Journal Article

Energetic and Environmental Constraints on the Community Structure of Benthic Microbial Mats in Lake Fryxell, Antarctica

Eisen, Jonathan A, Jungblut, Anne D, Hawes, Ian, Sumner, Dawn Y, Doran, Peter T, Dillon, Megan L, Mackey, Tyler J

2020

Overview

ABSTRACT Ecological communities are regulated by the flow of energy through environments. Energy flow is typically limited by access to photosynthetically active radiation (PAR) and oxygen concentration (O2). The microbial mats growing on the bottom of Lake Fryxell, Antarctica, have well-defined environmental gradients in PAR and (O2). We analyzed the metagenomes of layers from these microbial mats to test the extent to which access to oxygen and light controls community structure. We found variation in the diversity and relative abundances of Archaea, Bacteria and Eukaryotes across three (O2) and PAR conditions: high (O2) and maximum PAR, variable (O2) with lower maximum PAR, and low (O2) and maximum PAR. We found distinct communities structured by the optimization of energy use on a millimeter-scale across these conditions. In mat layers where (O2) was saturated, PAR structured the community. In contrast, (O2) positively correlated with diversity and affected the distribution of dominant populations across the three habitats, suggesting that meter-scale diversity is structured by energy availability. Microbial communities changed across covarying gradients of PAR and (O2). The comprehensive metagenomic analysis suggests that the benthic microbial communities in Lake Fryxell are structured by energy flow across both meter- and millimeter-scales. Energy input affects the composition and diversity of microbial mats growing at the bottom of an Antarctic lake.

• Publisher: Oxford University Press,Federation of European Microbiology Societies
• Subject: Antarctic Regions / Archaea / Archaea - classification / Archaea - genetics / Archaea - isolation & purification / Archaea - metabolism / Bacteria - classification / Bacteria - genetics / Bacteria - isolation & purification / Bacteria - metabolism / Benthos (Aquatic organisms) / Biodiversity / Community structure / Ecology / Energy consumption / Energy flow / Energy Metabolism / Environmental aspects / Environmental gradient / Eukaryotes / Geologic Sediments - chemistry / Geologic Sediments - microbiology / Lakes / Lakes - chemistry / Lakes - microbiology / Metagenomics / Microbial activity / Microbial colonies / Microbial mats / Microbiology / Microbiota - genetics / Microorganisms / Optimization / Oxygen / Oxygen - analysis / Oxygen - metabolism / Photosynthetically active radiation / Physiological aspects / Sunlight