2025-09-09 カリフォルニア大学サンディエゴ校（UCSD）
Researchers use Remotely Operated Vehicle SuBastian to collect sediment push cores next to barrels discarded on the seafloor. Credit: Schmidt Ocean Institute.
＜関連情報＞
- https://today.ucsd.edu/story/decades-old-barrels-of-industrial-waste-still-impacting-ocean-floor-off-la
- https://academic.oup.com/pnasnexus/article/4/9/pgaf260/8249340
深海盆地における産業廃棄物コンテナ投棄と関連する極限環境生物のホットスポット Extremophile hotspots linked to containerized industrial waste dumping in a deep-sea basin
Johanna Gutleben, Sheila Podell, Kira Mizell, Douglas Sweeney, Carlos Neira, Lisa A Levin, Paul R Jensen
PNAS Nexus Published:09 September 2025
DOI:https://doi.org/10.1093/pnasnexus/pgaf260
Abstract
Decaying barrels on the seafloor linked to DDT contamination have raised concerns about the public health implications of decades old industrial waste dumped off the coast of Los Angeles. To explore their contents, we collected sediment cores perpendicular to five deep-sea barrels. The concentration of DDT and its breakdown products were highly elevated relative to control sites yet did not vary with distance from the barrels, suggesting that they were not associated with the contamination. Sediment cores collected through white halos surrounding three barrels were enriched in calcite and had elevated pH. The associated microbial communities were low diversity and dominated by alkalophilic bacteria with metagenome-assembled genomes adapted to high pH. A solid concretion sampled between a white halo and barrel was composed of brucite, a magnesium hydroxide mineral that forms at high pH. Based on these findings, we postulate that leakage of containerized alkaline waste triggered the formation of mineral concretions that are slowly dissolving and raising the pH of the surrounding sediment pore water. This selects for taxa adapted to extreme alkalinity and drives the precipitation of “anthropogenic” carbonates forming white halos, which serve as a visual identifier of barrels that contained alkaline waste. Remarkably, containerized alkaline waste discarded >50 years ago represents a persistent pollutant creating localized mineral formations and microbial communities that resemble those observed at some hydrothermal systems. These formations were observed at one-third of the visually identified barrels in the San Pedro Basin and have unforeseen, long-term consequences for benthic communities in the region.
