STUDIES ON THE MANGROVE ECOSYSTEM OF THE JIULONGJIANG RIVER ESTUARY IN CHINA III. ACCUMULATION AND BIOLOGICAL CYCLE OF CALCIUM AND MAGNESIUM IN Kandelia candel COMMUNITY

This is a paper dealing mainly with the accumulation and biological cycle of calcium and magnesium elements of the artificial 20-years old Kandelia candel community in the Jiulongjiang River Estuary of Fujian Province, China. The result of measurements is that the quantities of the two elements in the standing crop are (kg·ha-1) 772.91 for Ca and 526.57 for Mg. In the biological cycle of the two elements, the annual uptakes are 174.86 for Ca and 89.30 for Mg (kg·ha-1); the amounts of Ca and Mg returned via litter fall are estimated to be (kg·ha-1·a-1) 103.28 for Ca and 40.42 for Mg; the annual retention are (kg·ha-1·a-1) 71.58 for Ca and 48.88 for Mg, respectively. The turnover periods of Ca and Mg are 8 and 13 years, respectively.     

STUDIES ON THE MARINE CLADOCERA OF CHINA Ⅲ. REPRODUCTION

Studies are made on the reproduction of two common marine Cladocera (Penilia avirostris, Evadne ter-gestina) of China with emphasis on the fertility of parthenogenetic females (P♀). A positive correlation exists between the fertility and the size of the same species; but no such correlation is found between the fertility and the size of different species. The fertility is, on the whole, higher in summer and is related to the seasonal fluctuation of population density, both attaining their maximum period in summer; but the former appears about half a month earlier than the latter, A brief account is given of the sexual reproduction, including the respective size and the seasonal variation of sexual individuals (S♀,♂) together with a note on the sex-ratio and the characteristics of resting egg.     

STUDIES ON THE CULTURE OF CHAETOCEROS MUELLERI LEMMERMANTHE EFFECT OF SEA SOIL EXTRACT AND VARIOUS NITROGEN SOURCES ON THE RATE OF GROWTH

This paper shows that the use of sea soil extract instead of vitamin and biotin to culture Chaet. muelleri is possible. The effect of the different nitrogen sources on Chaetoceros muel-leri was studied in order to suggest a more simple and better fertilizer for the mass culture of this species.     

ON THE AGE AND GROWTH OF Pseudopleuronectes yokohamae (GUNTHER) IN THE BOHAI SEA

The present paper deals with the age and growth of P. yokohamae, whose specimens were collected monthly from April 1982 to May 1983 by trawl in the Bohai Sea. In the study the age and growth of P. yokohamae is determined by annual ring on otolith. On the basis of calculation of monthly changes in appearing frequency for opaque zones on the otolith edgs it is determined that the annual ring of P. yokohamae is formed in January-March every year.The relation of the standard length to the body weight is W=3.2×10-5L2.3018. The relationship between the otolith radius and the standard length is R=-5.43× 10-3 1.71 ×10-2L- 1.20× 10-5L2. The growth for this species is expressed by von-Bertalanffy equation, Lt = L∞[1-e-K(t-t0)], where L∞ = 418mm, t0 = -0.7475 and K=0.252.The P. yokohamae grows faster at the age of 1-2, but slower after two years old. The coordinate of weight-growth inflexion point is at t =3.84 and W=386 g.     

INVESTIGATION ON THE EFFECT OF ACCELERATING SILT ACCUMULATION OF THE COMPOSITE PROJECT OF GROIN SYSTEM AND DETACHED DYKEANALYSIS OF THE DDSGSHAN ACCELERATING BEACH ACCRETION PROJECT IN RUIAN,ZHEJIANG PROVINCE

In this paper the effect of accelerating silt accumulation of the composite project of groin system with different spacings and detached dyke constructed on the silt coast is analysed, taking Dingshan accelerating beach accretion project in Ruian County of Zhejiang Province as an example. The above-mentioned is discussed from the aspects of deposit pattern of the beach surface, rule of deposition and deposition rate within the groin basins. On the basis of these analysed results, the principle of overall layout for constructing this kind of project and the proposals for selecting the rational structures are presented.     

THE EFFECT OF FOUR HEAVY METALS ON THE GROWTH RATE AND CHLOROPHYLL CONTENT OF Chaetoceros muelleri LEMMERMANN

Chaetoceros muelleri Lemmermann was cultured in solution of different concentrations of Cu2 , Pb2 , Zn2 and Cd2 , and in mixtures of any two of them. After 6 days the effect of these heavy metal cations on the growth rate and chlorophyll contents of the diatom were determined and an Opton microscope was used to observe the morphology and size of the cells.The experimental results show that the effects of toxicity of these four heavy metals on Chaetoceros muelleri are: Cu2 >Pb2 >Zn2 >Cd2 . However, the cells did not differ significantly in their morphology and size from the controled ones.In any of the mixed metals cultures, its growth rate came close to and was higher than that of the single metal culture of higher concentration.     

A PRELIMINARY STUDY ON THE CIRCULATION RELATED OF THE COLD WATER-MASS OF THE YELLOW SEA I. THE THERMAL STRUCTURE AND THE CHARACTERISTICS OF THE CIRCULATION IN THE CENTRAL PART OF THE

This paper is a preliminary study on the hydrodynamical model describing the thermal stucture and the properties of circulation, related to the Cold Water-mass of yellow Sea. From analysis of observations we obtain following five characteristics: 1. The variation of temperature is larger than that of salt, the variation of density is, therefore, essentially dependent on the variation of temperature. The state equation of the sea water may be approximately written as ρ=ρo(1—aT). There is a thermocine layer which varies with season, and divides the Cold Water-mass into upper and lower homo-     

PALEOMAGNETIC STUDY OF Dc1 AND Dc2 CORES IN THE EAST CHINA SEA

We got two cores from 10 miles east of Zhoushan islands about 29 m in water depth in 1979 and 1980.Dc1 core, 26 m long, can be divided into two layers; 0-19.4 m, brown-yellow, silty-clay, rich in foraminifera, 19.3-26 m, grey silt. DC1 core, 91 m long, 7 miles south of DC1 core. The colour for 0-16.6 m is the same as for 0-19.4 m of Dc2 core, brown silty-clay, rich in foraminifera too. The results of paleomagnetic measurements show: there are 464 specimens in DC1 and Dc2 cores altogether; AF demagnetization often shows that 95 % of all the specimens belong to normal polarity epoch, and the others are reversal ones.We consider that more stranger intensity may represent the warming period and transgression period, and vice versa. At least DC, and Dc2 cores provide such an evidence for this. It is obvious that glacial period should be low peak period of intensity, and interglacial period should be its high peak period.