Assessing Net Primary Productivity
To explore the concept of net primary productivity and to see how it varies in different biological communities, go to www-eosdis.ornl.gov/NPP/npp_home.html, a research page maintained by the Oak Ridge National Laboratory. This clickable map shows 55 sites around the world where long-term ecological data are being collected. Click on a tropical forest, a hot desert, a grassland, and a temperate forest to go to their individual pages. At the bottom of each site page, find highlighted links such as "NPP data" or "treatments" that take you to NPP measurements. Look at the range of data over time and compare the maximum amount of aboveground biomass—generally the seventh column from the left—for each of these sites. How would you account for the variation you observe between different seasons of the year and different sites in this key ecological measurement?
