Some benthic assemblages studies have tested the effects of different preservation procedures on biomass, but their influence on quantitative patterns (number of species and abundance) is still unclear. We evaluated the influence of two sample preservation procedures on quantitative patterns in benthic ecology. Ten sampling points were systematically interspersed on two types of sediment (sandy and muddy). At each sediment type, samples from five sampling points were fixed in 10% formalin, and the other five points were preserved in 70% ethanol (without previous fixation). Three replicates were collected at each sampling point, and samples were washed in 0.5 mesh size and sorted in laboratory. A cost/benefit analysis was performed considering the washing time in laboratory and the costs of substances. A total of 1970 individuals were collected (muddy sediment: 132; sandy sediment: 1838), belonging to 121 taxa (muddy: 49; sandy: 83). Assemblages preserved in ethanol were composed of 795 individuals and 80 taxa, while those fixed with formalin had 1173 individuals and 94 taxa. Polychaeta predominated as the most abundant group for both preservation procedures. For the whole benthic community, significant differences occurred only between sediment types. Significant differences in the number of individuals of polychaetes were observed for the different preservation procedures in sandy sediment. Ethanol has the best cost/benefit ratio in both sediment types due to additional costs to attend safety requirements for formalin-fixed samples. Further studies should evaluate how quantitative patterns are affected by exposure time of preservation, anesthesia interaction, and morphological deformations (e.g. impossibility of identification).

中文翻译：

---

底栖生态系统的成本/效益以及样品保存程序对定量模式的影响

一些底栖组合研究已经测试了不同保存程序对生物量的影响，但是它们对定量模式（物种数量和丰度）的影响仍不清楚。我们评估了两个样本保存程序对底栖生态学定量模式的影响。十个采样点被系统地散布在两种类型的沉积物（沙质和泥质）上。在每种沉积物类型下，将五个采样点的样品固定在10％福尔马林中，其他五个点则保存在70％乙醇中（无需事先固定）。在每个采样点收集三份重复样品，然后将样品以0.5目大小洗涤并在实验室中分类。进行成本/收益分析时要考虑实验室的清洗时间和物质成本。总共收集了1970个人（泥泞的沉积物：132；沙质的沉积物：1838），属于121类群（泥泞的：49；沙质的：83）。保存在乙醇中的集合体由795个个体和80个分类单元组成，而用福尔马林固定的个体则有1173个个体和94个分类单元。在两个保存程序中，Polychaeta是最丰富的组。对于整个底栖生物群落，仅在沉积物类型之间发生显着差异。对于沙质沉积物中的不同保存程序，观察到多毛cha个体数量的显着差异。在满足两种福尔马林固定样品安全性要求的额外费用方面，乙醇在两种沉积物中均具有最佳的成本/收益比。进一步的研究应评估保存方式的暴露时间如何影响定量模式，