Coral Reef Info
 

Coral Reefs Articles -> Deep water Coral “Reefs”

Recent studies have indicated that deep water coral structures occur more frequently than previously believed, and they are rich in biota. For example, Norwegian studies have identified 300 species in deep water coral structures in areas off Norwegian coasts.

Stemming from the debate surrounding the analogy made between coral reefs and rainforests, participants discussed how to define coral assemblages that live in deep and cool water. Are they reefs in the true sense of the word? Or would a different definition be more accurate? The discussion expanded to include other coral-related terminology.
Deep Soft Coral
Soft coral species such as these are found in both cold, deep waters and shallow, warm waters. These corals reside off the coast of Hawaii.

A Discussion of Terminology

Several participants admitted that they were uncertain about how to correctly define deep/cool water corals. One participant posited that to interpret all coral masses as reefs would be misrepresentative. Another noted that he commonly used the term “grove” to describe deep/cool water corals, but asked if anyone knew of a widely accepted official definition of corals that would differentiate between tropical and deep/cool coral assemblages.

a manipulator arm reaches for a soft coral

Deep sea submersibles (DSVs) can be used to study deep or cold water reefs. Here, a DSV manipulator arm reaches for a soft coral.

His question prompted several responses. One participant quoted a general definition of a reef as a “structure on which ships can run aground; a chain of rocks or ridge of sand at or near the surface of water that can be a hazardous obstruction.” The definition leaves no room for deep/cool water corals, according to the participant.

Another participant further differentiated deep/cool water corals from coral reefs by noting that reefs are structures built by hermatypic (reef-building) corals and other associated organisms, and they usually contain zooxanthellae. In contrast, deep/cool water corals generally do not contain zooxanthellae and are regarded as ahermatypic.

One participant further explained that in most cases, a coral is either zooxanthellate or azooxanthellate. However, a coral is not inherently hermatypic or ahermatypic. Rather, environmental factors determine whether coral can accrete limestone faster than it is eroded or covered. For example, Montastrea spp. occurs in both the Caribbean and off the coast of Florida. Environmental factors allow it to be hermatypic in the Caribbean but not on the West Florida Shelf, the participant stated.

gold coral growing on pillow lava

Although little light can reach depths below 500 ft., this gold coral grows on pillow lava in depths of more than 1000 ft. off the coast of Hawaii.

The participant concluded by touching on the practical implications of the definition. The distinction made between hermatypic and ahermatypic conditions affects management decisions made in conservation efforts. For example, environmental conditions that support the survival of Montastrea could differ significantly from conditions that would support reef development. Managers should consider these circumstances before making conservation decisions.


Top


 
Top Coral Reef News
10/16/2017
Harvey runoff is threatening coral reefs in the Gulf of Mexico
Oct. 16 (UPI) --New research suggests a massive plume of freshwater from Hurricane Harvey runoff is threatening coral reefs in the Gulf of Mexico. Last month, monitoring buoys measured a 10 percent drop in salinity at the Flower Garden Banks National ... more info

10/17/2017
Tough species of corals can go mobile and lay the foundations for new reefs in otherwise inhospitable areas, a stud
Close up of polyps are arrayed on a coral, waving their tentacles. There can be thousands of polyps on a single coral branch. Credit: Wikipedia Tough species of corals can go mobile and lay the foundations for new reefs in otherwise inhospitable areas, a ... more info

10/16/2017
Coral reefs in the Gulf of Mexico plundered by run-off from Harvey
We are only just starting to understand the impacts of the hurricanes that plundered the southern United States and Puerto Rico in the last two months. A recent study from scientists at Rice University shows that the intense flooding that came with Harvey ... more info



 
Coral Reef | Coral | Saltwater Fish | Great Barrier Reef | Reef Tanks | Glossary
Copyright © 2015 Coral Reef Info | Privacy Policy