Red tides are the worst-named algal anomaly out there—they’re not always red, but these blooms of algae can be harmful to humans and other animals.

Hey, teachers! Here’s a cheat sheet of what’s included in this episode of Long Story Shorts:
- Red tides and harmful algal blooms: what are they, what causes them, how can they affect other life in and near the ocean (both positively and negatively), misconceptions about them
- Ocean food web
- Toxins
- Phytoplankton, algae

This episode is part of our series Long Story Shorts—fun, quick explainers about all things coastal science!

Created by the Hakai Institute
Produced by Katrina Pyne and Josh Silberg
Animations by Katrina Pyne
Illustrations by Mercedes Minck
Stock images by Shutterstock
Google Earth imagery by Data SIO, NOAA, U.S. Navy, NGA, GEBCO