Population growth of some genera of cladocerans (Cladocera) in relation to algal food (Chlorella vulgaris) levels
Population growth of some genera of cladocerans (Cladocera) in relation to algal food (Chlorella vulgaris) levels
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DOI：
10.1023/a:1024410314313
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发表时间：
2003-01-01
期刊：
影响因子：
2.6
通讯作者：
Sarma, SSS
中科院分区：
文献类型：
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作者：
Nandini, S;Sarma, SSS
采用0.05 × 10(6)、0.1 × 10(6)、0.2 × 10(6)、0.4 × 10(6)、0.8 × 10(6)和1.6 × 10(6)个细胞ml（-1）的小球藻密度，研究了7种支海纲（长角独角藻、长角鳞藻、长角鳞藻、大角鳞藻、大角鳞藻和小角鳞藻）在18 ~ 30 d内的种群生长规律。就碳含量而言，这些藻类浓度分别对应于0.29、0.58、1.16、2.33、4.65和9.31马克毫升（-1）。在测试的藻类水平范围内，支大洋的反应类似，因为增加食物浓度会导致更高的数量丰度和种群增长率(r)。峰值种群密度为（平均值+/-标准误差）71 +/- 5；分别为17.1 +/- 0.4、3.6 +/- 0.3、12.7 +/- 1.1、18.2 +/- 2.7、15.8 +/- 1.0和10.9 +/- 0.02 μ ml（-1）。结果表明，当小球藻含量为1.6 × 10(6)个细胞ml（-1）时，小球藻的r值为0.283 +/- 0.004，小球藻含量为0.05 × 10(6)个细胞ml（-1）时，小球藻的r值最低（0.01 +/- 0.001）。当我们将每个枝海物种的峰值种群密度数据与体长进行对比时，我们发现了一个反比关系，形状大致呈曲线状。根据食物水平与种群增长率之间的回归方程，我们计算了每个枝海物种维持种群零增长（r = 0）所需的理论食物量（阈值水平），根据体型的不同，其变化范围为0.107至0.289马克毫升（-1）d（-1）。当我们根据相应的阈值食物水平绘制支海动物的体型时，我们得到了一条正态分布曲线。由此可见，在1300母体重之前，阈值摄取量随体重增加而增加；然而，除此之外，阈值水平降低了，支持了早期对轮虫和大型枝海动物的观察。
We studied the patterns of population growth of 7 cladoceran species (Alona rectangula, Ceriodaphnia dubia, Daphnia laevis, Diaphanosoma brachyurum, Moina macrocopa, Scapholeberis kingi and Simocephalus vetulus) using 6 algal densities, viz. 0.05 x 10(6), 0.1 x 10(6), 0.2 x 10(6), 0.4 x 10(6), 0.8 x 10(6) and 1.6 x 10(6) cells ml(-1), of Chlorella vulgaris for 18 - 30 days. In terms of carbon content these algal concentrations corresponded to 0.29, 0.58, 1.16, 2.33, 4.65 and 9.31 mug ml(-1), respectively. Cladocerans in the tested range of algal levels responded similarly, in that increasing the food concentrations resulted in higher numerical abundance and population growth rates (r). The peak population densities were (mean +/- standard error) 71 +/- 5; 17.1 +/- 0.4, 3.6 +/- 0.3, 12.7 +/- 1.1, 18.2 +/- 2.7, 15.8 +/- 1.0 and 10.9 +/- 0.02 ind. ml(-1), respectively for A. rectangula, C. dubia, D. laevis, D. brachyurum, M. macrocopa, S. kingi and S. vetulus. In general, the lowest r values were obtained for D. laevis (0.01 +/- 0.001) at 0.05 x 10(6) cells ml(-1) food level while the highest was 0.283 +/- 0.004 for A. rectangula at 1.6 x 10(6) cells ml(-1) of Chlorella. When the data of peak population density for each cladoceran species were plotted against the body length, we found an inverse relation, broadly curvilinear in shape. From regression equations between the food level and rate of population increase, we calculated the theoretical food quantity ( the threshold level) required to maintain a zero population growth (r = 0) for each cladoceran species, which varied from 0.107 to 0.289 mug ml(-1) d(-1) depending on the body size. When we plotted the cladoceran body size against the corresponding threshold food levels, we obtained a normal distribution curve. From this it became evident that for up to 1300 mum body size, the threshold food level increased with increasing body size; however, beyond this, the threshold level decreased supporting earlier observations on rotifers and large cladocerans.