To Bloom or Not to Bloom

    The Challenge

    Your challenge is to solve the mystery behind algal blooms! What factors cause blooms in some water bodies but not others, and how can we better predict their occurrence to prevent harm to aquatic and human life?

    Background

    What are algae? If you answered phytoplankton, or plant-like microscopic organisms in water, you are correct! If you answered large hundred-foot seaweeds like kelp, you are also correct!

    Algae are diverse, photosynthetic organisms that naturally occur in marine and freshwater systems. They are vital to many ecosystems, supporting aquatic food chains and affecting air quality.

    One type of algae, known as phytoplankton, can bloom periodically, just like your house plants.

    Certain conditions can cause a rapid, out-of-control algal growth causing “blooms” that can alter the quantity of light and the levels of oxygen in water, causing harm to marine life. Some algae can be particularly harmful to humans, producing toxins that cause rashes, breathing problems, and liver damage.

    Several factors that play a role in the occurrence of blooms have been identified:

    - Wind and water currents

    - Presence of nutrients (such as phosphorus, nitrogen, and carbon)

    - Warmer than usual water temperatures

    - Extreme events, such as floods, hurricanes, and droughts

    - Sluggish water circulation

    This list is not comprehensive, so the mystery of what cause algal blooms remains unsolved.

    Potential Considerations

    • Consider addressing some or all of the following questions:
      • What is the interplay between known factors that causes blooms in some water bodies and not others?
      • Are there other factors, e.g. seasonality, that affect when and where blooms occur?
      • Do some factors play a larger role in causing blooms in freshwater lakes versus salty oceans?
      • What proximate human activities or events increase the likelihood of blooms in water bodies?
    • Satellite-based images of ocean color, specifically, phytoplankton chlorophyll a, a major light-absorbing pigment, can help identify and forecast the development and presence of algal blooms in water bodies. Specific spectral bands and their ratios can distinguish areas of high algal growth. But are there other clues within satellite-based data that are yet to be discovered?