Variability of UVR effects on photosynthesis of summer phytoplankton assemblages from a tropical coastal area of the South China Sea

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	Variability of UVR effects on photosynthesis of summer phytoplankton assemblages from a tropical coastal area of the South China Sea
	Gao, Kunshan ; Li, Gang ; Helbling, E. Walter ; Villafane, Virginia E.
	2007
会议名称	33rd Annual Meeting of the American-Society-of-Photobiology
会议日期	JUL, 2006
会议地点	San Juan, PR
关键词	SOLAR ULTRAVIOLET-RADIATION TEMPERATE MARINE-PHYTOPLANKTON B RADIATION ARGENTINA PATAGONIA DNA SENSITIVITY ESTUARY DIATOMS IMPACT
页码	802-809
通讯作者	Gao, KS, Shantou Univ, Inst Marine Biol, Shantou, Guangdong, Peoples R China
中文摘要	From June to September 2005, we carried out experiments to determine the ultraviolet radiation (UVR) -induced photoinhibition of summer phytoplankton assemblages from a coastal site of the South China Sea. Variability in taxonomic composition was determined throughout the summer, with a peak chlorophyll a (chl a similar to 20 mu g chl a L-1) dominated by the diatom Skeletonema costatum that was detected early in the study period; the rest of the time samples were characterized by monads and flagellates, with low chi a values (1-5 chl a mu g L-1). Surface water samples were placed in quartz tubes, inoculated with radiocarbon and exposed to solar radiation for 2-3 h to determine photosynthetic rates under three quality radiation treatments (i.e. PAB, 280-700 nm; PA, 320-700 nm and P, 400-700 nm) using different filters and under seven levels of ambient irradiance using neutral density screens (P vs E curves). UVR inhibition of samples exposed to maximum irradiance (i.e. at the surface) varied from -12.2% to 50%, while the daytime-integrated UVR-related photoinhibition in surface seawater varied from -62% to 7%. The effects of UVR on the photosynthetic parameters p(max)(B) and E-k were also variable, but UV-B accounted for most of the observed variability. During sunny days, photosynthesis of microplankton ( > 20 mu m) and piconanoplankton ( < 20 mu m) were significantly inhibited by UVR (mostly by UV-B). However, during cloudy days, while piconanoplankton cells were still inhibited by UVR, microplankton cells used UVR (mostly UV-A) as the source of energy for photosynthesis, resulting in higher carbon fixation in samples exposed to UVR than the ones exposed only to photosynthetically active radiation (PAR). Our results indicate that size structure and cloudiness clearly condition the overall impact of UVR on phytoplankton photosynthesis in this tropical site of South China. In addition, model predictions for this area considering only PAR for primary production might have underestimated carbon fixation due to UVR contribution.
收录类别	SCI
会议主办者	Amer Soc Photobiol
会议录	PHOTOCHEMISTRY AND PHOTOBIOLOGY
语种	英语
WOS记录号	WOS:000248537200005
内容类型	会议论文
源URL	[http://ir.ihb.ac.cn/handle/342005/11761]
专题	水生生物研究所_中科院水生所知识产出（2009年前）_会议论文
推荐引用方式 GB/T 7714	Gao, Kunshan,Li, Gang,Helbling, E. Walter,et al. Variability of UVR effects on photosynthesis of summer phytoplankton assemblages from a tropical coastal area of the South China Sea[C]. 见:33rd Annual Meeting of the American-Society-of-Photobiology. San Juan, PR. JUL, 2006.