首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 765 毫秒
1.
INTRODUCTIONThelargeyellowcroakerPseudosciaenacroceaoncewasoneofthefourimportantmarinefish eryobjectsinChina (Hongetal.,1 983;HuangandCarl,1 983;ChenandGong ,1 983) .TheproductionofthewildP .croceain 1 974reached 1 971 78metrictons (MT)inChina (Li,1 998) .Becauseofoverfishing ,th…  相似文献   

2.
INTRODUCTIONKnowledgeofthedistributionandcompositionofthechlorophyllandcarotenoidpigmentsincoastalmarinewatersprovidesinformationonthephytoplanktonbiomassandalsoonitschemotaxon omy ,thecontributionofriverineinputs,andtheearlydegradationroutesoccurringi…  相似文献   

3.
1 INTRODUCTIONInrecentyearstheecoenvironmentoftheChangjiangRiverbasinsufferedfromseveredestruction,sedimentcontentintheriverwatergreatlyincreased,thedownstreamcoursewasseriouslysiltedupandfloodcontrolcapacitywasweakened.Thesimilarsituationalsooccu…  相似文献   

4.
INTRODUCTIONMorethanadecadehaspassedsincebacteriawasrecognizedasquantitativelyimportantcon sumersoforganiccarboninmarinefoodwebsandmarineecosystems (Fuhrman ,1 992 ) .ThebasicinformationonthesignificanceofthemicrobialfoodwebwaspresentedbyPomeroy ( 1 974 ) ,whopie…  相似文献   

5.
INTRODUCTIONResearchesonsea floorhydrothermalactivitiesandhydrothermalsulfidesyieldedthenewestknowledgeaboutmodernmarinegeologicalevolutionandmineralizationpatterns.Sincethe 1 980s,scientistshavebeenapplyingtheoxygenisotopemethodtorecoverthenotdirectlyde…  相似文献   

6.
THE STEPS FORWARD OF GIS IN CHINA   总被引:2,自引:0,他引:2  
1 HISTORICALSTEPS—ATEMPORALANA LYSISResearchesofGISinChinacandatebacktotheearly 1980s .Atthattime ,aremotesensingapplica tionprojectwascarriedoutinSouthwestChinausingGISmethodintegratedwithremotesensingdatatosolvetheareameasurementautomatically .Afterthefir…  相似文献   

7.
INTRODUCTIONTheWesternPacificWarmPool (WP)isaseaareawhereseasurfacetemperature (SST)isthehighestintheglobaloceansandair seainteractionisthemostviolentinthePacific.Manyre centresearchesshowedthatvariationsinthethermalconditions (inSST ,especially)oftheWPplay…  相似文献   

8.
INTRODUCTIONBillard ( 1 986)studiedthespermatozoonultrastructuresinteleostsandfounddistinctdifferencesa mongdifferentspecies.Studyonspermatozoonmorphologyandfunctionisachallengebecauseofthesperm’sspecialenvironment (Gageetal.,1 998;WangandZhang,1 999) .Sinceleft ey…  相似文献   

9.
1INTRODUCTIONJianghanPlainisoneoftheimportantbasesofChina′sagriculturalproductivitylocatedinthemiddleChangjiangRivervalleyofcentralChina.TheJianghanplainapproximately6.6×104km2inareaandover30millioninpopulationistherenowned“countryoffishandrice"in…  相似文献   

10.
INTRODUCTIONTheSouthChinaSea (SCS)isasemi enclosedoceanbasinlocatedataspecialgeographicpo sition ,oneoftheworld’spronouncedmonsoonregions,withnortheastwindsprevailinginwinterandsouthwestwindsinsummer,andisacrucialregionofintensiveair seainteractionofgreat…  相似文献   

11.
1 CHANGESOFINDUSTRIALSTRUCTURE1.1 ChangesofStructureofThreeEconomicSectorsSincethereformofeconomicsystemandopeningtotheoutsideworldinthelate1970s,theindustrialstructureofGuangdongProvincehasbeenexperiencinganobviousprocessofnonagriculturalizationw…  相似文献   

12.
1 Introduction18Oinmarineenvironmentplaysanimportantroleinoceanographicalstudy .Asastableisotopeofoxygen ,18OtogetherwithhydrogenatomsconstituteswatermoleculeH218OandmoveswithalargeamountofH2 Omoleculesinseawater.Sothatδ18Obecomesanidealtracerforthemovemento…  相似文献   

13.
INTRODUCTIONMicrocystisaeruginosawasthemainbloom formingspeciesinDonghuLake;occurredonlysporadicallyinthe 1 950s,increasedrapidlyinnumberinthe 1 960s.Fromthemiddleofthe 1 970stothemiddleofthe 1 980s,thicklayerofitsbloomcoveredthelakesurfaceeverysummer,attract ingfo…  相似文献   

14.
INTRODUCTIONPhosphorusisakeynutritiveelementforthegrowthofmarinephytoplankton .Recently ,be causeofenvironmentalpollution ,theeutrophicationproblemsincoastalandoceanicwatershavebe comemoreandmoreserious.Theenvironmentecologicalresponseinthelong termtothef…  相似文献   

15.
1INTRODUCTIONTheremarkablesocialandeconomicchangeinthePearlRiverZhujiangDeltaPRDsincethelate1970shasmadeitafocalpointinreformeraacademiccircles.ManystudieshavebeendoneonthePRDitsregionaleconomicdevelopmentandrestructuringLIN1997LINetal.1995…  相似文献   

16.
I.INTRODUCTIONTheglobalaveragesurfaceairtemperatureoftheearthhasincreasedbyabout0.5℃sincethemid19thcentury(Houghtonetal.,19...  相似文献   

17.
GLOBAL OCEAN TIDES FROM GEOSAT ALTIMETRY BY QUASI-HARMONIC ANALYSIS   总被引:2,自引:0,他引:2  
INTRODUCTIONOceantidesplayaveryimportantroleinthedynamicsoftheEarthandhaveattractedmanypeople’sattentionsinceancienttimes.Beforethelate 1 970s,tidesweremeasuredmainlybycoastalgauges .Directmeasurementsaswellasnumericalsimulations,canprovidefairlyaccurateu…  相似文献   

18.
INTRODUCTIONTheSouthChinaSea (SCS)isauniquesemi encloseddeepoceanbasinlocatednearthewest ernperipheryofthePacificOcean .Spreadingfromtheequatorto 2 0°Nandspanningzonallyabout1 5°N ,theSCSliesbetweentheSouthChinacoastandthemaritimecontinent.TheSCSbottomtopogr…  相似文献   

19.
INTRODUCTIONLimnodrilushoffmeisteri,aubiquitoustubificid ,isapredominantbenthicinvertebrateinmostshalloweutrophiclakesinChina (Liang,1 979) .Sofar,therearenodataonthesecondaryproduc tionofthiswormandfewdataonthatofotherzoobenthosreportedinChina .Withthefisher…  相似文献   

20.
INTRODUCTIONEriochoirsinensisinChinaiscommonlycalledmittencrab .Itisanadromous,withindividualsmovingfromfreshtomarinewatertospawn .Therearetwocommercialpopulations:ChangjiangRiv er (CR)andLiaoheRiver (LR) .Thesetwopopulationsareverydifficulttoidentifyfromth…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号