Describing the Effect of Thin Layer Sediment Placement on Coastal Microbial Communities using Foraminifera Diversity

Salt marshes are rich ecosystems that play an important role in aquatic food systems and prevent erosion while also providing essential habitats for wildlife. Climate change has resulted in rising sea levels and erosion of these coastal wetlands. Thin Layer Sediment Placement (TLP) is a restoration effort being implemented to mitigate the effects of climate change on coastal ecosystems. The TLP process raises elevation of the marsh and provides substrates for vegetative growth by spraying dredged sediment over existing marsh. The impacts of TLP on microbial populations is not widely understood, therefore metrics are required to study the effects of TLP on salt marshes. Foraminifera are marine microbial eukaryotes that have previously been used as bioindicators of benthic health. These microbes are abundant in the top 1 cm of sediments and would potentially be directly impacted by a TLP event. To test this hypothesis, the Quonochontaug Salt marsh was selected as a model site. Located in Charlestown, Rhode Island, the Quonochontaug Salt Marsh was the target of a TLP restoration event in 2017. Experimental sites were chosen from the TLP region of the march and control sites were selected in the non-TLP region of the marsh. Following sample collection, foraminifera were identified using light and scanning electron microscopy alongside sanger sequencing of the 18S rRNA gene. Abundance and Shannon diversity were then calculated for replicate samples. Preliminary results indicate that there is varied diversity in TLP samples compared to the control site, suggesting that disturbance during a TLP event might influence foraminifera diversity