Caribbean Sea

Deep under the Caribbean Sea, the sea floor is very slowly pulling apart.

It moves only about 15 millimeters a year.

Deep under the Caribbean Sea lies a long valley called the Cayman Trough. In it, a ridge about 110 kilometers long is slowly pulling apart, by about 15 millimeters a year, and has been for about 49 million years.

The floor of this ridge lies between 4,200 and more than 6,000 meters down. Scientists call it the deepest spreading ridge in the world.

Connelly and colleagues (2012) describe the Mid-Cayman spreading center as a 110 km-long ultraslow ridge in the Cayman Trough, with a full spreading rate of 15 mm per year, active for 49 million years, and an axis 4,200 to more than 6,000 m deep, which makes it the world's deepest seafloor spreading center.

It is isolated by about 4,000 km from the contiguous mid-ocean ridge system. On the western flank of its axial valley, an off-axis feature called Mount Dent rises 2,700 m above the spreading center.

Far down on the sea floor, very hot water shoots out of rock chimneys.

Thousands of little shrimp crowd around them!

In 2012 scientists reported two fields of hydrothermal vents, hot springs on the sea floor, in the Cayman Trough. The Beebe Vent Field lies 4,960 meters down, and the scientists called it the deepest known hydrothermal system in the world at that time.

Its plume of water rises 1,100 meters, which suggests the water is hotter than 400 °C. Around the vents live crowds of shrimp, more than 2,000 in a single square meter.

The study reported the Von Damm Vent Field at 2,300 m on the upper slopes of an oceanic core complex, and the Beebe Vent Field at 4,960 m on the spreading axis, emitting copper-enriched fluids and a buoyant plume rising 1,100 m, consistent with venting hotter than 400 °C: the world's deepest known hydrothermal system at the time.

At both sites a new morphospecies of alvinocaridid shrimp dominates, at more than 2,000 individuals per square meter, in assemblages resembling those of Mid-Atlantic vents. The fields were named after naturalist William Beebe and geochemist Karen Von Damm.

Along the coast of Belize there is a long coral reef.

Sea turtles, manatees and crocodiles live there, among mangrove trees and little sandy islands.

Along the coast of Belize lies the largest barrier reef in the northern hemisphere, UNESCO says. Together with offshore atolls, several hundred sandy cays, mangrove forests and lagoons, it became a World Heritage Site in 1996.

It is an important home for threatened animals, including sea turtles, manatees and the American crocodile.

UNESCO's Belize Barrier Reef Reserve System, a serial property of seven sites inscribed in 1996 under criteria (vii), (ix) and (x), includes the largest barrier reef in the northern hemisphere, offshore atolls, several hundred sand cays, mangrove forests, coastal lagoons and estuaries.

The seven sites illustrate the evolutionary history of reef development and are a significant habitat for threatened species, including marine turtles, manatees and the American marine crocodile. The property was on the List of World Heritage in Danger from 2009 to 2018.

Big storms called hurricanes can come from June to November. Grown-ups check the weather.

Swim only where lifeguards watch. If the water pulls you, swim along the beach.

The Atlantic hurricane season, which includes the Caribbean Sea, runs from June 1 to November 30, says the US National Hurricane Center. Check the forecast before a trip in those months.

At the beach, swim only where lifeguards are on duty; rip currents can form even on calm, sunny days. If one pulls you, don't swim straight back. Swim parallel to the shore, then head in at an angle.

The National Hurricane Center's climatology gives the Atlantic season, which covers the Caribbean Sea, as June 1 to November 30; based on 1991-2020, an average season has 14 named storms, 7 hurricanes and 3 major hurricanes, with the first major hurricane typically forming in late August or early September.

The National Weather Service advises checking the beach forecast, talking to lifeguards and swimming at guarded beaches. NOAA's National Ocean Service notes rip currents can reach 8 feet (about 2.4 m) per second; swim parallel to the shore and return at an angle.