A cross-system analysis of sedimentary organic carbon in the mangrove ecosystems of Xuan Thuy National Park, Vietnam   总被引：1，自引：0，他引：1  

Nguyen Tai Tue  Nguyen Thi NgocTran Dang Quy  Hideki HamaokaMai Trong Nhuan  Koji Omori 《Journal of Sea Research》2012,67(1):69-76

A cross-system analysis of bulk sediment composition, total organic carbon (TOC), atomic C/N ratio, and carbon isotope composition (δ¹³C) in 82 surface sediment samples from natural and planted mangrove forests, bank and bottom of tidal creeks, tidal flat, and the subtidal habitat was conducted to examine the roles of mangroves in sedimentation and organic carbon (OC) accumulation processes, and to characterize sources of sedimentary OC of the mangrove ecosystem of Xuan Thuy National Park, Vietnam. Sediment grain sizes varied widely from 5.4 to 170.2 μm (mean 71.5 μm), with the fine sediment grain size fraction (< 63 μm) ranging from 11 to 99.3% (mean 72.5%). Bulk sediment composition suggested that mangroves play an important role in trapping fine sediments from river outflows and tidal water by the mechanisms of tidal current attenuation by vegetation and the ability of fine roots to bind sediments. The TOC content ranged from 0.08 to 2.18% (mean 0.78%), and was higher within mangrove forests compared to those of banks and bottoms of tidal creeks, tidal flat, and subtidal sediments. The sedimentary δ¹³C ranged from − 27.7 to − 20.4‰ (mean − 24.1‰), and mirrored the trend observed in TOC variation. The TOC and δ¹³C relationship showed that the factors of microbial remineralization and OC sources controlled the TOC pool of mangrove sediments. The comparison of δ¹³C and C/N ratio of sedimentary OC with those of mangrove and marine phytoplankton sources indicated that the sedimentary OC within mangrove forests and the subtidal habitat was mainly composed of mangrove and marine phytoplankton sources, respectively. The application of a simple mixing model showed that the mangrove contribution to sedimentary OC decreased as follows: natural mangrove forest > planted mangrove forest > tidal flat > creek bank > creek bottom > subtidal habitat.  相似文献   

CH₄/N₂/H₂ spark hydrophilic tholins: A systematic approach to the characterization of tholins     

Marta Ruiz-Bermejo  César Menor-Salván  Susana Osuna-Esteban  Sabino Veintemillas-Verdaguer 《Icarus》2008,198(1):232-241

Tholins are complex organic materials produced by irradiation of several carbon and nitrogen rich atmospheres. They could have played a key role in the origin of life on Earth because their ability to release important bioorganics, which are nowadays present in proteins, nucleic-acid bases and other important biostructures. Usually, the yield of these compounds is higher after acid hydrolysis, however little is known about the structure and chemical composition of the tholins. In this work, we propose the use of different spectroscopic and separation techniques, which are not usually applied in this field, in order to obtain complete information about the tholin structure and behavior. Two different simulation experiments of prebiotic synthesis were carried out in CH₄/N₂/H₂ atmosphere out from spark discharge activation of aqueous aerosols and liquid water, respectively. In both cases, a hydrophilic tholin and a hydrophobic tholin were obtained. Herein, we report the application of this methodology to our hydrophilic tholins and we review, briefly, some astrobiological aspects related to these complex substances.  相似文献   

Characteristics and Fertilizer Effects of Soil‐Like Materials from Landfill Mining          下载免费PDF全文

Chuanbin Zhou  Wanying Xu  Zhe Gong  Wenjun Fang  Aixin Cao 《洁净——土壤、空气、水》2015,43(6):940-947

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Effect of Nitrogen Management on Soil Microbial Community and Enzymatic Activities in Jatropha curcas L. Plantation          下载免费PDF全文

Doongar Ram Chaudhary  Ritesh Kumar Gautam  Arup Ghosh  Jitendra Chikara  Bhavanath Jha 《洁净——土壤、空气、水》2015,43(7):1058-1065

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Fish biological effect monitoring of chemical stressors using a generalized linear model in South Sea,Korea     

《Marine pollution bulletin》2014,78(1-2):230-234

To evaluate the health status at six different study areas, we used the generalized linear model approach with selected biochemical markers in resident fish from uncontaminated and contaminated sites. We also confirmed the independence between the biochemical indices and the morphometric indices including the hepato-somatic index (HSI), gonado-somatic index (GSI), and condition factor (CF) in fish from the sampling areas. The effect of area on the presence of biotransformation markers (ethoxyresorufin-O-deethylase activity; EROD) was significantly high in Masan Bay. The area with the greatest effect on acetylcholinesterase (AChE) activity was Jindong Bay, while there was no significant effect of GSI, HSI, CF, and sex in the EROD model and HSI, CF and sex in the AChE model. These results clarify that fish from Masan, Gwangyang and Jindong Bay were affected by pollutant stress, and the analysis of sensitive biochemical responses allowed for an improved interpretation of the results.  相似文献   

The inversion of density structure by graphic processing unit (GPU) and identification of igneous rocks in Xisha area          下载免费PDF全文

Lei Yu  Jian Zhang  Wei Lin  Rongqiang Wei  Shiguo Wu 《地震科学（英文版）》2014,27(1):117-125

Organic reefs, the targets of deep-water petroleum exploration, developed widely in Xisha area. However, there are concealed igneous rocks undersea, to which organic rocks have nearly equal wave impedance. So the igneous rocks have become interference for future exploration by having similar seismic reflection characteristics. Yet, the density and magnetism of organic reefs are very different from igneous rocks. It has obvious advantages to identify organic reefs and igneous rocks by gravity and magnetic data. At first, frequency decomposition was applied to the free-air gravity anomaly in Xisha area to obtain the 2D subdivision of the gravity anomaly and magnetic anomaly in the vertical direction. Thus, the distribution of igneous rocks in the horizontal direction can be acquired according to high-frequency field, low-frequency field, and its physical properties. Then, 3D forward modeling of gravitational field was carried out to establish the density model of this area by reference to physical properties of rocks based on former researches. Furthermore, 3D inversion of gravity anomaly by genetic algorithm method of the graphic processing unit (GPU) parallel processing in Xisha target area was applied, and 3D density structure of this area was obtained. By this way, we can confine the igneous rocks to the certain depth according to the density of the igneous rocks. The frequency decomposition and 3D inversion of gravity anomaly by genetic algorithm method of the GPU parallel processing proved to be a useful method for recognizing igneous rocks to its 3D geological position. So organic reefs and igneous rocks can be identified, which provide a prescient information for further exploration.  相似文献   

The Degradation of Natural Organic Matter in Surface Water by a Nano‐TiO2/Diatomite Photocatalytic Reactor          下载免费PDF全文

Wen Sun  Huaqiang Chu  Dawen Cao  Shuilin Zheng 《洁净——土壤、空气、水》2014,42(9):1190-1198

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The inversion of density structure by graphic processing unit （GPU） and identification of igneous rocks in Xisha area   总被引：1，自引：0，他引：1  

Lei Yu  Jian Zhang  Wei Lin  Rongqiang Wei  Shiguo Wu 《地震学报(英文版)》2014,(1):117-125

Organic reefs, the targets of deep-water petroleum exploration, developed widely in Xisha area. However, there are concealed igneous rocks undersea, to which organic rocks have nearly equal wave impedance. So the igneous rocks have become interference for future exploration by having similar seismic reflection characteristics. Yet, the density and magnetism of organic reefs are very different from igneous rocks. It has obvious advantages to identify organic reefs and igneous rocks by gravity and magnetic data. At first, frequency decomposition was applied to the free-air gravity anomaly in Xisha area to obtain the 2D subdivision of the gravity anomaly and magnetic anomaly in the vertical direction. Thus, the distribution of igneous rocks in the horizontal direction can be acquired according to high-frequency field, low-frequency field, and its physical properties. Then, 3D forward modeling of gravitational field was carried out to establish the density model of this area by reference to physical properties of rocks based on former researches. Furthermore, 3D inversion of gravity anomaly by genetic algorithm method of the graphic processing unit(GPU) parallel processing in Xisha target area was applied, and 3D density structure of this area was obtained. By this way, we can confine the igneous rocks to the certain depth according to the density of the igneous rocks. The frequency decomposition and 3D inversion of gravity anomaly by genetic algorithm method of the GPU parallel processing proved to be a useful method for recognizing igneous rocks to its 3D geological position. So organic reefs and igneous rocks can be identified, which provide a prescient information for further exploration.  相似文献   

Recent surface marine sediments of Cocos Island in Costa Rica     

Jeffrey A.SIBAJA-CORDERO  Jesús S.TRONCOSO  Eddy GóMEZ-RAMíREZ 《国际泥沙研究》2014,29(1):59-72

Subtidal sediments of Isla del Coco(Cocos Island),Costa Rica were described in their grain size,sorting,organic matter,and carbonates from 27 dredge samples(3-75 m),collected in April 2010.The organic matter range between 1.37-3.31%and carbonates presented a mean of 74±17%.The sorting was moderately or poorly.The grain size ranged between 0.1-1.1mm.The pattern is that sediment change from inner to mouth of bays.Carbonates and gravel fractions increased offshore and organic matter have high values inner the bays.Input of vegetal debris and mud was from the rivers of this island covered with rain and cloud forest.  相似文献   

Identifying the Chemical Composition of Decomposed Residues From Cyanobacterial Bloom Biomass by Pyrolysis‐GC/MS          下载免费PDF全文

Xin Liu  Rui He  Yuan Shi  Zaisheng Yan  Changhui Wang  Helong Jiang 《洁净——土壤、空气、水》2016,44(12):1636-1643

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