Queen Mary University of London, School of Biological and Chemical Sciences, Mile End Road, London E1 4NS, United Kingdom.
Ecology. 2010 Feb;91(2):497-507. doi: 10.1890/08-1248.1.
The production of heterotrophic biomass is an important aspect of overall ecosystem functioning. However, single-celled organisms or microscopic metazoans are often ignored in studies of secondary production, despite being very abundant and possessing high mass-specific population growth rates, relative to the more widely studied larger taxa. Here, we focused on how life history parameters scale with body size of ciliates and meiofauna (body mass range from approximately 0.001 to 90 mg C/individual) and integrated experimental and survey data to calculate secondary production of these groups. First, we derived a single allometric scaling relationship between the intrinsic rate of population increase and body mass in a laboratory experiment. We then used this relationship to calculate secondary production for over 260 of these small species in the field, using survey data from two contrasting streams; one of which was nutrient rich, the other nutrient poor. Results from laboratory cultures showed that the scaling relationship between body mass and both daily intrinsic rate of population increase and generation time followed a power law. The relationship between body mass and annual secondary production was consistent in both streams, but the number of taxa was greater in the more productive site. Both ciliates and meiofauna had high rates of biomass production, with annual P/B ratios (production divided by biomass) for the whole assemblage exceeding 11 in both streams. We conclude that a large fraction of benthic production is overlooked when protozoans and microscopic metazoans are excluded from estimates of biomass turnover.
异养生物量的产生是整个生态系统功能的一个重要方面。然而，在次级生产的研究中，单细胞生物或微观后生动物通常被忽略，尽管它们非常丰富，并且与更广泛研究的较大分类群相比，具有更高的质量特异性种群增长率。在这里，我们关注的是纤毛虫和小型后生动物（个体生物量范围约为 0.001 至 90 毫克 C/个体）的生活史参数如何随体型大小而变化，并整合了实验和调查数据来计算这些群体的次级生产量。首先，我们在实验室实验中得出了种群内增长率与体型之间的单一比例关系。然后，我们使用该关系，使用来自两个具有对比性溪流的调查数据，计算了野外 260 多种这些小型物种的次级生产量；其中一个溪流富含有机物，另一个则贫含有机物。实验室培养的结果表明，体型与每日种群内增长率和世代时间之间的比例关系遵循幂律。这一关系在两条溪流中都是一致的，但在生产力较高的地方，分类群的数量更多。纤毛虫和小型后生动物的生物量产量都很高，整个集合的年度 P/B 比（生产量除以生物量）在两条溪流中都超过了 11。我们得出的结论是，如果将原生动物和微观后生动物排除在生物量周转率的估计之外，那么很大一部分底栖生物量的产生就被忽视了。
