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Seasonal variability in bacterial abundance, production and protistan bacterivory in the lower Urdaibai estuary, Bay of Biscay 西班牙畢斯蓋灣 Urdaibai 下游河口細菌數量 . 生產力與原生生物攝食 細菌的季節性變化 Arantza Iriarte*, Aitziber Sarobe, Emma Orive. AQUATIC MICROBIAL ECOLOGY Vol. 52: 273–282, 2008. - PowerPoint PPT Presentation
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Seasonal variability in bacterial abundance, production and protistan bacteriv
ory in the lowerUrdaibai estuary, Bay of Biscay
西班牙畢斯蓋灣 Urdaibai 下游河口細菌數量 .生產力與原生生物攝食細菌的季節性變化
Arantza Iriarte*, Aitziber Sarobe, Emma Orive
AQUATIC MICROBIAL ECOLOGY
Vol. 52: 273–282, 2008
Reporter: Sheng-Hsuan Wu
Introduction
virus
Physical factorsex. temp. supply of substrate(Revilla et al. 2000, Schultz et al. 2003, Staroscik & Smith 2004)
In many estuaries, temperature has been shown to exert a strong influence on bacterial activity (Schultz et al. 2003, McManus et al. 2004, Staroscik & Smith, 2004).
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Seasonal variations in bacterial abundance and production rates were measured in thisestuarine zone in a previous work (Revilla et al. 2000).Bacterivory rates were measured in another studyconducted in May 2001 (Iriarte et al. 2003).
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Materials and Methods
May 1998 – May 1999
Inorganic nutrientsNitrate, ammonium and phosphate
Abundance of heterotrophic microbial planktonCiliates, small HNF (1-8μm) and heterotrophic bacteria
Bacterial production and bacterivoryTdRRadioactively labelled bacteria (RLB)
Chl a (<1, 1-8, 8-100 μm), PP and extracellular release of carbon (ERC)
Bacteria and protozoa counts
a. Bacteria
b. Heterotrophic flagellates
Glutaraldehyde(1%)
1-2ml
10-20ml
DAPI 染色
0.2µm
0.8µm
固定
• 利用 3H-thymidine標定細菌的方式得出細菌的成長與耗損
3H
90 min
以 NaOH 固定
過濾
磨碎閃爍計數儀計數
0.2 µm 濾膜
Results and Discussion
Seasonal variation in bacterial production
Seasonal variation in bacterial production
A similar pattern has been observed in other low productivity, high salinity estuarine zones (e.g. the lower Schelde estuary, Goosen et al. 1997)
Seasonal variation in bacterial production
Seasonal variation in bacterivory
This appears to be a general trend in the marine environment (Wikner et al. 1990, Weisse 1999, Ichinotsuka et al. 2006)
Seasonal variation in bacterivory
Grazing and subtrate control of heterotrophic nanoflagellate abundance
Gasol & Vaqué (1993)
Conclusion
Substrate supply exerts a more important control than temperature on BP and growth.
Small HNF consumed larger amounts of bacteria than ciliates did, but bacteria were not the only food supply for small HNF.
Small HNF consumed larger amounts of bacteria than ciliates did, but bacteria were not the only food supply for small HNF.
Small HNF were largely under a substrate supply (bottom-up) control.
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The End! Thank you~