Coral Feeding

[lduncan]

Exactly right. The way I see it, what could be better for them than what they eat in nature.

Zooplankton isn't the only food for them in nature. It's not always around. It's presence is cyclic, they need other methods. They have multiple sources of food in nature:

Cnidarians posses polytrophic feeding capacities including: 1) endocytosis ofpaniculate food, 2) absorption of dissolved organic material, 3) utilization of assimilates from zooxanthellae.

The polytrophic nature of anthozoans enable the utilization of up to four independent possibilities to suffice their energy supply: 1) They use living and/or dead particulate organic material either as macrophages or microphages.

2) They absorb dissolved organic material through the epidermal tissue (ectoderm).

3) Zooxanthellate species profit from their endocytosymbiotic algae (zooxanthellae = unicellular algae of the genus Symbiodinium).

4) Finally, the skeletons of a multitude of scleractinian corals are colonized by endolithic red and green algae (e.g. Ostreobium quekettii), whose photoassimilates like those of the zooxanthellae, are used by the corals.

Depending on the availability of trophic resources in the different habitats, different species compensate the shortage of one resource e.g. mesozooplankton by specializing on using another e.g. picoplankton or microplankton. The versaltility of such a specialized species enables them to settle in "trophic niches" far out of reach for the less adaptable species. These species-specific qualities especially of the scleractinian corals in relation to environmental conditions have been a topic of discussion for decades.

And each of these sources have different nutritional value. So why the HUGE focus on zooplankton, which is just ONE of several methods? Especially when they actually eat (compete) one of the other (which also happens to be one of the most nutritious) sources of coral food? Which is also the most ubiquitous coral food. ALL corals can eat bacteria.

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]

It's not temper. It's the truth. If you did understand more, you wouldn't have asked that question. But i'll persist...

It was temper & it was abusive.

Didn't ask any question either, I drew your attention to the facts, which in this case, are the nutritional value of bacteria, and pointed out that a sandbed generates bacteria, not phytoplankton.

[wasp]

Zooplankton isn't the only food for them in nature. It's not always around. It's presence is cyclic, they need other methods. They have multiple sources of food in nature:

And each of these sources have different nutritional value. So why the HUGE focus on zooplankton, which is just ONE of several methods? Especially when they actually eat (compete) one of the other (which also happens to be one of the most nutritious) sources of coral food? Which is also the most ubiquitous coral food. ALL corals can eat bacteria.

Layton

Layton you missed the point. Nobodies saying zooplankton are the only food. Perhaps that is where you are confused?

HUGE focus on zooplankton? What HUGE focus on zooplankton? For me anyway, I'm simply refering to the many food types as bacteria, and critters.

[lduncan]

I drew your attention to the facts, which in this case, are the nutritional value of bacteria, and pointed out that a sandbed generates bacteria, not phytoplankton.

Is it really a fact that sand beds don't generate phytoplankton?

Where do phytoplankton get the nutrients?

Layton

[wasp]

Where do they live? The water column.

Where do they get their nutrients? The water column.

Now I know what you are going to say, that having a sand bed will eventually add nutrients to the water column.

But that is not some new breakthrough Layton, we do know that that can sometimes, but not always, be the case.

No argument there.

[lduncan]

How about we boil this whole thing down to what matters.

If you want to feed your corals more. Physically put more food in your tank.

Don't pretend that by adding sand you are somehow providing more food for your corals or enhancing the nutritional value of it. You're not. If anything it makes it less available.

If you're going to have sand in you're tank, AND feel the need to justify why, at least come up with reasons which are true. Some examples might be as, "i find critters interesting" or "i like the look of sand" or something like that. That's all.

Sand isn't a solution or aid in feeding corals.

Layton

[lduncan]

Where do they live? The water column.

Where do they get their nutrients? The water column.

Now I know what you are going to say, that having a sand bed will eventually add nutrients to the water column.

But that is not some new breakthrough Layton, we do know that that can sometimes, but not always, be the case.

No argument there.

Too simplistic. What specifically do they use, and where does that come from specifically?

Layton

[wasp]

Not too simplistic at all. It's a fact.

Also, if you want to boil this whole thing down, here's how I'd do it. let's look at 3 classes of tank. BB corals unfed, BB corals fed, and finally certain well run tanks I know with sand.

There may be more, but the only BB unfed that I know of is yours Layton. Then I know several BB fed, and several well run with sand.

The fact of the matter is I'm currently seeing the best coral growth colour and form, in the well run with sand tanks. There are also some good ones in the BB fed catagory.

To boil it right down, proof's in the pudding.

[lduncan]

It is too simplistic, and it's not a fact that sand beds don't produce phytoplankton. They do.

There may be more, but the only BB unfed that I know of is yours Layton.

Really. I don't feed my tank? I guess I should find some food to go with that half a sheet of nori, a couple of cocktail shrimp, and a cube or two of brineshrimp I put in the tank everyday.

Layton

[lduncan]

The fact of the matter is I'm currently seeing the best coral growth colour and form, in the well run with sand tanks.

And it's that sand which makes the difference? How so?

[wasp]

It is too simplistic, and it's not a fact that sand beds don't produce phytoplankton. They do.Layton

Already and anticipated that response Layton. To repeat, here is the answer to your statement, which I gave before you even made it.

Now I know what you are going to say, that having a sand bed will eventually add nutrients to the water column.

But that is not some new breakthrough Layton, we do know that that can sometimes, but not always, be the case.

No argument there.

[wasp]

And it's that sand which makes the difference? How so?

Think Bacteria, critters. Bacteria, critters. Bacteria, critters........

[lduncan]

Already and anticipated that response Layton. To repeat, here is the answer to your statement, which I gave before you even made it.

That's not the whole answer.

Do you think that a tank with a sand bed will produce less phytoplankton, than one without?

Layton

[lduncan]

What are the things which make food available to phytoplankton?

[lduncan]

wasp, do corals need to eat these critters to survive?

[Feelers]

I dont follow the poor food of eukaryotic organisms for their shell casings. After watching the Blue Planet documentary the corals are shown at night catching tiny particles with their extended polyps. As you know every step up in the food chain nurtients/metals accululate - perhaps it's iron or something of the like

Also a point on the chitin casing - it is only a casing, I would imagine that they dont bother digesting it, they probably have it in some sort of acidic gut that allows the internals to leech out of the shell without the energy expense of digesting it.

When I eat a crayfish I throw the shell away too, but I still manage to get the good stuff out. I definately think that it could be possible for the enzymes in the polyp gut to work around the shell, perhaps by dissolving the ligaments that hold the shell together.

I think there is much speculation about the nutritional value of both bacteria and eukaryotes to the corals due to it being very difficult to measure, there isnt much info to go on. The nutritional content of the eukaryotes is heavily dependent on what they have been eating - so much so that it can make the difference between a poor food and an excellent one.

And in a DSB- there must be more bacteria floating around in the water, the biomass is huge compared to a BB without one.

Anyway I think at that anyone has is theorys with points both for and against DSBs. However from looking at the TOTM's on reef central there is a very definate pattern occuring, it's got to be more than just coincidence.

That is why I'm so keen to see Wasp's tank with a dsb added, he will be able to tell whether it makes a difference to his corals or not, its not often you get to see such an experiment.

How about you trying it Layton? Seriously - that would be really interesting, you know it wouldnt likely screw up your tank, just give things a wee shuffle.

And who knows you might come over to the dark side.

[Feelers]

Bloody edit thing :evil:

Should read:

Anyway I think at that all anyone has is theorys,

[lduncan]

I dont follow the poor food of eukaryotic organisms for their shell casings. After watching the Blue Planet documentary the corals are shown at night catching tiny particles with their extended polyps. As you know every step up in the food chain nurtients/metals accululate - perhaps it's iron or something of the like

That's not really what i'm getting at. We know corals use them as a food source.

Also a point on the chitin casing - it is only a casing, I would imagine that they dont bother digesting it, they probably have it in some sort of acidic gut that allows the internals to leech out of the shell without the energy expense of digesting it.

But that casing has to come from somewhere. I comes at the expense of the nutritious coral food that the critter was eating.

When I eat a crayfish I throw the shell away too, but I still manage to get the good stuff out. I definately think that it could be possible for the enzymes in the polyp gut to work around the shell, perhaps by dissolving the ligaments that hold the shell together.

Same thing as above. It takes longer to digest longer for the coral to do this and therefore takes more energy.

I think there is much speculation about the nutritional value of both bacteria and eukaryotes to the corals due to it being very difficult to measure, there isnt much info to go on. The nutritional content of the eukaryotes is heavily dependent on what they have been eating - so much so that it can make the difference between a poor food and an excellent one.

You have to compare apples with apples here. 1kg of bacterial food, is going to be more nutritious hands down, than 1kg of critters. And if all your putting in a tank is 1kg of food, it's going to best serve the corals in the form of bacteria, rather than bacteria and critters.

And in a DSB- there must be more bacteria floating around in the water, the biomass is huge compared to a BB without one.

No, that implies that the DSB is fed more than the BB, that doesn't have to be the case.

Anyway I think at that anyone has is theorys with points both for and against DSBs. However from looking at the TOTM's on reef central there is a very definate pattern occuring, it's got to be more than just coincidence.

Stats never lie Look at it a little more closely and you'll see why it's not particularly surprising that that's the case.

That is why I'm so keen to see Wasp's tank with a dsb added, he will be able to tell whether it makes a difference to his corals or not, its not often you get to see such an experiment.

If you think the corals aren't getting enough food, why not just put more food in your tank?

How about you trying it Layton? Seriously - that would be really interesting, you know it wouldnt likely screw up your tank, just give things a wee shuffle.

And who knows you might come over to the dark side.

Been there done that. It's not a solution to feeding. Plus there are all sorts of other things you have to worry about with sand.

[lduncan]

How about we look at it from the other side. How does adding sand benefit corals?

[wasp]

How about we look at it from the other side. How does adding sand benefit corals?

Haven't we already established that?

Think Bacteria, critters. Bacteria, critters. Bacteria, critters........

[lduncan]

I went into detail. How about you start from the start and explain to me, as if I knew nothing, how sand is more beneficial to corals, than the alternative, which is no sand?

Because nothing you have come up with so far suggests that.

Layton

[Caryl]

Can't you just agree to disagree? Does one way have to be "right" and the other "wrong"?

[lduncan]

It's not about one way being right and the other being wrong.

It's about the reasons, logic and justifications behind the choice of doing something one way being right or wrong.

I think it's an important discussion.

[suphew]

I went into detail. How about you start from the start and explain to me, as if I knew nothing, how sand is more beneficial to corals, than the alternative, which is no sand?

Because nothing you have come up with so far suggests that.

Layton

Maybe because we have all tried to do this already, and you seem to be either ignoring, not reading or just not getting it. I have given up posting because it was just becoming pointless saying the same thing over and over.

[JoeBlog]

Can't you just agree to disagree? Does one way have to be "right" and the other "wrong"?

What's the point of this????

I think this is a great discussion for which we can take what we want from it. If everyone just agreed to disagree, then what would we all learn from that? :roll: