Albion College is a private liberal arts college in Albion, Michigan. The college was founded in 1835 and its undergraduate population was approximately 1,500 students in 2014.They participate in NCAA Division III and the Michigan Intercollegiate Athletic Association (MIAA). The college's athletic teams are nicknamed the Britons, and their colors are purple and gold.
Water-soluble polymers, such as polyacrylamide (PAM), are industrially important chemicals that end up in our wastewater streams. Their free-radical degradation impacts the fate and treatment during use and in waste streams, the understanding of which is limited to oxidative chain scission at relatively low polymer concentrations. Here, using persulfate as the radical source, we demonstrated that cross-linking could dominate over chain scission under oxic conditions at industrially relevant high polymer and radical concentrations. Due to cross-linking, hydrogel-like solids precipitated from the solutions, the extent of which increased with concentrations of PAM and persulfate and with radical-to-polymer ratio. X-ray photoelectron spectroscopy and sulfate analysis revealed the incorporation of inorganic ions into the solid. Some solids could be redissolved in water and were more cross-linked than the cross-linked polymer that remained dissolved. A higher initial molecular weight of PAM (40-150 kDa) further promoted an earlier solid precipitation during the reaction-cooling process at lower PAM and radical concentrations; the solids were water-insoluble due to the high degree of cross-linking. These findings challenge the conventional understanding of free-radical polymer degradation and highlight the role of cross-linking, which can drastically change the environmental mobility, biodegradability/bioavailability, and treatability of PAM in waste streams.
The earthworm fauna of North America consists of a dynamic pool of native and non-native species. History of glaciation during the Pleistocene may strongly affect present earthworm assemblages, but its importance relative to other factors is unclear. We used a standard sampling protocol at 94 sites across 13 states to better understand the factors affecting diversity and abundance of earthworms in the eastern and central United States. We divided our sites into Northeastern Glaciated, Midwestern Glaciated, and Non-glaciated regions. Habitat type, proximity to water and roads, soil type and drainage, and soil pH were measured. A small number of European species was dominant throughout the sampled region. Native earthworms were rare and pheretimoid (“jumping worm”) species were present only at a small portion of our sites. Earthworms were most abundant and diverse in the Midwestern Glaciated region, where non-native earthworm invasion was the most recent, and least common and diverse below the southern limit of glaciation. Soil pH had a subtle positive effect on earthworm abundance and diversity. Community composition differed among regions and habitats. Assemblages also differed between summer and autumn/spring, probably due to seasonal sampling biases. Earthworm communities in previously glaciated areas, and especially in the recently invaded Upper Midwest, may benefit from soil organic matter accumulated during millennia without earthworms since glacial retreat.
Zizania spp. (Mnomen [wild rice]) are annual aquatic plants found in rivers and lakes in Michigan, forming emergent beds that are home to many macroinvertebrates. Macroinvertebrates are key components of aquatic food webs and indicators of river quality. We compared macroinvertebrate community composition and diversity inside and outside of Mnomen beds in the Kalamazoo River (Michigan). Our study locations outside of Mnomen beds generally lacked any aquatic vegetation. We used leaf-pack collectors deployed in the river in 3 seasons. We identified animals collected using morphology and calculated taxon diversity and richness with Simpson's and Margalefs indices, respectively. Season and Mnomen presence both impacted community composition in our study area. When looking at macroinvertebrate diversity and richness, seasonal patterns were stronger than differences between habitat with and without Mnomen. Taxon richness was marginally higher, though not significantly so, in areas with Mnomen, but diversity was not related to Mnomen presence. Many invertebrates were more abundant in and some taxa were found to be strongly associated with sites with Mnomen. In this respect, our results are consistent with the idea that Mnomen facilitates the presence of invertebrates, and demonstrate the importance of further research to understand the community-level relationships in this system.
