The Quest for the Essentials: Analyzing Microbial Successional Diversity in a Novel Experimental Material at Two Island Locations in Colombia

Abstract

The microbial successional process has been studied with different materials to assess biodiversity and its relationship with other environmental variables. Nevertheless, it has been shown that the material used and its position directly impact the type of microorganism that will attach. Therefore, the use of a standardized material and method is a necessity. Here, we evaluate the microbial successional diversity on San Andrés and Gorgona Island, Colombia, and its relationship with depth. Experimental blocks were placed on two different diving depths (6 and 12 meters) for nine months. Every two months, blocks were collected for each study site and the two different depths. DNA extraction and PCR amplification were performed on each block. After the end of the experiment, all DNA isolations were sent for library preparation and sequencing for bacteria, fungi, and eukaryote identification with their corresponding marker genes 16sV4, ITS2, and 18sV9, respectively. Taxonomic identification was performed using QIIME2 and analyzed with alpha and beta diversity metrics and a differential abundance analysis. Our results indicate that different taxonomic groups vary in their alpha and diversity metrics based on their study site and depth. Proteobacteria was more abundant in San Andrés samples and Cyanobacteria in Gorgona samples. On eukaryotes, Annelida and Arthropoda were the most abundant in both study sites. Lastly, on fungi, Ascomycota was the most abundant phylum. In conclusion, the experimental units attracted many microorganisms to dwell and start their natural successional processes. Using a standardized method allowed us to compare study sites and variables, such as depth.