Roy Shovonlal
School of Mathematics, The University of Manchester, Manchester M13 9PL, UK.
Biosystems. 2009 Feb;95(2):160-5. doi: 10.1016/j.biosystems.2008.10.001. Epub 2008 Oct 18.
A small group of phytoplankton species that produce toxic or allelopathic chemicals has a significant effect on plankton dynamics in marine ecosystems. The species of non-toxic phytoplankton, which are large in number, are affected by the toxin-allelopathy of those species. By analysis of the abundance data of marine phytoplankton collected from the North-West coast of the Bay of Bengal, an empirical relationship between the abundance of the potential toxin-producing species and the species diversity of the non-toxic phytoplankton is formulated. A change-point analysis demonstrates that the diversity of non-toxic phytoplankton increases with the increase of toxic species up to a certain level. However, for a massive increase of the toxin-producing species the diversity of phytoplankton at species level reduces gradually. Following the results, a deterministic relationship between the abundance of toxic phytoplankton and the diversity of non-toxic phytoplankton is developed. The abundance-diversity relationship develops a unimodal pathway through which the abundance of toxic species regulates the diversity of phytoplankton. These results contribute to the current understanding of the coexistence and biodiversity of phytoplankton, the top-down vs. bottom-up debate, and to that of abundance-diversity relationship in marine ecosystems.
一小群能产生有毒或化感化学物质的浮游植物物种对海洋生态系统中的浮游生物动态有着重大影响。大量无毒浮游植物物种会受到这些物种的毒素化感作用影响。通过分析从孟加拉湾西北海岸采集的海洋浮游植物丰度数据，建立了潜在产毒物种丰度与无毒浮游植物物种多样性之间的经验关系。变点分析表明，无毒浮游植物的多样性随着有毒物种数量的增加而增加，直至达到一定水平。然而，对于产毒物种数量的大幅增加，物种水平上的浮游植物多样性会逐渐降低。根据这些结果，建立了有毒浮游植物丰度与无毒浮游植物多样性之间的确定性关系。丰度 - 多样性关系形成了一条单峰路径，通过这条路径，有毒物种的丰度调节着浮游植物的多样性。这些结果有助于当前对浮游植物共存和生物多样性、自上而下与自下而上的争论以及海洋生态系统中丰度 - 多样性关系的理解。
