Interacting nutrient enrichment and moisture modify plant-microbe relationships in a coastal plain wetland

Link To Share This Poster: https://cdmcd.co/LdDzW7
Live Discussion Link: https://cdmcd.co/mXy8W9

Daniya Stephens, Jasper Leavitt and Ariane L. Peralta, Department of Biology, East Carolina University, Greenville, NC

Background/Question/Methods
Changes in soil nutrient concentrations and moisture availability can modify plant-microbe interactions; fertilization of low nutrient ecosystems can disrupt positive plant-microbe interactions. interactions in unpredictable ways. To examine how changes in nutrients and hydrology influences the relationship between plant and bacterial community composition, we examined patterns in fertilization and soil moisture in plant-microbe community composition and species diversity in a nutrient-limited coastal plain wetland. We hypothesize that fertilization and drier soil conditions will result in a more competitive relationship (i.e., weaker association) between plant and bacterial communities. We expect that fertilization will decrease plant-microbe associations over time. We tested this hypothesis at East Carolina University’s West Research Campus (Greenville, North Carolina, USA); Long-term fertilization (N-P-K fertilizers) and disturbance (by mowing) experiment was established in 2003. At this coastal plain wetland, there is an adjacent ditch which results in distinct soil moisture areas (i.e., half the replicates are on the wet side and the other half are on the dry, ditch side). To determine how fertilization, and hydrology affect plant and microbial communities, we analyzed the relationship between plants ( annual plant community surveys) and associated bacterial community composition (16S rRNA amplicon sequencing) from 2014 to 2020 in mowed plots only.
Results/Conclusions
Results revealed that bacterial taxonomic diversity (16S rRNA amplicon sequencing) was higher in fertilized compared to unfertilized soils and also in plots furthest from the ditch over time. This suggests both interacting factors affect the physicochemical properties of the soil in a way that hinders bacterial richness. Results also showed that fertilization and dry conditions could be disrupting the relationship between plant and bacterial community composition as evidenced by decreased community correlations in fertilized compared to unfertilized plots. This ongoing work suggests that over time nutrient enrichment and soil moisture variation modifies bacterial and plant community relationships. Observed wetland community patterns could represent an increasingly competitive relationship for nutrients between plants and soil microbes due to nutrient enrichment. Future research will include the effects of fertilization in a historically nutrient-limited coastal plain wetland and microbial carbon storage capacity. This study will address and highlight how human disturbances and vegetation affect plant and microbes relationship regarding nutrient cycling and metabolic turnover rates.