Changes in microbial community phylogeny and metabolic activity along the water column uncouple at near sediment aphotic layers in fjords

Author(s)
Sven P. Tobias-Hünefeldt, Stephen R. Wing, Federico Baltar, Sergio E. Morales
Abstract

Fjords are semi-enclosed marine systems with unique physical conditions that influence microbial community composition and structure. Pronounced organic matter and physical condition gradients within fjords provide a natural laboratory for the study of changes in microbial community structure and metabolic potential in response to environmental conditions. Photosynthetic production in euphotic zones sustains deeper aphotic microbial activity via organic matter sinking, augmented by large terrestrial inputs. Previous studies do not consider both prokaryotic and eukaryotic communities when linking metabolic potential and activity, community composition, and environmental gradients. To address this gap we profiled microbial functional potential (Biolog Ecoplates), bacterial abundance, heterotrophic production (H-3-Leucine incorporation), and prokaryotic/eukaryotic community composition (16S and 18S rRNA amplicon gene sequencing). Similar factors shaped metabolic potential, activity and community (prokaryotic and eukaryotic) composition across surface/near surface sites. However, increased metabolic diversity at near bottom (aphotic) sites reflected an organic matter influence from sediments. Photosynthetically produced particulate organic matter shaped the upper water column community composition and metabolic potential. In contrast, microbial activity at deeper aphotic waters were strongly influenced by other organic matter input than sinking marine snow (e.g. sediment resuspension of benthic organic matter, remineralisation of terrestrially derived organic matter, etc.), severing the link between community structure and metabolic potential. Taken together, different organic matter sources shape microbial activity, but not community composition, in New Zealand fjords.

Organisation(s)
Functional and Evolutionary Ecology
External organisation(s)
University of Otago, Leibniz-Institut für Gewässerökologie und Binnenfischerei
Journal
Scientific Reports
Volume
11
No. of pages
7
ISSN
2045-2322
DOI
https://doi.org/10.1038/s41598-021-98519-2
Publication date
09-2021
Peer reviewed
Yes
Austrian Fields of Science 2012
106021 Marine biology
Keywords
ASJC Scopus subject areas
General
Sustainable Development Goals
SDG 14 - Life Below Water
Portal url
https://ucris.univie.ac.at/portal/en/publications/changes-in-microbial-community-phylogeny-and-metabolic-activity-along-the-water-column-uncouple-at-near-sediment-aphotic-layers-in-fjords(34892953-9f35-4693-b22c-8726ced3f748).html