Red tide is that naturally-occuring phenomenon during which algae take over a stretch of ocean, turning it red. At their most intense, these algal blooms produce toxins that sicken - and at times kill - sea animals.
Scientists say red tides are happening more frequently in Southern California, and with more toxicity. But they don't know why.
In the latest story in our Beachcombing series, KPCC's Sanden Totten introduces us to a robot that scientists hope will find some answers.