Eleocharis mutata thrives in oil‑spoiled wetlands, boosting microbes and cleaning water

Researchers studied Eleocharis mutata, a water plant, growing in soils that contained fresh crude oil or weathered crude oil. The experiment ran for 56 weeks in controlled wetland microcosms. The soil was pre‑treated to mimic natural wetland conditions.

When the soil received fresh oil at 30, 60 or 90 grams per kilogram, the plant showed a positive response. Its height increased, it produced more flower structures, and its total dry weight grew. These stimulatory effects were reflected in higher physiological index values greater than one.

In contrast, a larger amount of weathered oil at 126 grams per kilogram slowed the plant down, reducing its growth and reproductive output. At the same time, the plant helped six groups of soil microbes thrive, raising the overall microbial index. The inhibitory impact of the weathered oil was evident as the plant’s growth rate dropped and flower formation was reduced.

Both the natural breakdown and the plant‑assisted method removed similar totals of petroleum hydrocarbons, yet the plant‑helped version cleared a bit more oil at 60‑90 g/kg fresh oil and at the 126 g/kg weathered oil level. Overall, the study demonstrates that Eleocharis mutata can both tolerate and actively engage in the breakdown of petroleum residues, offering a natural solution for polluted wetlands.

These results highlight the plant’s ability to survive oily conditions and suggest it could be a useful tool for cleaning oil‑contaminated tropical wetlands. Because of this resilience, the plant shows promise for use in bioremediation projects aimed at restoring healthy ecosystems in oil‑affected areas.