A paleoecological record in a day (PLE day 13)
One afternoon. Nine students. Approximately 8500 years of history.
The Pymatuning wetlanders spent the morning learning about wetland development and the roles that wetlands play in the broader earth system. In the afternoon, we examined the sediment core that we collected from Titus Bog yesterday – all 8.5 meters of it! The students sieved samples from along the core, and identified and tallied plant macrofossils (e.g., leaves, seeds). By applying age-depth information from previous work on the bog (Ireland et al., 2011), we estimated the age of the samples along the length of the core.
The diagram below shows our paleoecological results, and clearly shows that the site started as a deep kettle lake (the lower samples lacked macrofossils) some 8500-10,000 years ago, and was occupied by a shallow lake with abundant submerged aquatics like nodding waternymph (Najas flexilis) and pondweed (Potamogeton sp.) throughout much of the mid Holocene. In the later Holocene the area was shallower, supporting a mix of submerged aquatic plants like nodding waternymph, along with floating leaved plants like white water lilies (Nymphaea odorata). About 800-900 years ago a floating peatland established at the site, with various sedges, Sphagnum, cranberries (Vaccinium oxycoccos), and leatherleaf shrubs (Chamaedaphne calculata) characterizing the surface vegetation. We will discuss the record in the context of peatland developmental models tomorrow…