THE INFLUENCE OF THE INVASIVE CHINESE TALLOW (TRIADICA SEBIFERA) LEAF LITTER ON AQUATIC CHEMISTRY AND MICROBIAL COMMUNITY COMPOSITION

Global climate change and anthropogenic activity have facilitated the movement and invasive potential of nonnative plants in native environments. These invasions can have negative effects on ecosystem diversity and function. The nonnative and invasive plant, Chinese Tallow (Triadica sebifera), has already invaded much of the south eastern US where it is outcompeting native tree species and changing ecosystem diversity in a variety of habitats. Leaf litter from the Chinese tallow has been shown cause changes in dissolved oxygen and pH in the aquatic environment. Turbidity is also affected when Chinese tallow litter is present in water. A series of experiments were performed to determine the causes of these chemical changes in water when Chinese tallow litter is present. I determined that Chinese tallow litter has a different chemical composition from native litter, a different concentration of essential soluble nutrients from native litter, and a faster decomposition rate compared to native plant litter. Sterilization experiments suggest that Chinese tallow litter is promoting microbial activity through the rapid release of elemental nutrients, which subsequently influences a change in dissolved oxygen thorough stimulated microbial respiration. Changes in pH are not fully understood, but sterilization experiments suggest that unknown secondary chemicals, perhaps tannins and phenolic compounds, are the source of declining pH when Chinese tallow litter is present in water. Using high throughput 16s and 18s rRNA mass parallel gene sequencing, followed by Non-metric Multidimensional Scaling ordination scatter plots, I determined that Chinese tallow litter can promote differences in microbial community composition from that of native plant litter. NMDS ordination scatter plots demonstrate that both bacterial and fungal communities were different in Chinese tallow treatments when compared to native plant litter treatments. These results provide strong evidence that Chinese tallow litter can promote changes in the microbial community composition of an aquatic/wetland habitat