Elkhorn and Staghorn

[Anonymous]

Taking a core sample of a significant/major reef-building coral, a Porites, I think.

Montastrea annularis complex.

 

[Anonymous]

So it is a sun coral? Thanx.

 

[Anonymous]

So it is a sun coral? Thanx.

Star coral.

 

[Anonymous]

Sun is a star, so I am not that far off...

 

[Anonymous]

Sun is a star, so I am not that far off...

:lol: Point taken.

 

[GSchiemer]

FWIW, by any definition, Acropora palmata (AKA Elkhorn Coral) IS a reef-building coral. In fact, it's THE PRIMARY reef-building coral in the Caribbean.

Totally false. Have you ever looked at a coral reef core?

To dismiss it as a "weed" is really doing it an injustice.

Nobody is dismissing anything, just simply stating how it reacts and responds to environmental changes and favorable conditions. Weed is a good analogy.

A quick search on the internet will support my contentions. Here is a comment from a web site discussing A. palmata as it relates to reefs off of Puerto Rico:

Web site information is worth what you pay for it. Mostly nothing. Also, your search does not mention the reef building capabilities (or lack there of) of elkhorn coral at all.

I'm not sure what you're trying to prove with this. Is it just a game of semantics? There is no question that Acropora palamata is THE primary reef-building coral in the Caribbean. That's indisputable. All the barrier and fringing reefs in the Caribbean are primarily composed of A. palmata. So what's your point? How many references do you want me to post? The fact that A. palmata is not massive by nature does not negate the fact that it is a "reef-building" coral. Whether those reefs last 30 years or 3000 years is irrelevant.

Greg

 

[Anonymous]

i believe elkhorn coral forms what the hobby calls Tonga branch live rock.

Wrong ocean.

a bit of a tangent here...

i was under the impression that the common names applied to live rock had little to do with where they are from and more to do with what they are composed of.

i have no doubts that i could be, and likely am, very wrong about the coral species that forms what we refer to as "tonga branch" but is it only found near the island of Tonga?

and something else.... is elkhorn only found near Fla.?

 

[Anonymous]

There is no question that Acropora palamata is THE primary reef-building coral in the Caribbean. That's indisputable.

Acropora palmata is one of the most intolerant corals in the world. Save for a few deeper spots with unique current patterns (such as the Dry Tortugas), it grow on shallow reef crests and highs. It needs the wave energy and strong currents prevalent near the surface in order to keep itself swept free of sediment, as the branch shapes would tend to act as a sediment trap. Any sedimentation or nutrient toxicity is death. Any sediment placed on branches and allowed to sit will kill the colony back rapidly. Habitat like this represents a relatively small percentage of extant (past and present) coral reef habitat in the Caribbean. Common sense then dictates, that a coral that only grows under these specific parameters cannot have been the primary reef builder. Corals that are tolerant of a wide variety of physicochemical conditions, like Montastrea and Diploria (which are actually the primary reef building corals in the Caribbean) are the ones that allow the habitats that Acropora palmata colonize to form in the first place.

All the barrier and fringing reefs in the Caribbean are primarily
composed of A. palmata.

Simply wrong.

Whether those reefs last 30 years or 3000 years is irrelevant.

In fact, it's incredibly relevent, ask any paleoceanographer or carbonate geologist.

 

[Anonymous]

i was under the impression that the common names applied to live rock had little to do with where they are from and more to do with what they are composed of.

Hi Pod, I don't know. I do know that the only rock likely to be coming out of a place anywhere near where elkhorn grows is Gulf aquacultured, and there definitely ain't no elkhorn in the Gulf.

i have no doubts that i could be, and likely am, very wrong about the coral species that forms what we refer to as "tonga branch" but is it only found near the island of Tonga?

I doubt it.

and something else.... is elkhorn only found near Fla.?

The most northerly known stand is off the coast of Key Biscayne. It ranges from south of that point (the Keys reef tract), through out the Tropical West Atlantic, as well as the Caribbean Sea. It has very specific habitat requirements, though (see above post).

 

[GSchiemer]

There is no question that Acropora palamata is THE primary reef-building coral in the Caribbean. That's indisputable.

Acropora palmata is one of the most intolerant corals in the world. Save for a few deeper spots with unique current patterns (such as the Dry Tortugas), it grow on shallow reef crests and highs. It needs the wave energy and strong currents prevalent near the surface in order to keep itself swept free of sediment, as the branch shapes would tend to act as a sediment trap. Any sedimentation or nutrient toxicity is death. Any sediment placed on branches and allowed to sit will kill the colony back rapidly. Habitat like this represents a relatively small percentage of extant (past and present) coral reef habitat in the Caribbean. Common sense then dictates, that a coral that only grows under these specific parameters cannot have been the primary reef builder. Corals that are tolerant of a wide variety of physicochemical conditions, like Montastrea and Diploria (which are actually the primary reef building corals in the Caribbean) are the ones that allow the habitats that Acropora palmata colonize to form in the first place.

If you examine average growth rates between large colonies and small colonies from recently fragmented branches that have managed to anchor, the growth rate of the larger colonies is exponentially faster. Anybody care to take a stab at why?

All the barrier and fringing reefs in the Caribbean are primarily
composed of A. palmata.

Simply wrong.

Whether those reefs last 30 years or 3000 years is irrelevant.

In fact, it's incredibly relevent, ask any paleoceanographer or carbonate geologist.

It's very easy to say "simply wrong" without backing it up. In fact, you are the one that is "simply wrong." Acropora palmata is not only a reef building coral but occurs in the Gulf of Mexico. Here are just a few references to back up these FACTS. This is my last post on the topic because anyone can easily search the most rudimentary book on Caribbean/Gulf coral reefs and refute your statements.

-HUBBARD, Dennis K., Dept. of Geology, Oberlin College, 52 West Lorain St, Oberlin, OH 44074: A. palmata has been the dominant shallow-water Caribbean species throughout the Quaternary

-Jackson, J. B. C., 1994. Community Unity. Science 264: 1412-1413:
Most scholars agree that the critical point of the Caribbean coral reef health was reached in the early 1980's, when the primary reef-builder in the Caribbean, acroporid corals, began to undergo widespread regional declines (Ritchie and Smith, 1998; Hoegh-Guldberg, 2000; Miller et al., 2002). For nearly 500,000 years, acroporid corals, Acropora palmata and Acropora cervicornis, characterized and structured coral reefs throughout the Caribbean.

-Andrew Bruckner, Ph.D, letter to Puerto Rico Department of Natural Resources. December 6, 2001: In shallow water (0.5-3 m depth) the reef is dominated by Acropora palmata (Elkhorn)with isolated brain, star and mustard hill corals. Elkhorn colonies form a dense stand that begins about 5 m offshore and extends seaward 20-30 m.... A. palmata formed characteristic thickets in the shallowest, exposed areas, on fringing reefs and the outer portions of offshore reefs.


-"Taphonomic differentiation of Acropora palmata facies in cores from Campeche Bank Reefs, Gulf of Mexico" Paul Blanchon & Chris Perry-Reef Systems Unit, Institute of Marine Sciences and Limnology, National University of Mexico: Cores from the reef-front zone(2-10 m depth) are characterized by sections of Acropora palmata...

-NOAA Fisheries Office of Habitat Conservation (NOAA/F/HC)
Ecosystem Assessment Division:
Elkhorn and staghorn corals are the two major reef-building corals in Florida and throughout the Caribbean that once formed dense thickets at shallow and intermediate depths, contributing significantly to reef growth, island formation, coastal protection, fisheries habitat and coral reef biodiversity. These species have declined in abundance throughout most of their range by 80-98% of their 1970s baseline, converting three-dimensional, high-relief habitat into flat "parking lot" stretches of seascape. Both species still occupy their historic range, although localized range reductions and extirpations have occurred.

-NASA Ames Research Center: Acropora palmata is a major reef-building coral prevalent in the Bahamas, but is suffering from white band disease. Elkhorn coral has severely declined in many areas of the Caribbean and may be on the verge of becoming an endangered species..

Sincerely,

Greg

 

[Anonymous]

Acropora palmata is not only a reef building coral but occurs in the Gulf of Mexico.

Greg, yeah, that is my mistake. It doesn't grow in the North Gulf of Mexico.

You aren't posting any references I haven't seen before.

Here are just a few references to back up these FACTS.

They aren't facts. They're opinions. And they're wrong.

A. palmata has been the dominant shallow-water Caribbean species throughout the Quaternary

Just because it's present does mean it's building reef, does it? Not to mention, this goes to support my last post about tolerance of specific conditions.

Most scholars agree that the critical point of the Caribbean coral reef health was reached in the early 1980's, when the primary reef-builder in the Caribbean, acroporid corals, began to undergo widespread regional declines (Ritchie and Smith, 1998; Hoegh-Guldberg, 2000; Miller et al., 2002).

All biologists. The idea that Elkhorn is a reef "builder" is a misnomer that has been tossed around without a second thought for a long time before coral became recognized as important paleoceanographic proxies. Long term paleoceanographic records of temperature and salinity are reconstructed from massive species, and never from Acropora palmata. In fact, the only historical reconstruction that A. palmata has been used for is C14 dating to determine recent sea level fluctuations, due to its hyper-shallow tendencies (1-5 meters). Even then, these are made from surface framework (rubble that was poorly transported after fragmentation) and not actual reef. I ask you again, how does a coral that only grows shallower than 5 meters act as the major reef builder?

It doesn't.

Lighty, RG; MacIntyre, IG; Stuckenrath, R. 1982. Acropora palmata framework: A reliable indicator of sea level in the western Atlantic for the past 10,000 years. Coral Reefs, 1(2): 125-130.

A minimum sea-level curve for the past 10,000 years has been constructed on the basis of radiocarbon dates of Acropora palmata (Lamarck) samples from the shallow-water framework of both relict and modern reefs of the tropical western Atlantic. A. palmata framework is a reliable reference for reconstructing the history of late Quaternary sea levels owing to its restricted depth range (< 1 to 5 m),

Cohen, AL; Smith, SR; McCartney, MS; Etten, J van. 2004. How brain corals record climate: An integration of skeletal structure, growth and chemistry of Diploria labyrinthiformis from Bermuda. Marine ecology progress series, 271: 147-158.

Shinn, EA; Reich, CD; Hickey, TD; Lidz, BH. 2003. Staghorn tempestites in the Florida Keys. Coral Reefs, 22(2): 91-97.

Thirty-one samples of transported Holocene Acropora cervicornis "sticks" sampled from carbonate sand tempestite accumulations at 19 sites along a 180-km-long stretch of the Florida reef tract were dated using the radiocarbon ( super(14)C) method. The "modern fossils" collected from just a few centimetres below the surface ranged in age from 0.5 to 6.4 ka. The majority lived between 3.5 and 5.5 ka. The time of transport and deposition is not known. There were no A. cervicornis samples centered around 4.5 ka. Acropora cervicornis is living on many Florida reefs, but the youngest tempestite sample was 500 years old. Two 500-year-long gaps in dated staghorn suggest that the documented decline in living A. cervicornis over the past 25 years may not be without precedent.

That's a good one. I wish you could see the photos that go with that one. Photos don't seem to do much for you, though.

MacIntyre, IG; Adey, WH. 1990. Buck Island Bar, St. Croix, USVI: A reef that cannot catch up with sea level. Atoll Research Bulletin, 336.

Frequent storms have disrupted reef growth on Buck Island Bar at the shelf edge off the north coast of St. Croix, U.S. Virgin Islands and have prevented the reef from catching up with the rising seas of the Holocene Transgression. An 8-m-long core hole in this reef indicates that Acropora palmata has been established here for > 4,000 years. Although this branching coral is capable of growing at rates in excess of 10 m/1,000 years, extratropical swell and perhaps hurricane damage have limited framework accumulation, and the remaining geological record is dominated by massive coral heads and well-lithified bare pavements.

Man, citing an Adey paper makes me feel dirty.

And this is my favorite one:

Shinn, E.A. 1980. Geologic history of Grecian Rocks, Key Largo Coral Reef Marine Sanctuary. Bull. Mar. Sci., 30(3): 646-656.

Grecian Rocks Reef is composed of five major ecologic zones: (1) a deep seaward rubble zone ranging in depth from 6-8 m; (2) a poorly developed spur and groove zone composed of massive head corals and Millepora (4-6 m water depth); (3) a characteristic high-energy oriented Acropora palmata zone extending from the surface down to 4 m; (4) a distinct broad reef flat composed of in situ A. palmata and coral rubble, followed by (5) a narrow low-energy back-reef zone of unoriented A. palmata thickets of A. cervicornis , and various massive head corals in water 0-3 m deep. An extensive grass-covered carbonate sand flat 3-4 m deep extends in a landward direction from zone 5. Cores revealed that all the zones except the massive coral head zone are superficial coatings over a carbonate sand and rubble accumulation. A thin 1-m thick layer of lime mud and peat was found 11.5 m below sea level on the Pleistocene bedrock beneath the sand and rubble in the reef flat core hole. Carbon-14 analyses of coral from 7 m below the reef surface indicate that the reef began growing approximately 6,000 years before present.

 

[Kalkbreath]

In the 1971 photos ....I see a reef.
You might still see a reef in the 2001 photos ,
.....but my idea of a reef is something that buffers the beach from waves, Shelters fish from the open water.. etc.
Being a" reef "as a verb....not being a reef as a cement builder.
A reef is not only defined by what it accomplishes over a millennium or how long its calcium remains intact.
One can also define a reef by what it it does, even in a short period like a single day.
My personal reef tank for example: Its a reef .....And you cant convince the hundred or so inhabitants in the aquarium that its not a reef.
Even though the acropora in Florida or in my aquarium might only be around for a few short decades ....
To the animals that live in those "weeds" .......Its they the animals that define who the real reef "builders "are. Building a reef involves much more the laying down calcium.....its getting animals life to show up that counts

 

[Mouse]

In terms of reef building corals, i thought elkhorn and staghorn were usefull in adhereing the other coral masses together, Like if you had a big Porites die the broken bits of stag and elkhorn that fell in arround it would basically help to compact it down , fill in the spaces. Allthough ive never considered it the primary shape for building reefs, i think its a very important factor, maybee just the aggressiveness assists in keeping softys from invading the true reef builders.

 

[Mouse]

Galleon, im one pic away from jacking this job in, grabbing my dive gear, and becoming the first reef assasin and joining Greenpeace.

Thats such a sad pic, if only to see that big domed coral head dead, porites i think (but then i allways think domes are porites) That coral must have taken years and years

 

[Ben1]

On the reef I snorkle the most, off JVD in the BVI there is very little in the way of Acropora growth. I havent seen and cervicrnis in years but there was one palmata that I have been watching for about five years now. It grows right up to the surface from about 3' deep. Last year it was run over by a dingey and broken in many pieces. I placed some of the branchs that landed in the sand high up in a shallow high energy area further out on this reef still only a few feet deep and when I went back last week I got to see a few new A. Palmatas growing up and the old one fully recovered.

I do see a decent amount of A. cerviscornis (sp?) on some of the dives further out facing a lot less population/polution and open ocean like off of Ginger island.
The reef off ginger had a goof amount of hard coral, heres a couple of pics I took.

 

[Kalkbreath]

Anyone question where the dead corals went? Where are the Skeletons?
Most of the live rock currently collected in Tonga died in 1983,the same time the Fla corals lost their skins.......... With Tonga, a cyclone ripped the area apart. Why are the Tongan corals still lying around on the bottom, yet the Florida Skeletons are MIA? Did they turn to sand so quickly?The sand in the Keys is mostly Calcium based old corals. That sand did not come from Reef Building Porites..........it came from deceased weed corals. Judging fom the amount of Coral based sand laying around in the Keys, 1910 to 1980 were not the only decades in which weed corals flourished in the area. What were the 1800s like? how about the 1500s?How about 100BC? In order to fully answer the question of why is this happening now {soft coral phase] We need to understand the full history of the Fla. reefs. Not using a man and his train as the measuring stick. Acropora corals may or may not be "reef builders" in a text book sense.
But you dont really have a reef without them......... when they are gone the reef and most of the reef life seems to vanish as well.
Isnt that your definition of a true reef builder?

 

[mark78]

Why are the Tongan corals still lying around on the bottom, yet the Florida Skeletons are MIA?

Hurricanes? Storms around south Florida tend to be pretty bad and frequent compared to weather in the south pacific no? (typically)

 

[Kalkbreath]

But the corals in the 1971 photo survived all the big storms of the 1930, 40s, 50s and 60s. , There has not been a big storm to hit the area since 1971 .
A lot of near misses but no real coral grinders.Plus it takes more then a ten hour hurrican to turn acropora into arragonite. What happened to the skeletons between 1971 and the 2001 photo?
Anybody got pictures from the 1980s ?