Research press release


Nature Geoscience

Declining phosphorus in Chinese lakes



Yan Linたちは、2006年から2014年までの間で中国全土862か所の湖で得られた水の化学的データを、その地方のリン発生源と流れと共に分析した。彼らは、リン濃度の中央値は、リン濃度が富栄養化をもたらす閾値の濃度まで減少したこと、そして極度に汚染された湖の数は3分の2に減少したことを発見した。下水設備が改善され下水汚物が減少したことが減少の主な原因であるが、より遠隔地でリン濃度が上昇している湖があることの原因はよく分からず、おそらく森林の衰えと浸食により影響を受けていると思われる。

同時掲載のNews & Viewsで、Jessica Cormanは、「Linたちの分析は中国が自国の湖の保護においてかなり大きな進歩を遂げたことを明らかにした」と述べている。

Phosphorus pollution in Chinese lakes declined by over one-third between 2006 and 2014, according to a paper published online in Nature Geoscience this week. The study finds that the Chinese government’s introduction of policies to reduce water pollution in 2000 has helped to lower the risk of excessive algal blooms from phosphorus pollution in urban regions, though phosphorus concentrations have increased in lakes in some undeveloped regions.

Eutrophication - the excessive growth of algae as a consequence of increased nutrient availability - can occur naturally in lakes. However, the release of nutrients into water bodies as a consequence of human activity has broadly expanded eutrophication across the world, contributing to reductions in water quality, fish die-off, and declines in biodiversity.

Yan Lin and colleagues analysed water chemistry data from 862 lakes across China, along with provincial data on phosphorus sources and flows, between 2006 and 2014. They find that median phosphorus levels declined roughly to the concentration threshold at which phosphorus leads to eutrophication, and the number of extremely polluted lakes was reduced by two-thirds. Improved sanitation and reduction in sewage wastes were major drivers of the reduction; the cause of increasing phosphorus levels in some more remote lakes was less certain, but may be influenced by forest degradation and erosion.

In an accompanying News & Views, Jessica Corman writes that: “the analysis of Lin and colleagues has revealed that China has made some good progress in protecting its lakes."

doi: 10.1038/ngeo2967


メールマガジンリストの「Nature 関連誌今週のハイライト」にチェックをいれていただきますと、毎週各ジャーナルからの最新の「注目のハイライト」をまとめて皆様にお届けいたします。