Study Of The Stream Macroalgae In Xin'An Spring, Shanxi Province

Xin'an Spring is the second largest cold spring in north China. It is located at 36°20′- 36°27′N, 113°26′-113°27′E, in a river valley at the borders between Lucheng, Licheng and Pingshun Counties. It lies to the south of Taihang Mountain, and the area is a mid-low mountain landscape with a continental climate. The spring basin comprises two spring groups: Shihui and Wangqu. Shihui Spring Group includes Anle, Shihui, Dongshu and Beidanche; Wangqu Spring Group includes Xiliu, Wangqu and Nanliu. The spring is almost 16 km long. The annual average rainfall is 586 mm. The water temperature of the spring is 14℃-16℃.From 1995 to 2005, 11 times investigations were undertaken, summing to 167 specimens. In the research, fifty-five species (including varieties) of stream macroalgae have been identified, comprising 6 divisions, 15 families and 30 genera. Chlorophyta was the most diversified division, with 30 species in 7 families and 18 genera. Cyanophyta was ranked as second, with 13 species in 2 families and 6 genera. The third was Xanthophyta, with 7 species in 2 families and 2 genera. In Bacillariophyta, there were 3 species in 2 families and 2 genera. Which was ranking as the last were Rhodophyta and Charophyta, they had only 1 species in 1 family and 1 genus, respectively.There were 6 types of stream macroalgal communities in Xin'an Spring, namely Cladophora community, Chara community, Spirogyra-Zygnema community, Diatoma-Melosira community, Vaucheria community and Batrachospermum community. The morphological forms of stream macroalgae in Xin'an Spring were also reviewed. There were primarily five types, mats, gelatinous colonies, gelatinous filaments, free filaments and tufts. The free filament was the most common form.The distribution characteristics of stream macroalgae in Xin'an Spring were also studied. The results all showed Chlorophyta was the most diversified division, whatever from planar distribution or from the annual comparison.The result of planar distribution of stream macroalgae in Xin'an Spring showed that the total species number reduced from the headwater to downwater (SXXAS1→SXXAS2→SXXAS3→SXXAS4). The result of annual comparison of stream macroalgae in Xin'an Spring indicated that the total species number was approximately increasing along with the temporal process. The result of comparison of stream macroalgae in Xin'an Spring with other areas in the world showed the Sorensen similarity indices were all very low. Maybe because the stream water comes out of the underneath or near the spring mouth, so they can't easily cross with each other like river or lake. It also showed that the stream macroalgae in different locations have significant reproductive isolation.Effects of environmental factors on stream macroalgae in Xin'an Spring were studied from July 2004 to April 2005, including the influences on the species number, species richness and percent cover. The statistical analysis methods of Pearson correlation coefficient and Principal component analysis (PCA) were applied. The analysis result of Pearson correlation coefficient showed that the species richness per sampling segment was negatively correlated with pH. Principal component analysis revealed that no single variable had much influence on the macroalgal seasonal dynamics.In this research, grey correlative-regression analysis method was applied to investigate the influence of enviornmental factors on the species number of stream macroalgae. The result showed the key factors that affect the species number of stream macroalgae in Xin'an Spring were water temperature, current velocity and specific conductance; but the maximum depth and width influenced at least. The established linear regression model also abetted this conclusion.In this paper, phenology of Batrachospermum acuatum and Chara vulgaris were studied.The results of phenology of Batrachospermurn acuatum indicated that there were seven morphological characteristics had significant seasonal differences, only three haven't seasonal differences. There were eight maximum values of morphological characteristics observed in spring (April-2005), and the entire minimum values observed in summer (July-205). This illuminated that B. acuatum could grow well in spring when the temperature was relatively low, but reversely bad in summer. There were significant positive correlations among the morphological characteristics. It indicated that the growth and development of B. acuatum were isochronous. The relationship between environmental factors and morphological characteristics showed there was only negative correlation between carpogonium length and pH. It opened out that in spite of the development of B. acuatum was affected by environmental factors in some extent, but the settled factor still was its own biological rhythm.The phenology of Chara vulgaris in Xin'an Spring was also studied. The results showed that all the morphological characteristics had seasonal dynamics in different extent, and some of them had significant fluctuations, which indicated difference in their seasonality. There were nine maximum values of morphological characteristics observed in fall (October-2004), and among the nine morphological characteristics there were four sexual reproductive characteristics. Undoubtedly, this can illuminate there is hearty reproductive ability of C. vulgaris in fall. The analysis of relationship between environmental factors and morphological characteristics showed there were some correlations, but the correlations were only between some environmental factors and the vegetative proportion of the frond, but the reproductive characteristics were relatively steady. So the sexual reproductive characteristics were usually used to identify the species.Epiphytic algae on three stream macroalgae (Chara vulgaris, Cladophora fracta and Batrachospermum acuatum) in Xin'an Spring were also studied. The result showed that epiphytic algal species number on the three stream macroalgae was different and the predominance division was Bacillariophyta. There was an obvious seasonal trend in the species number of epiphytic algae: spring＞autumn＞summer＞winter. The grey correlative analysis indicated that the environmental factors had some influence on the epiphytic algae, and the most key factors were current velocity, maximum depth and specific conductance.Finally, the survival crises of stream macroalgae in Xin'an Spring were analyzed and in view of this situation, some conservation strategies were suggested in this paper.