Level 4
Relating SST to Productivity
Phytoplankton are microscopic plants that live near the surface of the ocean and provide food for larger organisms. They form the base of the food chain. Nutrients carried by upwelling from deeper water up to sunlit surface water encourage phytoplankton growth. This process can be compared to the addition of fertilizers to soil to encourage land plants to grow faster and larger.
Phytoplankton also contain chlorophyll, which enables them to use photosynthesis. Scientists estimate the amount of phytoplankton in the ocean by using data from satellites that can detect chlorophyll by color.
During an El Niño, when upwelling is disrupted, scientists measure a decrease in chlorophyll in areas of the eastern Pacific. This signals a decline in phytoplankton productivity.
Use the images below to check your understanding. Then investigate the relationship between sea surface temperature and productivity for yourself by making maps and graphs of real data.
| Set A | |
|---|---|
Sea surface temperature |
Chlorophyll-a |
| Set B | |
Sea surface temperature |
Chlorophyll-a |