Mikrofaunal

Mikrofaunal, also written microfaunal, refers to the small animal life in soils, sediments, and waters that is typically less than about one millimeter in size. The group includes protozoa (such as amoebae and flagellates), nematodes, rotifers, tardigrades, and many micro-arthropods, as well as other minute metazoans. Because of their small size, mikrofauna are usually studied with light microscopy and, in some cases, electron microscopy or molecular methods.

In terrestrial and aquatic ecosystems, mikrofauna play essential roles in nutrient cycling and organic matter decomposition. They feed on bacteria, fungi, algae, and detritus, helping regulate microbial communities and influence soil structure and carbon cycling. They are widely used as bioindicators of environmental conditions, soil health, moisture regimes, and pollution effects, reflecting short- and medium-term ecosystem changes.

In geology and paleoenvironmental research, mikrofauna are recovered as microfossils from sediments and rocks. Commonly studied groups include foraminifera, radiolarians, tintinnids, and ostracods. Their assemblages provide information on past salinity, temperature, productivity, and water mass movements, aiding in biostratigraphy and climate reconstructions.

Methods for studying mikrofauna involve extracting organisms from soil or sediment via sieving and density or sugar-gradient separations, followed by microscopy and, increasingly, DNA-based sequencing to identify taxa and assess diversity. The term mikrofaunal is sometimes favored in non-English contexts, but microfauna remains the standard in English-language literature.