Roitfer Occurrence and pH,
an article summary by Austin Cumber, BIOL 490 Fall 2014

Berzins & Pejler (1987) looked at the distribution of more than 200 species of benthic, planktonic, and periphytic rotifers that are best known for their role in the food chains of aquatic ecosystems. The authors were motivated by a concern for the rising and falling levels of pH in these water habitats due to decomposing chemicals and pollution. They wanted to focus on rotifers in local environments of south central Sweden which included a variety of aquatic habitats like swamps, rivers, lakes, and bogs. This was to determine if there were more differences in abundance levels in certain depths than others and whether those abundance levels were affected by temperature, pH levels, or other environmental factors. Samples were collected using a bottle to suck in the moist macrophyte material at various depths and locations from a variety of open water sources to test for pH, temperature and other chemical factors. These samples were then either filtered or unfiltered through a 20 μm mesh net depending on the type of experiment to identify soft-bodies, then score them on an abundance density scale from one to ten. The analysis scaled the value of the three species with abundance being correlated with various environmental factors. The authors concluded that most non- or semi-planktonic species tolerated a broad range of pH levels. Species indicating high oxygen content with low organic content had their pH below 7.0, and species indicating low oxygen content with higher organic content had their pH above 7.0.

Berzins, B. & B. Pejler. 1987. Rotifer occurrence in relation to pH. Hydrobiologia 147: 107-116.