Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient

Freshwater bacterioplankton communities are influenced by the transport of bacteria from the surrounding terrestrial environments. It has been shown that, although most of these dispersed bacteria gradually disappear along the hydrologic continuum, some can thrive in aquatic systems and become domi...

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Main Authors: Clara Ruiz-González, Juan Pablo Niño-García, Martin Berggren, Paul A. del Giorgio
Format: Article
Language:English
Published: PAGEPress Publications 2017-12-01
Series:Advances in Oceanography and Limnology
Subjects:
Online Access:https://pagepressjournals.org/index.php/aiol/article/view/7232
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spelling doaj-834527b9d07044dcbd1cd7d6f437512b2020-11-25T00:28:53ZengPAGEPress PublicationsAdvances in Oceanography and Limnology1947-57211947-573X2017-12-018210.4081/aiol.2017.7232Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradientClara Ruiz-González0Juan Pablo Niño-García1Martin Berggren2Paul A. del Giorgio3Instituto de Ciencias del Mar (ICM-CSIC)Universidad de Antioquia, Escuela de MicrobiologíaLund University, Department of Physical Geography and Ecosystem ScienceUniversité du Québec à Montréal, Département des Sciences Biologiques Freshwater bacterioplankton communities are influenced by the transport of bacteria from the surrounding terrestrial environments. It has been shown that, although most of these dispersed bacteria gradually disappear along the hydrologic continuum, some can thrive in aquatic systems and become dominant, leading to a gradual succession of communities. Here we aimed at exploring the environmental factors driving the structure of such contrasting bacterial populations as well as their functional properties. Using Illumina sequencing of the 16S rRNA gene, we characterized the taxonomic composition of bacterioplankton communities from 10 streams and rivers in Québec spanning the whole hydrologic continuum (river Strahler order 0 to 7), which were sampled in two occasions. With the aim to understand the fate and controls of the transported bacteria, among the taxa present at the origin of the hydrologic gradient (i.e., in the smallest headwater streams) we identified two types of dynamics: i) ‘Tourist’ taxa, which were those that decreased in abundance from the headwaters towards the largest rivers, and ii) ‘Seed’ taxa, those that increased their abundances along the hydrologic continuum. Communities changed gradually from the fast-flowing headwater streams dominated by ‘Tourist’ taxa (ca. 95% of the sequences) towards the largest rivers (Strahler order 4-7) where ‘Seed’ taxa comprised up to 80% of community sequences. Variation in taxonomic composition of the communities dominated by ‘Tourist’ taxa in streams seemed related to different degree of terrestrial inputs, whereas compositional changes in ‘Seed’ communities in the large rivers were linked to differences in autochthonous processes. Finally, the two types of communities differed significantly in their metabolic potential assessed through Biolog Ecoplates. All this suggests that hydrologic transport modulates the gradual replacement of two contrasting population types subjected to different environmental controls and with different metabolic potentials. Moreover, we show that the separate exploration of the two pools of taxa allows unveiling environmental drivers and processes operating on them that remain hidden if explored at the whole community level. https://pagepressjournals.org/index.php/aiol/article/view/7232Dispersalriver continuumenvironmental sortingaquatic bacterial communitiesIllumina sequencing.
collection DOAJ
language English
format Article
sources DOAJ
author Clara Ruiz-González
Juan Pablo Niño-García
Martin Berggren
Paul A. del Giorgio
spellingShingle Clara Ruiz-González
Juan Pablo Niño-García
Martin Berggren
Paul A. del Giorgio
Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
Advances in Oceanography and Limnology
Dispersal
river continuum
environmental sorting
aquatic bacterial communities
Illumina sequencing.
author_facet Clara Ruiz-González
Juan Pablo Niño-García
Martin Berggren
Paul A. del Giorgio
author_sort Clara Ruiz-González
title Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
title_short Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
title_full Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
title_fullStr Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
title_full_unstemmed Contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
title_sort contrasting dynamics and environmental controls of dispersed bacteria along a hydrologic gradient
publisher PAGEPress Publications
series Advances in Oceanography and Limnology
issn 1947-5721
1947-573X
publishDate 2017-12-01
description Freshwater bacterioplankton communities are influenced by the transport of bacteria from the surrounding terrestrial environments. It has been shown that, although most of these dispersed bacteria gradually disappear along the hydrologic continuum, some can thrive in aquatic systems and become dominant, leading to a gradual succession of communities. Here we aimed at exploring the environmental factors driving the structure of such contrasting bacterial populations as well as their functional properties. Using Illumina sequencing of the 16S rRNA gene, we characterized the taxonomic composition of bacterioplankton communities from 10 streams and rivers in Québec spanning the whole hydrologic continuum (river Strahler order 0 to 7), which were sampled in two occasions. With the aim to understand the fate and controls of the transported bacteria, among the taxa present at the origin of the hydrologic gradient (i.e., in the smallest headwater streams) we identified two types of dynamics: i) ‘Tourist’ taxa, which were those that decreased in abundance from the headwaters towards the largest rivers, and ii) ‘Seed’ taxa, those that increased their abundances along the hydrologic continuum. Communities changed gradually from the fast-flowing headwater streams dominated by ‘Tourist’ taxa (ca. 95% of the sequences) towards the largest rivers (Strahler order 4-7) where ‘Seed’ taxa comprised up to 80% of community sequences. Variation in taxonomic composition of the communities dominated by ‘Tourist’ taxa in streams seemed related to different degree of terrestrial inputs, whereas compositional changes in ‘Seed’ communities in the large rivers were linked to differences in autochthonous processes. Finally, the two types of communities differed significantly in their metabolic potential assessed through Biolog Ecoplates. All this suggests that hydrologic transport modulates the gradual replacement of two contrasting population types subjected to different environmental controls and with different metabolic potentials. Moreover, we show that the separate exploration of the two pools of taxa allows unveiling environmental drivers and processes operating on them that remain hidden if explored at the whole community level.
topic Dispersal
river continuum
environmental sorting
aquatic bacterial communities
Illumina sequencing.
url https://pagepressjournals.org/index.php/aiol/article/view/7232
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