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Updated: Jan 18, 2026
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Bioprospecting of Extremophilic Microorganisms to Address Environmental Pollution
Published on: December 30, 2021
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Extremophile hotspots linked to containerized industrial waste dumping in a deep-sea basin
Johanna Gutleben1, Sheila Podell1, Kira Mizell2
1Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA 92093, USA.
PNAS Nexus
|September 11, 2025
Summary
Decades-old industrial waste barrels on the seafloor are leaching alkaline substances, creating mineral formations and unique microbial communities. This persistent pollution impacts deep-sea ecosystems, despite not being linked to DDT contamination.
Area of Science:
- Marine chemistry
- Microbiology
- Environmental science
Background:
- Industrial waste, including decades-old barrels, has been dumped off the coast of Los Angeles.
- Concerns exist regarding the public health implications of this legacy pollution.
- Previous studies suggested DDT contamination from these barrels.
Purpose of the Study:
- Investigate the contents and environmental impact of decaying barrels on the seafloor.
- Determine the source of observed mineral formations and altered sediment chemistry.
- Characterize microbial communities associated with the barrels.
Main Methods:
- Collected sediment cores near deep-sea barrels and control sites.
- Analyzed sediment for DDT and its breakdown products.
- Examined mineral composition and pH of sediment halos around barrels.
- Characterized microbial communities using metagenomics.
Main Results:
- DDT concentrations were elevated but not directly linked to barrel proximity.
- Sediment halos showed high calcite, elevated pH, and low microbial diversity.
- Alkaliphilic bacteria dominated microbial communities.
- Brucite concretions were found, indicating alkaline waste leakage.
- White halos are anthropogenic carbonates formed by alkaline waste.
Conclusions:
- Leakage from alkaline waste barrels, discarded over 50 years ago, causes persistent pollution.
- This pollution leads to mineral concretions and localized extreme alkalinity.
- Unique microbial communities adapted to high pH are established.
- These formations impact benthic ecosystems and resemble hydrothermal vent systems.
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