Evaluation of Soil Re-mineralizer from By-Product of Volcanic Rock Mining: Experimental Proof Using Black Oats and Maize Crops     

Ramos  Claudete Gindri  dos Santos de Medeiros  Diego  Gomez  Leandro  Oliveira  Luis Felipe Silva  Schneider  Ivo André Homrich  Kautzmann  Rubens Muller 《Natural Resources Research》2020,29(3):1583-1600

Natural Resources Research - This study was focused on physical, petrographical, mineralogical, and chemical characterization of a volcanic-rock mining by-product (dacite rock), as well as on...  相似文献   

Trophic modeling of the Northern Humboldt Current Ecosystem, Part I: Comparing trophic linkages under La Niña and El Niño conditions   总被引：1，自引：1，他引：0  

Jorge Tam  Marc H. Taylor  Vernica Blaskovic  Pepe Espinoza  R. Michael Balln  Erich Díaz  Claudia Wosnitza-Mendo  Juan Argüelles  Sara Purca  Patricia Ayn  Luis Quipuzcoa  Dimitri Gutirrez  Elisa Goya  Noemí Ochoa  Matthias Wolff 《Progress in Oceanography》2008,79(2-4):352

The El Niño of 1997–98 was one of the strongest warming events of the past century; among many other effects, it impacted phytoplankton along the Peruvian coast by changing species composition and reducing biomass. While responses of the main fish resources to this natural perturbation are relatively well known, understanding the ecosystem response as a whole requires an ecotrophic multispecies approach. In this work, we construct trophic models of the Northern Humboldt Current Ecosystem (NHCE) and compare the La Niña (LN) years in 1995–96 with the El Niño (EN) years in 1997–98. The model area extends from 4°S–16°S and to 60 nm from the coast. The model consists of 32 functional groups of organisms and differs from previous trophic models of the Peruvian system through: (i) division of plankton into size classes to account for EN-associated changes and feeding preferences of small pelagic fish, (ii) increased division of demersal groups and separation of life history stages of hake, (iii) inclusion of mesopelagic fish, and (iv) incorporation of the jumbo squid (Dosidicus gigas), which became abundant following EN. Results show that EN reduced the size and organization of energy flows of the NHCE, but the overall functioning (proportion of energy flows used for respiration, consumption by predators, detritus and export) of the ecosystem was maintained. The reduction of diatom biomass during EN forced omnivorous planktivorous fish to switch to a more zooplankton-dominated diet, raising their trophic level. Consequently, in the EN model the trophic level increased for several predatory groups (mackerel, other large pelagics, sea birds, pinnipeds) and for fishery catch. A high modeled biomass of macrozooplankton was needed to balance the consumption by planktivores, especially during EN condition when observed diatoms biomass diminished dramatically. Despite overall lower planktivorous fish catches, the higher primary production required-to-catch ratio implied a stronger ecological impact of the fishery and stresses the need for precautionary management of fisheries during and after EN. During EN energetic indicators such as the lower primary production/total biomass ratio suggest a more energetically efficient ecosystem, while reduced network indicators such as the cycling index and relative ascendency indicate of a less organized state of the ecosystem. Compared to previous trophic models of the NHCE we observed: (i) a shrinking of ecosystem size in term of energy flows, (ii) slight changes in overall functioning (proportion of energy flows used for respiration, consumption by predators and detritus), and (iii) the use of alternate pathways leading to a higher ecological impact of the fishery for planktivorous fish.  相似文献   

DNA strand breaks in grass shrimp embryos exposed to highway runoff sediments and sediments with coal fly ash     

Lee RF  Niencheski LF  Brinkley K 《Marine environmental research》2008,66(1):164-165

Embryo production was reduced in female grass shrimp exposed to sediments with added coal fly ash and to sediments collected from an estuarine station containing high PAH concentrations due to its proximity to a highway storm drain. Grass shrimp embryos exposed to pore water from the high PAH and high metal sediments showed both reduced hatching and increases in DNA strand breaks (comet assay). Sediments with added coal fly ash had high concentrations of vanadium and selenium which may have contributed to effects similar to those observed with sediments with high PAH. The embryo pore water bioassay (hatching/DNA strand breaks) gave results comparable to those observed for reproduction effects (reduced embryo production/embryo hatching) with female grass shrimp exposed to whole sediment.  相似文献   

Safety level of damaged RoPax ships: Risk modelling and cost-effectiveness analysis     

Luis Guarin  Dimitris Konovessis  Dracos Vassalos 《Ocean Engineering》2009,36(12-13):941-951

This paper elaborates on results of a recent risk analysis study for RoPax vessels, carried out as part of the activities of the SAFEDOR Integrated Project, targeting possible improvements on safety levels following large scale flooding. The study is based on a comprehensive analysis of accident statistics for the period 1994–2004, through which a high-level risk model (in the form of event trees) is established. This is then used to determine the current safety level of RoPax vessels (in various risk metrics, such as individual risk, potential loss of life and on an F–N curve), reconfirming that even though safety levels are improving, risk is still “high in the ALARP region”. In search of ways to further improve the situation possible risk control options are examined, by performing a sensitivity analysis on the effects of the Attained Index of Subdivision A onto the safety levels and by evaluating their cost-effectiveness.  相似文献   

Humic substances in estuarine soils colonized by Spartina maritima     

Cristina Santín  Martha Gonzlez-Prez  Xos Luis Otero  Miguel ngel lvarez  Felipe Macías 《Estuarine, Coastal and Shelf Science》2009,81(4):481-490

This study characterizes humic substances (HS) from two soils colonized by Spartina maritima at different physiographical positions in estuarine environments on the north-western coast of the Iberian Peninsula: the Villaviciosa site, a stand close to the main tidal channel, and the Ortigueira site, located in the low salt marsh. Humic and fulvic acids were extracted from the soils and characterized qualitatively by the following spectroscopic techniques: Fourier transform infrared spectroscopy, fluorescence spectroscopy and solid-state ¹³C nuclear magnetic resonance.The characterized HS showed a predominance of low humified compounds with a high proportion of aliphatic components and a low degree of aromaticity. The HS composition differed substantially between sites. In the Villaviciosa soil, the large amount of nonpolar aliphatic components and the very low degree of aromaticity may indicate a significant contribution of marine organic matter and/or microbial material to the HS. However, in the HS from the Ortigueira soil, the higher proportion of polysaccharides together with the presence of lignin-derived compounds may indicate greater inputs of vascular plant material. The δ¹³C isotopic composition of the bulk soils highlights the large input of Spartina maritima debris to the Ortigueira site, whereas in the Villaviciosa site, organic contributions from this C4 vascular plant were not so evident.The results indicate that in these soils colonized by Spartina maritima, physiographical position has an important effect on the composition of soil HS and, therefore, must be considered in the study of organic matter characteristics in such estuarine environments.  相似文献   

Distributions of dissolved vitamin B₁₂ and Co in coastal and open-ocean environments     

Caterina Panzeca  Aaron J. Beck  Antonio Tovar-Sanchez  Jose Segovia-Zavala  Gordon T. Taylor  Christopher J. Gobler  Sergio A. Saudo-Wilhelmy 《Estuarine, Coastal and Shelf Science》2009,85(2):223-230

Distributions of dissolved vitamin B₁₂ and total dissolved Co were measured to gain an understanding of the cycling of these interdependent micronutrients in six marine settings including; an upwelling location, a semi-enclosed bay, two urban coastal systems, and two open ocean locations. Along the coast of Baja California, Mexico, concentrations of B₁₂ and dissolved Co varied from 0.2 to 11 pM and 180 to 990 pM, respectively. At a nearby upwelling station, vitamin B₁₂ and Co concentrations ranged from 0.3 to 7.0 pM and 22 to 145 pM, and concentrations did not correlate with upwelling intensity. Concentrations of B₁₂ were highest within Todos Santos Bay, a semi-enclosed bay off the coast of Baja California, Mexico, during a dinoflagellate bloom, ranging from 2 to 61 pM, while Co concentrations varied between 61 and 194 pM. In the anthropogenically impacted Long Island Sound, NY, U.S.A., B₁₂ levels were between 0.1 and 23 pM and Co concentrations varied from 60 to 1900 pM. However, anthropogenic inputs were not evident in B₁₂ levels in the San Pedro Basin, located outside Los Angeles, Ca, U.S.A., where concentrations of B₁₂ were 0.2–1.8 pM, approximating observed open ocean B₁₂ concentrations. In the Southern Ocean and North Atlantic Ocean, B₁₂ levels were 0.4–4 pM and 0.2–2 pM, respectively. Total Co concentrations in the Southern Ocean and North Atlantic tended to be low; measuring 26–59 pM and 15–80 pM, respectively. These low Co concentrations may limit B₁₂ synthesis and its availability to B₁₂-requiring phytoplankton because the total dissolved Co pool is not necessarily entirely bioavailable.  相似文献   

The relationship of anchovy and sardine to water masses in the Peruvian Humboldt Current System from 1983 to 2005   总被引：6，自引：1，他引：6  

Gordon Swartzman  Arnaud Bertrand  Mariano Gutirrez  Sophie Bertrand  Luis Vasquez 《Progress in Oceanography》2008,79(2-4):228

The Humboldt Current System (HCS) is dominated by two pelagic species; Peruvian anchovy or anchoveta (Engraulis ringens) and sardine (Sardinops sagax). Using data from 43 acoustic surveys conducted from 1983 through 2005 by the Peruvian Marine Institute (IMARPE), we examined the distribution of these two species relative to water masses. We tested the hypothesis that anchovy was found more frequently in upwelled cold coastal water (CCW) and mixed waters (MCW) than in other water types and that sardine was more associated with more offshore oceanic surface subtropical water (SSW). Surface temperature, salinity, latitude, season and distance to the coast data were used to define water masses. Results using generalized additive models (GAM), modelling sardine and anchovy presence–absence as a function of year, water body, bottom depth and latitude, showed that anchovy were primarily found in CCW and MCS, while sardine were more ubiquitous relative to water masses with some predilection for SSW. These results were supported by various indexes of anchovy and sardine distribution versus water mass as well as temporal and location variables.  相似文献   

Single-beam acoustic ground discrimination of shallow water habitats: 50 kHz or 200 kHz frequency survey?     

Rosa Freitas  Ana Maria Rodrigues  Edward Morris  Jose Lucas Perez-Llorens  Victor Quintino   《Estuarine, Coastal and Shelf Science》2008,78(4):613-622

The single-beam acoustic ground discrimination system QTC View, Series V, was used in the Bay of Cadiz, Southwest Spain, for the identification and mapping of the bottom acoustic diversity. The acoustic data were obtained through two successive surveys, each conducted with one of the following echo sounder frequencies: 50 kHz and 200 kHz. The performance of each survey frequency for the identification of the sedimentary gradients was analyzed. The surveys were conducted during high tide given that the majority of the surveyed area is shallower than 5 m, although depth may occasionally reach 20 m in specific areas located in a navigation channel. The acoustic data obtained at the two different frequencies were, individually, submitted to manual clustering and a final solution consisting of three acoustic classes was reached for both datasets. However, only the geographical distribution of the acoustic classes obtained with 50 kHz echo sounder frequency was coincident with the spatial distribution of the superficial sediment groups (silty medium sand, very silty fine sand and mud), identified through multivariate analysis of the grain-size data of ground-truth sediment samples. The results obtained with the 200 kHz echo sounder frequency did not match the sedimentary gradients obtained for the area surveyed, not even the separation of muddy and sandy areas.  相似文献   

Dissolved copper speciation behaviour during estuarine mixing in the San Simon Inlet (wet season,Galicia). Influence of particulate matter     

Juan Santos-Echeandia  Luis M. Laglera  Ricardo Prego  Constant M.G. van den Berg 《Estuarine, Coastal and Shelf Science》2008

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Numerical modeling of nonlinear resonance of semi-enclosed water bodies: Description and experimental validation   总被引：1，自引：0，他引：1  

Inigo J. Losada  Jose M. Gonzalez-Ondina  Gabriel Diaz-HernandezErnesto M. Gonzalez 《Coastal Engineering》2008

The purpose of this work is to a present a numerical model to solve a set of modified Boussinesq equations to analyse nonlinear resonance of semi-enclosed water bodies. The equations are solved on a finite element unstructured grid in order to achieve an optimal mesh resolution with the local geometry. The model is able to simulate long time lapses and realistic forcing in real bathymetries with a reasonable computational cost. To validate the numerical results, a set of experiments was carried out in a physical model of two adjacent elongated basins. Comparisons between numerical and experimental results for different geometries and nonlinear conditions show that the model is able to simulate with an excellent agreement the transient nonlinear resonant process.  相似文献