The temporal-spatial variation of bacterioplankton in the upwelling region, East China Sea

本研究利用2003 年10 月至次年11 月期間，在台灣東北角湧升流區的10 個航次資料，分析初級生產力(97~1614 mg C m-2 d-1)、細菌生物量(2.54~17.5 mgC m-3)、細菌生產力(0.34~22.9 mgC m-3 d-1)、細菌置換率(=細菌生產力/細菌生物量；0.03~2.66 d-1)及其他 水文參數的時空變異。湧升流在冬季初春(1~4 月)規模較大，水體平均溫度較低(21~25℃)，硝酸鹽(最大值12.8 µM)及磷酸鹽（最大值1.00 µM）在有光層內濃度較高。在黑潮入侵期間(5 月及8~10 月)，湧升規模較小，有光層內硝酸鹽及磷酸鹽濃度最大值則較低，分別為3.8 µM 及0.27 µM。研究區硝酸鹽對磷酸鹽莫爾比值為5.7，對植浮來說可能為一氮限制的環境。在湧升流區硝酸鹽與細菌生產力及其置換率呈正相關，暗示此區細菌活性(生產力與置換率)可能受到無機氮鹽供應的控制。本研究最獨特的發現是：湧升流區初級生產力與細菌活性在季節的分佈上，呈現非耦合(decoupling)現象，亦即高初級生產力出現於6~7 月及11 月，而細菌活性的高值則是出現於1~4 月及9 月。推論在冬季春初時為一個低光照，營養鹽較高，但溫度(>20℃)仍適宜細菌生長的環境，細菌較植浮更具競爭營養鹽的優勢；在夏季與秋季時，營養鹽低，但在高光照的條件下，植浮藉由轉化為體型較小的群聚以及改變本身對貧營養鹽的較高耐受性，在競爭營養鹽的過程中取得優勢。論文中也針對本調查所得的非耦合性現象與前人研究所提出的phytoplankton-bacteria paradox 理論的關聯性，進行討論。本研究可能是第一個野外調查 報告，顯示植浮–細菌非耦合現象也會出現在營養鹽供應較為充裕的湧升流區。Primary productivity (97~1614 mg C m-2 d-1), bacterial biomass (2.54~17.5mgC m-3),bacterial productivity (0.34~22.9 mgC m-3 d-1), bacterial turn-over rate (=BP/BB; 0.03~2.66d-1), and physical-chemical hydrography in the upwelling region, southern of East China seawere examined for their temporal-spatial variation based on observations during October,2003~November, 2004. Strengthened upwelling was dominant during the winter and earlyspring (January ~April) with lower temperature value (21~25℃), highnitrogen conc.(maximum:12.8 µM) and phosphate conc. （maximum:1.00 µM） in the euphotic zone. During the Kuroshio intrusion (May and August~ October), the upwelling current was un-dominantwith low nutrient concentration. The NP ration was 5.7 in this studying region. It implied that the upwelling region was an N-limitation environment for phytoplankton. Nitrogen concentration in the upwelling region was shown associated with bacterial productivity and turn-over rate that implied bacterial activity was controlled by the nitrogen supply. Especially,there was the decoupling appearance between primary productivity and bacterial activity in the upwelling region. This is, the primary productivity was high during June ~July, but bacterial activity during January ~April. and in Sep. There was a suitable for bacteria with low illumination, high nutrient conc., more optimal temperature (>20℃) in the winter and early spring when bacteria had the advantage over phytoplankton. In the summer and autumn when there was a low nutrient conc. and high illumination, the phytoplankton took more advantage over the bacteria by transferring their community composition to smaller size and better oligotrophic enduring-ability. Further more, this study discussed the relationship between this decoupling appearance and phytoplankton-bacteria paradox from pre-researches. It is possible that this study is the first reporter about the decoupling appearance between phytoplankton-bacteria in the nutrient-laden upwelling region.目錄………………………………………i 表目錄……………………………………ii 圖目錄……………………………………ii 中文摘要…………………………………iii 英文摘要…………………………………iv 前言………………………………………1 材料與方法………………………………4 結果………………………………………8 討論………………………………………12 結論………………………………………19 參考文獻…………………………………20 表列………………………………………24 圖列………………………………………28 附錄1……………………………………40 附錄2……………………………………4