Patterns and trends in nutrients and phytoplankton in Dutch coastal waters: comparison of time-series analysis, ecological model simulation, and mesocosm experiments   总被引：8，自引：0，他引：8  

de Vries  I.; Duin  R. N. M.; Peeters  J. C. H.; Los  F. J.; Bokhorst  M.; Laane  R. W. P. M. 《ICES Journal of Marine Science》1998,55(4):620-634

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内蒙古典型草原N2O研究刍议   总被引：15，自引：1，他引：14  

王艳芬  陈佐忠  周涌 《气候与环境研究》1997,2(3):280-285

利用中国科学院内蒙古草原生态定位研究站（ＩＭＧＥＲＳ）的气候、土壤、植被、土地利用方式和家畜等方面的资料,根据目前国际上Ｎ２Ｏ的研究进展,分析了内蒙古典型草原区影响Ｎ２Ｏ收支作用的可能控制因子,认为：（１）作为Ｎ２Ｏ主要来源的土壤,其理化性状,尤其是土壤温度、水分状况、土壤有机质和土壤结构等,是影响该地区Ｎ２Ｏ收支平衡的主要控制因子;（２）土地利用方式的改变对Ｎ２Ｏ的释放的影响还不十分清楚。草场农用与一定的耕作管理措施以及对天然草场的人为影响（割草、放牧等）是对Ｎ２Ｏ收支平衡影响的主要方面;（３）家畜排泄物,无论作为本地区的主要燃料,还是作为肥料,在典型草原区Ｎ２Ｏ的释放中起着不可忽视的作用。  相似文献   

The influence of lipid-extraction on the δ¹³C of mesopelagic and demersal fish in the South China Sea: modification and application of lipid normalization models     

Linyu Wang  Fuqiang Wang  Zuozhi Chen  Ying Wu 《海洋学报(英文版)》2023,42(1):35-43

Mesopelagic fish,the most important daily vertically migrating community in the oceans,are characterized by high lipid content which may obscure the interpretation of stable isotopes analysis.Demersal fish,which are important consumers in the food web dominated by mesopelagic fish,also have a high lipid content.Here we collected 127 fish samples from the South China Sea and evaluated the effect of lipid contents on δ¹³C of mesopelagic and demersal fish.In lipid-extracted mesopelagic f...  相似文献   

Variation of alkaline phosphatase activity in sediments of shrimp culture ponds and its relationship with the contents of C,N and P   总被引：1，自引：0，他引：1  

SU Yuepeng  MA Shen  and DONG Shuanglin Mariculture Research Laboratory  Ocean University of China  Qingdao  P.R. China 《中国海洋大学学报(英文版)》2005,4(1):75-79

1Introduction Activities of extracellular enzymes can serve as theindicators of organic matter content.Enzyme assayinghas been used in the analyses of dissolved organic ma-terials in aquatic environments(Chrost,1991),massloss of plant litter in terrestrial systems(Sinsabaughet al.,1992;Sinsabaugh et al.,1994),processing ofpaniculate and dissolved organic carbon(POC,DOC)in streams(Sinsabaugh and Findlay,1995;Findlayet al.,1998),and processing of particulate organicmatter(POM)in wetlands(J…  相似文献   

Late Holocene mangrove dynamics dominated by autogenic processes          下载免费PDF全文

Caio A. Moraes  Neuza A. Fontes  Marcelo C.L. Cohen  Marlon Carlos França  Luiz C.R. Pessenda  Dilce F. Rossetti  Mariah I. Francisquini  José A. Bendassolli  Kita Macario 《地球表面变化过程与地形》2017,42(13):2013-2023

Generally, palaeoenvironmental interpretations consider only allogenic processes, when autogenic factors may have a strong influence on proxies of stratigraphic sequences. For instance, the Holocene history of the vegetation along the southern littoral of the State of Bahia in north‐eastern Brazil is characterized by mangrove dynamics controlled by allogenic processes. However, over smaller timescales (~700 years), autogenic processes may have controlled vegetation dynamics and hence observed pollen distribution. This work proposes tidal channel dynamics as one of the main cause for changes in pollen assemblage along the studied stratigraphic profiles during the last centuries, based on sedimentology, pollen and elemental analysis (δ¹³C, δ¹⁵N and C/N) and radiocarbon dating of sedimentary organic matter from two cores sampled from an abandoned meander and a tidal flat at the mouth of the Jucuruçu River. One core was sampled from a mangrove formed during the past ~550 cal yr bp . Another core recorded sediments in a várzea forest (swamp seasonally and permanently inundated by freshwater) located ~2.7 km from the current shoreline, which displayed a maximum age of ~680 cal yr bp . Two facies associations were identified: tidal channel (A) and tidal flat/oxbow lake (B). This work proposes allogenic processes as the main driving forces controlling the wetlands dynamics at the studied site during the Holocene. However, our data also reveal that part of the changes in vegetation over the last ~700 years reflect tidal channels and tidal flats development, which represent autogenic processes. The change in timescale analysis from the Holocene to recent centuries may have weakened the influence of allogenic factors. However, this needs interpretation with reference to the spatial scale of the depositional environment as the larger the depositional system analyzed, the stronger the influence of autogenic processes on stratigraphic sequences over longer timescales. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   

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   

基于双还原体系与膜进样质谱快速测定¹⁵N加富水样中¹⁵NO₃^-的方法     

罗畅  宋国栋  刘素美 《海洋与湖沼》2022,53(2):320-329

海洋中的氮循环是海洋生物地球化学研究的热点领域之一,而硝化过程是氮循环的关键一环,准确获取硝化速率对于丰富海洋氮循环的认识至关重要。¹⁵N标记同位素技术是目前国际上最为广泛使用的硝化速率测定方法,该方法的核心在于准确测定¹⁵N加富样品产生的¹⁵NO₂^-和¹⁵NO₃^-的含量,但目前的方法普遍存在测试时间较长、测试成本较高、所需样品体积较大或者检测限较高等问题。研究以低成本的膜进样质谱作为¹⁵N加富样品测试设备,建立了基于镉柱与氨基磺酸双还原体系测定¹⁵N加富样品中¹⁵NO₃^-含量的方法。经条件优化实验确定的具体方法:采用1 mol/L HCl配制15 mmol/L的氨基磺酸（SA）作为反应试剂除去样品原有的NO₂^-,然后利用镉柱将¹⁵NO  相似文献   

小波分析在提高核磁共振找水信号信噪比中的应用探讨     

曾亮  李振宇  王鹏 《CT理论与应用研究》2006,15(2):1-5

地面核磁共振(SNMR)找水方法是目前唯一能直接找到地下水的地球物理新方法。由于该方法接收灵敏度高,因此对电磁噪声也很敏感。为了提高信噪比和新方法的找水效果,必须对接收到的信号进行去噪处理。本文使用了小波分析去噪提高核磁共振信号信噪比的方法,并通过对湖北省新洲工区和王家湾工区实测数据的小波处理和对比分析,证明了这种方法的有效性。  相似文献   

Mass fluxes in the Canary Basin   总被引：1，自引：1，他引：0  

F. Machín  A. Hernndez-Guerra  J.L. Pelegrí 《Progress in Oceanography》2006,70(2-4):416

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湿地生态系统氮素输入过程的研究进展   总被引：6，自引：0，他引：6  

孙志高  刘景双  王金达  李新华  杨继松 《地理与地理信息科学》2006,22(1):97-102

湿地生态系统的氮素输入过程主要包括大气氮沉降、生物固氮、人为氮和径流氮输入等途径,它们通过影响湿地系统自身的营养状况而决定氮素生物地球化学过程的运行。综述国内外湿地氮素各种输入途径的研究进展,分析当前研究中存在的问题,指出淡水沼泽湿地是目前研究的薄弱点。展望湿地氮素输入过程的研究前景,建议积极开展淡水沼泽湿地、湿地系统氮素交换的环境效应1、5N技术与氮素模型的结合以及各氮素输入途径的模型表征研究。  相似文献