alleryStart learning →Fertilizer washes off farmland and into a river mouth. Which process follows?
ANitrification and oxygen gain
BDenitrification and pH rise
CSublimation and salinity rise
DEutrophication and oxygen loss
Answer & Solution
Correct answer: D. Eutrophication and oxygen loss
1. Fertilizer is rich in the nitrogen and phosphorus that normally limit growth.
2. Runoff delivers both into the water in large amounts.
3. Microorganisms grow to excess on that sudden supply.
4. As they grow and then decompose, dissolved oxygen levels are drawn down.
5. The loss of oxygen kills the animals living there, and that whole process is eutrophication.
_Source: OpenStax Biology 1e (CC BY 4.0), Chs 44 and 46, section 46.3 Biogeochemical Cycles_
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