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海洋沉积物作为生源要素氮的重要源与汇，在其生物地球化学循环中起着至关重要的作用。该项研究旨在查清海洋沉积物中氮的存在形态及其生态学意义。氮是生物生命活动必需的营养要素，海洋中的氮往往是海洋初级生产力的限制因子，氮的吸收与再生释放在估算海洋新生产力和生源要素的生物地球化学循环率上也有重要贡献。海洋沉积物中的氮作为海水中氮的重要供给源是海洋生物赖以生存的重要物质基础，对维持海洋生态平衡、修复失衡的海洋生态环境具有重要意义。但由于不同海区海洋沉积物的来源和环境不同，氮的形态和含量亦不相同，可被生物吸收和利用的数量就不相同，因此造成了不同海区生物种群和环境不同，进而影响生态环境。因此，研究海洋沉积物中氮的形态，了解各个形态与沉积物中生物种群及与环境的关系，确定其生物和化学活性，査清氮不同形态的生态学功能，对于深入探讨海洋生物资源可持续利用的方法和策略具有重要意义。本文主要阐述海洋沉积物中氮的存在形式与分布、氮的早期成岩和去营养化作用、硝化和反硝化作用以及氮与生物特定种群的关系等，探讨了影响海洋沉积物中的氮循环的主要因素，并分析了海洋沉积物中的氮与生态系的关系，以期对研究氮的海洋生物地球化学过程有所帮助。 相似文献
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70年来中国化学海洋学研究的主要进展 总被引：5，自引：3，他引：2
我国的海洋化学工作者通过70年来，特别是近30年来的化学海洋学研究，实现了我国与世界先进水平进入同步发展的快车道，其显著的特点是:(1)化学海洋学研究从元素地球化学分布系统转向了以揭示深层次海洋生物地球化学过程为核心的研究；(2)化学海洋学研究实现了多领域、多视点的综合交叉研究；(3)更加关注了人为影响与自然变化共同作用下的海洋生态环境变化研究，对近海和海岸带而言，更加注重从海陆统筹一体化角度探析化学物质的分布迁移特征。本文从生源要素的海洋生物地球化学过程、微/痕量元素与同位素的海洋化学研究、生物过程作用下的化学海洋学过程等角度，重点总结归纳和分析了30年来我国海洋化学研究的重要进展和发展状况，以期对化学海洋学的进一步研究提供借鉴和启迪。 相似文献
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揭示以碳为核心海洋生源要素的海洋生物地球化学过程是全球变化重大国际计划IGBP中的GLOBEC ,LOICZ ,JGOFS ,SOLAS核心科学问题 ,其科学意义不仅会使人类对自然科学规律的认识有重大突破 ,而且将对解决人类面临的人口、资源、环境的重大科学问题产生巨大影响 .因此 ,近年来 ,作为地学学科前沿和与国家资源环境息息相关的海洋生物地球化学过程研究得到了迅速发展 ,其研究具有重要的科学意义 .为顺应这一趋势由中国科学院海洋研究所宋金明博士完成的 80余万字的我国第一部海洋生物地球化学研究专著———《中国近海生物地球化学》… 相似文献
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氮(N)是生物生命活动的基本营养元素，N循环是整个生物圈物质和能量循环的重要组成部分。近几十年来，环境和资源问题的日益突出促进了人们对海洋生态系统的研究及对海洋资源的开发和利用，海洋中的N循环亦受到了广泛关注。尤其是20世纪90年代以来，随着国际地圈与生物圈计划(IGBP)、全球海洋通量联合研究(JGOFS)、全球海洋生态系统动力学研究(GLOBEC)等重大国际合作计划的实施，海洋中的N循环研究取得了重大进展。
本文主要对海洋沉积物中的N循环过程进行了阐述，包括海洋沉积物中N的生物地球化学循环(海洋中N与生物生产过程的关系、早期成岩作用及N的去营养化、沉积物中N循环及其控制机制、颗粒N的形成及其功能、N与其他生源要素循环的关系)及沉积物中N循环的研究方法等，以期对进一步开展N循环的研究有所帮助。 相似文献
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宋金明,男,1964年4月出生,河北枣强人,汉族。1985年毕业于长春地质学院（现长春科技大学）,其后在中国科学院海洋研究所获得海洋学硕士和博士学位。现任中国科学院海洋研究所海洋化学研究室副主任、研究员,并兼任中国海洋湖沼学会海洋化学分会常务理事兼秘书长。多年来,宋金明研究员一直从事海洋生物地球化学及海洋沉积物一海水界面化学研究,主持和参与完成的有国家自然科学基金项目、中国科学院重大项目、国家攻关项目等7项,正在进行研究的有国家海洋863项目、国家九五攻关项目等5项,涉及生源要素的海洋生物地球化学过程、海洋生… 相似文献
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海洋沉积物/颗粒物在生源要素循环中的作用及生态学功能 总被引：2，自引：1，他引：1
海洋沉积物/颗粒物是生源要素循环过程中的关键源与汇，沉积物/颗粒物一方面是海水生源要素的主要归宿，生源要素从溶解态经复杂的生物-化学过程转变为颗粒态，颗粒物质再沉降形成沉积物，另一方面，海洋沉积物/颗粒物经过微生物-浮游动物-底栖生物作用分解形成溶解态的生源要素，并释放到海水中再次被浮游植物利用，进入下一轮循环，所以，海洋沉积物/颗粒物具有异常重要的生态学功能。浮游植物是海水溶解态生源要素的利用者和海源颗粒态生源要素的初始形成者，浮游动物通过摄食浮游植物或其他有机颗粒物可释放出溶解态生源要素或形成更大的颗粒物，颗粒物沉降后形成的沉积物又通过底栖生物摄食-扰动-破碎等过程将颗粒生源要素释放进入水体参与再循环。生态系统不同类群的生物在颗粒生源要素的释放-沉降中所起的作用不同而又相互关联，其中浮游动物-底栖生物的摄食与代谢、微生物参与的分解过程起着非常重要的作用。所以，海洋沉积物/颗粒物生态学功能研究作为支撑海洋环境和资源的持续利用的科学基础，已成为海洋科学的前沿领域，必将获得跨越发展。 相似文献
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海洋生物对二甲基硫生产的控制作用研究 总被引：1，自引：0，他引：1
二甲基硫(DMS)是参与全球硫循环的最主要的海洋生源硫化物,对全球气候变化和环境酸化产生重要影响.海洋中DMS的产生是一个极为复杂的生物学和生态学过程,主要涉及的生物过程包括浮游植物病毒感染、浮游动物摄食和DMSP裂解酶的活动.根据海洋生物活动在二甲基硫的全球生物地球化学循环中所起着的重要作用,作者综述了国际海洋科学工作者十几年来在DMS生物生产过程研究方面的进展. 相似文献
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海水中二甲基硫的光化学氧化研究 总被引：3，自引：0，他引：3
二甲基硫(DMS)是海洋中最重要的挥发性生源硫化物,其在大气中的氧化产物会对全球气候变化和酸雨的形成产生重要影响。海水中DMS的光化学氧化,作为一个重要的去除途径,是控制海水中DMS浓度的重要因素。这个复杂的动态过程会受到光照、深度、海水中的溶解无机和有机物这些物理、化学因素的影响。根据光化学降解在DMS的全球生物地球化学循环中的重要作用,作者综述了国际海洋科学工作者近20年来在海水中DMS光化学研究方面的最新进展。 相似文献
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The contents of biogenic elements in China marginal sea sediments are related to their grain sizes, river transport, et al. In general, the finer the grain size is, the higher the contents of organic matter and OC, N, P are, the lower the contents of S and Si are. The biogeochemical environments of sediments are related to Eh, pH, temperature content of OC,Fe3 /Fe2 radio, water dynamics condition, grain size of sediment, S system in sediment interstitial waters, et al., and they influence the early diageneses and cycle of biogenic elements in sediments. In most regions of China marginal sea, the flux directions of S2-, HS-,3- NH4 H4SiO4, PO4 , across the sediment-water interface are from sediment to the overlying seawater, the flux directions of SO42-, HCO3-, NO3-, NO2- across the sediment-water interface are from the overlying seawater to sediment. The irrigation of living things is important in the cycle of the biogenic elements across sediment-water interfaces. 相似文献
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Dimethylsulfide (DMS) was determined in surface seawater and vertical hydrographic profiles in the Atlantic Ocean during two cruises from Hamburg to Montevideo (Uruguay), and from Miami (Florida) into the Sargasso Sea. These data cover most of the ecological zones of the Atlantic. DMS concentrations are related to the levels of marine primary production, in agreement with its release by marine phytoplankton in laboratory cultures. The vertical distribution of DMS in the euphotic zone follows that of primary production, with a maximum at or near the ocean surface and a decrease with depth. Below the level of 1% light penetration, DMS levels decline gradually, but DMS remains detectable even in the bottom waters. The mean DMS concentration in surface water is 84.4, and in deep water 3.2 ng S (DMS) 1?1. No steep gradients of DMS exist near the sea surface on scales of centimeters to tenths of millimeters. At a drift station, DMS was observed to be diurnally variable, with an increase in concentration in the euphotic zone throughout the day. DMS is actively turned over in the surface ocean with a residence time of a few days, but it is apparently very stable in the deep sea. DMS is the major volatile sulfur compound in the ocean, and its transfer across the air-sea interface contributes significantly to the atmospheric sulfur budget. 相似文献
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A.J. Gabric P.A. Matrai R.P. Kiene R. Cropp J.W.H. Dacey G.R. DiTullio R.G. Najjar R. Sim D.A. Toole D.A. delValle D. Slezak 《Deep Sea Research Part II: Topical Studies in Oceanography》2008,55(10-13):1505
The major source of reduced sulfur in the remote marine atmosphere is the biogenic compound dimethylsulfide (DMS), which is ubiquitous in the world's oceans and released through food web interactions. Relevant fluxes and concentrations of DMS, its phytoplankton-produced precursor, dimethylsulfoniopropionate (DMSP) and related parameters were measured during an intensive Lagrangian field study in two mesoscale eddies in the Sargasso Sea during July–August 2004, a period characterized by high mixed-layer DMS and low chlorophyll—the so-called ‘DMS summer paradox’. We used a 1-D vertically variable DMS production model forced with output from a 1-D vertical mixing model to evaluate the extent to which the simulated vertical structure in DMS and DMSP was consistent with changes expected from field-determined rate measurements of individual processes, such as photolysis, microbial DMS and dissolved DMSP turnover, and air–sea gas exchange. Model numerical experiments and related parametric sensitivity analyses suggested that the vertical structure of the DMS profile in the upper 60 m was determined mainly by the interplay of the two depth-variable processes—vertical mixing and photolysis—and less by biological consumption of DMS. A key finding from the model calibration was the need to increase the DMS(P) algal exudation rate constant, which includes the effects of cell rupture due to grazing and cell lysis, to significantly higher values than previously used in other regions. This was consistent with the small algal cell size and therefore high surface area-to-volume ratio of the dominant DMSP-producing group—the picoeukaryotes. 相似文献
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Roles of Biogeochemical Processes in the Oceanic Carbon Cycle Described with a Simple Coupled Physical-Biogeochemical Model 总被引：1，自引：0，他引：1
To evaluate the contribution of biogeochemical processes to the oceanic carbon cycle and to calculate the ratio of calcium
carbonate to organic carbon downward export, we have incorporated biological and alkalinity pumps in the yoked high-latitude
exchange/interior diffusion-advection (YOLDA) model. The biogeochemical processes are represented by four parameters. The
values of the parameters are tuned so that the model can reproduce the observed phosphate and alkalinity distributions in
each oceanic region. The sensitivity of the model to the biogeochemical parameters shows that biological production rates
in the euphotic zone and decomposition depths of particulate matters significantly influence horizontal and vertical distributions
of biogeochemical substances. The modeled vertical fluxes of particulate organic phosphorus and calcium carbonate are converted
to vertical carbon fluxes by the biological pump and the alkalinity pump, respectively. The downward carbon flux from the
surface layer to the deep layer in the entire region is estimated to be 3.36 PgC/yr, which consists of 2.93 PgC/yr from the
biological pump and 0.43 PgC/yr from the alkalinity pump, which is consistent with previous studies. The modeled rain ratio
is higher with depth and higher in the Pacific and Indian Oceans than in the Atlantic Ocean. The global rain ratio at the
surface layer is calculated to be 0.14 to 0.15. This value lies between the lower and higher ends of the previous estimates,
which range widely from 0.05 to 0.25. This study indicates that the rain ratio is unlikely to be higher than 0.15, at least
in the surface waters. 相似文献
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海洋中生源活性气体的来源与迁移转化 总被引：1，自引：1，他引：0
海洋生源活性气体主要包括二甲基硫（DMS）、甲烷（CH4）、氧化亚氮（N2O）、一氧化碳（CO）、挥发性卤代烃（VHCs）和非甲烷烃（NMHCs）等。它们通过海-气交换进入大气，不仅在全球碳、氮和硫循环中发挥关键作用，而且会直接或间接地对环境和气候变化产生重要影响。海洋释放的活性气体一类属于温室效应气体（CH4、N2O、VHCs和CO等），另一类会在大气中发生化学反应，控制着大气氧化平衡和臭氧浓度（VHCs和NMHCs）。而DMS属于负温室效应气体，其在大气中被快速氧化形成硫酸盐气溶胶，进而对云的形成和辐射强迫产生重要影响。本文综述了国内外海洋生源活性气体的研究现状，着重介绍了DMS、CH4和N2O的来源、迁移转化、海-气通量及其影响机制，并指明了该领域存在的科学问题及今后的研究方向。 相似文献
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Cecelia C.S. Hannides Michael R. Landry Claudia R. Benitez-Nelson Renée M. Styles Joseph P. Montoya David M. Karl 《Deep Sea Research Part I: Oceanographic Research Papers》2009,56(1):73-88
Export processes play a major role in regulating global marine primary production by reducing the efficiency of nutrient cycling and turnover in surface waters. Most studies of euphotic zone export focus on passive fluxes, that is, sinking particles. However, active transport, the vertical transfer of material by migrating zooplankton, can also be an important component of carbon (C) and nitrogen (N) removal from the surface ocean. Here we demonstrate that active transport is an especially important mechanism for phosphorus (P) removal from the euphotic zone at Station ALOHA (Hawaii Ocean Time-series program; 22°45′N, 158°W), a P-stressed site in the North Pacific Subtropical Gyre. Migrant excretions in this region are P-rich (C51:N12:P1) relative to sinking particles (C250:N31:P1), and migrant-mediated P fluxes are almost equal in magnitude (82%) to P fluxes from sediment traps. Migrant zooplankton biomass and therefore the importance of this P removal pathway relative to sinking fluxes has increased significantly over the past 12 years, suggesting that active transport may be a major driving force for enhanced P-limitation of biological production in the NPSG. We further assess the C:N:P composition of zooplankton size fractions at Station ALOHA (C88:N18:P1, on average) and discuss migrant-mediated P export in light of the balance between zooplankton and suspended particle stoichiometries. We conclude that, because active transport is such a large component of the total P flux and significantly impacts ecosystem stoichiometry, export processes involving migrant zooplankton must be included in large-scale efforts to understand biogeochemical cycles. 相似文献
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Ｔｈｅｃｏｎｃｅｎｔｒａｔｉｏｎａｎｄｄｉｓｔｒｉｂｕｔｉｏｎｏｆｄｉｍｅｔｈｙｌｓｕｌｆｉｄｅｉｎｔｈｅｍａｒｉｎｅａｔｍｏｓｐｈｅｒｉｃｂｏｕｎｄａｒｙｌａｙｅｒｎｅａｒｔｈｅｅｑｕａｔｏｒ￥ＬｉＸｉｎｇｓｈｅｎｇ；ＬｉＺｈｅ；Ｆ．Ｐａｒｕｎｇｏ... 相似文献
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In situ experiments using isotopically labeled mercury species (199Hg(II) and Me201Hg) are used to investigate mercury transformation mechanisms, such as methylation, demethylation and reduction, in coastal and marine surface waters of the Mediterranean Sea. The aim of this work is to assess the relative contribution of photochemical versus biological processes to Hg transformation mechanisms. For this purpose, potential transformation rates measured under diurnal and dark incubation conditions are compared with major biogeochemical parameters (i.e. hydrological and biological data) in order to obtain the relative contribution of various biotic and abiotic mechanisms in both surface (high light) and bottom (low light) waters of the euphotic zone. The results demonstrate that coastal and marine euphotic zones are significant reactors for all Hg transformations investigated (i.e. methylation, demethylation, reduction). A major outcome demonstrates that Hg methylation is taking place in oxic surface seawater (0.3–6.3% day− 1) and is mainly influenced by pelagic microorganism abundance and activities (phyto- and bacterioplankton). This evidences a new potential MeHg source in the marine water column, especially in oligotrophic deep-sea basins in which biogeochemistry is mostly governed by heterotrophic activity. For coastal and marine surface waters, although MeHg is mainly photochemically degraded (6.4–24.5% day− 1), demethylation yields observed under dark condition may be attributed to microbial or chemical pathways (2.8–10.9% day− 1). Photoreduction and photochemical reactions are the major mechanisms involved in DGM production for surface waters (3.2–16.9% day− 1) but bacterial or phytoplanktonic reduction of Hg(II) cannot be excluded deeper in the euphotic zone (2.2–12.3% day− 1). At the bottom of the euphotic zone, photochemical processes are thus avoided due to the attenuation of UV-visible sunlight radiation allowing biotic processes to be the most significant. These results suggest a new potential route for Hg species cycling in surface seawater and especially at the maximum biomass depth located at the bottom of the euphotic zone (i.e. maximum chlorophyll fluorescence). In this environment, DGM production and demethylation mechanisms are thus probably reduced whereas Hg methylation is enhanced by autotrophic and heterotrophic processes. Experimental results on mercury species uptake during these investigations further evidenced the strong affinity of MeHg for biogenic particles (i.e. microorganisms) that correspond to the first trophic level of the pelagic food web. 相似文献