Deepest U.S. reef found

[Unarce]

Deepest U.S. reef found

ST. PETERSBURG, Florida (AP) -- Marine researchers have discovered the deepest coral reef ever found in the United States in about 250 feet of water off the Florida coast.

The discovery in the Gulf of Mexico was announced last month by the U.S. Geological Survey.

It was tentatively identified as a coral reef in 1999 by a team from the University of South Florida. But it took several more years of research to confirm it as a living reef that depends on light filtering down from the surface.

"We were all blown away by this bizarre, flat, living sea floor covered with blue and brown corals and lettuce-like green algae," researcher Bret Jarrett said of seeing live video from an unmanned submersible.

The video revealed a stunning number of fish, both deep and shallow water species: giant red grouper, scamp, damselfish, angelfish, rock beauty, hogfish and bass.

The reef is on Pulley Ridge, a vast area west of the Dry Tortugas, a cluster of seven islands 70 miles west of Key West. The reef is up to three miles wide and runs for about 20 miles.

Shallow-water reefs tend to grow vertically, like those off the Florida Keys. Pulley Ridge coral grows flat because it has adapted to the low light.

"Corals require light to grow, and so they spread out laterally as opposed to vertically," Jarrett said. "They've adapted to the situation, they've maximized the sunlight."

Officials who oversee the gulf are now wondering how to preserve the reef.

The scientists' research has been presented to the Gulf of Mexico Fishery Management Council, which will decide in the coming months whether to restrict fishing or trawling in the area.

Copyright 2005 The Associated Press. All rights reserved.This material may not be published, broadcast, rewritten, or redistributed.

http://www.cnn.com/2005/TECH/science/01 ... index.html

 

[Anonymous]

Ahem. :wink:

http://reefs.org/phpBB2/viewtopic.php?t=61494


Regards,
David Mohr

 

[Anonymous]

Very interesting. a reef living with algae corals and fish. And at 250' deapth.

Perhaps the expensive high intensity lighting is not absolutely required after all.

 

[spsmike]

Well I wonder what type of corals are down there?

 

[Anonymous]

Keep in mind this is a very rare find. These corals are probably best described as "struggling to survive" down there, seeing as how we don't find 250 foot deep reefs all over.

If that's the type of biotope you'd like to emulate in your tank, go for it I'll stick with the shallow water reefs with non-brown corals.

 

[Anonymous]

Actually, I kinda wonder about two things. First is this a hoax? And secondly (if not a hoax) what is the deapest coral reef in the world? After all this is only the deapest in the US. Which must mean there is one deaper somewhere else in the world.

 

[ReefMon]

http://coastal.er.usgs.gov/pulley-ridge/index.html

Pulley Ridge is a 100+ km-long series of N-S trending, drowned, barrier islands on the southwest Florida Shelf approximately 250 km west of Cape Sable, Florida (Fig. 1). The ridge has been mapped using multibeam bathymetry, submarines and remotely operated vehicles, and a variety of geophysical tools. The ridge is a subtle feature about 5 km across with less than 10 m of relief. The shallowest parts of the ridge are about 60 m deep. Surprisingly at this depth, the southern portion of the ridge hosts an unusual variety of zooxanthellate scleractinian corals, green, red and brown macro algae, and typically shallow-water tropical fishes.

The corals Agaricia sp. and Leptoceris cucullata are most abundant, and are deeply pigmented in shades of tan-brown and blue-purple, respectively. These corals form plates up to 50 cm in diameter and account for up to 60% live coral cover at some localities. Less common species include Montastrea cavernosa, Madracis formosa, M. decactis, Porities divaricata, and Oculina tellena. Sponges, calcareous and fleshy algae, octocorals, and sediment occupy surfaces between the corals. Coralline algae appear to be producing as much or more sediment than corals, and coralline algal nodule and cobble zones surround much of the ridge in deeper water (greater than 80 m).

In addition to coralline algae other abundant macro algae include Halimeda tuna, Lobophora variegata, Ventricaria ventricosa, Verdigellas peltata, Dictyota sp., Kallymenia sp., and particularly striking fields of Andaymonene menzeii. The latter algae covers many hectares at densities of tens of individuals per square meter, constructing regions that appear like lettuce fields growing in the dusk at this depth on the sea floor.

The fishes of Pulley ridge comprise a mixture of shallow water and deep species sharing this unusual habitat. More than 60 species have been identified. Commercial species include Epinephelus morio (red grouper) and Mycteroperca phenax (scamp). Typical shallow-water tropical species include Thalassoma bifasciatum (bluehead), Stegastes partitus (bicolor damselfish), Cephalopholis fulva (coney), Lachnolaimus maximus (hogfish), Pomacanthus paru (French angelfish), and Holacanthus tricolor (rock beauty). The deepwater fauna is represented by Chaetodon aya (bank butterflyfish), Sargocentron bullisi (deepwater squirrelfish), Bodianus pulchellus (spotfin hogfish), Pronotogrammus martinicensis (roughtongue bass), and Liopropoma eukrines (wrasse bass). Malacanthus plumieri (sand tilefish) and several other species construct large burrows and mounds that serve as refuge for multiple species. Mounds and pits larger than 1m2 are apparent on side-scan sonar images and have been counted in excess of 200/km2 for parts of the ridge.

The extent of algal cover and abundance of herbivores suggest benthic productivity is moderate to high on parts of the ridge. Such productivity is unusual, if not unique at this depth in the Gulf of Mexico and Caribbean. Several factors help to account for the existence of this community. First, the underlying drowned barrier islands provided both elevated topography and lithified substrate for the hard bottom community that now occupies the southern ridge. Second, the region is dominated by the western edge of the Loop Current that brings relatively clear and warm water to the southern ridge. Third, the ridge is within the thermocline, a water mass that is known to provide nutrients during upwelling to shallow reefs in Florida.

Notwithstanding the positive factors for reef growth listed above, this largely photosynthetic community appears to be thriving on 1-2% (5-30 microEinsteins/1m2/sec) of the available surface light (PAR) and about 5% of the light typically available to shallow-water reefs (500 – 1000 microEinsteins/1m2/sec). The corals generally appear to be healthy, with no obvious evidence of coral bleaching or disease. Although the community is clearly one adapted to low light conditions, the variety and extent of photosynthetic organisms between 60 and 70 meters depth is impressive.

Is southern Pulley Ridge the United State's deepest coral reef? That depends, of course, on one's preferred definition of a coral reef. There are deeper, ahermatypic coral buildups both in the Gulf of Mexico and Atlantic off Florida coasts. Classically, a coral reef is a wave resistant structure built by hermatypic corals and hazardous to shipping. From a geologist's point of view, Pulley Ridge corals appear to have built a biostrome, an accumulation at least a few meters thick, although corals may not account for the bulk of the topography. From that of a biologist, the most abundant corals in the ridge are hermatypic corals but they are lying, mostly unattached, on the surface. Clearly a ship's captain could not run his vessel aground on this reef, so mariners would not consider this a reef. Nevertheless, from the scientific perspective of a structure built from hermatypic corals, southern Pulley Ridge may well be the deepest coral reef in the United States.

 

[Anonymous]

Perhaps the expensive high intensity lighting is not absolutely required after all.

You never seem to miss an opportunity to confirm your ignorance.

 

[Anonymous]

Perhaps the expensive high intensity lighting is not absolutely required after all.

You never seem to miss an opportunity to confirm your ignorance.

That's kind of unnecessary Guy. I don't agree with what he's saying either but there are more constructive ways of saying it.

 

[Anonymous]

It's just an observation.

 

[ChrisV]

Think a clam or an acro could tuff it out at those depths? The water would need some good clarity for light to make it that far...

 

[Anonymous]

Officials who oversee the gulf are now wondering how to preserve the reef.

Well, it's good to see that it's still all about the money :roll:

They want to manage it and get money to manage it, that's why you see it here in the mainstream news and not quietly being published in the peer reviewed journals like most finds. It's in someone's best interest to manage it.

There is a reef, whose location i won't reveal, that has the largest and healthiest population of Atlantic staghorn anywhere. It's in a spot that's considered polluted, with algae overgrown reefs to the north and south, and you'd never believe it was there unless you saw it with your own eyes. A find just as big if not bigger than a deep reef, especially when Atlantic Staghorn is considered so threatened. So why haven't you heard about this reef? Because it's close to a popular, wealthy beach area that will require renourishment in the future. It's in someone's best interest, therefore, to keep their mouths shut about this place, to keep it from being well known and "protected", so they can proceed with their renourishment when necessary without any hindrances.

 

[spsmike]

One day the only corals left will be the ones in our tanks

 

[Anonymous]

It's just an observation.

one of my observations from my own aquarium experience is that many corals don't need as high a light, or par level, as some seem to think, in order to grow and thrive :wink:

 

[Unarce]

one of my observations from my own aquarium experience is that many corals don't need as high a light, or par level, as some seem to think, in order to grow and thrive :wink:

Although a certain amount of intesity should be met, especially for corals like SPS, I've always maintained that PAR takes a back seat to Spectrum. When considering how corals and zooxanthellae utilize light, high intensity, low kelvin lighting, seem like overkill. Not to mention, unnatural.

 

[Anonymous]

A friend of mine had a stark white Montipora digitata that grew to fist sized from a tiny frag in his unlit refugium. I wouldn't believe it if I hadn't seen it myself. Must have just caught enough worm larvae, baby copepods and the like to sustain itself.