Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance ...Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.展开更多
A survey of the seasonal distribution of macroalgae in a stream system in Shanxi Province, north China, was undertaken from July 2004 to April 2005. The relative abundance and percentage cover of macroalgae, and sever...A survey of the seasonal distribution of macroalgae in a stream system in Shanxi Province, north China, was undertaken from July 2004 to April 2005. The relative abundance and percentage cover of macroalgae, and several environmental factors were monitored along a 20-m stretch at each of four sites, at intervals of approximately three months （one sampling per season）. Several stream conditions were relatively constant over the sampling period （pH, maximum width and maximum depth）, whereas others exhibited a distinct seasonal pattern （water temperature and specific conductance）, and some fluctuated with no discernable seasonal pattern （current velocity and dissolved oxygen）. Forty-two species of macroalgae were found, with a predominance of Chlorophyta （26 species, 61.9%）. Rhodophyts and Charophyta represented the smallest proportion （1 species each, 2.38%）. Six macroalgae species were the most widespread, occurring in all four sampling sites. Twelve species were found at only one site each. In terms of seasonality, eight species occurred throughout the year, whereas 16 species were found in only one season each. The macroalgal community at Xin＇an Spring was species rich relative to other streams. Species richness per sampling site was negatively correlated with pH. Principal component analysis revealed that no single variable had much influence on the macroalgal seasonal dynamics. We calculated Sorensen similarity indices to compare our study with other continent-wide surveys of stream macroalgae, but the similarity indices were all very low. This study also shows that macroalgae in different locations have significant reproductive isolation.展开更多
基金Supported by the National Nature Science Foundation of China (No. 30470118 and 30270119)the Nature Science Foundation of Shanxi Province, China (No. 20021079).
文摘Fourteen stream segments were investigated throughout the Xin’an Spring in Shanxi Province, China in 2004. The variation ranges in stream size, current velocity, discharge, dissolved oxygen, and specific conductance were large. Twenty-two macroalgae species were found in the stream. Major divisions in terms of species numbers were Chlorophyta (59.1%), Cyanophyta (22.8%), Xanthophyta (9.1%), Rhodophyta (4.5%) and Charophyta (4.5%). The most widespread species, Cladophora rivularis (50.0%), also Oedogonium sp. (42.9%) and Spirogyra sp. (42.9%) were well represented throughout the stream, whereas another 10 species were found in only one sampling site. Total percentage cover varied from <1% to 90%. Red algae Batrachospermum acuatum and the charophytes Chara vulgaris have the highest percentage cover. Among the parameters analyzed, the stream width, specific conductance and dissolved oxygen were the ones that more closely related to the species number and percentage cover of macroalgal communities. The species number of each site was negatively correlated with dissolved oxygen content. The total percentage cover of the macroalgae was negatively correlated with the stream width and the specific conductance.
文摘A survey of the seasonal distribution of macroalgae in a stream system in Shanxi Province, north China, was undertaken from July 2004 to April 2005. The relative abundance and percentage cover of macroalgae, and several environmental factors were monitored along a 20-m stretch at each of four sites, at intervals of approximately three months （one sampling per season）. Several stream conditions were relatively constant over the sampling period （pH, maximum width and maximum depth）, whereas others exhibited a distinct seasonal pattern （water temperature and specific conductance）, and some fluctuated with no discernable seasonal pattern （current velocity and dissolved oxygen）. Forty-two species of macroalgae were found, with a predominance of Chlorophyta （26 species, 61.9%）. Rhodophyts and Charophyta represented the smallest proportion （1 species each, 2.38%）. Six macroalgae species were the most widespread, occurring in all four sampling sites. Twelve species were found at only one site each. In terms of seasonality, eight species occurred throughout the year, whereas 16 species were found in only one season each. The macroalgal community at Xin＇an Spring was species rich relative to other streams. Species richness per sampling site was negatively correlated with pH. Principal component analysis revealed that no single variable had much influence on the macroalgal seasonal dynamics. We calculated Sorensen similarity indices to compare our study with other continent-wide surveys of stream macroalgae, but the similarity indices were all very low. This study also shows that macroalgae in different locations have significant reproductive isolation.
