Cryptic Sponge & Sea Squirt Filtration Methodology

[Louis Z]

Likewise Timfish

[karimwassef]

Confused again - organics will naturally break down into inorganics over time.
The purpose of a living filter is to either consume the organics or inorganics to sequester them. The new biomass can either be exported or remain in the tank.

If sponges are doing the opposite- converting organics into inorganics, they would be polluting, not cleaning the water... unless the rate of sequestration is orders greater than the rate of pollution.

[Timfish]

Well, to start with de Goeij showed inorganic nitrogen and inorganic phosphate was being converted from DOC sources in minutes not days or weeks. Also the cryptic sponges are only feeding on the labile portion of DOC released by algae and corals. The majority is refractory DOC (~ 2/3) and is not being consumed by sponges, at least not in the time scale de Goeij did his experiments. (This refractory portion is why we have to do water changes.) As pointed out in the research posted by Louis Z a lot is sequestered but de Goeij showed these sponges should be growing by something like 30%-35% on a daily basis but they're not. What they are doing sloughing off cells at a tremendous rate (cells splitting in 5 1/2 hours) and the nutrients in this cellular detritus finds it's way into filter feeders in hours.

[karimwassef]

So the sponges are making food for corals out of their own dead tissue while consuming bacteria and DOCs to replenish?

So they're a food factory converting bacteria (that corals usually can't eat) to floating sponge cells (that corals can eat)?

Sorry to dumb it down so much but I like to be very clear and simple so everyone can participate.

[dz6t]

Coral eat bacteria too


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[Timfish]

@Karimwassif,
No worries, I keep rereading de Goeij's research to try to understand it all. I think though it's mostly the labile DOC that is being consumed by sponges and being converted into nitrogen rich detritus that is then quickly finding it's way into the food chain. The closed cavity experiments do show a decline in the bacterioplankton over time so it's resaonble to me sponges (and for new readers that haven't read earlier posts the sponge's holobiont or microbial simbionts) are feeding off them but he makes a point the POC (particulate organic carbon) which I understand to include microbes only supplies a fraction of it's diet. It's also important I think to point out de Goeij's research show's the inorganic nitrogen and phosphate sponges are producing and releasing into the water was fairly small.

@dz6t,
Yes, corals are grabbing whatever they can, both organic and inorganic and we need to think in terms of total notrogen, organic and inorgainc, and total phosphate, organic and inorganic. Not just nitrate and PO4. What we are learning is the microbial life is far more complex than we though even just a few years ago. A good place to start to learn more about the microbial roles with corals is Forest Rohwer's book "Coral reefs in the Microbial Seas".

[karimwassef]

Ok. I'll simplify.

I look simply at organisms in my tank either as sequesters or converters. Most are both, but usually heavier one than the other.

Algae are sequesters in my view. They grab N and P inorganics and without needing additional C, sequester them in biomass.

Fish are converters in my view. They consume organic foods, sequester a little, but mostly convert it to other finer organics and inorganics..

Looking at sponges as converters - what's the in and what's the out?

[Steve Tyree]

Every animal type will react differently to sudden shear forces. I once tore a Botryllus colonial sea squirt just by moving it through the water. Now that was delicate. True cryptic.
Sponges do consume oxygen and I run a bubbler in the semi-cryptic and cryptic zones. So they will need access to oxygen in a power outage. You can help that access by designing large open water surface areas.

[Steve Tyree]

Karim, algae are not total sequestors. They produce slime while they are illuminated. You have to separate organic from inorganic. Algae sequestors some inorganic nutrients, but convert carbon into organic sugars. Excess production produces slime. Just like in photyosynthetic corals. The issue gets much worse then that though.

[karimwassef]

yes. I was simplifying

They're primarily sequesters, but they do generate organics and can promote bacteria too... In my tank, I recycle them through my fish to generate more finer organics...

I don't think anything on the reef does just one thing, but I'm looking for the broad strokes and then the margins can be feathered in.

[Steve Tyree]

...they tend to promote the wrong kind of bacteria. We need to test out the algae. Some species may be safer to use than others.

[karimwassef]

I've been a heavy algal turf scrubber user and my results have been excellent.

My biggest pains have been bacteria due to the scarcity of algae in my DT due to a very aggressive population of rabbitfish and tangs. So the rapidly growing algae biomass drives very low inorganics in the water + heavy feeding and NO mechanical filtration drives a high organic load. That mimics what happens in nature which it why my coral growth rate is so high. The sponges inside my rock cavities thrive with the high organics too.

Maybe the sponges keep the algae-promoted bacteria in check. They would be converting them into either granules that precipitate out or flaking cells that could be coral food.

[Steve Tyree]

Very possible. Sounds like you have turf algae in the DT which has been found to be very productive algae. On a natural oceanic reef, inorganic nutrients are actually very low. The inorganic nutrients are bound up within the organic molecules of living reef biomass.

[karimwassef]

I don't have turf in my DT. I do have it in my scrubber and it does lock up a lot of nutrients in its bioamass.

when I feed it back to my herbivores, it creates a cloud of food and all my corals open up.



I do feed other foods though.. like bananas



the cloud of particulate foods permeates the tank, but N and P are below measurement.

[saf1]

@karimwassef - what made you add a banana? Recycle of turf makes a whole lot of sense and I don't know why many others who use them don't do that. Maybe they do /shrug. Also - pretty sailfin(s).

[karimwassef]

I experimented with different vegetables and fruits... kale, spinach, lettuce, and thought about bananas ... tried it and they prefer it over all other foods... all .. other .. foods.

I would put nori and bananas and and they would move the nori aside to get to the bananas. ??

Also, when we go to cancun, you can feed the fish that come up to the shore and they, also, prefer bananas... no idea why.

I recycle because I find fish poop valuable to my reef ecosystem. So, on one side, I was tossing this thick green biomass... and on the other side, I was adding 4-8 sheets of nori a day. My 8 year old asked me why I was doing that... and I decided that there was no good reason.

So... in went the turf, out came the poop... and everything opened up.

In addition to the sequestered vegetable biomass, the turf was full of particulates, worms, pods, etc... and it was all alive.

[saf1]

Originally Posted by karimwassef

I experimented with different vegetables and fruits... kale, spinach, lettuce, and thought about bananas ... tried it and they prefer it over all other foods... all .. other .. foods.

I would put nori and bananas and and they would move the nori aside to get to the bananas. ??

Also, when we go to cancun, you can feed the fish that come up to the shore and they, also, prefer bananas... no idea why.

I recycle because I find fish poop valuable to my reef ecosystem. So, on one side, I was tossing this thick green biomass... and on the other side, I was adding 4-8 sheets of nori a day. My 8 year old asked me why I was doing that... and I decided that there was no good reason.

So... in went the turf, out came the poop... and everything opened up.

In addition to the sequestered vegetable biomass, the turf was full of particulates, worms, pods, etc... and it was all alive.

Makes sense. I've been diving and the local dive masters would feed bananas. Especially in the shallower areas. I'd wager there is a lot of opportunistic feeding

[karimwassef]

I do believe that the turf is more natural though. The "cloud" released probably feeds the sponges as much as it does the corals.

I've been criticized for keeping a "dirty" tank, but my corals love it - so I guess I'm doing what's best for them even if it makes the water less pristine and clear for my viewing pleasure.

[saf1]

Originally Posted by karimwassef

I do believe that the turf is more natural though. The "cloud" released probably feeds the sponges as much as it does the corals.

I've been criticized for keeping a "dirty" tank, but my corals love it - so I guess I'm doing what's best for them even if it makes the water less pristine and clear for my viewing pleasure.

That is all that matters at the end of the day. How you measure success. I'm sure I am in the dirty tank corner also because I don't like to stick my hands in the tank. So I do very little in regards to water changes if ever but also keep corals that thrive in that environment. Xenia, kenya trees, hammers, etc. Surprisingly my rose bubble tips also do well.

I never gave sailfins much food for thought has a possible purchase. The two you had though looked nice I have to say. Different.

[karimwassef]

most of mine is SPS. The Xenia are a pain since they grow so fast. My SPS can hold them off, but just barely.

[Steve Tyree]

Karim,

The definition of turf is fairly broad. Referenced an article in my book about what it has meaned. But basically it is any close cropped assemblage of algae. Species is not as important as the constant grazing.
From what I can gather you are feeding your algae inorganics produced from fish waste, after bacterial breakdown to inorganic, and then feeding the manufactured carbon algal biomass back to fish. If you add external food you must harvest something or let excess production sink into a deposit bed. My reef is producing wafers of coralline algae with no external food input. Plus coral frags, sponge frags and tunicate reproduction.

[Steve Tyree]

Karim,

Just glancing through thread when I have time. Is nori high in potassium ?
https://www.google.com/search?q=bana...b-b&channel=sb

[karimwassef]

That's right. Any additional food maintains a larger algal biomass in the scrubber.

I do have sps and LPS corals dropping frags in the sand constantly. I don't have the reach to rescue them, so many get buried. Those that survive end up quite healthy for the experience.

[karimwassef]

I don't think Nori is particularly high in K.

Are you thinking that the fish gravitate towards the bananas to get more K?

[saf1]

Originally Posted by Steve Tyree

Karim,

Just glancing through thread when I have time. Is nori high in potassium ?
https://www.google.com/search?q=bana...b-b&channel=sb

No - small amounts only. If I had to guess it is more of an opportunistic food source. Like I mentioned in one post while diving in some areas I've seen the dive masters feed banana's. I wouldn't expect Tangs to munch on them but have seen damsels and other fish around the reef crest going to town. If it works, it works. Probably similar to people feeding some worms and other non local sources of food.

But Karim's fish like them so why not