Poo? Really. POO?! Where did this theory start? I'm calling Shenanigans!

[StarF]

"care"? Perhaps a language translation snafu?

Well, if you want to put it that way I guess my corals don't "care" to eat poop but I've seen them eat coral food and fish food.
I get my foods pretty cheap.

I spend a significant amount of money trying to keep my reef aquarium "poop free".

ofc corals dosent litteraly eat the poop, like they eat real food. But they do use the byproducts of poop. that being n/p. The goal is to get as much food into your system as possible, while also maintaining a good water chemestry.

 

[ryshark]

High import of nutrients with High export of nutrients, works for many. A tank with lots of fish pooing and high export of nutrients would do better than a sterile tank with no fish.
So I'm thinking, do sps eat poo? No. Does it indirectly help the system? Yes. But it must be controlled through, water changes, skimming etc.

 

[cloak]

I do get a great response from certain corals when I stir things up with a powerhead. That detritus is pretty much poop in one form or another. Too much crap is bad, don't get me wrong, but I think these corals are smart enough to know when to take advantange. Polyps out for nothing, NO.

JMO.

 

[Gary Majchrzak]

A tank with lots of fish pooing and high export of nutrients would do better than a sterile tank with no fish.

the wrong conclusion. Try it.

Don't forget to feed the fishless tank some foods that corals actually eat

 

[Gary Majchrzak]

I do get a great response from certain corals when I stir things up with a powerhead. That detritus is pretty much poop in one form or another. Too much crap is bad, don't get me wrong, but I think these corals are smart enough to know when to take advantange. Polyps out for nothing, NO.

JMO.

pulverize some fish poo and zoom in on SPS polyps while you sprinkle the turds around the aquarium. IME Acropora (and most other clean water loving SPS) will let the turds slide right through their polyps. (FWIW so do anemones.)

Poo doesn't trigger the polyps like appropriate foods do.
It's actually quite fascinating that corals can "taste" (sense) the difference.

 

[dzhuo]

Gary,
Do you have any comment on these findings which seem to indicate SPS and various other corals do in fact "eat" debris and "poo".

- particulate organic matter (POM)

This group of particles usually describes detritus; the small remnants of feces and decayed organisms. In the aquarium, food which is not consumed and removed also becomes detritus. Detritus eventually precipitates on the ocean floor or aquarium bottom as sediment. This layer of organic material is partially degraded by bacteria, and converted into inorganic molecules such as nitrate and phosphate. This process is called mineralization.

The sediment which is present on coral reefs contains bacteria, protozoa and their excrements, microscopic invertebrates, microalgae and organics29. These sedimentary sources can all serve as coral nutrients, especially for colonies which grow in turbid waters15,30. Experiments during which sedimentary carbon was radioactively labeled showed that corals such as Fungia horrida and Acropora millepora readily took up sediment31,32. The more sediment present, the more uptake is measured; 50-80% of this material is converted into biomass by several species. This has also been found for the Caribbean species Montastrea franksi, Diploria strigosa and Madracis mirabilis; detritus is taken up by the polyps, and the available nitrogen is converted into biomass.

The findings also reveal corals take up urea:

Figure 5: Nitrogen budget for Stylophora pistillata colonies in their natural environment. It is clear that ammonia and nitrate provide the bulk of the nitrogen, and that organic nitrogen in the form of amino acids provides 21%. The balance between dissolved molecules and particles such as plankton however depends on what is available to the coral (Renaud Grover et al, Journal of Experimental biology 2008).

It is intriguing that many corals also take up urea from the water, and they can do this in even greater quantities compared to nitrate (at least in nature). This indicates these animals may have adapted to the presence of higher animals on the reef, such as fish, which collectively produce large amounts of this nitrogen-rich compound on a daily basis27.

Scientists also found that urea, similar to amino acids, is more actively taken up during the day. These molecules may be important for building the organic matrix, the 'protein-scaffold' around which calcium carbonate is deposited. It was shown that this matrix is mainly produced at night, whereas calcification mainly takes place during the day34 (see archive). The organic matrix helps the formation of aragonite crystals, increasing both the density and strength of the coral skeleton35-37.

 

[abrian]

Thanks for highlighting those sections from the article dzhuo, I found those passages very interesting when reading it and wondered how they would inform the debate.

 

[dzhuo]

No problem abrian. On a side note, it seems like although corals do take up POM; the majority of their daily nitrogen source is from various plankton:

Figure 13: Daily nitrogen budget for Stylophora pistillata. For these estimations, scientists took an average of 50 polyps per cm2. When this species is fed with natural zooplankton at a concentration of 1500 prey/l, this provides the coral with 1.8 μg nitrogen/cm2/day. The uptake of pico- and nanoplankton provides up to 1.4 μg N/cm2/day. Dissolved organic nitrogen, at the lowest concentrations found in seawater, contributes 0.5 μg N/cm2/day. In total, this yields 3.7 μg N/cm2/day. Although these values may fluctuate under various conditions, they provide a unique insight into the balance between different nutrient sources. Plankton may deliver over six times the amount of nitrogen compared to dissolved organic nitrogen (Houlbrèque & Ferrier-Pagès, Biological Reviews, 2009).

 

[Gary Majchrzak]

great article- thanks for the link!

great article- thanks for the link!

Gary, Do you have any comment on these findings which seem to indicate SPS and various other corals do in fact "eat" debris and "poo". The findings also reveal corals take up urea

the article reinforces everything that I've already posted to this thread. I addressed the fact that urea isn't poo on page two.

carefully re-read the article and thread.


particulate organic matter (POM)
This group of particles usually describes detritus; the small remnants of feces and decayed organisms. In the aquarium, food which is not consumed and removed also becomes detritus. Detritus eventually precipitates on the ocean floor or aquarium bottom as sediment. This layer of organic material is partially degraded by bacteria, and converted into inorganic molecules such as nitrate and phosphate. This process is called mineralization.
we all know that even with the best cone skimmer and strong water flow that there's no shortage of detritus in any aquarium. You sure don't need fish poo to cook up some nutritious detritus!

The sediment which is present on coral reefs contains bacteria, protozoa and their excrements, microscopic invertebrates, microalgae and organics29. These sedimentary sources can all serve as coral nutrients, especially for colonies which grow in turbid waters15,30.
we already adressed that in this thread.

Experiments during which sedimentary carbon was radioactively labeled showed that corals such as Fungia horrida and Acropora millepora readily took up sediment31,32. The more sediment present, the more uptake is measured; 50-80% of this material is converted into biomass by several species. This has also been found for the Caribbean species Montastrea franksi, Diploria strigosa and Madracis mirabilis; detritus is taken up by the polyps, and the available nitrogen is converted into biomass.
Interesting observations for sure but not shockingly so. I wonder if these observations were obtained on a wild reef or in a captive closed system?

Reminder:
don't forget to cut and paste the findings on orthophosphates inhibiting calcification in scleractinians- something that's much more relevent to coral health in a closed system.

tip: get rid of fish poo in your aquarium and introduce some plankton producers

 

[dzhuo]

I wonder if these observations were obtained on a wild reef or in a captive closed system?

Not sure. Probably a little on both. It seems like certain experiments are controlled in a closed system while others are from natural reef. I think the conclusion from the article pretty much sums it up:

In the wild, coral reefs are not only exposed to strong irradiance, they also receive ample nutrition from the available plankton and detritus. The interaction between light and feeding, in combination with high water quality, is the key to high coral growth (photograph: Leo Roest).

I think most people's point is to properly balance these nutrient sources. I don't think anyone suggest excess amount of poos is desirable (which you seem to reiterate).

tip: get rid of fish poo in your aquarium and introduce some plankton producers

Are there commercial plankton foods you would recommend?

 

[Gary Majchrzak]

I use certain commercial coral foods but I'm not recommending them here.

besides, the very best plankton producers are the ones that you introduce into your system that keep reproducing

 

[ryshark]

I use certain commercial coral foods but I'm not recommending them here.

besides, the very best plankton producers are the ones that you introduce into your system that keep reproducing

Why not recommend them? I'm sure you have a legitimate reason, but at a glance that reminds me of the 3rd grade. "I know, but I'm not going to tell you."

 

[Gary Majchrzak]

I've already made enough recommendations

 

[ousnakebyte]

Are there commercial plankton foods you would recommend?

I will happily recommend tried and true Artemia nauplii (newly-hatched brine - decapsulate the eggs first), for reasons I've already stated, and feed a few hours after lights out if possible (though I don't think this is a necessity).

I also recommend frozen rotifers.

I just ordered in a new food called "Coral Frenzy" but I have yet to try it; so, I have nothing to report here...

Cheers
Mike

 

[psykobowler]

How about fish poo broken down in the water, increases PO4 and Nitrate, gets absorbed by bacteria that multiplies and the sps feed on the bacteria? I believe I have read somewhere here in RC UNLS tanks that are not fed coral food just bacteria from shaking rocks.

 

[samuelkl]

the article brought up the topic of fish pee (ie urea) not poo. so in more ways than one, fish are beneficial to have in the system. the pee is used directly by the corals as a nitrogenous source to increase biomass while the poo may contribute to the sediment in the tank, which in turn produces other life forms to feed the corals.
article also stated artemia, baby brine shrimp as a very good source of food for sps. that much it recommends.

 

[samuelkl]

my apologies dp

 

[samuelkl]

sorry triple post. servers were packed

 

[laud]

After my effort to say poo isn't bad for the corals, I sat in a lecture with (Copps) and have reversed my opinion. I have way too much detritus in my tank and have begun a diligent effort to remove any and all detritus, sump included.

He said, if you ask all the long term successful SPS reefers how they have succeeded, a commonality between them would be "remove detritus".

 

[dzhuo]

I just ordered in a new food called "Coral Frenzy" but I have yet to try it; so, I have nothing to report here...

I will be interested to heard your experience on this product. Please report back (perhaps in it's own thread).