1. Primary Production and Satellite Remote Sensing
Nastassia Patin
Summer Workshop in Marine Science at Georgia Tech
June

2. Phytoplankton are primary producers
~50% of all oxygen in the atmosphere is produced by single-celled photosynthetic algae known as phytoplankton

3. Primary production regulates climate and forms the foundation of the marine food web
Herndl and Reinthaler 2013 Nat. Geosci.

4. Types of phytoplankton
Coccolithophores
“brussels sprouts covered in chalk”
Diatoms
“brussels sprouts covered in glass”
Dinoflagellates
“brussels sprouts covered in wood”
Cyanobacteria
“bacteria”

5. Photosynthesis relies on chlorophyll

6. Chlorophyll a reflects green light (500-600 nm)

7. Satellite remote sensing
Aqua and Terra satellites use the Moderate Resolution Imaging Spectroradiometer (MODIS) to look at irradiance of Earth’s surface
MODIS views the entire planet every 1-2 days and covers a swath of 2330 km
podaac.jpl.nasa.gov/Terra

8. Satellite remote sensing
MODIS scans for irradiance at the wavelengths emitted by chlorophyll a
We can use those readings as a proxy for phytoplankton population density
en.wikipedia.org/wiki/Moderate-resolution_imaging_spectroradiometer

9. What causes phytoplankton blooms?
Limiting nutrients (eg nitrogen and phosphorous)
What are some nutrient sources?
Coastal runoff, upwelling
oceanservice.noaa.gov

10. Harmful Algal Blooms (HABs)
Gulf of Mexico dead zone
Phytoplankton blooms like this “red tide” can produce toxins that harm fish, birds, humans

11. Algal blooms precede dead zones
High nutrient loads can lead to algal blooms
These blooms are then consumed by heterotrophic bacteria that deplete the water of oxygen
Gulf of Mexico dead zone

12. Exercises Part A: Chlorophyll and Sea Surface Temperature (SST)
neo.sci.gsfc.nasa.gov
Under “Ocean” navigate to “Chlorophyll Concentration” and “Sea Surface Temperature (MODIS)”
Part B: MODIS Chlorophyll a
Printout has wrong URL! Instead use:
giovanni.gsfc.nasa.gov