Related Experiment Video
Updated: May 10, 2026
09:11
Evaluating the Impact of Hydraulic Fracturing on Streams using Microbial Molecular Signatures
Published on: April 4, 2021
Stream hydrological fragmentation drives bacterioplankton community composition
Stefano Fazi1, Eusebi Vázquez, Emilio O Casamayor
1Water Research Institute, National Research Council of Italy (IRSA-CNR), Monterotondo, Roma, Italy. fazi@irsa.cnr.it
Plos One
|June 7, 2013
Summary
Mediterranean streams experience seasonal drying, impacting bacterial communities. This study shows that while habitat fragmentation alters conditions, seasonal changes are the dominant factor shaping microbial composition.
Area of Science:
- Ecology
- Microbiology
- Hydrology
Background:
- Mediterranean intermittent streams face seasonal hydrological fragmentation.
- This provides a unique setting to study microbial community dynamics under changing environmental conditions.
- Understanding these shifts is crucial for aquatic ecosystem management.
Purpose of the Study:
- To investigate bacterial community responses to hydrological fragmentation in intermittent streams.
- To determine if seasonal shifts in microbial communities are more influential than episodic fragmentation.
- To analyze the impact of altered biogeochemical conditions on bacterial composition.
Main Methods:
- In situ hybridization, fingerprinting, and 16S rRNA gene sequencing were used.
- Bacterial communities were assessed in the Fuirosos intermittent stream (Spain).
- Biogeochemical conditions, including redox state and dissolved organic carbon, were analyzed.
Main Results:
- Hydrological fragmentation altered biogeochemical conditions, depleting oxidized solutes and changing dissolved organic carbon.
- Isolated ponds showed increased abundance of beta-Proteobacteria and Actinobacteria, with reduced alpha-diversity.
- Community composition shifted significantly between summer and autumn, indicating seasonal dominance.
Conclusions:
- Seasonal shifts in community composition are more dominant than episodic fragmentation effects.
- Temporary stream fragmentation impacts local environmental conditions and reduces microbial dispersal.
- These combined factors tightly shape bacterioplankton community composition in intermittent streams.
Related Concept Videos
01:24Freshwater Microbial Ecology
Freshwater systems such as streams, rivers, and lakes exhibit distinct physical and biological characteristics that influence their microbial communities. These environments are broadly categorized into lotic systems—those with flowing waters like streams and most rivers—and lentic systems, which include still or slow-moving waters such as lakes, ponds, and marshes.In lentic systems, phytoplankton drive primary production, generating autochthonous organic carbon. In contrast, lotic systems...
01:30Marine Microbial Ecology
Marine microbial ecosystems are shaped by distinct physicochemical limits, including high salinity, low nutrient availability, and fluctuating oxygen levels. These conditions favor smaller microbial cell sizes, which maximize their surface-to-volume ratio for efficient nutrient uptake.Microbial activity and community composition are closely linked to biogeochemical cycles, particularly in dynamic environments like estuaries, where halotolerant microbes thrive in response to variable salinity...
01:25Microbial Mats
Microbial communities forming biofilms and mats represent complex, spatially structured ecosystems where metabolic processes are stratified according to light, oxygen, and nutrient gradients. Biofilms are initial colonization stages, only a few millimeters thick, while mature microbial mats can reach centimeter-scale thickness and display intricate vertical organization. Their structural and functional heterogeneity allows microorganisms to occupy distinct ecological niches within a few...
01:26Microbial Interactions: Competition
Microbial competition is an ecological interaction in which microorganisms vie for limited resources within shared environments. These resources may include nutrients, space, or light, depending on the system. The intensity and outcome of competition are influenced by the environmental context, such as nutrient availability, spatial constraints, and the diversity of microbial species present. These competitive interactions significantly influence the structure, function, and resilience of...
01:18Deep Sea Microbial Ecology
The deep ocean and its underlying sediments represent vast, largely unexplored microbial habitats that extend far beyond the sunlit photic zone. The photic (euphotic) zone typically spans the upper ~100–200 meters of pelagic waters in the open ocean, but its depth varies geographically and seasonally, where sufficient light supports photosynthetic life. Below this lies the deep sea, spanning roughly 1000–6000 meters (bathypelagic to abyssal zones), with deeper hadal trenches extending beyond...
01:22Microenvironments
Microorganisms inhabit highly localized spaces known as microenvironments, which are defined by distinct physical and chemical characteristics. These include oxygen concentration, pH, temperature, light availability, and nutrient levels. The conditions within a microenvironment can differ markedly from those in the surrounding area and significantly influence microbial growth, metabolism, and community structure.Microenvironments often display sharp physicochemical gradients over small spatial...