BIO 121 Lecture 16: BIO 121L - Week 10 - Lecture 16 (pt. 2)
Document Summary
Bio 121l - week 10 - lecture 16. Npp is controlled by climate in terrestrial ecosystems. At very high temperatures, npp may decrease if the photosynthetic enzymes become denatured. Precipitation affects photosynthesis by the opening of the stomata. With very high precipitation, npp may decrease because of greater cloud cover and less sunlight. Npp is controlled by nutrient availability in aquatic ecosystems. Phosphorus limits npp in lakes and ponds. Npp in rivers and streams is usually low. Water flow restricts the growth of phytoplankton. The majority of energy in rivers and streams is derived from terrestrial organic matter. Coral reefs, kelp forests, and estuaries (where river meets ocean) are very productive. Nitrogen and iron limit npp in the open ocean. 54% of global npp comes from terrestrial ecosystems. The remaining 46% comes from aquatic ecosystems. The average rate of npp on land is much higher than that in the ocean.
