Experimental study of the interspecific competition between two sibling marine herbivorous rotifers in relation to food availability and initial population density

作     者：Divya S P Kathiresan K Asha P Sekar V Rajasekaran R 

作者机构：Centre of Advanced Study in Marine BiologyFaculty of Marine SciencesAnnamalai University School of Environmental StudiesCochin University of Science and Technology 

出 版 物：《Acta Oceanologica Sinica》 (海洋学报（英文版）)

年 卷 期：2012年第31卷第4期

页      面：113-126页

核心收录：

学科分类：07[理学] 0713[理学-生态学] 

主　　题：competition food level B. plicatilis B. rotundiformis population density interspecificcompetition 

摘      要：Our laboratory study concerns the competitive interaction between two marine rotifer species Bra- chionus plicatilis and Brachionus rotundiformis at five algal （ Nannochloropsis salina） concentrations （0.4＊106 to 32.4x106 cells/ml） and at four initial inoculation densities （numerically, 100% B. pli- catilis; 75% B. plicatilis and 25% B. rotundiforrnis, 50% each of the two species; 25% B. plicatilis and 75% B. rotundiformis and 100% B. rotundiforrnis. The initial biomass varied as 0.33 and 0.22 #g/ml for B. plicatilis and B. rotundiformis respectively. Experiments were performed at （25±1）C. Population densities were enumerated and the medium was changed daily up to 8 d in the ex- periment. At the lowest food level tested, B. rotundiformis formed superior competitor than B. plicatilis, regardless of starting inoculation density. Generally when the food concentrations in- creased, B. plicatilis showed a greater increase in biomass than B. rotundiforrnis. B. rotundiformis formed the largest in population growth, regardless of increasing food concentrations. When grown alone, B. plicatilis reached peak abundances of （1.311 5±0.028） and （137.5±0.014） μg/ml at low and high food densities respectively. The corresponding values of B. rotundiformis were 0.724 5±0.016 and 18.15±0.021. The adverse effects of B. rotundiforrnis on the peak abundances of B. plicatilis were observed at the lowest food level and higher initial density. The rate of population growth in controls varied from （0.792±0.162） to （1.482±0.132） ttm/d for B. plicatilis and （0.445~0.041） to （0.856±0.012） μm/d for B. rotundiformis, depending on food level. When both species were intro- duced together, low food levels favoured higher abundance of B. rotundiforrnis than B. plicatilis, suggesting that increased population density of the smaller B. rotundiforrnis was more successfull than larger B. plicatilis in brackish waters. Our work reveals that available food （type and quan- tity） along with starting inoculat