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| Registros recuperados: 17 | |
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| Duran Encinas, Yazmin. |
| Crassostrea gigas is a marine invertebrate that inhabits the intertidal zone and therefore, is commonly exposed to multiple environmental stressors, including temperature. In recent years mass mortality events have been reported in Mexico in C. gigas associated with the increase in temperature during the summer. Organisms under thermal stress present an increase in prostaglandins (PG) production by cyclooxygenases (COX), an enzymatic route using arachidonic acid (ARA) present in the phospholipids (FL) of the cell membrane as substrate, but PG can also increase non-enzymatically by reactive oxygen species (ROS) that are produced during increased metabolism. It has been reported that some organisms exposed to stress accumulate a higher concentration of ARA... |
| Tipo: Text |
Palavras-chave: Arachidonic acid; Stress; Phospholipid; Isotope; Mollusk; Temperature; Triglyceride; Prostaglandin. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00620/73193/72387.pdf |
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| Elkins, Lynne J.; Meyzen, Christine M.; Callegaro, Sara; Marzoli, Andrea; Bizimis, Michael. |
| The driving processes responsible for producing the Central Atlantic Magmatic Province, the Large Igneous Province associated with end-Triassic rifting of Pangea, remain largely debated. Because their compositions encompass most of the Central Atlantic basalt spectrum, tholeiites from southern Eastern North America are considered pivotal for identifying magma origins. New(176)Hf/Hf-177 measurements for 201 Ma Eastern North American tholeiites dominantly record a local petrogenetic history. Their epsilon(Hf)ratios, corrected to an emplacement age of 201 Ma (-7.85 to +5.86), form a positive but shallowly sloped array slightly deviating from the terrestrial array on a epsilon(Hf)versus epsilon(Nd)diagram. Comparison of(176)Hf/Hf-177 to other isotope ratios... |
| Tipo: Text |
Palavras-chave: Basalt; CAMP; Hafnium; Rift; LIP; Isotope. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00687/79862/82716.pdf |
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| Ratie, G.; Quantin, C.; Maia De Freitas, A.; Echevarria, G.; Ponzevera, Emmanuel; Garnier, J.. |
| Ultramafic derived soils are characterized by low nutrient soils, a low Ca:Mg ratio, and high metal contents such as Ni, Co and Cr. The vegetation growing on these soils is highly adapted and includes both Ni hyperaccumulator and accumulator species. Today, approximately 530 Ni hyperaccumulator species are listed worldwide and the Ni concentration can be extremely high, e.g. up to 25% in latex from Pycnandra acuminata (Sapotaceae), a tree found in New Caledonia. The aim of this study is to identify the potential role of Ni hyperaccumulator plants in the Ni biogeochemical cycle at the soil surface by using Ni isotopes. A set of Ni hyperaccumulator and Ni accumulator plants as well as topsoils were sampled on the Barro Alto and Niquelândia ultramafic... |
| Tipo: Text |
Palavras-chave: Nickel; Isotope; Ni hyperaccumulator species; Ultramafic environment. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00464/57565/59740.pdf |
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| Ratie, G.; Jouvin, D.; Garnier, Julien; Rouxel, Olivier; Miska, S.; Guimaraes, E.; Cruz Vieira, L.; Sivry, Y.; Zelano, I.; Montarges-pelletier, E.; Thil, F.; Quantin, C.. |
| Although Ni isotopes have been shown to be significantly fractionated in terrestrial samples, their use in continental environmental studies has not yet been evaluated. The present study focuses on an ultramafic (UM) massif (Barro Alto, Goias, Brazil) because such areas are naturally rich in Ni. We present developed lateritic weathering profiles. The goal of the study is to evaluate the potential of using Ni isotopes in environmental continental studies by combining its isotopic signature with mineralogy, in order to better understand the geochemical cycling of Ni in UM settings during weathering. As such, Ni isotope values were measured in samples from the Barro Alto UM complex in the main stages of the lateritic weathering profile of UM rocks, including... |
| Tipo: Text |
Palavras-chave: Nickel; Isotope; Weathering; Mineralogy; Soil. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00254/36553/35098.pdf |
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| Moleana, Thibaud; Della Patrona, Luc; Meziane, Tarik; Letourneur, Yves. |
| Background Most of the 29 Siganidae species are widely distributed through the Indo-Pacific area. In New Caledonia, these family was represented by 12 species. The present report is the first record of Siganus randalli in New Caledonian waters and provide information on its diet. Methods Three specimens of Siganus randalli were caught in shallow mangrove waters of the southern part of New Caledonia. Their stomach contents and isotopic signatures (carbon and nitrogen) were analyzed and compared to others siganids species. Results and conclusion This note provides the most southerly record of the rabbitfish Siganus randalli, which extends its distribution range by 1200 km southward and 1300 km southwest. The data on its diet, when compared with other... |
| Tipo: Text |
Palavras-chave: Variegated rabbitfish; Diet; Stomach content; Isotope; SW pacific. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00350/46161/45859.pdf |
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| Zheng, Li-wei; Hsiao, Silver Sung-yun; Ding, Xiao-dong; Li, Dawei; Chang, Yuan-pin; Kao, Shuh-ji. |
| Total organic carbon to total nitrogen ratios (C/N) and their isotopic compositions (δ13CTOC and δ15NTN) are oft-applied proxies to discern terrigenous from marine-sourced organics and to unravel ancient environmental information. In high depositional Asian marginal seas, the inclusion of N-bearing minerals in the bulk sediment dilutes or masks signals sought after in δ15N and δ13C analyses, thus leading to incorrect and even contradictory interpretations. We used KOH-KOBr to separate operationally defined total organic matter into oxidizable (labile) and residual fractions for content and isotope measurements. In a sediment core in the Okinawa Trough, significant amounts of carbon and nitrogen existed in the residual phase, in which the C/N ratio was ~9,... |
| Tipo: Text |
Palavras-chave: Carbon; Nitrogen; Isotope; Okinawa Trough; Sediment; Total organic carbon. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00295/40584/39503.pdf |
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| Chauvaud, Laurent; Lorrain, Anne; Dunbar, Robert; Paulet, Yves; Thouzeau, Gérard; Jean, Frédéric; Guarini, Jean-marc; Mucciarone, David. |
| We investigate the environmental and biological controls on oxygen isotope ratios in the shells of modern Pecten maximus bivalves collected alive in the Bay of Brest (France). Seasonal delta(18)O profiles, obtained by drilling the daily calcite ridges deposited at the surface of the left valve, were compared with in situ measurements of temperature and salinity. We show that P. maximus delta(18)O values accurately track seasonal variations in bottom water temperature. Shell growth rate has no significant effect on shell delta(18)O values. Our study demonstrates that daily variations in water temperature can be reconstructed within about 0.5 degrees C. Temperatures estimated with the paleotemperature equation established in this study were compared with... |
| Tipo: Text |
Palavras-chave: Pecten Maximus; Brittany; Paleoenvironment; Estimation; Daily varition; Water temperature; Isotope; Calcite; Shell; Ëecten maximus; Paleotempérature; Variation saisonnière; Température eau; Strie croissance; Isotope; Coquille. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-643.pdf |
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| Ratie, G.; Quantin, C.; Jouvin, D.; Calmels, D.; Ettler, V.; Sivry, Y.; Cruz Vieira, L.; Ponzevera, Emmanuel; Garnier, J.. |
| Nickel isotope ratios were measured in ores, fly ash, slags and FeNi samples from two metallurgical plants located in the Goiás State, Brazil (Barro Alto, Niquelândia). This allowed investigating the mass-dependent fractionation of Ni isotopes during the Ni-laterite ore smelting and refining. Feeding material exhibits a large range of δ60Ni values (from 0.02 ± 0.10 ‰ to 0.20 ± 0.05 ‰, n=7), explained by the diversity of Ni-bearing phases, and the average of δ60Nifeeding materials was found equal to 0.08 ± 0.08‰ (2SD, n=7). Both δ60Ni values of fly ash (δ60Ni = 0.07 ± 0.07‰, n=10) and final FeNi produced (0.05 ± 0.02 ‰, n=2) were not significantly different from the feeding materials ones. These values are consistent with the very high production yield of... |
| Tipo: Text |
Palavras-chave: Nickel; Isotope; Smelting; Refining; Source; Soil. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00278/38961/37501.pdf |
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| Karr, Jd; Showers, Wj. |
| A detailed hydrographic survey of the water column of the Amazon shelf was performed using stable oxygen and hydrogen isotopes to determine the source and fate of waters on the shelf. delta(18)O-H2O and deltaD measurements were made on water column samples from approximately 60 stations (three depths per station) which were each collected during four Amasseds (A Multidisciplinary Amazon Shelf SEDiment Study) cruises: I8909-August 1989, falling river discharge; I9002-March 1990, rising river discharge; I9004-May 1990, peak discharge: I9113-November 1991, minimum discharge. Isotopes were compared with salinity and temperature measurements in order to identify water masses and mixing. The characteristics (salinity, temperature, delta(18)O, deltaD and d) are... |
| Tipo: Text |
Palavras-chave: Amazone; Isotopes; 18O; Deutérium; Hydrologie; Amazon; Isotope; O-18; Deuterium; Hydrography. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/00322/43321/42933.pdf |
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| Xie,Zhijian; He,Yaqin; Xu,Changxu; Tu,Shuxin. |
| Abstract Nicotine concentration is a key index and directly affects the industrial quality and availability of flue-cured tobacco (FCT). Seedlings transplanted at different times were subjected to different climatic conditions, which were closely correlated with the growth, development, and nicotine synthesis of FCT. An appropriate transplanting time is imperative for ensuring high-quality tobaccos. Hence, a 15N tracing experiment in the field (which included three treatments: FCT seedlings transplanted on 5th, 15th, and 25th May) was carried out to evaluate the influence of different transplanting dates on 15N utilization and nicotine concentration in FCT leaves. Results showed that compared to the tobacco seedlings transplanted on 5th May, the seedlings... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Cash crop; Agronomy measurement; Nicotine; Nutrient use efficiency; Isotope. |
| Ano: 2017 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832017000100534 |
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| Registros recuperados: 17 | |
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