Welch – Science
The phosphorus cycle is the biogeochemical cycle that describes the movement of phosphorus through the lithosphere, hydrosphere, and biosphere. Unlike many other biogeochemical cycles, the atmosphere does not play a significant role in the movement of phosphorus, because phosphorus and phosphorus-based compounds are usually solids at the typical ranges of temperature and pressure found on Earth.
On the land, phosphorus gradually becomes less available to plants over thousands of years, since it is slowly lost in runoff. Low concentration of phosphorus in soils reduces plant growth, and slows soil microbial growth - as shown in studies of soil microbial biomass. Since phosphorus is found in low concentration it is referred to as a limiting nutrient of plant growth. Locally, transformations of phosphorus are chemical, biological and microbiological: the major long-term transfers in the global cycle, however, are driven by tectonic movements in geologic time.
Humans have caused major changes to the global phosphorus cycle through shipping of phosphorus minerals, and use of phosphorus fertilizer, and also the shipping of food from farms to cities, where it is lost as effluent.
1. According to the model, which of the following would not be an input of phosphorus into the soil.
2. Of the following, which one does not have a cyclical (cycle) pattern?
3. Algal blooms, like found on our nearby ponds covered with green vegetation, is a result of excess phosphorus. Which of the following would be the most likely reason for the excess plant growth in these ponds due to the presence of phosphorus?
4. Locally, human activity has the greatest impact on the phosphorus cycle. Which of the following would be associated with that impact?
5. Of the phosphorus inputs, which would be a man-made input.
6. Which of the following is best at long term removal of phosphorus from the soil?