Related Experiment Video
Updated: Jun 22, 2026
07:26
Visualizing Methane-Cycling Microbial Dynamics in Coastal Wetlands
Published on: January 31, 2025
Extensive carbon isotopic heterogeneity among methane seep microbiota
Christopher H House1, Victoria J Orphan, Kendra A Turk
1Department of Geosciences and Penn State Astrobiology Research Center, The Pennsylvania State University, University Park, PA 16802, USA. chouse@geosc.psu.edu
Environmental Microbiology
|June 11, 2009
Summary
Microbial communities in Eel River Basin methane seeps exhibit significant carbon isotope (delta(13)C) heterogeneity. This suggests diverse metabolic activities, including both methanogenesis and methanotrophy, by archaea and bacteria.
Area of Science:
- Geochemistry
- Microbiology
- Environmental Science
Background:
- Methane seeps are crucial ecosystems for carbon cycling.
- Understanding microbial carbon metabolism in these environments is vital.
Purpose of the Study:
- To investigate the carbon isotope (delta(13)C) heterogeneity of microorganisms in Eel River Basin methane seeps.
- To determine the metabolic capabilities of different microbial groups.
Main Methods:
- Analysis of delta(13)C values in sediment cores and in situ incubated artificial surfaces.
- Radiotracer experiments to assess microbial metabolic activity.
- Stable isotope analysis of archaea (ANME-1, ANME-2) and bacterial filaments.
Main Results:
- Observed a wide range of delta(13)C values (>50 per mil) in archaea.
- ANME-1 rods: -24 to -87 per mil; ANME-2 sarcina: -18 to -75 per mil.
- Bacterial filaments showed ubiquitous growth with a mean delta(13)C of -38 +/- 3 per mil.
Conclusions:
- Significant isotopic heterogeneity implies diverse metabolisms within microbial communities.
- ANME-1 and ANME-2 archaea likely perform both methanogenesis and methanotrophy.
- Bacterial filaments demonstrate rapid colonization and growth potential in seep environments.
Related Concept Videos
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...
01:26Microbes and Methanogenesis
Methanogenesis is a critical microbial process in anaerobic ecosystems responsible for the biological production of methane, a potent greenhouse gas and valuable biofuel. This metabolic pathway is primarily facilitated by methanogenic archaea, which thrive in anoxic environments such as wetlands, sediments, and animal gastrointestinal tracts. The absence of oxygen in these habitats prevents aerobic respiration, thereby favoring alternative biochemical pathways for organic matter degradation.In...
01:30Diversity of Archaea I
Archaea, a domain of single-celled microorganisms, are classified into five major phyla based on genetic and biochemical characteristics: Euryarchaeota, Crenarchaeota, Thaumarchaeota, Korarchaeota, and Nanoarchaeota. Among these, the phylum Euryarchaeota is notable for its remarkable diversity in morphology, metabolism, and ecological adaptations.Morphological and Metabolic DiversityMembers of Euryarchaeota exhibit a variety of cellular shapes, including rods and cocci. Their metabolic pathways...
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...
01:27Diversity of Archaea III
Crenarchaeota, a prominent phylum of Archaea, is remarkable for its ability to thrive in extreme environments characterized by high temperatures and acidity. These microorganisms inhabit sulfuric hot springs, volcanic systems, and submarine hydrothermal vents, where temperatures often exceed 100°C. The unique adaptations of Crenarchaeota not only allow survival under such extreme conditions but also provide insights into the mechanisms of life in primordial Earth-like environments.Morphological...
01:29Overview of Archaea
Archaea, named after the Archaean eon, represent a unique domain of life, distinct from bacteria and eukaryotes, with remarkable traits. Their cellular and molecular features, ecological adaptability, and industrial relevance highlight their importance in understanding life processes and leveraging biotechnology.Cellular and Molecular CharacteristicsA defining feature of archaea is their unique membrane composition. Archaeal membranes contain ether-linked isoprenoid lipids, which confer...