The Phosphorus Cycle: An Introduction

Phosphorus is difficult for plants and animals to access in nature because

• a.it reacts quickly with other elements, like oxygen.
• b.most phosphorus in the environment is bound to carbon, nitrogen, and hydrogen.
• c.it is typically found as a phosphate.
• d.most phosphorus in the environment is stored in reservoirs.

Dr. Schindler and his team of researchers at the Experimental Lakes Area noticed a significant growth in algae when they added fertilizer heavy in _________ to the water.

• a.phosphorus
• b.carbon
• c.nitrogen
• d.calcium

Without phosphorus, living beings cannot grow, reproduce, or move. This is because phosphorus

• a.forms part of the structure of DNA and RNA.
• b.provides structure to cell membranes.
• c.is needed for energy transport in cells.
• d.all of the choices

Phosphorus does NOT travel through which of the following spheres?

• a.lithosphere
• b.atmosphere
• c.biosphere
• d.geosphere

Review the diagram below. Which statement BEST reflects what is shown?

• a.The phosphorus cycle moves in one direction – from soil to plant to animal.
• b.Fungi, plants, and animals are the main converters of elemental phosphorus to phosphates.
• c.The phosphorus cycle is made up of many, smaller cycles.
• d.Phosphates in solution can only move into soil.

Humans do not influence the phosphorus cycle in any significant way.

• a.true
• b.false

The Experimental Lakes Area was an important contribution to environmental science because

• a.it showed how dangerous algae can be to an aquatic ecosystem.
• b.it made clear connections between phosphate fertilizers and eutrophication in lakes.
• c.it was the first instance of extreme science.
• d.it resulted in recorded data on depth, visibility, and conductivity in 463 lakes.