[Campbell Biology P.23] According to the provided text and Figure 56.23, which statement ab... | Practice Question
According to the provided text and Figure 56.23, which statement about "dead zones" is correct?
A: Dead zones are characterized by unusually high levels of dissolved oxygen, which leads to the death of aquatic organisms.
B: The 2017 dead zone in the Gulf of Mexico, as mentioned, was caused primarily by plastic waste accumulation.
C: Eutrophication, driven by nutrient load from watersheds, can lead to the formation of large "dead zones" in aquatic ecosystems with dissolved O2 levels typically below 2.0 mg/L.
D: The Mississippi watershed contributes to the Gulf of Mexico dead zone by draining industrial waste directly into the Gulf.
Explanation
The text under 'Unit 8 ECOLOGY' mentions new material in Concept 55.2 on eutrophication and how it can cause 'dead zones' in aquatic ecosystems. Figure 56.23 further illustrates this, specifically stating that the dead zone is due to 'nitrogen pollution' and showing the < 2.0 mg/L dissolved O2 level.