What causes red tide?

Red tide is primarily caused by harmful algal blooms (HABs), which are rapid increases in the population of certain types of microscopic algae, notably dinoflagellates. These algae can multiply quickly under favorable conditions, such as nutrient-rich water, warm temperatures, and sunlight. During a red tide event, these algal blooms can produce toxins that are harmful to marine life and even to humans, leading to respiratory issues, fish kills, and other detrimental environmental impacts.

While storm water runoff and increased temperatures can contribute to the conditions that favor algal blooms, they are not the direct cause of red tide itself. Overfishing, though it affects marine ecosystems significantly, does not directly cause red tide. Instead, it is the presence and proliferation of specific algae that characterizes red tide events, making harmful algal blooms the most accurate description of what causes this phenomenon.