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Diel patterns in the abundance of photosynthetic picoeukaryotes in the coastal waters northeast of Taiwan
|Authors: ||Lin, Jie-Sian|
picoeukaryotes;prasinophytes;haptophytes;diel patterns;growth rate;grazing rate
|Issue Date: ||2017-11-15T08:45:42Z
|Abstract: ||超微真核藻類 (< 3μm; photosynthetic picoeukaryotes)，是在大洋中重要的基礎生產力的貢獻者。本研究主要目的是要了解台灣東北沿岸海域不同種類的超微真核藻類日夜數量變動，並利用分割培養法量測其成長率與被攝食率。研究結果顯示，整體超微真核藻類與聚球藻的數量變動經常是同步變動，白天數量較晚上低，其原因可能是超微真核藻類在白天成長，當晚上時數量達到高值時，會受Top-down control造成數量下降。以種類組成來看，青綠藻 (prasinophyte) 數量平均佔超微真核藻類的21%，其數量變動與聚球藻的數量同步。而著鞭毛藻 (haptophyte) 的數量平均佔超微真核藻類的12%，其數量變動與聚球藻較不同步，其原因可能是著鞭毛藻多行混營方式生活。根據分割培養法的結果顯示，青綠藻與著鞭毛藻之成長率大多高於被攝食率，在整體超微真核藻類的平均攝食可佔成長之80%，但攝食率與野外的情況並不一致，因此未來須研發更加靈敏的方法去量測不同種超微真核藻類之死亡率。|
Photosynthetic picoeukaryotes (< 3μm) are the major contributors to primary productivity in various marine systems. The objectives of this study was to investigate the diel variations in abundance of different photosynthetic picoeukaryote taxonomic groups in the coastal water northeast of Taiwan. Size fractionation was applied to measure their growth rate and grazing rate. Our results indicated that photosynthetic picoeukaryotes always follow Synechococcus in fluctuation of abundance. Abundance of Synechococcus is higher in nighttime than in daytime, probably because photosynthetic picoeukaryotes grow in the daytime. After reaching maximum at night, the abundance declined due to the the top-down control by their consumers. For taxonomic composition in photosynthetic picoeukaryotes, abundance of prasinophytes on average is 21% of the total picoeukaryotes which fluctuated synchronously with Synechococcus. Abundance of haptophytes on average is 12% of the total picoeukaryotes, but does not fluctuate synchonously with Synechococcus, probably due to the mixotrohic life history of the haptophytes. Our results of size fractionation experiments show that the growth rate of prasinophytes and haptophytes are often higher than grazing mortality. Furthermore, in picoeukaryotes, the grazing mortality removes about 80% of the growth rate in the total population. But grazing mortality measured in laboratory is seldom identical with that in the field. We should develop more precise and sensitive approaches to measure grazing rate of different kinds of taxonomic among photosynthetic picoeukaryotes.
|Appears in Collections:||[海洋環境與生態研究所] 博碩士論文|
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