Testate amoebae as a potential tracer of organic matter dislodged from peat extraction areas

In the boreal zone, surface waters mostly receive external organic matter (OM) from surrounding peatlands. The lake’s biological communities may respond to changes in OM inputs caused by anthropogenic activities in the catchment. Testate amoebae (TA) possess an outer shell that preserves well in lake sediments and are commonly used in paleo-environmental studies. Additionally, they fall into the size range of particles transported from peatlands to lakes, making them potential particle tracers. Here, we compared TA communities of current and pre-peat extraction sediments from lakes receiving OM only from peat extraction areas (impact lakes) with lakes receiving OM from peatlands under other uses (control lakes). We found no differences between control and impact lakes, neither between current and pre-peat extraction. In conclusion, there is either no significant increase in the amount of organic matter discharge from peatland areas, or dislodged testate amoeba are retained in areas upstream of the lakes.