Reproductive rate of a marine planktonic copepod Labidocera euchaeta Giesbrecht in Xiamen Harbor was studied during the period from April 1986 to August 1987. Results showed that rate of egg production (F, eggs/(,d)) ...Reproductive rate of a marine planktonic copepod Labidocera euchaeta Giesbrecht in Xiamen Harbor was studied during the period from April 1986 to August 1987. Results showed that rate of egg production (F, eggs/(,d)) was positively correlated with temperature (T,℃) ) and body weight of spawning female (We,ugC ) as: F=0.0637 (T-7)0.7445Wc. Each month a maximum rate of egg production occurred at one of the five experimental temperatures (10°, 15°, 20°, 25°, and 30℃) near the monthly mean field temperature. The available food density (P, ugC/ml) had significant effect on specific rate of egg production (Fc, %C/d) as :Fc=0.1732(P-0.0179)/P. The gross efficiency of egg production of ca 62% in carbon was independent of food density snd ingestion rate. Observations on in situ egg production and hatching rate demonstrated that this species reproduces continuously all the year round, with summer as its high reproductive season and winter a low one. Ten generations a year is also suggested based on the展开更多
Observations on gonad development of 84 species of marine fishes in Jiaozhou Bay waters showed the breeding periods of more than 50 of these species are mostly from April to August, with peaks between May to June. A g...Observations on gonad development of 84 species of marine fishes in Jiaozhou Bay waters showed the breeding periods of more than 50 of these species are mostly from April to August, with peaks between May to June. A great many of the species spawn in the warm season, only a few species in the cold season. The number of spawning species increases with the rise and decreases with the fall in water temperature. The absolute fecundity of 50 teleost species, which usually increases with body length and weight, was estimated to range from about 300 to 9,000,000 eggs. The reproductive patterns of fishes in Jiaozhou Bay waters are discussed.展开更多
We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurife...We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.展开更多
文摘Reproductive rate of a marine planktonic copepod Labidocera euchaeta Giesbrecht in Xiamen Harbor was studied during the period from April 1986 to August 1987. Results showed that rate of egg production (F, eggs/(,d)) was positively correlated with temperature (T,℃) ) and body weight of spawning female (We,ugC ) as: F=0.0637 (T-7)0.7445Wc. Each month a maximum rate of egg production occurred at one of the five experimental temperatures (10°, 15°, 20°, 25°, and 30℃) near the monthly mean field temperature. The available food density (P, ugC/ml) had significant effect on specific rate of egg production (Fc, %C/d) as :Fc=0.1732(P-0.0179)/P. The gross efficiency of egg production of ca 62% in carbon was independent of food density snd ingestion rate. Observations on in situ egg production and hatching rate demonstrated that this species reproduces continuously all the year round, with summer as its high reproductive season and winter a low one. Ten generations a year is also suggested based on the
基金This paper was presented at the Ⅳ International Congress of Ecology, held at Syracuse, USA in August, 1986 Contribution No. 1553 from the Institute of Oceanology, Academia Sinica.
文摘Observations on gonad development of 84 species of marine fishes in Jiaozhou Bay waters showed the breeding periods of more than 50 of these species are mostly from April to August, with peaks between May to June. A great many of the species spawn in the warm season, only a few species in the cold season. The number of spawning species increases with the rise and decreases with the fall in water temperature. The absolute fecundity of 50 teleost species, which usually increases with body length and weight, was estimated to range from about 300 to 9,000,000 eggs. The reproductive patterns of fishes in Jiaozhou Bay waters are discussed.
基金funded by Algerian Ministry of Higher Education and Scientific Research through the Project(CNEPRU No.D04N01UN170120140017)
文摘We used energy dispersive X-ray fluorescence（EDXRF） to determine the seasonal variation of selected trace elements（Cr, Mn, Zn, Cu, Se and Fe） and some potential toxic elements（Cd, Pb and Br） in Juniperus thurifera subsp. africana Maire（Cupressaceae） a rare medicinal tree, growing indigenously in Aures Mountains of Algeria. The precision of the results was assessed by analyzing the certified reference material IPE44（WEPAL）grass leaves. Results showed J. thurifera was characterized by high Cr and Mn contents. During autumn and winter mineral concentrations were higher in general. The levels of Cr, Se and Mn were higher during autumn and winter than during spring and summer. Zn contents were higher during summer than in other seasons. Cu content did not vary by season. The potential toxic elements in J. thurifera（Pb [ Cd [ Br） were below the permissible limits recommended by the Joint WHO/FAO guidelines except for Pb in autumn and winter.
