You know that nutrients are an important concern in the Chesapeake Bay watershed in genera...

You know that nutrients are an important concern in the Chesapeake Bay watershed in general, but now you can examine the details and see how conditions have changed. Go to www.eco-check.org/reportcard/chesapeake. This site is maintained by the University of Maryland and the National Oceanic and Atmospheric Administration (NOAA), with support of many collaborators and data providers.

Chlorophyll is something you’ve read about in this chapter. Concentrations of chlorophyll in Chesapeake Bay indicate amounts of tiny floating algae cells—algae nourished by nitrogen and phosphorus from onshore sources. Take a look at chlorophyll-a levels in the bay: roll your mouse over the Indicators and Indices, and click on the “chlorophyll-a” icon (this is one of several kinds of chlorophyll).

Take a few minutes to look at the Threshold map, as well as the definitions to answer the questions below.

Refer to your chapter, and explain what chlorophyll needs to perform photosynthesis. Why are nitrogen and phosphorus needed for plant growth?