Why is elkhorn coral endangered

It is a fast growing species and is one of the most important reef-building species in the Caribbean. It was formerly one of the most common corals on reefs throughout its range. Today, it is very rare and is considered critically endangered by reef scientists. Elkhorn coral structures are actually colonies of several genetically identical animals living together.

These colonies can reproduce both sexually and asexually, and they are hermaphroditic — each animal produces both eggs and sperm. During just a few days surrounding full moons in the fall, elkhorn corals release bundles of eggs and sperm that float to the surface, break apart, and mix.

Sperm do not fertilize eggs from the same colony, so several colonies release their gametes at the same time, in a process known as broadcast spawning. The fertilized egg quickly hatches and the baby coral spends a few days in the water column before settling on the reef and beginning to form a new colony.

It also requires greenhouse-gas-emitting industries to grapple with their impacts on vulnerable coral species. If we can keep the polluters at bay, these colorful critters can and will make a comeback. Two nasty sunscreen chemicals are damaging our coral reefs. Please tell the feds toxic chemicals don't belong on our bodies or in vital ocean habitats. Coral reefs cover less than 1 percent of the ocean floor, yet they support 25 percent of all marine creatures.

Colonies of elkhorn coral are relatively fast growing, with branch length increasing about 2 to 4 inches per year. Colonies reach maximum size in about 10 to 12 years.

Coral age can be determined by counting coral growth rings the same way that tree rings are counted to determine tree age. Elkhorn colonies typically grow in water depths of less than 20 feet but may be present down to a depth of about 65 feet.

The species ranges geographically from its northern limit in Biscayne National Park to its southern limit in Venezuela. Large, continuous elkhorn thickets once extended along the front side of most coral reefs and supported a diverse assemblage of other invertebrates and fish.

Since , elkhorn populations have collapsed throughout their range from disease outbreaks, with losses compounded locally by hurricanes, predation, bleaching, elevated temperatures, and damage from sedimentation. In , researchers documented the first case of white pox disease in a reef off the shore of Key West. Within four years after the white pox was found, the population of elkhorn coral in that reef had decreased by 82 percent.

Further research determined that the cause of white pox is a jellybean-shaped bacterium called Serratioa marcescens that is common in human intestines but is not known to be typical in healthy reefs. In addition, other coral diseases discovered since the mids have been traced to bacteria found in human waste. The rapidly increasing trend in coral die-offs may be partially explained by the growing populations of people living along and visiting tropical coasts and the resulting greater volumes of human waste spilling into coastal waters.