Coral Feeding

[lduncan]

Does anyone else find this a weird conclusion from Dr Ron?

Ok here's what I find wierd. First he says that bacteria are better than pods for providing nutrients. Bigger bang for your buck.

Then he says that detritus is a good food source for this bacteria to colonise.

He then goes on to say that sand dwelling creature are a big competitor to corals for this nutrients:

But then goes on to promote the use of sand as a food source:

To me that's just a weird conclusion. Using something which actually eats one of the most nutritious forms of food for corals (bacteria), and converts much of it into a form which is harder for corals to digest, and provide less nutrition.

Seems kind of backwards to me. Surely you want the food which is in you tank to be easy for corals to digest and nutritious? The habitat sand provides does the opposite, by Ron's own writing.

Layton

[wasp]

Don't see anything weird at all Layton, or at least not in what you quoted from the article .

Your problem seems to be that you believe the bacteria get eaten by "critters" in a sand bed, making them unavailable as food to corals. Partly true, BUT -

You forgot the second 1/2 of the story. Critters beget baby critters, many of these are top notch coral food of the highest order, and what I am wanting from the DSB I am going to set up. Apart from that, if the critters eat bacteria & do not turn them into baby critters, they turn it into fecal material, once again food for bacteria.

Ain't the circle of life a beautiful thing?

[lduncan]

Don't see anything weird at all Layton, or at least not in what you quoted from the article .

Your problem seems to be that you believe the bacteria get eaten by "critters" in a sand bed, making them unavailable as food to corals.

Less available.

Partly true, BUT -

You forgot the second 1/2 of the story.

Critters beget baby critters, many of these are top notch coral food of the highest order, and what I am wanting from the DSB I am going to set up.

Didn't forget that. Critters are critters, big or small. They are not as top notch as the bacterial coral food that they just ate. Plus the coral has to use more energy to digest it. So it's a double hit. Maybe a recap:

Of the two sources, weight for weight, bacterial tissue contains more nitrogen than animal flesh

Apart from that, if the critters eat bacteria & do not turn them into baby critters, they turn it into fecal material, once again food for bacteria.

But they have also taken their slice out of it. They don't crap exactly what they ate, there is a reduction there.

Layton

[wasp]

Critters are critters, big or small. They are not as top notch as the bacterial coral food that they just ate.Layton

Well I'll have to agree, critters are critters. Learn something new every day.

The second part of your statement though, you sure about that? Any references?

[lduncan]

Which part?

[reef]

Plankton ingestion methods

The branched tentacles of the small-polyped stony corals and horn corals are perfectly designed to filter and ingest each and every nutritious particle from the water sweeping over them.

With their sensory cells corals discern the chemical traces prey leave behind in the water and then the corals will extend their tentacles to capture the prey. Cnidoblasts – they are the most highly advanced cells in the animal kingdom – shoot out microscopically small harpoons and turn every little plankton crustacean within the reach of their tentacles into sure prey. Some corals secret films or use strands of mucus to capture bacteria or fine organic particles from their environment.

Leather corals and soft corals have finely feathered tentacles with which they filter plankton out of the water; special digestive enzymes can even break down the complex carbohydrates of marine algae. Plankton captured in this way not only significantly contributes to the energy supply and the growth rate of corals but also delivers all the main and trace nutrients in a concentrated form that are vital for the properly working symbiotic relationship with zooxanthellae. Scientific tests have verified the growth promoting effect of a plankton diet in reef-building, small-polyped stony corals (Houlbrèque et al. 2003 and 2004).

[reef]

Corals have to be feed!

Even if it is an often overlooked fact with respect to plankton filter feeders that are often fastened to the substrate: all animals depend on ingesting the energy for motion and metabolic processes from the food they eat. The spectrum of marine invertebrates that cover a part or their entire nutritional needs from zooplankton or phytoplankton ranges from sponges to soft and leather corals all the way up to whales. Reef-building stony corals also belong to the family of plankton filter feeders, even though another source of nutrients is available to them because of their symbiotic relationship with zooxanthellae.

[wasp]

Which part?

Sheesh Dude, this part:-

They are not as top notch as the bacterial coral food that they just ate.Layton

[suphew]

good on you wasp couldn't have said it better myself.

I thought I explained that. Food (bacterial detritus) drops into it from above. Critters are able to reproduce in the safer confines of the sand. They feed on this bacterial detritus, producing an organism of lower nutritional value which itself produces waste, but it doesn't create more waste than previously eaten, it's not possible. Then it may or may not be possible for corals to eat some of these critters which reduces the availability even further. Corals are good at digesting bacteria, so good that researchers had trouble determining whether they do in fact eat them, as the time from collection to doing a gut analysis was long enough that the bacteria was unrecognisable (sometimes only several minutes), all they could find were partially digested pod shells.

I think you need to re-read or re-think what you are saying, as wasp says, sooner or later the everything ends up as bacteria, or is removed by the skimmer. It doesn't matter how many critters it passes through before it gets there, physic's 101, you can't distroy energy only change it. No one has said that extra food appears by magic, but you seem to believe that it hits the sand bed and disappears by magic.

The thing is that by actively encouraging other critters to feed on bacteria, you are reducing this proportion of highly nutritious coral food.

But you are also increasing the numbers of critters producing waste, either pooh or bodies. Again the energy isn't disappearing just going to different forms before ending up as bacteria.

But if that's what your saying, then you're supporting my claim that BB has more food available to corals.

Not at all, you are again confusing your two different statements, 1) tanks with matched imports and exports and 2) tanks with the same food in the water column, these are two completely different statements and can't be interchanged to prove a point.

suphew wrote:

And I'll say it again, and try and make it simple, if you put something in, and something takes some of it out (like a sand bed) then you most end up with less coming out than you put in?? If you then take the sand bed out of the equation, so are no longer taking that extra bit out, them you must be getting more out at the end??????

I've read that a couple of times I still don't see what you mean?

This was in response to your "matched imports and exports" statement, it's a simple concept, and I can't think of any way to make it simpler. And I think we have moved past this now anyway.

Rons statement only seems weird if you have problems accepting that sand beds will produce coral feeding bacteria. In refference to sand bed's he even states

"Such a system will provide sufficient food to provide much of the food necessary for the proper and balanced nutrition of coral reef animals."

[wasp]

EXCELLENT POSTS Reef. Accompanied by reference to a proper scientific study also, kind of clinches it.

The extension of the tentacles of the sps polyps mentioned, is something I have observed in my own corals when feeding Reef Roids coral food, it stimulates them to stick their tentacles out & catch them.

I also use Coral Vital, which does not have such an effect on polyp extension, but non the less has helped achieve some great growth in times past.

[lduncan]

Dr Ron told us that:

Of the two sources, weight for weight, bacterial tissue contains more nitrogen than animal flesh

And this from Eric is interesting:

Given the importance of bacteria as a food source in marine ecosystems, it might not be surprising to learn that they are also a primary food source for corals. It has been found that bacteria alone can supply up to 100% of both the daily carbon and nitrogen requirements of corals. All corals studied consume dissolved organic material, bacteria, and detrital material. This is more than can be said for any other food source, including zooplankton and light.

Layton

[wasp]

And this from Reef is interesting!

Plankton ingestion methods

The branched tentacles of the small-polyped stony corals and horn corals are perfectly designed to filter and ingest each and every nutritious particle from the water sweeping over them.

With their sensory cells corals discern the chemical traces prey leave behind in the water and then the corals will extend their tentacles to capture the prey. Cnidoblasts – they are the most highly advanced cells in the animal kingdom – shoot out microscopically small harpoons and turn every little plankton crustacean within the reach of their tentacles into sure prey. Some corals secret films or use strands of mucus to capture bacteria or fine organic particles from their environment.

Leather corals and soft corals have finely feathered tentacles with which they filter plankton out of the water; special digestive enzymes can even break down the complex carbohydrates of marine algae. Plankton captured in this way not only significantly contributes to the energy supply and the growth rate of corals but also delivers all the main and trace nutrients in a concentrated form that are vital for the properly working symbiotic relationship with zooxanthellae. Scientific tests have verified the growth promoting effect of a plankton diet in reef-building, small-polyped stony corals (Houlbrèque et al. 2003 and 2004).

[wasp]

And this from Eric is interesting:

Absolutely it's interesting! Says dissolved organic material, bacteria, and detrital material, all of which obviously exist in a sand bed, can meet 100% of certain coral requirements, unlike zooplankton & light!!!

Given the importance of bacteria as a food source in marine ecosystems, it might not be surprising to learn that they are also a primary food source for corals. It has been found that bacteria alone can supply up to 100% of both the daily carbon and nitrogen requirements of corals. All corals studied consume dissolved organic material, bacteria, and detrital material. This is more than can be said for any other food source, including zooplankton and light.

[lduncan]

I think you need to re-read or re-think what you are saying, as wasp says, sooner or later the everything ends up as bacteria, or is removed by the skimmer. It doesn't matter how many critters it passes through before it gets there, physic's 101, you can't distroy energy only change it. No one has said that extra food appears by magic, but you seem to believe that it hits the sand bed and disappears by magic.

Not at all, it just becomes less available, than if it never hit sand. I don't think you get it. The fact is is that by introducing large populations of critters into the equation, you are actually reducing the available food for corals, than if it is left to bacteria alone.

But you are also increasing the numbers of critters producing waste, either pooh or bodies. Again the energy isn't disappearing just going to different forms before ending up as bacteria.

Then why bother going to all the trouble of culturing all these critters in the first place? Why not just leave it to bacteria?

Not at all, you are again confusing your two different statements, 1) tanks with matched imports and exports and 2) tanks with the same food in the water column, these are two completely different statements and can't be interchanged to prove a point.

I don't think you get it. What matters is what's in the water column. That where the corals can get it. Higher concentrations of food in the water column, means more food available to the corals, which also results in more stuff skimmed by the skimmer. A tank with the same skimmer and lower output means that there isn't as much food in the water for corals.

That dynamic is the key.

Rons statement only seems weird if you have problems accepting that sand beds will produce coral feeding bacteria. In refference to sand bed's he even states

"Such a system will provide sufficient food to provide much of the food necessary for the proper and balanced nutrition of coral reef animals."

But why bother going through the critters? What's the point? When if the critters aren't there to compete for this stuff, it gets to the corals in the most nutritious form, without going through all those other processes?

The sand doesn't create anymore food than what you put in. Why do you need it? Bacteria are more than capable of living without sand, and providing corals nutrition. They don't need critters, it just makes life harder for them.

Layton

[lduncan]

And this from Eric is interesting:

Absolutely it's interesting! Says dissolved organic material, bacteria, and detrital material, all of which obviously exist in a sand bed, can meet 100% of certain coral requirements, unlike zooplankton & light!!!

But we also know that sand isn't required for this to stuff to exist. We also know that sand introduces critters into the equation, which are less nutritious, and require more expenditure of energy to digest.

Not to mention the other pitfalls of sand beds.

Layton

[wasp]

I don't think you get it. Layton

Oops! Temper!!!

[wasp]

We also know that sand introduces critters into the equationLayton

BINGO!

[lduncan]

What do you mean by bingo? The critters come at the expense of bacteria.

Layton

[lduncan]

There's no free lunch.

[lduncan]

Anyone here subscribe to Coral List? Here is a recent posting by Charles Delbeek, a name which is probably familiar to many.

There are a couple of points in this discussion that I feel the need

to address:

1) Shops selling phytoplankton as coral food - most research that I

have read involving feeding in stony corals deals mainly with the

ingestion of ZOOplankton. Soft corals, particularly azooxanthellate

ones such as Dendronephthya have been shown to feed on phytoplankton.

This makes sense to me since most of these corals lack nematocysts

and their polyp structures appear to be more suited for sieving food

from passing water than stinging and capturing it as can be seen in

stony corals which all seem to have nematocysts ... why sting a

phytoplankton cell to capture it which is basically a passive entity

unlike a struggling copepod?

I have a pet theory that people who report responses from corals when

fed phytoplankton could be seeing the result of any number of factors

such as the addition of nutrients, the decay of phytoplankton leading

to increased nitrogen and phosphorous levels, to the increase in

filter feeders and hence, an increase in reproduction of these i.e.

more zooplankton being generated.

2) Feeding vs. non-feeding of corals in captivity - yes corals will

feed on zooplankton and more meaty food in the case of corals with

polyps large enough to take them. No one disputes this. What is in

question is do corals in captivity need this? Given that nitrogen,

phosphorous and organic nutrient levels are generally several times

that found on natural reefs is this enough to keep the corals

"happy"? The success of aquarists in Europe with stony and soft

corals in the 1970s and 1980s, without any feeding, would tend to

support this idea.

3) The role of dissolved nutrients - The Waikiki Aquarium has been

keeping, propagating and spawning stony corals, mainly Acropora,

Montipora etc since the late 1970s. We have never added any sort of

zooplankton or phytoplankton to our systems. We use a saltwater well

as a water source for the majority of our exhibit and they are

semi-open systems. The well is 80ft down in coral rock, the chemistry

of this water has been discussed in Atkinson et al. 1995, there is no

zooplankton or phytoplankton in this water. That is not to say that

there isn't any bacteria in the water, or that there could be

plankton being generated in the systems themselves. All I can say

with absolute certainty is that WE do not feed the corals. Yet, we

have observed the release of eggs, sperm and egg/sperm bundles in

corals such as Acropora, Sandalolitha, Montipora, Euphyllia and

Goniopora. What our water IS rich in is nitrogen, phoshporous, iron,

managense, carbon dioxide etc. ... so my feeling is that the

zooxanthellae and perhaps the coral tissue itself, is getting more

than enough of what they need from the water.

4) Increasing contact with the aquarium community - there is an

annual conference in North America called The Marine Aquarium

Conference of North America (MACNA), this year it will be held the

weekend of Sept 23rd in Houston, Texas. This annual conference is the

best place to meet with and observe what hobbyists are doing. There

have been several marine scientists who have spoken at this

conference such as Giselle Mueller-Parker, Daphne Fautin, Marlin

Atkinson, Charlie Veron, Robert Myers, Bob Richmond, Cindy Hunter ...

to name just a few. While there is some contact with hobbyists by the

scientific community there is certainly room for much more. I think

this sort of interaction will only increase for the simple fact that

many of the up and coming marine scientists today have started off by

keeping reef tanks as a hobby, and I am in fact seeing this already.

There are of course other such conferences in Europe held in Germany,

France, Belgium and The Netherlands. Next April there will be a

conference in The Netherlands dealing specifically with the captive

husbandry of corals in public aquariums, of which I am a member of

the steering committee ... we would dearly love to have a strong

representation from the scientific community especially in the field

of coral nutrition, effects of UV, coral colouration, coral

reproduction, etc etc. The days of marine scientists claiming it was

impossible to keep live coral while hobbyists in Europe and elsewhere

were already doing so, are thankfully behind us for the most part.

Finally, I think one needs to be cautious about making sweeping

generalizations about what corals need or don't need in terms of

feeding when it is becoming increasingly obvious that the corals have

various abilities to gather, use and process sources of nutrition

spread across the genera.

Aloha!

J. Charles Delbeek M.Sc.

Aquarium Biologist III

Waikiki Aquarium,

University of Hawaii

2777 Kalakaua Ave.

Honolulu, HI, USA 96815

www.waquarium.org

808-923-9741 ext. 0 VOICE

808-923-1771 FAX

[wasp]

What do you mean by bingo? Layton

I mean, basically, BINGO! :bounce:

You have realised the connection between a sand bed, and critters.

Trouble is, you said that critters are less nutritious than bacteria. You sure about that? I doubt you have much literature to support that.

Way I see it, pound for pound, they may be, but there is more to it than just pound for pound, hence the importance of critters as a way to deliver nutrition.

Also, at night I have observed by torchlight, cauluastrea catching & eating various types of pods and amphipods. Even seen zoanthids do it. GOT to be a GREAT source of natural food for them.

[wasp]

Your comments Layton....

Plankton ingestion methods

The branched tentacles of the small-polyped stony corals and horn corals are perfectly designed to filter and ingest each and every nutritious particle from the water sweeping over them.

With their sensory cells corals discern the chemical traces prey leave behind in the water and then the corals will extend their tentacles to capture the prey. Cnidoblasts – they are the most highly advanced cells in the animal kingdom – shoot out microscopically small harpoons and turn every little plankton crustacean within the reach of their tentacles into sure prey. Some corals secret films or use strands of mucus to capture bacteria or fine organic particles from their environment.

Leather corals and soft corals have finely feathered tentacles with which they filter plankton out of the water; special digestive enzymes can even break down the complex carbohydrates of marine algae. Plankton captured in this way not only significantly contributes to the energy supply and the growth rate of corals but also delivers all the main and trace nutrients in a concentrated form that are vital for the properly working symbiotic relationship with zooxanthellae. Scientific tests have verified the growth promoting effect of a plankton diet in reef-building, small-polyped stony corals (Houlbrèque et al. 2003 and 2004).

[lduncan]

I mean, basically, BINGO! :bounce:

You have realised the connection between a sand bed, and critters.

Trouble is, you said that critters are less nutritious than bacteria. You sure about that? I doubt you have much literature to support that.

Umm, yeah i've been on about the critters from the start. So what's the bingo for? It's pretty common knowledge that bacteria are more nutritious than a critter encased in chitin, with a lot of water etc. Are you saying Ron's sources are wrong? Eric say the same thing.

Way I see it, pound for pound, they may be, but there is more to it than just pound for pound, hence the importance of critters as a way to deliver nutrition.

Well you can't create mass from nowhere, pound for pound is important, as is energy expenditure to digest this stuff. There are easier sources of food for corals than critters, they are not required at all.

Also, at night I have observed by torchlight, cauluastrea catching & eating various types of pods and amphipods. Even seen zoanthids do it. GOT to be a GREAT source of natural food for them.

Why does it have to be a GREAT source, maybe it's just A source? One of many possible.

Layton

[wasp]

Your comments Layton....

Plankton ingestion methods

The branched tentacles of the small-polyped stony corals and horn corals are perfectly designed to filter and ingest each and every nutritious particle from the water sweeping over them.

With their sensory cells corals discern the chemical traces prey leave behind in the water and then the corals will extend their tentacles to capture the prey. Cnidoblasts – they are the most highly advanced cells in the animal kingdom – shoot out microscopically small harpoons and turn every little plankton crustacean within the reach of their tentacles into sure prey. Some corals secret films or use strands of mucus to capture bacteria or fine organic particles from their environment.

Leather corals and soft corals have finely feathered tentacles with which they filter plankton out of the water; special digestive enzymes can even break down the complex carbohydrates of marine algae. Plankton captured in this way not only significantly contributes to the energy supply and the growth rate of corals but also delivers all the main and trace nutrients in a concentrated form that are vital for the properly working symbiotic relationship with zooxanthellae. Scientific tests have verified the growth promoting effect of a plankton diet in reef-building, small-polyped stony corals (Houlbrèque et al. 2003 and 2004).

[lduncan]

Your comments Layton....

Be patient. I'm going to call it a night soon.

I'll read that reference and see if the manufacturer of the plankton products it's promoting has interpreted it very well. But there is nothing particularly new there. I wonder what they are classifying as "plankton" here.

Layton