Coral Bacterial-Core Abundance and Network Complexity as Proxies for Anthropogenic Pollution

Abstract

Acclimatization via changes in the stable (core) or the variable microbial diversity and/or abundance is an important element in the adaptation of coral species to environmental changes. Here, we explored the spatial-temporal dynamics, diversity and interactions of variable and core bacterial populations associated with the coral Mussismilia hispida and the surrounding water. This survey was performed on five reefs along a transect from the coast (Reef 1) to offshore (Reef 5), representing a gradient of influence of the river mouth, for almost 12 months (4 sampling times), in the dry and rainy seasons. A clear increasing gradient of organic-pollution proxies (nitrogen content and fecal coliforms) was observed from Reef 1 to Reef 5, during both seasons, and was highest at the Buranhém River mouth (Reef 1). Conversely, a clear inverse gradient of the network analysis of the whole bacterial communities also revealed more-complex network relationships at Reef 5. Our data also indicated a higher relative abundance of members of the bacterial core, dominated by Acinetobacter sp., at Reef 5, and higher diversity of site-stable bacterial populations, likely related to the higher abundance of total coliforms and N content (proxies of sewage or organic pollution) at Reef 1, during the rainy season. Thus, the less “polluted” areas may show a more-complex network and a high relative abundance of members of the bacterial core (almost 97% in some cases), resulting in a more-homogeneous and well-established bacteriome among sites/samples, when the influence of the river is stronger (rainy seasons).

The Microbiome of the Worldwide Invasive Ascidian Didemnum vexillum

“…This further suggests the role of the environment on the horizontal transfer, but with an enrichment promoted by the host. A small but abundant core and a highly diverse variable microbiome component, with marked selective enrichment from the pool of water prokaryotes, has also been found in sponges (Turon et al, 2018) and may contribute to the host resilience to environmental changes (Leite et al, 2018;Turon et al, 2019).…”

“…All multicellular organisms can be considered holobionts hosting diverse microbial communities that are essential for the evolution of the organism (Uriz et al, 2012;Zilberg-Rosenberg, 2016, 2018;Leite et al, 2018;Pollock et al, 2018;Cleary et al, 2019). The ubiquity and importance of bacteria in the living world have been recently showcased by the application of new genomic technologies (McFall-Ngai et al, 2013).…”

The microbiome of pest insects: it is not just bacteria

“…Microbial interactions influence both how communities are formed (Dini‐Andreote et al., , ; Jia et al., ) and how they respond (Jurburg et al., ; Mallon et al., ). Such patterns have also been observed in microbial communities associated with hosts such as plants (Wang et al., ), corals (Leite et al., ,), and birds (van Veelen et al., ), indicating that similar rules drive microbiome assembly in several habitats.…”

Molecular tools for coral reef restoration: beyond biomarker discovery

“…Corals associate with unicellular algal symbionts (Symbiodiniaceae) as well as with other members of the microbial community, such as bacteria (for recent reviews, see Hernandez-Agreda et al 2018;LaJeunesse et al 2018). The presence/absence or relative abundance of particular Symbiodiniaceae (Bay et al 2016;Parkinson et al 2018) and bacteria Leite et al 2018) have been proposed as potential biomarkers (reviewed by Roitman et al 2018). Specific genomic regions that differentiate taxa, such as 16S or ITS, can be targeted using amplicon sequencing and/or quantitation, such as real-time PCR (e.g.…”