Isotopic evidence of subtle nutrient enrichment in mangrove habitats of Golfo Dulce,Costa Rica          下载免费PDF全文

Jimena Samper‐Villarreal  Jorge Cortés  Nicholas V.C. Polunin 《水文研究》2018,32(13):1956-1964

Mangroves are of great ecological and socio‐economic importance, yet they are under threat from urban development on the southern Pacific coast of Costa Rica. To test for possible nutrient‐related impacts, we compared water‐column nutrient concentrations, C and N stable isotope values and other environmental variables between mangroves with known sewage loading (three “nutrient loaded” locations) and those without such loading (three “reference” locations). Instantaneous nutrient concentrations were low at all locations, Secchi depth was greater at reference locations, and chlorophyll concentrations were higher at nutrient loaded mangroves. Suspended matter did not vary between reference and nutrient loaded mangroves, and nor did bivalve and algal δ¹³C and δ¹⁵N values. Enrichment of δ¹⁵N and δ¹³C of red mangrove leaves at the nutrient loaded locations is attributed to pulsed inputs of materials that were not detected in the instantaneous nutrient data. We provide evidence of isotopic enrichment at nutrient loaded locations from mangrove material and recommend that adequate waste water treatment be carried out on all anthropogenic discharges into this vulnerable marine system.  相似文献   

The scattering map in the planar restricted three body problem     

E. Canalias  A. Delshams  J. J. Masdemont  P. Roldán 《Celestial Mechanics and Dynamical Astronomy》2006,95(1-4):155-171

We study homoclinic transport to Lyapunov orbits around a collinear libration point in the planar restricted three body problem. A method to compute homoclinic orbits is first described. Then we introduce the scattering map for this problem (defined on a suitable normally hyperbolic invariant manifold) and we show how to compute it using the information already obtained for the homoclinic orbits. An example application to Astrodynamics is also proposed.  相似文献   

First-look XMM–Newton EPIC observations of the prototypical starburst galaxy M82     

Ian R. Stevens  rew M. Read  Jimena Bravo-Guerrero 《Monthly notices of the Royal Astronomical Society》2003,343(2):L47-L52

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Origin of uncontrolled water emissions in Alicante: use of discriminant analysis     

Servando Chinchón-Payá  Bravo I. De Blas  Roldán M. J. Nueda  Andreu F. Garcia 《Environmental Earth Sciences》2010,61(5):1005-1012

A model has been developed to predict the origin of uncontrolled water flows. For this purpose, we analysed a total of 52 elements using ICP techniques on 72 water samples in all: 40 of them from leaks in the drinking water supply network and the remaining 32 from groundwater outcrops. The study focused on the cases registered within the Alicante town limits (Spain). The use of multivariate statistical classification tools such as discriminant analysis made it possible not only to reduce the number of analytes, but also to design a predictive model capable of assigning the group to which a new sample belongs. The elements that comprise the model are B, Mn, Te, Ce, Re, Sr, Li and Tl. Given the concentration of each element in the sample, the model can assign its precedence with a total success rate higher than 94%.  相似文献   

Seagrass Organic Carbon Stocks Show Minimal Variation Over Short Time Scales in a Heterogeneous Subtropical Seascape     

Jimena Samper-Villarreal  Peter J. Mumby  Megan I. Saunders  Chris Roelfsema  Catherine E. Lovelock 《Estuaries and Coasts》2018,41(6):1732-1743

Blue carbon initiatives require accurate monitoring of carbon stocks. We examined sources of variability in seagrass organic carbon (C_org) stocks, contrasting spatial with short temporal scales. Seagrass morphology and sediment C_org stocks were measured from biomass and shallow sediment cores collected in Moreton Bay, Australia. Samples were collected between 2012 and 2013, from a total of 77 sites that spanned a gradient of water turbidity. Environmental measures of water quality between 2000 and 2013 revealed strong seasonal fluctuations from summer to winter, yet seagrass biomass exhibited no temporal variation. There was no temporal variability in C_org stocks, other than below ground biomass stocks were slightly higher in June 2013. Seagrass locations were grouped into riverine, coastal, and seagrass loss locations and short temporal variability of C_org stocks was analysed within these categories to provide clearer insights into temporal patterns. Above ground C_org stocks were similar between coastal and riverine meadows. Below ground C_org stocks were highest in coastal meadows, followed by riverine meadows. Sediment C_org stocks within riverine meadows were much higher than at coastal meadows and areas of seagrass loss, with no difference in sediment C_org stocks between these last two categories. Riverine seagrass meadows, of higher turbidity, had greater total C_org stocks than meadows in offshore areas irrespective of time. We suggest that C_org stock assessment should prioritise sampling over spatial gradients, but repeated monitoring over short time scales is less likely to be warranted if environmental conditions remain stable.  相似文献   

The effect of climate-change-related heat waves on mortality in Spain: uncertainties in health on a local scale     

E. Roldán  M. Gómez  M. R. Pino  J. Pórtoles  C. Linares  Julio Díaz 《Stochastic Environmental Research and Risk Assessment (SERRA)》2016,30(3):831-839

Different epidemiological studies have shown that high temperatures are directly related to mortality, furthermore many studies on the effects of climate change on future mortality are being conducted. The objective of this study is to estimate the effect of extreme hot temperatures on daily mortality in Zaragoza (Spain) from 2014 to 2021, utilising various climate-change scenarios. The relationship between temperature and mortality is defined by the concepts of heat wave, threshold temperature and the relative risk of daily deaths according to extreme temperatures in 1987–2006 period. The effect on future mortality is projected by estimating deaths attributable to extreme temperatures in 2014–2021. This estimation was calculated utilising exposure–response functions for three scenarios (A1B, A2 and B1) from the ECHAM5 general circulation model after applying a statistical downscaling technique. Because this study considers the effect of rising temperatures from a health perspective, minimising uncertainty was added to the numerical values obtained from the projected future relation between temperature and mortality. The results shows that expected mortality in Zaragoza will increase by 0.4 % for the period 2014–2021, an excess that can be directly attributed to extreme temperatures. This effect is expected to increase in the 2040s and 2050s until the end of the twenty first century because of a predicted increase in temperatures over this period, with special emphasis on the need to continue studying this line of inquiry and local studies as which arises. Finally, this study will luckily be used to create prevention plans for minimising the effect on health of the high temperatures.  相似文献   

Using beryllium-7 to evaluate soil erosion processes in agricultural lands in semiarid regions of Central Argentina     

Juan Pablo de Rosas  Alexander Dario Esquivel  Diego Martinez Heimann  Agustin E. Negri  Flavia Lohaiza  Diego Leonardo Valladares  Alejandro I. Zavala  Hugo Huck  Jimena Juri Ayub 《Environmental Earth Sciences》2018,77(16):587

This work presents the results of a soil erosion study using the ⁷Be technique. This technique estimates the water erosion/deposition from the comparison between ⁷Be soil content of a reference site and an eroded or sedimented site. The soil samples were collected from an agricultural area of the semiarid region of Argentina near San Luis City, which has a marked rainfall season. The area has been used for crop cultivation, being subjected to plowing practices. The ⁷Be in the Reference Site was in the first centimeter of soil, showing the typical exponential decreasing of ⁷Be soil content with depth, with the ⁷Be inventories value being 340?±?50 Bq m^?2 for the dry season and 571?±?48 Bq m^?2 for the rainy season. The ⁷Be technique was applied to a potential eroded site subjected to traditional tillage practices (plowing). A net soil erosion value of 13.5 t ha^?1 (1.35 kg m^?2) was obtained. From the assumptions of the applied technique, we can draw the inference that this erosion was caused by rains produced in the month prior to the date of soil sampling.  相似文献   

Electron-impact rotational excitation of water     

Alexandre Faure  Jimena D. Gorfinkiel  Jonathan Tennyson 《Monthly notices of the Royal Astronomical Society》2004,347(1):323-333

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Formative pre-Hispanic agricultural soils in northwest Argentina     

María Marta Sampietro Vattuone  Jimena Roldán  Liliana Neder  Marta Amelia Vattuone 《Quaternary Research》2011,75(1):36-44

Our study area is from an early agricultural archaeological site named “El Tolar” (1st to 9th century AD), located in Tafí Valley (Tucumán, northwest Argentina). The objective was to identify geochemical signatures generated by the sustained agrarian use of soils. Chemical and pedological studies were made in different archaeological contexts. Physical and chemical features, such as bulk density, pH, organic and inorganic phosphorus, and available copper, manganese and iron, were taken into account. The results suggested that a buried paleosol identified was contemporary with the occupation of the site. It also showed characteristics clearly related to pre-Hispanic agrarian production. The concentrations of organic phosphorus and iron in agricultural soils probably reflect the use of fertilizers. The application of geoscience techniques allowed us to obtain important information on their behaviour and socio-economic development. This paper constitutes the first pedogeochemical approach to the study of Argentinean pre-Hispanic agricultural soils.  相似文献   

Effect of sulphur species on the hydrocarbon biodegradation of oil sludge generated by a gas processing facility     

J. Reyes-Avila  T. Roldán-Carrillo  G. Castorena-Cortés  I. Zapata-Peñasco  P. Olguín-Lora 《International Journal of Environmental Science and Technology》2013,10(3):551-558

Oily sludge from gas processing facilities contains components that are major environmental pollutants. Biodegradation is an alternative treatment, but can be affected by other components of the sludge, such as sulphur compounds, so it is important to evaluate the effect of these on oil biodegradation in order to prevent negative impacts. This work studied the transformation of sulphur compounds in oily sludge biodegradation systems at the microcosm level. The predominant sulphur compounds in the original sludge were elemental sulphur and pyrite (9,776 and 28,705.4 mg kg^?1, respectively). In the biodegradability assays, hydrocarbon concentrations decreased from 312,705.6 to 186, 760.3 mg kg^?1 after 15 days of treatment. After this time, hydrocarbon degrading activity stopped, corresponding with a decrease in hydrocarbon degrading bacteria. These changes were related to a reduction in pH that inhibits biodegradation. During the assay, sulphur compounds were gradually oxidized and transformed. The concentration of sulphate increased from 5,096 to 64,868.3 mg kg^?1 after 30 days in the assay, although controls were unchanged. Therefore, it is important to determine changes to the main compounds of the waste in order to assess their impact.  相似文献