Thermal discharge-induced seawater warming alters richness, community composition and interactions of bacterioplankton assemblages in a coastal ecosystem

Abstract

Despite accumulating evidence on the impact of global climate warming on marine microbes, how increasing seawater temperature influences the marine bacterioplankton communities is elusive. As temperature gradient created by thermal discharges provides a suitable in situ model to study the influence of warming on marine microorganisms, surface seawater were sampled consecutively for one year (September-2016 to August-2017) from the control (unimpacted) and thermal discharge-impacted areas of a coastal power plant, located in India. The bacterioplankton community differences between control (n = 16) and thermal discharge-impacted (n = 26) areas, as investigated using 16S rRNA gene tag sequencing revealed reduced richness and varied community composition at thermal discharge-impacted areas. The relative proportion of Proteobacteria was found to be higher (average ~ 15%) while, Bacteroidetes was lower (average ~ 10%) at thermal discharge-impacted areas. Intriguingly, thermal discharge-impacted areas were overrepresented by several potential pathogenic bacterial genera (e.g. Pseudomonas, Acinetobacter, Sulfitobacter, Vibrio) and other native marine genera (e.g. Marinobacter, Pseudoalteromonas, Alteromonas, Pseudidiomarina, Halomonas). Further, co-occurrence networks demonstrated that complexity and connectivity of networks were altered in warming condition. Altogether, results indicated that increasing temperature has a profound impact on marine bacterioplankton richness, community composition, and inter-species interactions. Our findings are immensely important in forecasting the consequences of future climate changes especially, ocean warming on marine microbiota.

Climate change-related warming reduces thermal sensitivity and modifies metabolic activity of coastal benthic bacterial communities

“…Previous studies show that long-term exposure to elevated temperature reduces the diversity of bacterial communities [ 31 , 55 ]. One reason could be the individual bacterial response to higher temperatures, while some bacterial taxa are sensitive others are resistant and therefore, can increase/decrease or be replaced [ 55 , 56 ].…”

Effect of Various Local Anthropogenic Impacts on the Diversity of Coral Mucus-Associated Bacterial Communities

“…Intriguingly, the bacterium Marinobacter, which was present exclusively in seawater, was found to be the predominant oil-degrading bacteria in polluted seawater of the Yellow Sea, China [73]. Rajeev et al [74] noticed that the thermal discharge-impacted coastal areas were overrepresented by several potential pathogenic bacteria (e.g., Acinetobacter) and other native marine bacterial genera (e.g., Marinobacter and Halomonas). Streptobacillus sp., for instance, which was exclusively isolated from seawater samples, was related to seawater disease in farmed Atlantic salmon [75].…”

Bacterial community structure of early-stage biofilms is dictated by temporal succession rather than substrate types in the southern coastal seawater of India

“…The isolated DNA was eluted in an aliquot of 50 μL PCR-grade water and the quality and quantity were measured by picogreen (Invitrogen) using Victor 3 fluorometry. The extracted metagenomic DNA was used as a template for the preparation of 16S rRNA gene amplicon libraries following standard Illumina library preparation procedure as described in our earlier studies [ 42 , 43 ]. Briefly, the V3-V4 hypervariable regions of the 16S rRNA gene were initially amplified using a universal pair of primer: 341F ( and 805R ( ) resulting in an amplicon length of ~464 bp [ 44 ].…”