Contreras Jorge Jimenez, Sarma S S S, Merino-Ibarra Martin, Nandini S
Laboratory of Aquatic Zoology, Division of Research and Postgraduate Studies National Autonomous University of Mexico, Los Reyes, Tlalnepantla State of Mexico, Mexico.
J Environ Biol. 2009 Mar;30(2):191-5.
We studied the zooplankton community composition at different depths (2, 4, 8, 12 and 20 m) of Valle de Bravo, a drinking water reservoirin central Mexico during December 2005 to November 2006. Temperature, dissolved oxygen, pH and chlorophyll a were measured simultaneously. While physicochemical values were similar to those found in previous studies, total zooplankton abundance was higher (mean 847 ind. l(-1)), doubling the mean abundance found in the previous year. Nevertheless, Zooplankton remained dominated by the rotifer genera Keratella, Polyarthra and Trichocerca, which constituted nearly 80% of the total numerical abundances. We encountered 23 rotifer species of which 5 of them (Lepadella rhomboides, Cephalodella catellina, Trichocerca elongata, T porcellus and Dicranophorus forcipatus) were recorded for the first time from this reservoir. Shannon Wiener diversity index showed that the annual mean species diversity index was similar at depths of 2, 4 and 8 m, but were reduced at 12 and 20 m. Regardless of depth, the highest diversity value of 1.82 was observed during January, while the lowest (0.07) during March. Principal component analysis showed that temperature, dissolved oxygen, water column depth and chlorophyll a have combined effects on the abundance of dominant rotiferspecies. The highest rotifer density was observed in April (> 1600 individuals l(-1)), while the lowest was recorded during January (<50 ind. l(-1)). During the study period, the most abundant rotifer species were Keratella chochlearis, Polyarthra vulgaris, Trichocecra elongata and Anuraeopsis fissa.
2005年12月至2006年11月期间，我们对墨西哥中部饮用水水库巴耶德布拉沃不同深度（2米、4米、8米、12米和20米）的浮游动物群落组成进行了研究。同时测量了温度、溶解氧、pH值和叶绿素a。虽然理化值与之前研究中的值相似，但浮游动物总丰度更高（平均847个个体/升），是上一年平均丰度的两倍。尽管如此，浮游动物仍以轮虫属的角突臂尾轮虫、多肢轮虫和三肢轮虫为主，它们占总数量丰度的近80%。我们共发现23种轮虫，其中5种（菱形鞍甲轮虫、卡氏头冠轮虫、长三肢轮虫、猪吻三肢轮虫和叉形巨腕轮虫）是首次在该水库记录到。香农-维纳多样性指数表明，2米、4米和8米深度处的年平均物种多样性指数相似，但在12米和20米深度处降低。无论深度如何，1月份观察到的最高多样性值为1.82，而3月份最低（0.07）。主成分分析表明，温度、溶解氧、水柱深度和叶绿素a对优势轮虫物种的丰度有综合影响。4月份观察到最高的轮虫密度（>1600个个体/升），而1月份记录到最低密度（<50个个体/升）。在研究期间，最丰富的轮虫物种是螺形龟甲轮虫、普通多肢轮虫、长三肢轮虫和裂足臂尾轮虫。
