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Jéssica Bassetto Carra Marciéli Fabris Jeferson Dieckow Osmar Rodrigues Brito Pedro Rodolfo Siqueira Vendrame 《Communications in Soil Science and Plant Analysis》2019,50(4):421-434
Near-infrared (NIR) spectroscopy is a rapid, non-destructive and accurate technique for analyzing a wide variety of samples, thus, the growing interest of using this technique in soil science. The objective of this study was to evaluate the potential of NIR spectroscopy to predict organic carbon (OC), total nitrogen (TN), available phosphorus (P) and available potassium (K) in the soil. NIR spectra from 20 cm3 of soil samples were acquired on the range of 750 to 2500 nm in diffuse reflectance mode, resolution of 16 cm?1 and 64 scans. Eight models of calibration/validation were constructed. Calibration and validation models showed that the predictive potential of NIR varied with the specific soil property (OC, TN, P and K) under evaluation and according to the methodology employed in the model construction (cross-validation or test set). Good prediction models were obtained for OC and TN content based on the statistical parameters. Test set methodology was able to predict soil OC, TN, P, and K better than cross-validation methodology. 相似文献
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David A Feary Morgan S Pratchett Micheal J Emslie Ashley M Fowler Will F Figueira Osmar J Luiz Yohei Nakamura David J Booth 《Fish and Fisheries》2014,15(4):593-615
Climate change is resulting in rapid poleward shifts in the geographical distribution of many tropical fish species, but it is equally apparent that some fishes are failing to exhibit expected shifts in their geographical distribution. There is still little understanding of the species‐specific traits that may constrain or promote successful establishment of populations in temperate regions. We review the factors likely to affect population establishment, including larval supply, settlement and post‐settlement processes. In addition, we conduct meta‐analyses on existing and new data to examine relationships between species‐specific traits and vagrancy. We show that tropical vagrant species are more likely to originate from high‐latitude populations, while at the demographic level, tropical fish species with large body size, high swimming ability, large size at settlement and pelagic spawning behaviour are more likely to show successful settlement into temperate habitats. We also show that both habitat and food limitation at settlement and within juvenile stages may constrain tropical vagrant communities to those species with medium to low reliance on coral resources. 相似文献
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Detecting and determining the validity of local extinctions is an important conservation measure in order to uncover management failures. There are quantitative and qualitative methods that estimate extinction probability based on past sighting records. However, because current baselines about species’ abundances and distributions in the sea were mostly established after humans had started affecting marine populations, researchers must often rely on historical data to elucidate past environmental conditions. We review early historical records from the Archipelago of Saint Paul’s Rocks, together with data from recent expeditions, with the aim of testing the hypothesis that reef sharks (Carcharhinus spp.) have become extinct there. Our analyses are based on non-parametric probabilistic tests for extinction and on a qualitative framework to examine and judge as objectively as possible the likelihood of local extinction. Until the mid-20th century, visitors to St. Paul’s Rocks invariably commented on the remarkable number of sharks around the Archipelago. These observations contrast with those of expeditions carried out during the last decade, which report no carcharhinid reef sharks while scuba diving in the archipelago, despite many more hours of underwater fieldwork than previous expeditions. All quantitative and qualitative methods conclude that the reef shark Carcharhinus galapagensis is locally extinct at St. Paul’s Rocks after a sharp decrease in abundance that took place following the commencement of fishing. However, the persistence of occasional individuals of the once locally common Carcharhinus falciformis in the vicinity of the Archipelago, as a result of constant immigration of this oceanic species from outside the area, suggest that the population might recover if the present fishing pressure was removed. 相似文献
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Tales Tiecher Luiz Gustavo De Oliveira Denardin Amanda Posselt Martins Osmar Henrique Pias Leonardo Rodrigues Nunes Tadeu Luis Tiecher 《Archives of Agronomy and Soil Science》2013,59(14):1998-2012
ABSTRACTThe objective of this study was to evaluate the short-term dynamics of chemical species of sulfate and the main basic cations in the soil solution affected by the application of different sulfur (S) rates using agricultural gypsum. The experiment was carried out in an Ultisol with 14% clay, managed under no-tillage for 14 yrs in Southern Brazil. Four rates of S (0, 5, 10 and 20 kg of S ha?1) were evaluated using agricultural gypsum (CaSO4) as S-source. The soil solution was collected using porous capsule lysimeters before and at 9, 17, 37, 60, 76 and 109 d after the gypsum application, at depths of 20 and 60 cm. Surface application of gypsum rapidly increases the sulfate concentration in the soil solution at 20 cm depth. However, in less than 30 d, the effect of the S rates on the soil solution at 20 cm was minimal, with an increase in sulfate concentration in the soil solution at 60 cm depth after 17 d. Sulfated fertilization via agricultural gypsum at rates greater than 10 kg ha?1 in sandy soil with low cation exchange capacity increased the mobility of Ca and Mg in the soil profile. 相似文献
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Cristiéle S Ribeiro Renata G Moreira Osmar A Cantelmo Elisa Esposito 《Aquaculture Research》2014,45(5):812-827
The purpose of this study was to evaluate the use of single cell proteins (Kluyveromyces marxianus) as fishmeal substitutes for Oreochromis niloticus during long‐term feeding under natural climatic conditions. Juveniles (150) were divided into two groups: the control group, fed with conventional fish diet (T1); and the experimental group, fed with the alternative diet (T2). T1 animals had a higher final weight and per cent weight gain than T2 animals, which we mainly observed in winter and autumn. The lipid content ranged from 1.9% to 3.8% in liver and from 0.2% to 1% in white muscle for both groups. T2 animals had a higher protein concentration in the fillet and the lipid content in this tissue was not altered by diet. Liver and plasma protein content in both groups and the muscle content in T1 decreased during growth. Specific fatty acids (FAs) were selectively retained in fillet phospholipids (PLs), primarily as C22:6n3, which was found at high levels in the PLs of both groups during all seasons. Despite the differences observed, the percentage of polyunsaturated FAs in the fillet was similar throughout the experiment for both diets, reaching approximately 50% of the total FA in the PLs. 相似文献
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Adriana Reatto Ary Bruand Eder de Souza Martins Fabrice Muller Euzebio Medrado da Silva Osmar Abílio de Carvalho Jr. Michel Brossard Guy Richard 《CATENA》2009
Brazilian Latosols are characterized by low activity clay, little horizon differentiation, a weak macrostructure and a strong microgranular structure. The development of the latter that was reported as being possibly related to the fine material mineralogy, location in the landscape, parental material and biological activity is still under discussion. The aim of this study is to discuss the origin of the microgranular structure of Latosols located in the Brazilian Central Plateau. Ten Latosols (L) developed in different parent materials were selected along an approximately 350-km long regional toposequence across the South American Surface (SAS) (L1 to L4) and Velhas Surface (VS) (L5 to L10). The structure of the Latosols was studied in the field and samples of the diagnostic Bw horizons were collected for laboratory analyses. Basic soil characterization was performed on the < 2-mm material according to the Brazilian standard procedures. The SiO2, AL2O3, Fe2O3 and TiO2 content was determined after dissolution with 1:1 H2SO4. The microstructure was studied in optical microscopy and scanning electron microscopy in thin sections. The results showed a varying compound strong microgranular structure and weak to moderate medium sub-angular blocky structure independently of the landscape position as well as the parental material, except for the Latosol developed on a quartzite. The Latosols were classified as gibbsitic-sesquioxidic, kaolinitic non-sesquioxid, or kaolinitic-sesquioxid Latosols but there was no relationship between their composition and the development of the microgranular structure in the Bw horizon. The analyses showed indeed several types of microgranular structure with different proportions but without any relationship with their texture and mineralogy. Actually, the types of microgranular structure appeared to be mainly related to soil bioturbation by termites and eventually secondarily by ants. Thus, the weak macrostructure and strong microgranular structure of the Latosols studied, the little vertical differentiation of the horizons, and the lack of a clear relationship between their landscape position and parent material characteristics would result from long-term biotic action with high probability. 相似文献