Interrelations between Si and P biogeochemical cycles—a new approach to the solution of the eutrophication problem     

V. Krivtsov  E. Bellinger  D. Sigee  J. Corliss 《水文研究》2000,14(2):283-295

Because the biogeochemical cycles of P and Si in temperate lakes are strongly connected by the dynamics of primary producers, it should be possible to influence the former cycle by causing changes in the latter. It is shown using the mathematical model ‘Rostherne’ that winter levels of ambient Si have a major influence both on spring levels of ambient P and on the summer cyanobacterial maxima. Additions of Si to the lakes could be used for the fine regulation of the biogeochemical balance and may prescribe a recipe for improvement of water quality, as well as a new solution to the problem of eutrophication. Copyright © 2000 John Wiley & Sons, Ltd.  相似文献   

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  

宋金明  李学刚 《海洋学报》2018,40(10):1-13

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   

Cycling amongst Māori: Patterns,influences and opportunities     

Rhys Jones  Bruce Kidd  Kirsty Wild  Alistair Woodward 《New Zealand geographer》2020,76(3):182-193

This paper outlines the results of mixed-methods research on Māori and cycling. Our findings suggest that Māori cycle at similar rates to Pākehā (NZ European); however conditions may differ, possibly indicating higher levels of “necessity cycling” amongst Māori. Māori experience similar barriers to cycling, including a lack of suitable cycling infrastructure, but these occur against a backdrop of stark social, economic and transport-related inequities. Particular barriers for Māori may include inflexible work conditions, concerns about neighbourhood safety, inadequate provision for social cycling, and lack of access to places of importance to Māori. We identify potential solutions, including more whānau-friendly and culturally safe cycling infrastructure, and cycling programmes designed around Māori commitments to whanaungatanga and kaitiakitanga.  相似文献   

南海——我国深海研究的突破口   总被引：3，自引：1，他引：2  

汪品先 《热带海洋学报》2009,28(3):1-4

近两年来,海内外和海峡两岸的中国科学家围绕深海研究进行反复研讨,一致认为南海是我国深海研究的首选,并初步形成了“南海深部计划”的研究方案,提出以“构建边缘海的生命史”为主题,从洋壳深海盆的演化、深海沉积、生物地球化学过程三方面开展研究的建议方案。他们建议：利用现代技术重新测定南海磁异常条带,争取钻探大洋壳,系统研究火山链;观测现代深部海流和海底沉积过程,从深海沉积中提取边缘海盆演化的信息;认识海底溢出流体与井下流体的分布与影响,揭示微型生物在深海碳循环中的作用。争取在科学和技术全国性合作的基础上,在南海实现我国深海研究的突破。  相似文献   

Enzyme activities in the Delaware Estuary affected by elevated suspended sediment load     

K. Ziervogel  C. Arnosti 《Estuarine, Coastal and Shelf Science》2009

Extracellular enzyme activities were compared among surface water, bottom water, and sediments of the Delaware Estuary using six fluorescently labeled, structurally distinct polysaccharides to determine the effects of suspended sediment transport on water column hydrolytic activities. Potential hydrolysis rates in surface waters were also measured for the nearby shelf. Samples were taken in December 2006, 6 months after a major flood event in the Delaware Basin that was followed by high freshwater run-off throughout the fall of 2006. All substrates were hydrolyzed in sediments and in the water column, including two (pullulan and fucoidan) that previously were not hydrolyzed in surface waters of the Delaware estuary. At the time of sampling, total particulate matter (TPM) in surface waters at the lower bay, bay mouth, and shelf ranged between 31 mg l⁻¹ and 48 mg l⁻¹ and were 2 to 20 times higher than previously reported. The presence of easily resuspended sediments at the lower bay and bay mouth indicated enhanced suspended sediment transport in the estuary prior to our sampling. Bottom water hydrolysis rates at the two sites affected by sediment resuspension were generally higher than those in surface waters from the same site. Most notably, fucoidan and pullulan hydrolysis rates in bay mouth bottom waters were 22.6 and 6.2 nM monomer h⁻¹, respectively, and thus three and five times higher than surface water rates. Our data suggest that enhanced mixing processes between the sediment and the overlying water broadened the spectrum of water column hydrolases activity, improving the efficiency of enzymatic degradation of high molecular weight organic matter in the water with consequences for organic matter cycling in the Delaware estuary.  相似文献   

Short-term under-ice variability of prokaryotic plankton communities in coastal Antarctic waters (Cape Hallett, Ross Sea)     

Mauro Celussi  Alessandro Paoli  Erica Crevatin  Andrea Bergamasco  Francesca Margiotta  Vincenzo Saggiomo  Serena Fonda Umani  Paola Del Negro 《Estuarine, Coastal and Shelf Science》2009,81(4):491-500

During the 2006 Italian Antarctic expedition a diel sampling was performed close to Cape Hallett (Ross Sea) during the Austral summer. Under-ice seawater samples (4 m) were collected every 2 h for 28 h in order to estimate prokaryotic processes' variability and community structure dynamics. Prokaryotic and viral abundances, exoenzymatic activities (β-glucosidase, chitinase, lipase, alkaline phosphatase and leucine aminopeptidase), prokaryotic carbon production (³H-leucine incorporation) and community structure (Denaturing Gradient Gel Electrophoresis – DGGE fingerprints) were analysed. Results showed that the diel variability of the prokaryotic activity followed a variation in salinity, probably as a consequence of the periodical thawing of sea ice (driven by solar radiation and air temperature cycles), while negligible variation in viral and prokaryotic abundances occurred. The Bacterial and Archaeal community structures underwent an Operational Taxonomic Units (OTUs) temporal shift from the beginning to the end of the sampling, while Flavobacteria-specific primers highlighted high variations in this group possibly related to sea ice melting and substrate release.  相似文献   

金属稳定同位素示踪俯冲带挥发分循环SCIEI北大核心CSCD          下载免费PDF全文

刘盛遨 《岩石学报》2022,38(5):1512-1522

俯冲带挥发分的循环不仅深刻影响着地球各圈层之间的相互作用,而且在成矿金属元素迁移-富集以及全球气候变化等重要地质和环境过程中扮演着重要的角色。近年来,金属稳定同位素示踪俯冲带挥发分循环受到了广泛关注,取得了众多进展,但大多针对单个挥发性元素开展某个特定金属同位素的示踪研究。本文根据不同金属元素的地球化学性质差异及其与多种挥发分之间的结合形式,系统归纳了金属稳定同位素在示踪俯冲带不同挥发分循环方面的特点。整体上讲,镁和锌同位素体系示踪俯冲带碳循环最为有效;锂、镁、钾、钡、钼等金属同位素体系在示踪俯冲带水(流体)循环方面则具有各自的特点;锌同位素在示踪俯冲带硫循环方面有巨大潜力;铬同位素示踪俯冲带氯循环有独特优势;铁、铬、铜等变价金属同位素体系对挥发分的氧化还原状态较为敏感,有望示踪俯冲带氧循环。这些同位素体系对理解俯冲带挥发分循环提供了全新的视角,有望成为未来地球系统科学的重要研究方向。  相似文献   

海洋中锰的生物地球化学循环研究     

任景玲  张桂玲  刘素美  王召伟  张经 《海洋科学进展》2012,30(3):432-440

痕量元素在海洋生物地球化学循环中起的作用已受到越来越广泛的关注,近年来形成了新的国际科学计划———痕量元素及其同位素的海洋生物地球化学研究(GEOTRACES)。锰是GEOTRACES关键参数之一,国际GEOTRACES组织推荐各国组织的GEOTRACES航次对其在全球大洋中的分布进行重点研究。本研究就痕量元素锰的海洋生物地球化学研究进行了较为详细的综述,介绍了锰在海洋中的来源及输送通量、分布、水体中的赋存形式及其迁移转化、生态学功能以及主要的分析方法等。总结了在这一研究领域所取得的成果及存在的不足,并对今后的发展方向进行展望。  相似文献   

中国近海营养盐结构失衡与磷消耗问题及其生态环境效应的研究进展          下载免费PDF全文

冉祥滨  韦钦胜  于志刚 《海洋科学》2023,47(8):75-89

近海的生态环境问题态势严峻。在机制上，普遍认为富营养化是导致近海环境恶化的主导因子，但实际上，营养盐的结构失衡对近海生态环境问题的产生可能起到了更重要的作用。目前关于营养盐结构失衡的主导因素和机制尚缺乏全面系统的研究。本文基于对已有数据和文献资料的整合分析发现，由于存在强烈的人类活动影响，中国近海营养盐结构失衡问题较过去更为突出，且可能引发潜在“磷消耗”问题，其影响在某种程度上较传统意义上的磷限制要强，并进而产生深远的生态环境效应。据此提出，今后相关的研究应该特别关注河流流域-近海环境变化和它们之间的内在关联，阐明控制近海营养盐浓度、形态、分布和结构的关键生物地球化学过程，量化近海氮与磷的滞留机制与效率，揭示浮游植物群落结构变化与营养盐结构失衡和磷消耗的耦合关系及其生态效应等，最终制定中国入海河流与近海氮磷协同控制的适应性管理措施。  相似文献