THE COLD AND HOT DAMAGES TO THE CITRUS IN THE THREE GORGES AREA OF THE CHANGJIANG RIVER

ＴＨＥＣＯＬＤＡＮＤＨＯＴＤＡＭＡＧＥＳＴＯＴＨＥＣＩＴＲＵＳＩＮＴＨＥＴＨＲＥＥＧＯＲＧＥＳＡＲＥＡＯＦＴＨＥＣＨＡＮＧＪＩＡＮＧＲＩＶＥＲＣｈｅｎＺｈｅｎｇｈｏｎｇ（陈正洪）；ＹａｎｇＨｏｎｇｑｉｎｇ（杨红青）；ＮｉＧｕｏｇｕ（倪国裕）（Ａｇｒｏ...     

ECOLOGICAL STUDY ON PROTOZOA IN THE SEDIMENT OF THE THREE-GORGES AREA OF THE CHANGJIANG RIVER

This paper reports on the study on the protozoan community structure of the immersed sediment in the Three-Gorges Area of the Changjiang River. Protozoa observed included 7 phytoflagellates, 12 zooflagellates, 49 amoebae and 16 ciliates. Sarcodina dominated in sediment, ciliates in water. Analysis of species and horizontal density distribution of protozoan in sediment in 28 sampling points reflected the pollution degree of water quality at every site. It was shown that heavy metal contamination in sediment has some effects on the distribution of protozoan species in the Changjiang River.     

AN ANALYSIS OF THREE ELEMENTS OF WATER BALANCE IN THE CHANGJIANG RIVER BASIN

The general trend of three elements (precipitation, runoff and evaporation) of the water balance of the Changjiang River Basin is discussed from the regional distribution of the mean annual values of view, i.e. isogram. The distribution of precipitation is non-uniform. The distribution of runoff mainly supplied from precipitation is more uniform than that of precipitation. The distribution of the evaporation from land is much more uniform than that of precipitation and runoff. Time distribution of these three elements shows the characteristics of comparatively distinct yearly variation and few variation between years. The relationship between precipitation and runoff, and between precipitation and evaporation in the humid region in the Changjiang River is analyzed. The slopes of their straight line correlation are nearly equal. The internal relationship between variables should be paid attention to, otherwise, a pseudo correlation may be resulted in. The paper provides the method of quantitative computa     

ON THE VERTICAL STRUCTURE OF TIDAL CURRENTS IN SHALLOWWATER NEAR THE CHANGJIANG RIVER ESTUARY

This research on the vertical structure of tidal current in shallow water near the Changjiang River estuary is based on a great deal of observation data of current obtained recently, and a simple mathematic model. The essential features of the structure are: (1) the maximum velocity decreases with depth, the shallower the water, the lower the velocity; (2) the orientation of maximum velocity continuously deviates from the surface to the bottom to the left at the western side of the mouth bar and to the right at the eastern side; (3) the time of maximum velocity leads steadily with depth; (4) in general, tidal currents rotate clockwise, the nearer the sea-bed, the narrower the ellipse of the tidal current; (5) the ratio W1/W2 varies non-linearly with depth, and is smaller in the middle layer than at the surface and bottom. Bottom friction is the main cause of the vertical structure.     

DISTRIBUTION OF THE MAIN CROP GERMPLASM RESOURCES IN CHINA

Cropgermplasmresourcesaretheindispensablematerialbaseforcropbreedingandagriculturalproduction.Theresearchondistributionofcropgermplasmr~urcesisofgreatimportanceinstudyingonorigin,evolutionandclassificationofcrops,expeditingandcollectinggermplasm,ascertainingofcentersofdiversity,protectinggermplasmr~urcesandmakingagriculturalproductiondivision.Since1949,researchesofexploration,collection,preservation,cha-racterizationandevaluationofcropgermplasmresourceshavebeendoneinChina.Atpresent,thenational…     

CHARACTERISTICS OF PERIGLACIAL GEOMORPHOLOGY IN THE SOURCE AREA OF THE HUANGHE RIVER

There widely occur stretches of permafrost at more than 3,800-4,200 meters above sea level in the source area of the Huanghe (Yellow) River. The periglacial geomorphology develops quite well, including frozen disintegration geomorphology, freezing and thawing geomorphology in cold environments, periglacial dune, buried ices and fossil periglacial phenomena. In light of the relation between stratigraphy and periglacial phenomena, three periglacial periods can be divided, which are the Middle Pleistocene periglacial period, the Late Pleistocene periglacial period and modern periglacial period.     

THE STRENGTH OF THE DISSOLVED OXYGEN MAXIMUM IN THE VERTICAL DISTRIBUTION OF NANSHA ISLANDS WATERS

Observation data from a cruise in the Nansha Islands, in May to June 1990, December, 1993, September to October 1994, and July, 1999, respectively, were used to develop the method presented here to indicate the existing strength of the dissolved oxygen maximum in the vertical distribution of Nansha Islands waters. Its seasonal variation and regional distribution are discussed in this paper. Analysis results showed that the distribution of the strength of dissolved oxygen maximum (DOmax-DOsur) was closely related to the upper layer circulation and the bioactivity of Nansha Islands seawater.     

ORIGIN AND EVOLUTION OF THE ENTRANCE SANDBARS IN THE SOUTH PASSAGE OF THE CHANGJIANG RIVER ESTUARY

Based on the long-term hydrological and sedimental data and the hydrolographic charts or more than 100 years, comprehensive analyses and studies have been made on the river runoff, sediment, tides and waves outside the Changjiang river estuary.Origin and siltation characteristics of the entrance sandbars, recent evolution tendency of the planar axis of the passage and the decreasing capacity of the fluvial channel are also described in this paper, which can provide basic information necessary for the realignment of the sea-traffic channel through the area.     

A STUDY ON THE RELATIONSHIPS OF THE NUTRIENTS NEAR THE CHANGJIANG RIVER ESTUARY WITH THE FLOW OF THE CHANGJIANG RIVER WATER

Investigations from August, 1985 to July , 1986 showed that the high concentration area of PO4-P , SiO3-Si and NO3-N gradually reduced with the reduction of the area of the Changjiang River diluted water from summer, autumn to winter , and that the seasonal distributions and variations of the nutrients concentrations were mainly controlled by the river flow and were also related to the growth and decline of phytoplankton . The conservation of SiO3-Si and NO3-N in the estuary in the flood season was poorer than that in the dry season .. The behaviour of PO4-P in the estuary shows that aside from -biological removal, buffering of PCU-P is possible in the estuary . The highest monthly average concentrations and annual average concentrations in the river mouth were respectively 0.88 and 0.57 umol/L for PO4-P,191.5 and 96.2 umol/L for SiO3-Si, and 81.6 and 58.6 umol/L for NOs-N . The Changjiang's annual transports of PO4-P , SiO3-Si and NO3-N to the sea were about 1.4×104tons , 204.4×104 tons and 63.6×104     

INVESTIGATION ON FUNDAMENTAL CHARACTERISTICS OF HYDROCHEMISTRY IN HEAD AREA OF THE CANGJIANG RIVER

The results of water sample analyses and investigation in the head area of the Changjiang River reveal that the characteristics of hydrochemistry of the river vary with drainage basins. In the drainage basin of the Tuotuo River, the mineral concentration of water is generally high, ions of Cl and Na are obviously dominant. The water tends to be salty, and the type of hydrochemistry is rather complex. In the drainage basin of the Dam River, the mineral concentration is mainly in a low and middle level, ions of HCO3- and Ca2 are higher than others, and the type of hydrochemistry is relatively simple. The ground water in deep layers plays an important role in recharging surface water, and the stable recharging results in little change in chemical composition of surface water.     

THE EFFECTS OF THE THREE GORGES PROJECT ON ECOLOGY AND ENVIRONMENT

ＴＨＥＥＦＦＥＣＴＳＯＦＴＨＥＴＨＲＥＥＧＯＲＧＥＳＰＲＯＪＥＣＴＯＮＥＣＯＬＯＧＹＡＮＤＥＮＶＩＲＯＮＭＥＮＴＸｉａＹｉｃｈｅｎｇ（夏宜铮）（ＩｎｓｔｉｔｕｔｅｏｆＨｙｄｒｏｂｉｏｌｏｇｙ，ｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ，Ｗ...     

Growth of new economic sectors in second-tier extended cities in the Changjiang River Delta

The second-tier extended metropolises in the Changjiang (Yangtze) River Delta, including Suzhou, Wuxi and Changzhou near Shanghai, are becoming the most active and new innovative industrial agglomerating areas. Manufacturing industries in these second-tier cities have been in rapid growth due to increasing foreign investment. Nevertheless, the economic prospect of these cities is still constrained by a lack of local R&D capacity and production services, which are mainly dependent upon Shanghai. This paper analyses the impact of globalization on the new economic sectors in these cities, the change of industrial structure, the limitation of urban development and the problem of sustainability. Then, the paper analyses the conditions for the high-tech industry and production services in these areas. Also, it applies the industrial organization theory to these cities and examines how these cities can cooperate with each other in terms of horizontal linkages. Finally, the paper gives the future growth prospects in high-tech industry and production services. Foundation item: Under the auspices of the National Natural Science Foundation of China (No. 40371031) Biography: CHEN Wen (1967–), female, a native of Ningde of Fujian Province, professor, specialized in urban economic and urban geography. E-mail: wchen@niglas.ac.cn     

Nitrogen budget in the Changjiang River drainage area

We established a budget model of nitrogen (N) inputs and outputs between watersheds and waterbodies to determine the sources of riverine N in the Changjiang (Yangtze) River drainage area. Nitrogen inputs in the budget included N from synthetic fertilizer, biological fixation by leguminous and other crops, wet/dry atmospheric deposition, excreta from humans and animals, and crop residues. The total N input was estimated to be 17.6 Tg, of which 20% or 3.5 Tg N was transported into waterbodies. Of the total N transported into waterbodies, the largest proportion was N from animal waste (26%), followed by N from atmospheric wet/dry deposition (25%), synthetic fertilizer N (17%), N in sewage wastes (17%), N in human waste from rural areas (6%) and industrial wastewater N (9%). We studied the spatial patterns of N inputs and outputs by dividing the Changjiang River drainage area into four sub-basins, from upstream to downstream: the Tongtian River drainage area (TTD, the headwater drainage area, 138 000 km 2 , less disturbed by human activities); the Jinsha River drainage area (JSD, 347 000 km 2 , less disturbed by human activities, approx. 3 500 km upstream of the Changjiang estuary); the Pingshan-Yichang drainage area (PYD, 520 500 km 2 , large-scale human disturbance, about 2 000 km upstream of the Changjiang estuary); and the Yichang-Datong drainage area (YDD, 699 900 km 2 , large-scale human disturbance, approx. 620 km upstream of the Changjiang estuary). The average N input into waterbodies was 2.3, 7.3, 24.1, and 28.2 kg N/ha in the TTD, JSD, PYD, and YDD sub-basins, respectively, suggesting an increase of N-components of more than 10 times from upstream to downstream areas.     

Major problems of sustainable development along the bank area of the Changjiang River

TheChangiiangRiverisrichinfreshwaterandwaterpowerresources,themeanrunoffandwaterpoweroftheriverareabout37%and52%respectivelyoftotalonesofChina.Inaddition,theChanaiiangRiverhastheimmensenavigationpotentialandvaluableshorelineresources,thenavigablelengthreaches364okmandtheallshorelinelengthisabout6OOokmfromYihinCitytotheestuary.Moreover,theChangiiangRiver,withtheadvantagesofsuitablelocationandbroadhinterland,crossesEast,MiddleandWestEco-nomicZonewithdifferenteconomiclevelsofChina,soitsuniq…     

THE BACKGROUND VALUES OF RARE EARTH AND RADIOACTIVE ELEMENTS IN WATER SYSTEM OF SOURCE AREA OF THE CHANG JIANG RIVER

Using neutron activation analysis method we determined contents of rare-earth and radioactive elements (La, Ce, Nd, Sm, Eu, Tb, Yb, Lu, Cs, Rb, Sb, Sc, Sr, Ba, U, Th) in source water system of the Changjiang (Yangtze) River, which is mainly composed of the Tuotuo River, the Chumaer River, and the Buqu River. The contents of these elements in the unflltered water have a great variation and a close correlation with the water turbidity. The contents of these elements in filtered water only have a little variation and are lower than those in the unflltered water. The variations in contents of these elements in sediments are also very little. These elements in the unifiltered water are in geometric distribution, except Sc. Most of the elements in sediments are in arithmetic distribution, but Cs, Sb, Th, are in deviation distribution. The contents of most of these elements in the river source area correspond to the contents of fresh water of the earth. Most of these elements have a little variation in their c     

Assessment of the ecological security in the three gorges reservoir area by using the ecological footprint method

The ecological footprint concept and its calculation models are useful for the measurement of the sustainable level of social and economic development.The ecological security situation of the Three Gorges Reservoir Area(TGRA) was evaluated using this concept in this study.The construction of the Three Gorges Reservoir has led to the change in the ecology and immigration status of TGRA.The ecological footprint method is an important means to study the regional ecological security.Our results suggested that,by excluding the areas for biodiversity conservation(12% of the total land),the ecological footprint per capita was 0.57895 ha,which exceeded the ecological carrying capacity in TGRA.The total ecological deficit was found to be 11,522,193.34 ha,accounting for 95.02% of the ecological carrying capacity.These findings suggested that the ecological security of TGRA was not good.In order to compensate for the ecological deficit,it was essential to introduce natural resources from other regions.     

Occurrence and distribution of dissolved tellurium in Changjiang River estuary

With the implementation of the GEOTRACES program, the biogeochemical cycle and distribution of tellurium （Te） in marine environments are becoming increasing environmental concerns. In this study, the concentration of dissolved Te in the Changjiang （Yangtze） River estuary and nearby waters was determined in May 2009 by hydride-generation atomic fluorescence spectrometry to elucidate the abundance, dominant species, distribution, and relationship with environmental factors. Results show that： （1） dissolved Te was low owing to its low abundance in the Earth＇s crust, high insolubility in water, and strong affinity to particulate matter; （2） Te（IV） and Te（VI） predominated in surface water. Te（VI） was the dominant species in bottom water, and Te（IV） was the minor species; （3） Horizontally, resulting from low phytoplankton metabolism and the weak reduction from Te（VI） to Te（IV） in the shore, Te（IV） was concentrated in the central zone instead of the coastal region. However, Te（VI） was abundant near the mouth of the Changjiang River where the Changjiang water is diluted and in the area to the south where the Taiwan Warm Current invaded. In the adsorption-desorption process, Te（IV） was negatively related to suspended paniculate matter （SPM）, indicating that it was adsorbed by particulate matter. While for Te（VI）, the positive correlation with SPM suggested that it was desorbed from the solid phase. In the estuary, dissolved Te had a negative correlation to salinity. However, it deviated from the dilution line in high-salinity regions due to the invasion of the Taiwan Warm Current and the mineralization of organic matter. The relationship between Te（IV） and SPM nutrients indicated that it was more bioavailable and more related to phosphorus than to nitrogen. Progress in the field is slow and more research is needed to quantify the input of Te to the estuary and evaluate the biochemical role of organisms.