Urtide

Urtide is a term used in marine biology to describe a rapid and significant increase in the population of certain types of plankton, often dinoflagellates, which can color the water red, brown, or even green. This phenomenon is also commonly referred to as a harmful algal bloom (HAB) or, in some contexts, a red tide. While the term "tide" is part of the common name, urtides are not directly related to tidal cycles but rather to specific environmental conditions that favor rapid plankton growth.

These conditions typically include elevated nutrient levels, such as those resulting from agricultural runoff or sewage discharge, combined with suitable water temperatures and sunlight. Certain species of urtide-producing dinoflagellates can produce toxins that accumulate in shellfish, posing a risk to human health if these shellfish are consumed. These toxins can also harm or kill marine life, including fish, seabirds, and marine mammals. The economic impact can be substantial, affecting fisheries, aquaculture, and tourism. Monitoring and management strategies are employed to mitigate the risks associated with urtides, including public health advisories and closures of affected areas.