外源氮输入改变三江平原泥炭沼泽有壳变形虫群落结构

Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain,Northeast China

本文通过野外原位控制试验探讨三江平原外源氮素输入对泥炭沼泽有壳变形虫群落的影响.结果表明:从总体看,低氮浓度(6 g N·m-2)输入增加了有壳变形虫的生物量,而高浓度(>12 g N·m-2)的外源氮输入则降低其生物量;在属级水平上,外源氮输入提高了法帽虫属的生物量,降低了鳞壳虫属的生物量;而匣壳虫属的生物量只在低氮输入下显著增加.在物种水平上,氮输入降低了长圆鳞壳虫的生物量,而网匣壳虫和顶足法帽虫的生物量只在低氮浓度下显著增加.表明泥炭沼泽有壳变形虫对外源氮增加的响应具有物种间特异性,有壳变形虫是一类有效的湿地环境指示生物.

In the present study, an in situ control experiment was carried out to explore the re- sponse of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels （6 g N · m-2） , while decreased it at higher levels （〉12 g N · m-2）. At genus level, nitrogen addition sig- nificantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis. At species level, ni- trogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands.