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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.
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Seasonal variability in bacterial abundance, production and protistan bacterivory 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
v virus Physical factors ex. 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).
♠ 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 study conducted in May 2001 (Iriarte et al. 2003).
May 1998 – May 1999 Inorganic nutrients Nitrate, ammonium and phosphate Abundance of heterotrophic microbial plankton Ciliates, small HNF (1-8μm) and heterotrophic bacteria Bacterial production and bacterivory TdR Radioactively labelled bacteria (RLB) Chl a (<1, 1-8, 8-100 μm), PP and extracellular release of carbon (ERC)
Bacteria and protozoa counts a. Bacteria 固定 Glutaraldehyde(1%) b. Heterotrophic flagellates 0.2µm 1-2ml DAPI染色 10-20ml 0.8µm
3H 0.2 µm濾膜 以NaOH固定 • 利用3H-thymidine標定細菌的方式得出細菌的成長與耗損 90 min 過濾 磨碎 閃爍計數儀計數
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 bacterivory This appears to be a general trend in the marine environment (Wikner et al. 1990, Weisse 1999, Ichinotsuka et al. 2006)
Grazing and subtrate control of heterotrophic nanoflagellate abundance Gasol & Vaqué (1993)
♠ 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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