration Program (CERP), currently the largest wetland restoration project in the USA. Despite the hydrological importance of Taylor Slough in the water budget of Florida Bay, there are no fine scale (∼1 km2) hydrodynamic models of this system that can be utilized as a tool to evaluate potential changes in water flow, salinity, and water quality. Taylor River is one of the major creeks draining Taylor Slough freshwater into Florida Bay. We performed a water budget analysis for the Taylor River area, based on long-term hydrologic data (1999–2007) and supplemented by hydrodynamic modeling using a MIKE FLOOD (DHI,http://dhigroup.com/) model to evaluate groundwater and overland water discharges. The seasonal hydrologic characteristics are very distinctive (average Taylor River wet vs. dry season outflow was 6 to 1 during 1999–2006) with a pronounced interannual variability of flow. The water budget shows a net dominance of through flow in the tidal mixing zone...

Groundwater-surface water interactions : implications for nutrient transport to tropical rivers

Dixon-Jain, Prachi
Fonte: Universidade Nacional da Austrália Publicador: Universidade Nacional da Austrália
Tipo: Thesis (PhD); Doctor of Philosophy (PhD)
EN_AU
Relevância na Pesquisa
46.27%
The interaction between groundwater and surface water systems is a key component of the hydrological cycle and an understanding of their connectivity is fundamental for sustainable water resource management. Water is a vehicle for mobilising dissolved constituents, including nutrients, between surface and subsurface waters and between terrestrial and marine systems. Therefore, knowledge of surface-subsurface linkages is critical not only for water quantity allocation, but also for water quality and its implications for ecosystem health. In particular, ascertaining the significance of groundwater fluxes for river nitrogen budgets is an important motivation for characterising river-groundwater connectivity. This overarching theme is developed through the course of the thesis. The marked seasonality of tropical river systems provides a unique opportunity to investigate groundwater contributions to surface waters, especially when there are minimal overland flows. The Herbert River in northeast Queensland represents a useful case study in the Australian tropics for assessing the potential for transport of agricultural contaminants, such as dissolved forms of nitrogen, between surface and subsurface waters, and between terrestrial and marine systems...

Long-term effects of crop rotation, stubble management and tillage on soil phosphorus dynamics

Buenemann, E.; Heenan, D.; Marschner, P.; McNeill, A.
Fonte: C S I R O Publishing Publicador: C S I R O Publishing
Tipo: Artigo de Revista Científica
Publicado em //2006 EN
Relevância na Pesquisa
36.07%
The effects of various management practices on soil phosphorus (P) dynamics were investigated in a field experiment in New South Wales, Australia, during 24 years of different crop rotation, stubble management, and tillage treatments. Topsoil samples collected at the beginning of the trial and after 6, 12, 18, and 24 years were analysed for resin-extractable P, inorganic and organic P, and total P. According to the calculated P input–output budget, 9–14 of the 20 kg P/ha added as superphosphate annually remained in the system, depending on the treatment. The measured increase in total P in 0–0.20 m did not differ between treatments, showing an accumulation rate of only 9 ± 2 kg P/ha.year. These results suggest a loss of 4 ± 2 kg P/ha.year, presumably into lower soil layers. Resin-extractable P at 0–0.10 m increased by 1.7 kg P/ha.year, irrespective of the treatment. The increase in total P after 24 years was almost completely accounted for by the increase in total extractable inorganic P. Changes in organic P paralleled changes in organic carbon, with a significant loss in treatments with stubble burning (wheat–lupin rotation and continuous wheat), and a significant accumulation in a wheat–subterranean clover rotation with stubble retention and direct drilling. We conclude that on the time scale of this experiment...

Retention of nitrogen, phosphorus and silicon in a large semi-arid riverine lake system

Aldridge, K.; Cook, P.; Lamontagne, S.; Brookes, J.
Fonte: Kluwer Academic Publ Publicador: Kluwer Academic Publ
Tipo: Artigo de Revista Científica
Publicado em //2010 EN
Relevância na Pesquisa
36.36%
Lakes and reservoirs (impoundments) are often viewed as a sink for nutrients within the river continuum. To date, most studies on nutrient retention within impoundments are derived from the temperate climate zones of Europe and North America, only consider one nutrient, and are often short-term (1–2 years). Here, we present a long-term (17 year) data set and nutrient (nitrogen, phosphorus and silica) budget for two connected semi-arid lakes (the Lower Lakes) at the terminus of the River Murray, Australia. Most of the filterable reactive phosphorus and nitrate entering the lakes were retained (77 and 92%, respectively). Total phosphorus (TP) was also strongly retained (55% of the annual TP load on average) and the annual TP retention rates could be predicted as a function of the areal hydraulic loading rate (annual lake outflow/lake surface area). On average, there was a slight net retention (7%) of the annual total nitrogen (TN) load but a slight net export (6% of the load) of organic N. TN retention as function of the areal hydraulic loading rate was lower than expected from existing models, possibly because of high nitrogen fixation rates in the Lower Lakes. Silica was retained (39%) at similar rates to those observed in previous studies. There was also a marked increase in the TN:TP and TN:Si ratios within the lake (TN:TP~30 and TN:Si~0.67) compared to those entering (TN:TP~15...

A new MONERIS in-Stream Retention Module to Account Nutrient Budget of a Temporary River in Cyprus

TZORAKI Ourania; COOPER David; DÖRFLINGER Gerald; PANAGOS Panagiotis
Fonte: SPRINGER Publicador: SPRINGER
Tipo: Articles in Journals Formato: Online
ENG
Relevância na Pesquisa
46.4%
The nature of the nutrient budget for temporary rivers differs from that for permanent rivers because of the restricted nature of flow, the lack of adequate dilution, and weather conditions which are conducive to the development of algal blooms. We analyse the nutrient budget of three tributaries of a temporary river in Cyprus, the Kouris, with the aid of the MONERIS model. MONERIS in-stream retention module was modified to account for a 1-dimensional advection - dispersion pollutants transport rather than the general mass balance equation for mixed reactors. TRS plot classified Kryos stream as an Intermittent flow – Dry (I-D) stream (hydrologically altered) and Kouris and Limnatis as Intermittent – Pool (I-P) streams that need different lumped parameterization in MONERIS simulation. Point sources are important for nitrogen (64 %) and phosphorous emissions (22 %), and diffuse sources for nitrogen via erosion (15 %) and free grazing (12 %) and for phosphorous via free grazing (8 %). We estimate that around 40 % of N and 88 % of P entering streams is retained in the stream. An analysis of the model uncertainty and sensitivity to input data indicates that MONERIS model, even in semi-arid areas, may be used for the purpose of managing river basins.; JRC.H.5-Land Resources Management

Towards a LOICZ Biogeochemical Budget for the Mediterranean Sea - Initial Steps

STROBL Robert; EVANS B.; SOMMA Francesca; GARCIA GORRIZ Elisa; STIPS Adolf; ZALDIVAR COMENGES Jose'
Fonte: The Land-Ocean Interactions in the Coastal Zone International Project Office Publicador: The Land-Ocean Interactions in the Coastal Zone International Project Office
Tipo: Articles in Journals Formato: Printed
ENG
Relevância na Pesquisa
26.46%
Although making up about 1% of the total world ocean surface, the Mediterranean Sea is often used as a representative model of the world's oceans. Due to its practically enclosed character, it is also often used to assess the global change of the environment. Anthropogenic activities have contributed significantly to the existing nutrient enrichment and consequent eutrophication problems in the Mediterranean Sea. At the present, however, mainly due to the favourable circumstances regarding the hydrology, morphology as well as absence of significant upwelling of the Mediterranean basin as a whole, severe eutrophication cases are limited to specific coastal areas (UNEP 2003). To obtain a detailed knowledge of biogeochemical processes taking place in the Mediterranean Sea, a budget approach was adopted, as proposed by LOICZ. As part of the input to the LOICZ budget, the nutrient loads from contouring land need to be estimated. In fact, an evaluation of the nutrient loads from the adjacent land surfaces lends itself to be used to interpret past, existing and future legislation using scenario analyses, reflecting different expected or known events. The sequence of budgets follows four steps: water budget, salt budgets, nonconservative materials and stoichiometric linkages among non-conservative budgets.; JRC.H.3-Global environement monitoring

Significance of Halimeda bioherms to the global carbonate budget based on a geological sediment budget for the Northern Great Barrier Reef, Australia

Rees, Siwan; Opdyke, Bradley; Wilson, P.A.; Henstock, T J
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
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36.25%
Since the correlation between carbon dioxide (CO2) levels and global temperatures was established in the ice core records, quantifying the components of the global carbon cycle has become a priority with a view to constraining models of the climate system

Nutrient mass balance of the seagrass Posidonia oceanica: the importance of nutrient retranslocation

Alcoverro, Teresa; Manzanera, Marta; Romero Martinengo, Javier
Fonte: Inter Research Publicador: Inter Research
Tipo: Artículo Formato: 1064120 bytes; application/pdf
ENG
Relevância na Pesquisa
36.27%
The seasonal nutrient mass balance of the dominant seagrass of the Mediterranean, Posidonia oceanica (L.) Delde, was evaluated in NE Spain in order to test the hypothesis that the effect of seasonal nutrient imbalance can be reduced by the reutilization of internal nutrient pools. To this end we investigated the seasonal and age-dependent variability of nitrogen and phosphorus concentration of the leaves, inferring from these data values of seasonal nitrogen and phosphorus incorporation, uptake, losses and retranslocation. Incorporation of nitrogen and phosphorus in leaves peaked in June and was lowest in September, thus following the seasonal growth pattern of the plant. Retranslocation of nitrogen and phosphorus was high from May to September and close to zero during the rest of the year. Losses of nitrogen and phosphorus were highest at the end of summer, associated with the major biomass losses. Nitrogen uptake by leaves reached maximum values in winter and was lowest during August-September, while phosphorus uptake was highest in spring and lowest in August-September. On an annual basis nitrogen and phosphorus uptake accounted for 60 and 41 % of the total nutrient incorporation, respectively, while retranslocation of nutrients from old tissues accounted for the remaining 40 and 59%. Although roots and rhizomes function as sources of nutrients at the beginning of the summer...

Nutrient fluxes in a semi-arid microtidal mangrove wetland in the Gulf of California

Sánchez Carrillo, Salvador; Sánchez Andrés, Raquel; Alatorre, L. C.; Angeler, D. G.; Álvarez Cobelas, Miguel; Arreola Lizárraga, J. A.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 22264 bytes; application/pdf
ENG
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36.3%
9 pages, 6 figures, 3 tables; Nutrient (C, N and P) fluxes were monitored in a microtidal semi-arid mangrove system, which links a semi-enclosed shallow coastal lagoon with the Gulf of California. We assessed the role of the mangrove ecosystem as a nutrient sink/source and determined how mangrove litterfall rates, tidal regime and climate factors influence these fluxes. Despite high seasonal differences in DOC, POC, N-NO3 and TP levels, nutrient concentrations were only marginally influenced by either hydrological variables or the concentration of these fractions in the adjacent lagoon. The carbon budget appeared to be balanced throughout the study. Retention rates in the mangrove system were related to litterfall rates. Export of DIN was observed mainly in the wet season due to the low nitrogen assimilation efficiency of the system. Import of organic nitrogen was related to the high retention efficiency of particulate organic nitrogen. Phosphorus fractions were imported and retained in the mangrove supporting previous findings that mangroves are phosphorus sinks. Finally, through a simple meta-analysis we tested the quantitative importance of main variables (tidal flow, tidal elevation, tidal range, rainfall, mangrove catchment area...

An approach to assess and manage nutrient loads in two coastal catchments of the Eurobodalla region, NSW, Australia

Drewry, John; Newham, Lachlan; Greene, Richard; Jakeman, Anthony; Croke, Barry
Fonte: Modelling and Simulation Society of Australia and New Zealand Inc. Publicador: Modelling and Simulation Society of Australia and New Zealand Inc.
Tipo: Conference paper
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36.63%
This paper describes a research programme to estimate nitrogen (N), phosphorus (P) and sediment event-based loads in the Moruya and Tuross River catchments of the New South Wales south coast. The research programme is designed within the context of an integrated catchment modelling framework (CatchMODS), to assess relative contributions from diffuse sources of nutrient and sediment export loads, and provide information for catchment management. In particular, the relative potential risk to water quality from dairying in the Eurobodalla region is being evaluated using a farm-scale nutrient budget approach. Predominant land uses in the Moruya and Tuross River catchments are conservation and production forests, national parks, cattle grazing, and dairy production. There is little information on the quality of water entering the catchment estuaries, particularly during storm events when the majority of sediment and nutrients is transported to estuaries. The use of catchment models is commonly required to assist catchment managers to investigate water quality impacts at a catchment scale due to cost restrictions and data availability. To assess nutrient and sediment loads and enable management to achieve sustainable practices, the CatchMODS model is linked with a field-based data collection programme including water quality sampling to estimate suspended sediment...

Intensive culture of Litopenaeus vannamei without water exchange and with an artificial substrate

Audelo-Naranjo,Juan Manuel; Martínez-Córdova,Luis Rafael; Gómez-Jiménez,Silvia; Voltolina,Domenico
Fonte: UAM, Unidad Iztapalapa, Publicador: UAM, Unidad Iztapalapa,
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2012 EN
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36.05%
Aiming to determine the effect of the periphyton growing on artificial substrates, juveniles (3 g initial weight and 440 g m-3 stocking biomass) of the whiteleg shrimp Litopenaeus vannamei (Boone, 1931) , were grown during 32 days in eight 1 m³ cylindrical tanks with 3.7 m² of total submerged surface. Two culture treatments (with and without artificial substrate or control) were tested with four replicates each. Artificial substrate (AquamatsTM) provided an additional surface area of 7.2 m². The mean dissolved ammonium (NH4+) and ammonia (NH3) concentrations for the Aquamats group were 39 and 22% lower than the respective values obtained for the control cultures. The artificial substrate stimulated nutrient recycling among the biological components (shrimp, biofilm, bottom microfauna, etc.) since mean shrimp biomass yield was 13% higher for the Aquamats group, and it contained a significantly higher percentage of the total nitrogen and phosphorus inputs than the control treatment. The protein content of shrimp cultured with Aquamats was 21.4% higher than that obtained for the control group, which is explained by the higher availability (and diversity) of the natural food of the periphyton. In view of these results, the use of closed cultures added this artificial substrate seems a viable alternative for shrimp culture.

Budget and discharges of nutrients to the Gulf of California of a semi-intensive shrimp farm (NW Mexico)

Miranda,Anselmo; Voltolina,Domenico; Frías-Espericueta,Martín Gabriel; Izaguirre-Fierro,Gildardo; Rivas-Vega,Martha Elisa
Fonte: UAM, Unidad Iztapalapa, Publicador: UAM, Unidad Iztapalapa,
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2009 EN
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56.52%
A previous study conducted in 1998 assessed yearly nutrient discharge by the Sinaloa and Sonora shrimp farms to the coastal areas of the Gulf of California (1,509.4 and 438.7 tons of N and P corresponding to 2.1 and 1.05% of the total nutrient discharges to the Gulf along those two states coastlines). However, that estimate did not take into account other nutrient sources, nor the high daily water exchanges of the farms of Sonora, that are likely to increase the calculated amount of nutrients discharged. The evaluation of the nutrient budget of one semi-intensive shrimp farm of Sonora, including the nutrient sources not measured in other studies, showed that during one production cycle this farm discharged 547 kg N·ha-1 and 73 kg P·ha-1, with respective net exports of 122 kg N·ha-1 and 14 kg P·ha-1. Based on the results of this study, the recalculated totals for Sinaloa and Sonora, including rivers, agricultural runoff, and urban wastewater were 77,007.7 and 38,108.3 tons of N and P, and those of shrimp farms 3,556 tons of N and 620.7 tons of P (4.8 and 1.6%). The total discharges of 2003 may be estimated at 78,798.2 and 38,874.1 tons of N and P. In view of its high groth rate, the contributions of shrimp culture would be 10.1% and 3.3%.