The Thermal Dome of Costa Rica is a critical zone for the marine biodiversity of the Eastern Tropical Pacific. It is located in the west of Central America and can measure between 300 and 1000 kilometers wide.
The average position of the core of the Dome is near 9 ° North and 90 ° West, in areas outside of national jurisdictions. Its diameter and position vary from year to year and throughout a characteristic annual cycle (Fiedler, 2002).
This oceanographic phenomenon results from the action of winds and marine currents that produce the vertical displacement of deep, cold and nutrient-rich waters that approach the surface, creating an upwelling zone. This upwelling mobilizes a huge body of water (about 3.5 million m3 / s) 1 to the surface.
The Thermal Dome of Costa Rica is a biodiversity hotspot for marine life. The presence of a strong and shallow and seasonally predictable thermoclimate associated with cyclonic circulation and upwelling make the Costa Rica Dome a distinct biological habitat, with significantly higher zooplankton and phytoplankton biomass than in the surrounding tropical waters. The algae are strengthened by the huge amount of cold water, combined with sunlight. Inside the dome is the highest concentration of chlorophyll in the world, with approximately 60 milligrams per cubic centimeter of seawater. This helps feed the zoo-plankton which consists of larvae and larger animals such as sea sponges, worms, echinoderms, mollusks, crustaceans and other arthropods. An important aspect of the Costa Rican Dome is that it is made up of dense patches of krill at different depths.
The Dome is also a habitat for sharks, dolphins, eels, tuna, billfish, species of sea turtles: olive green and leatherback turtles, rays, octopuses, colonies of seabirds and species of whales: blue whale and orca.
The oceanic phenomenon of the Thermal Dome of Costa Rica was detected off the Central American country in 1948. This was through the use of bathythermographs, which is an instrument that consists of a thermometer that allows to measure and graphically represent the temperature of sea water at different depths. which were used on ships traveling from California to Panama. The Dome was founded by Townsend Cromwell, and it was he who named the oceanographic site the “Thermal Dome” of Costa Rica.