It was the largest algal bloom on record and it took place in June off the California coast. The planktonic algae made the water look green while producing a toxin. Seals, sea lions and dolphins eat fish that have eaten these algae, therefore hundreds died as a result. … Using satellite data, Gierach and other scientists created new ways to study the changes in the ocean. … Satellites can even measure color and temperature changes. A lot of the increase in algal bloom is caused by what we dump into the ocean, runoff, fertilizer and climate change.