Research press release


Nature Communications

Environment: Plastic pollution encourages bacterial growth in lakes

湖では、ポリ袋から溶出した化学物質が、細菌の増殖を促進しており、天然有機物よりも促進作用が大きいことを示唆した論文が、Nature Communications に掲載される。この知見は、スカンジナビアの29か所の湖で採取された試料に基づいており、場合によっては汚染削減戦略に役立つかもしれない。


今回、Eleanor Sheridanたちは、超高分解能の質量分析法を用いて、スカンジナビアの29か所の湖で採取された試料に含まれていた低密度ポリエチレン(LDPE)製レジ袋(淡水で最も一般的に見られるプラスチック)から溶出した化合物と有機物を分析した。その結果、プラスチックから溶け出した化合物が化学的に鑑別され、細菌類がそれを炭素源として利用しており、天然有機物よりも利用しやすいことが判明した。このように炭素を利用しやすくなったことで、細菌の増殖効率は1.72倍高まった。Sheridanたちは、細菌の増殖速度が、細菌の多様性と湖水中の天然有機物の特性の両方に依存していたことを指摘している。


Chemicals leached from plastic bags are found to stimulate more bacterial growth in lakes than natural organic matter, a paper published in Nature Communications suggests. The findings are based on samples from 29 Scandinavian lakes and may inform pollution mitigation strategies in certain instances.

Plastic waste widely pollutes freshwaters. The breakdown of plastic releases compounds that can provide energy for bacterial growth, but can also impair growth due to toxicity. However, how these compounds influence microbial metabolism and growth rates is not well understood.

Using ultra-high resolution mass spectrometry, Eleanor Sheridan and colleagues analysed compounds leached from low-density polyethylene (LDPE) plastic bags (the most common type of plastic found in freshwaters), and organic matter in samples from 29 Scandinavian lakes. They found that compounds dissolved from the plastic were chemically distinct and easier for bacteria to use as a carbon source than natural organic matter. This increased accessibility of carbon enhanced bacterial growth by 1.72 times. The authors note that the growth rates were dependent on both bacterial diversity and the characteristics of the natural organic matter within the lake.

The authors caution that their study is focused solely on bacteria and does not take into consideration the effect of plastic on other microorganisms, such as microalgae and fungi. However, they suggest that some bacterial taxa, such as Deinococcus and Hymenobacter, which occur naturally in lake environments, may be particularly well suited to removing plastic-derived compounds and could aid future pollution mitigation strategies.

doi: 10.1038/s41467-022-31691-9


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