太平洋中西部海域浮游植物营养盐的潜在限制  

Potential nutrient limitation of phytoplankton growth in the Western and Central Pacific Ocean

作　　者：徐燕青[1,2] 陈建芳[1] 高生泉[1] 王奎[1] 金海燕[1] 李洪亮[1] 曾淦宁[2] 

机构地区：[1]国家海洋局第二海洋研究所,国家海洋局海洋生态系统与生物地球化学重点实验室,杭州310012 [2]浙江工业大学化学工程与材料学院海洋系,杭州310014

出　　处：《生态学报》2012年第2期394-401,共8页Acta Ecologica Sinica

基　　金：国际海底区域研究开发"十一五"项目(No.DYXM-115-01-3-3);国家自然科学基金项目(40676044);中国博士后基金(20110491829)

摘　　要：2009年8月至9月期间在太平洋西部N1站和中部N2站进行现场营养盐加富培养实验。结果显示:N1站,浮游植物生物量对N或者P添加都有较强的响应,其中N+P+Si组和N+P组浮游植物长势迅速,叶绿素a从初始的0.03μg/L分别达到2.12μg/L和1.83μg/L,同时P先于N和Si之前被耗尽;说明N1站为N、P共同限制,P是首要限制因子。而N2站,浮游植物生物量仅对N、P共同添加有明显响应,N先于P和Si被浮游植物消耗殆尽。利用培养过程中营养盐比值变化推断,N1站浮游植物以低于Redfield ratio(16N∶1P)吸收N和P;而N2站浮游植物以高于Redfield ratio(16N∶1P)吸收N和P。这可能解释了太平洋西部的寡营养盐海域为潜在P限制,而在太平洋中部海域则为潜在N限制。An increase in N2 fixation by diazotrophic organism due to increased stratification driven by climate changes, may decrease phosphate concentrations and result in P limitation in the oligotrophic upper ocean, which challenges the traditional view that nitrogen is generally the primary nutrient limiting phytoplankton productivity in oceanic waters. Which nutrient, N or P, is the most limiting nutrient for phytoplankton growth in the oligotrophic Pacific Ocean has been on debate over recent years. More studies on nutrient limitation are apparently needed to resolve this debate in the Pacific Ocean. In August and September of 2009, nutrient enrichment bioassays were conducted at two representative stations, N1 （160.58° E, 21.61°N） in the western Pacific Ocean with extremely low nutrient （below detect limit） and Chl a concentrations, and N2 （154.12°W, 10. 12°N） in the eastern Pacific Ocean with shallower nutricline due to the influence of equatorial currents, in order to examine the spatial variability in the potential limiting nutrient for phytoplankton growth in the Pacific Ocean. Nutrients were added in 5 combinations in bioassays： control （no addition）, NO3 ＋PO4（ N＋P）; NO3 ＋SiO4（ N＋ Si）, PO4＋SiO4（P＋Si）, and NO3＋PO4＋SiO4（N＋P＋Si）. The limiting nutrient was judged based on the response of algal biomass and nutrient depletion among treatments. Phytoplankton exhibited different response to nutrient additions at two study sites. Phytoplankton biomass increased dramatically in response to both N and P additions at station N1 where theconcentrations of Chl a increased from 0.03 p^g/L at the beginning to 2.12 p^g/L and 1.83 p^g/L in N＋P＋Si and N＋P treatments at the end of incubation, respectively. However, the maximum Chl a concentration achieved in N＋Si treatment was slight higher than that in and P＋Si treatment. Furthermore, P was depleted before N and Si in the N＋P and N＋P＋Si treatments at station N1. In contrast, algal biomass was significantly

关 键 词：现场培养 营养限制 浮游植物 太平洋 

分 类 号：Q948.8[生物学—植物学]