英文的學習不能等

Long-term effects of low-level pollution may have been underestimated.

Nitrogen emitted into the atmosphere as a result of human activity could be changing plant communities worldwide. Although hot spots of high nitrogen pollution are known to change plant dynamics, new work predicts substantial effects from the lower,chronic levels of pollution found throughout most of the world.

A study of a prairie site in the middle of Minnesota shows that after more than 20 years of slow, chronic deposition of nitrogen — at levels typical of nitrogen pollution in most of the industrial world — cut the number of plant species by 17% compared with control plots not exposed to extra nitrogen.

The losers under this nitrogen regimen tended to be tender herb-like species, the researchers report in Nature. David Tilman, of the University of Minnesota in Saint Paul and one of the authors of the work, says that his personal favourites among the victims are the showy grey goldenrod and the light-purple blazing star.

The good news is that some of the diversity can be recovered if nitrogen pollution is reduced, they say. Plots that stopped receiving additional nitrogen in 1991 slowly recovered and began to look much like the control plots, as seeds from the lost species migrated back in from other areas. But Tilman cautions that without such reservoirs of plant diversity handy, recovery could take much longer than the 13 years it took in this study.

Stomps 頓足

Biodiversity 生物多樣性

Substantial 實在的

Chronic 慢性

Prairie 大草原

Deposition 沉澱

Plot 陰謀

Regimen 政體

Tender 柔軟

Showy 豔麗

Grey 灰色

Goldenrod 菊科

Blazing star 花色鮮明之植物

Migrate 遷移

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每天看美女或者是帥哥圖 有益身心健康!