What reservoir contains most of Earth's phosphorus over long time scales?

Weathering of apatite, a common rock-forming mineral, releases which nutrient into nearby soil and water?

In a terrestrial ecosystem, plants take up phosphorus primarily through their roots as what?

What process moves phosphorus from dead organisms and wastes back into soil or water?

Which human activity is the largest source of sulfur entering the atmosphere?

In the sulfur cycle, which reservoir stores a large amount of sulfur as dissolved sulfate ions?

A farmer applies phosphate fertilizer, and much of the phosphate binds tightly to soil particles. How does this phosphate usually reach a nearby stream?

Why does phosphorus have no significant gaseous phase in its biogeochemical cycle?

Compared with carbon and nitrogen, which reservoir is much less important in the phosphorus cycle?

A phosphate-bearing rock must weather before its phosphorus becomes available to plants. What does this show about the phosphorus cycle?

Which substance allows sulfur, unlike phosphorus, to move through the atmosphere after fossil-fuel combustion?

Phosphorus has no major gas form, yet small amounts still travel long distances through the air, such as from the Sahara to the Amazon. How?

Which statement best contrasts how sulfur and phosphorus move through the atmosphere?

Why can sulfur pollution from one region contribute to acid deposition far downwind?

Sulfur dioxide released by a coal-fired plant reacts in the atmosphere and later falls with rain. What transfer is occurring?

In an oxygen-poor wetland sediment, bacteria convert sulfate to hydrogen sulfide. What sulfur-cycle process is this?

Pyrite exposed during mining reacts with oxygen and water, releasing sulfate and acidity. What process moves sulfur from rock into water?

Sulfur-containing particles settle directly from polluted air onto tree leaves without precipitation. What is this transfer called?

Microbes decompose a dead plant containing sulfur-bearing proteins. What happens to its sulfur?

What natural event can inject sulfur dioxide directly into the atmosphere?

Phosphate fertilizer washes from cropland into a lake after heavy rain. What is the most likely initial ecological response?

A wastewater treatment plant releases phosphorus-rich effluent into a slow-moving river. What downstream condition is most likely after an algal bloom decomposes?

A phosphate mine leaves exposed spoil piles beside a stream. Heavy rain carries sediment into the stream. Which effect is most likely?

A power plant installs flue-gas scrubbers that remove much of its sulfur dioxide. What downstream environmental change should be expected?

Coal combustion increases sulfur dioxide emissions over a region with poorly buffered lakes. What is a likely effect on those lakes?