Sponges

[Steve W]

I have been doing some research into nutritional requirements of corals and the feeding of corals.

My research has turned up many interesting items, and my conclusions are somewhat disturbing. The inevitable conclusion of my research so far is that in most aquariums using the current best technology, i.e, protein skimming, and similar filtration methods, that many of our coral are probably malnourished if not outright starved, this is probably especially true of the SPSs. I currently feed on an alternating schedule with mysis or brine shrimp enhanced with spirolina one day (to mainly LPSs) and then two days later with Oysterfeast/phytoplankton/copepods enriched with vitamins, organic bonded minerals and fatty acids.

However, external feeding on a scale that I suspect might be necessary to alleviate this problem, inevitably introduces a new problem - excess nutrients which equals excess algae/cyanobacteria and the attendant problems. About two days after I do a targeted feeding with the planktonic mix, I predictably get a cyanobacteria bloom. I am checking nutrients and skimming and while the nutrients bump a little following the feedings they immediately drop to non-detectible levels and the cyano goes down, but not away.

I am looking for ways to enhance natural feeding of the corals in my tank. For now I am limited by my system constraints (nano tank with no place to put a refugium, so I am looking at enhancing natural in-tank means of feeding. One that my research has indicated is probably one of the best is to grow sponges. Sponges take up the same dissolved organic materials that a protein skimmer removes and in turn sluffs off old filtering cells which are excellent food for the SPS as well as many of the softies. This in turn would let me reduce my targeted feedings without starving my corals.

Does anyone have any suggestions as to methods to start/enhance the growth of sponges in our systems? Note: I am also vodka/glucose/vinagar dosing to augment bacterial growth twice a week. (another good food source for SPSs)

Thoughts? Suggestions? Comments?

Steve W
24 gallon nano w/ 150w NH

 

[cee]

1. Starved corals usually don't grow. SPS grow like weeds, so one must draw the conclusion that they are not starved. I read somewhere that corals derive something like 85-90% of their nutritional needs from zoanthellae.

2. If you're dosing a carbon source but no bacteria, cyano can result. After all, it is also a bacteria. Your "plankton" feeding schedule appears to track your carbon source dosing schedule so let's try to eliminate some variables first. Cut back on your carbon source and see if that helps.

3. I doubt dead sponge cells are of much nutritional value to corals. However, I'm not a marine biologist so take this statement as a matter of opinion.

4. Sponges will do well in a moderate to high nutrient system. I've heard of people using them to reduce nitrates/phosphates but this is the first I've heard of the sloughing tissue theory. Turnicates, clams, other filter feeders also remove some of these undesirable molecules.

5. You probably have a ton of sponges already in your system. The little beige ones that look like a vase, orange and yellow encrusting ones, the nasty white encrusting variety, etc. They like cryptic locations so are not always seen but are part of any healthy marine biosystem.

 

[Steve W]

Actually, while SPSs will grow with minimal nutrient additions, there is scientific evidence that they may be still be malnourished as evidenced by greatly reduced (if any) spawning events in captivity. There is a very good article in this month's Coral Magazine on the need for additional feeding. There are several articles on the roll of sponges in reef habitats on Phyorg.com, as well. Use their search engine to search "corals sponges". Another good article is at http://glassbox-design.com/2009/sponges-recycle-carbon-on-the-reef/ There are several other sources of information on the need to supplement the zoanthellae's undisputed contribution to the welfare of the corals.

Also, studies in the wild suggest that SPS corals while capable of producing their own sugars by zoanthellae are almost totally dependant upon capture of bacteria and other cellular detritus for the raw materials needed to produce proteins and enzymes necessary for full health. There is some evidence that susceptibility of SPSs and LPSs to a variety of diseases in captivity may be due to a lack of complex biological-based nitrogenous and sulfurous compounds that are the raw materials needed to support their immune responses.

SPSs and LPSs are almost totally incapable of utilizing dissolved organic compounds (DOCs), leaving them without some of those basic building blocks unless they get them from an outside source. There are a number of recent scientific articles that suggest that the roll of sponges in the wild is very similar to that of protein skimmers, i.e., removal of DOCs, but sponges also almost totally replace their interior cellular structure responsible for water filtration on practically a daily basis sluffing these cells into the water column thereby releasing large quanitities of very nutritious proteins and fatty acids recycling the absorbed nutrients into form that can be utilized by the corals. It is probable that the only reason that SPSs are successfully maintained in captivity is that the LR is good source of a variety of bacteria that they can utilize. I would like to move away from technically supported filtration and the constant need to feed toward more natural filtration and nutrition supplies. One source that I was directed to was a thread on R2R - http://www.*********.com/forums/lighting-hardware-diy-discussion/25956-cryptic-fuge.html.

I'll readily admit that I am new to the hobby, and have a lot to learn, but I think that there is sufficient evidence that feeding of corals promotes healthy growth and I believe that foods that mimic those available to corals in their native habitats are likely to be best at achieving that goal. I don't know if promoting sponge growth will provide the answers I am looking for. It is merely an idea I am exploring. If you have evidence that another approach is better, I am very open to any ideas that will ensure that my tank is as healthy and productive as possible.

Steve W.

 

[cee]

OK, that's items 1 & 3 on the list. Most people feed the fish, and between residual "scraps" of fish food, fish poop, pods, etc., the corals obtain enough supplemental nutrition. If you have lots of LPS that is another manner entirely. Experiment, find what works for you, and stick with that. There are numerous ways to keep a reef tank and I suspect that are 10X that many still yet to be discovered.

 

[macclellan]

Coral reefs are surrounded by a constant influx of fresh water. Reef aquariums are not. I don't see how you can promote sponge growth other than by feeding, which will make your nutrient levels go up, especially without a skimmer.

You could probably pull this off in the manner of those that have setups designed for nonphotosynthetic corals. This means heavy feeding and frequent large water changes, amongst other things. Most of us aren't willing to commit to that level of maintenance - coral growth is enough for me, no need for reproduction.

As Dave said, there are many ways to skin a cat.

BTW it's "role" not "roll".

 

[Steve W]

So it is. Typo on my part.

Steve