Examination of Silicate Limitation of Primary Production in Jiaozhou Bay, China Ⅱ. Critical Value and Time of Silicate L
Analysis and comparison of Jiaozhou Bay data collected from May 1991 to February1994 revealed the spatiotemporal variations of the ambient Si(OH)4 :NO3 (Si:N) concentration ratios and the seasonal variations of (Si: N) ratios in Jiaozhou Bay and showed that the Si: N ratioswere ＜ 1 throughout Jiaozhou Bay in spring, autumn, and winter. These results provide furtherevidence that silicate limits the growth of phytoplankton (i.e. diatoms) in spring, autumn and win-ter. Moreover, comparison of the spatiotemporal variations of the Si: N ratio and primary productionin Jiaozhou Bay suggested their close relationship. The spatiotemporal pattern of dissolved silicatematched well that of primary production in Jiaozhou Bay.Along with the environmental change of Jiaozhou Bay in the last thirty years, the N and P con-centrations tended to rise, whereas Si concentration showed cyclic seasonal variations. With thevariation of nutrient Si limiting the primary production in mind, the authors found that the range ofvalues of primary production is divided into three parts: the basic value of Si limited primary pro-duction, the extent of Si limited primary production and the critical value of Si limited primary pro-duction, which can be calculated for Jiaozhou Bay by Equations (1), (2) and (3), showing thatthe time of the critical value of Si limitation of phytoplankton growth in Jiaozhou Bay is around No-vember 3 to November 13 in autumn; and that the time of the critical value of Si satisfaction of phy-toplankton growth in Jiaozhou Bay is around May 22 to June 7 in spring. Moreover, the calculatedcritical value of Si satisfactory for phytoplankton growth is 2.15 - 0.76μmol/L and the critical val-ue of Si limitation of phytoplankton growth is 1.42- 0.36 μmol/L; so that the time period of Silimitation of phytoplankton growth is around November 13 to May 22 in the next year; the time peri-od of Si satisfactory for phytoplankton growth is around June 7 to November 3. This result also ex-plains why critical values of nutrient silicon affect phytoplankton growth in spring and autumn aredifferent in different waters of Jiaozhou Bay and also indicates how the silicate concentration affectsthe phytoplankton assemblage structure. The dilution of silicate concentration by seawater exchangeaffects the growth of phytoplankton so that the primary production of phytoplankton declines outsideJiaozhou Bay earlier than inside Jiaozhou Bay by one and half months. This study showed thatJiaozhou Bay phytoplankton badly need silicon and respond very sensitively and rapidly to the varia-tion of silicon.
作 者： 杨东方 张经 高振会 陈豫 孙培艳 作者单位： 杨东方(College of Fishery Science, Shanghai Fisheries University, Shanghai 200090, China;Beihai Monitoring Center of State Oceanic Administration, Qingdao 266033, China;Key Laboratory of Science and Engineering for Marine Ecological Environment, State Oceanic Ad)张经(College of Chemistry and Chemical Engineering, Ocean University of Qingdao, Qingdao 266003, China;State Key Laboratory of Estuarine and Coastal Research, East China Nornal University, Shanghai 200062, China)
高振会,孙培艳(Beihai Monitoring Center of State Oceanic Administration, Qingdao 266033, China)
陈豫(College of Computer Science, Shanghai Fisheries University, Shanghai 200090, China)
刊 名： 中国海洋湖沼学报(英文版) ISTIC SCI 英文刊名： CHINESE JOURNAL OF OCEANOLOGY AND LIMNOLOGY 年，卷(期)： 2003 21(1) 分类号： P7 关键词： phytoplankton limitation and satisfaction critical value Jiaozhou Bay