When diatoms undergo vegetative cell division the new siliceous wall components are slightly smaller than those of the parent because they are produced within the confines of the parent wall. Thus, with continued growth the mean size of cells in a population declines. Given this unique feature of diatom cell division, if the growth of a species in a lake increases (decreases) under more (less) favorable conditions, then the mean size of the resulting population will decline (increase). Numerous paleolimnological investigations rely on shifts in the relative abundances of diatom species over time to infer lake conditions. Although relative abundance data yield information about the dominance of species in the community, they do not necessarily provide evidence about growth of a given species. For instance, a species could have increased in growth, but simply to a lesser extent than other taxa, resulting in a decline in relative abundance. In a similar fashion, relative abundance values can be misleading when used to infer environmental change, such as trophic status change in lakes. We propose that including data on mean size of diatom valves can yield greater insight into changes in growth and improve observations and conclusions based on relative abundance data. To test this concept, we examined changes in the mean diameter of Aulacoseira ambigua (Grunow) Simonsen valves relative to known shifts in lake trophic status in a core from Bantam Lake, Connecticut, representing ~ 130 years of sediment accumulation. The mean valve diameter of A. ambigua declined from 9.7 to 7.6 µm, with the largest declines clearly tracking significant increases in trophic status. We conclude that changes in the mean size of diatom frustules over time can provide valuable information for understanding long-term environmental changes.

当硅藻进行营养性细胞分裂时，新的硅质壁成分要比亲代的硅质壁成分略小，因为它们是在亲代壁的范围内产生的。因此，随着持续增长，群体中细胞的平均大小下降。鉴于硅藻细胞分裂的这一独特特征，如果在更多（较差）的有利条件下，湖泊中某个物种的生长增加（减少），那么最终种群的平均大小将减少（增加）。许多古湖泊学研究依靠硅藻物种相对丰度随时间的变化来推断湖泊状况。尽管相对丰度数据产生了有关社区中物种优势地位的信息，但它们不一定提供有关给定物种生长的证据。例如，某物种的生长可能会增加，但仅在某种程度上低于其他分类单元，从而导致相对丰度下降。以类似的方式，相对丰度值在用于推断环境变化（例如湖泊的营养状态变化）时可能会产生误导。我们建议包括硅藻瓣平均大小的数据可以对生长变化有更深入的了解，并根据相对丰度数据改善观察结果和结论。为了检验这个概念，我们研究了平均直径的变化 我们建议包括硅藻瓣平均大小的数据可以对生长变化有更深入的了解，并根据相对丰度数据改善观察结果和结论。为了检验这个概念，我们研究了平均直径的变化 我们建议包括硅藻瓣平均大小的数据可以对生长变化有更深入的了解，并根据相对丰度数据改善观察结果和结论。为了检验这个概念，我们研究了平均直径的变化Aulacoseira ambigua（Grunow）Simonsen阀门相对于康涅狄格州Bantam湖的一个岩心中的湖泊营养状态的已知变化，代表了约130年的沉积物积累。的平均直径阀一个。ambigua从9.7 µm下降到7.6 µm，最大的下降清楚地表明了营养状态的显着增加。我们得出的结论是，硅藻壳的平均尺寸随时间的变化可以为理解长期的环境变化提供有价值的信息。