Live Rock vs. Seeded Dead Rock

[MrAnderson]

I've noticed a couple posts recently where this debate has popped up. I'd like to volunteer some biological considerations that I haven't seen discussed. I may go into too much detail for some, but remember there are some pre-high school kids in the audience so I'm just trying to cover the relevant topics.

 

Re: Biodiversity.

 

As we all know, coral reefs are notable for the fact that reef organisms, both macro and micro-organisms, exploit and occupy every square micrometer of the reef. Therefore, in a natural setting the biodiversity per unit area is unparalleled by any other habitat on the planet.

 

Now, in a hypothetical situation following a piece of live rock, let's say there are a certain finite total number of species of bacteria, microbes, algaes, corals, invertebrates, etc. in a given unit area of said LR. When this is harvested, prepped and shipped to our LFS', regardless of the techniques used there is some die-off. By "die-off" this means both "extinction" of organisms from that little world, never to be seen again, as well as reduced populations of surviving organisms. Rarely does anything increase it's population during this process, and never does anything new spontaneously appear. But remember, the population dynamics of reef organisms dictate that any available niche be filled by something.

 

Eventually, this live rock gets dropped into your LFS' or distributor's tank for "curing". Almost always, this entails yet another round of "die-off" due to differences from natural conditions like lighting, temperature, chemistry, competitive species etc.. This round is compounded by being in a closed system, where things like ammonia and nitrates are found in greater concentrations than would ever be encountered by these organisms in the wild reef, thus stressing the inhabitants even further. At this point too, some organisms go "extinct", survivors suffer reduced populations and rarely does anything get added. I say "rarely" because since the die-offs have made some niches available, something from the LFS' habitat may colonize these empty niches. But it's fair to say the net result is likely to be reduced biodiversity. Eventually this rock's populations reach an equilibrium with it's new environment.

 

Once this LR is purchased and put in yet another environment, the hobbyist's tank, once again different in terms of lighting, temp, water chemistry and competitive species, yet another round of selective pressures force population changes. Once again, rarely does anything get added. As we can see, it is pretty obvious that no matter how spectacular the tank eventually grows to be, it just isn't possible to have the biodiversity observed in the wild unless special collection techniques are employed in the first place (like your own scuba gear, a private jet and seawater circulated into the tank in an open loop). Even with great LR, it's a seriously suboptimal representation of natural reef diversity.

 

So now say you've got a friend who wants to get a chunk from you to seed his dead rock setup. Not only does this chunk undergo yet another round of die-off once placed in the new tank, but one relies on the active process of colonization where the new organisms must vigorously grow and colonize the dead rock. Some organisms might not like the chemistry of the tank or physical niches of the dead rock and remain static in population or die. Only those that are comfortable with the new environment will grow, but not necessarily all the survivors will. For example, some survivng bacterial species may survive but go into stasis for years, awaiting more favorable conditions. Others may grow at different rates, and competitive forces may result in unbalanced populations. It's a double whammy from both the stress of adaptation to the new environment and surviving/growing organisms outrunning or not keeping up with the others. Not only that, but certainly nothing new will be added to the biological pool. However, eventually all surfaces will be covered with life, as the hardiest of the reef microorganisms, algaes and invertebrates will fill these niches. Once that happens, the survivng but less than thriving populations will get out-competed for resources and die.

 

So in the end, a seeded tank will eventually have all of it's niches filled, but will necessarily be less diverse than one composed of high quality live rock, but for many this is really an academic consideration. For some, like those who like to keep biotope-specific tanks, or biologists like myself, the aesthetics of seeding dead rock is a less than optimal approach. But for many others, it is a perfectly acceptable approach, if the point is to simply keep a few macro-organisms.

 

There is no right or wrong, just preferences.

 

Re: biological filtration

 

As we all know, "biological filtration" refers to bacterial processing of harmful nitrogenous compounds. What many fail to appreciate, is that these bacteria are like any other life forms found on LR, and as such, can undergo population shifts, extinction or metabolic stasis. There can also be multiple species that contribute to accomplishing each step of the N-cycle. So as the LR is passed from tank to tank, some populations grow, others die, and some just shut down and wait for better conditions.

 

So if you look at the creatures that facilitate the N-cycle in our tanks in this way one can see that once again, all the die-offs that occur throughout the lifetime of the chunk of LR, as well as the pressure of recolonizing dead space, it is entirely possible that the new environment provided by the dead rock may be less than optimal. Certain steps, such as denitrification, which occurs in an anaerobic environment, may become unbalanced in reference to the other steps of the N-cycle. Suddenly, biodiversity becomes less of an academic concern, but actually a functional one. If there are a couple of species of denitrifiers in the live rock with varying tolerances for switching to anaerobic pathways (almost all marine denitrifiers are facultative, meaning they can respire aerobically as well as anaerobically, and some do this switch under greater stress than others), and fewer thrive in the new habitat than the old, we can see where lower biodiversity begins to have an impact on the function of the LR as a biological filter. However, weaknesses in biological filtration are easily identified and remedied by various technologies, so once again, there really is no right or wrong, just preferences about how to get certain goals accomplished.

 

When it comes to reef tanks, where the represented biology is an extraordinarily complex web of interrelationships, colonies, symbioses, dependencies, etc. one can see where an impact on biodiversity has an impact on the quality of life itself. However, this CAN be overcome with technology. So once again, there is no right or wrong, simply preferences.

 

 

Sorry for the book!! Feel free to question my assumptions, this has really been an more of a theoretical exercise rather than a conclusive dissertation. There are no citations because most of this is based on well-explored biological paradigms.

[HecticDialectics]

Well written and thought out imo. I like it! Underscores virtually every argument that has popped up in recent threads. Like you say, it really does just come down to preference.

 

Worth adding a method I think could increase diversity in either seeded dead or live rock tanks. It seems as though, theoretically, adding a bunch of rock or sand from a single location would be limited in its diversity. If diversity really is the end goal, what about trying to acquire rock from as many different sources and batches as possible? Purchase x pounds of each type of rock you can find from different suppliers...

[travisurfer]

Great right up Mr. Anderson.

 

That seems to appear very true on the first reading to me. One thing I do have to say is that semi-seeded rock setups are still a great option. You forgot to mention that, aside from liverock, there is also another addition of new corals. Most colonies come attached to rocks that have been highly preserved compared to commonly available "live rock". This new rock is continually added to many tanks over the course of at least a year and so therefore adding more life to the tank. Now, obviously this isn't as good as truly fesh rock but it still is a viable factor that should be considered.

 

Now, as good as that sounds, a lack of biodiversity will still occur overtime as what happens in all tanks. I have read quite a few threads on RC about large, established tanks that have simply crashed for "no real reason". It seems like many of these tanks suffered from the survival of the fittest. Competition outruled all but the most elite of organisms. In many cases, this is solved by the addition of new organisms to the tank. Premium Aquatics has what they call grunge or the like which can sometimes remedy the problem since it adds new bacteria and micro organisms to the system.

 

Now, obviously I am not a Biology Major, just a highschool student. But this is just my two cents in regards to the use of liverock and seeded rock. IMO there really isn't a "perfect" way to replicate the reef but there are many great attempts to do so in a closed system.

 

-Travis

[MrAnderson]

Yeah, you guys are both correct in that adding greater diverstiy at the start can't hurt, but each specimen added will still go through the attrition of curing stress, acclimation and competition in growth. But yes, the greatest initial diversity added at the start would theoretically be best.

 

The idea of coral rock beng added is interesting and that rock would probably be the best preserved, I agree. Theoretically that's a nice way to start off, but could the tank be stable enough early on for the addition of many corals (with their rocks)? I say "many" to combine this idea with the one above..

 

But if one is talking about adding new diversity to an established tank, remember that an established and mature tank has the niches which are "easiest living" already occupied, and anything new that is added not only has to survive, acclimate and grow, but has the additional impediment of evicting and/or outcompeting a section of the population of the extant inhabitants. Assuming of course that the new additions require occupied niches for survival, that is.

[travisurfer]

Makes sense. I suppose it really depends on how long it takes for the tank to really settle out with its organisms in their respective niches. I know for a fact that my tank is almost a year old and it still goes through the occasional cycles of life. Just as tanks see an outbreak of pods, flatworms, algaes, and brittle stars its highly possible that a dominant species could be introduced to take over said nich; however, I do see your point on adding as much biodiversity at the tanks beginning which is most obviously the most beneficial. A tank comprised of mostly corals and their respective rocks could be a good idea if the rocks were big enough and well preserved enough. I do think this could work although it tends to favor wild collecting of corals. A recent trend has been the propogation of corals in home aquaria. These frags are then placed on virtually dead plugs which offer no benefits to the tank at all. Although this is a great and necessary action imo, it will not aid in the tank's biodiversity. Ultimately, so called "reef rocks" could be implemented if included with fresh live sand although these would have to be highly preserved and the water quality would have to monitered very closely. Just another idea.

[lgreen]

Good stuff. Now this is the type of stuff that gets me going. I love microbio.

[MrAnderson]

Good stuff. Now this is the type of stuff that gets me going. I love microbio.

 

That's good!

 

Because IMO, microbiological considerations are the most important regarding setup of a tank and long-term stability. I consider those bugs (bacteria) pets as much as any fish or coral, and since they're the first to go in they're worth some thought.

[travisurfer]

As do I. I am still fascinated everytime I find a new little critter in my tank. Its a shame not to too many people seem to be reading and contributing to this thread. Oh well, at least I get to take a nice college level bio course next year Ecology is deffinitely the most interesting topic; atp processing and evolution is so so

[kismetsh]

Yes, doing research on this topic has definitely changed my mind about a few things...I am planning to set up a big tank in the next 6 months and originally thought I would buy dead rock and seed with live rock. This was purely for financial reasons. I have instead decided to proceed more slowly and buy rock from several different areas (and more than one vendor) to try to maximize diversity.

 

KC

[lgreen]

Mr. A,

 

You should change the title of this thread to "Why Many Of You Fail At Reefing". It's the truth.

[HecticDialectics]

The idea of coral rock beng added is interesting and that rock would probably be the best preserved, I agree. Theoretically that's a nice way to start off, but could the tank be stable enough early on for the addition of many corals (with their rocks)? I say "many" to combine this idea with the one above..

 

 

I think the greatest examples of rock that would have more diversity than normal in this fashion would be the aquacultured TBS liverock that is actually shipped in water straight out of the ocean and Dr. Mac's "pieces of the reef". Both would potentially offer more fragile life forms that may otherwise die from shipping.

 

On the niches, survival of the fittest... small tanks don't offer room for losers of competitions to go. Even big tanks may not. In a closed system, that seems very inevitable. Kinda like natural extinction. Is it really important to have a massive array of diverse life or life that is strong and resilient?

[Atlantis Reef]

That was by far the greatest detail write up I hhave read thanks alot and can I share it?

[Mudfish]

How much of this information, concerning the importance of diversity of the micro-species in the live rock, would y'all think also applies to the live sand beneath? Given that some folks make due with bare-bottom tanks, does that mean that it doesn't matter what we do with the sandbed, as far as diversity of lifeforms goes?

 

Or do you feel it is equally as important to seek out diverse seeding sources for a new sand bed?

[MrAnderson]

Is it really important to have a massive array of diverse life or life that is strong and resilient?.

 

? ... Importance is arbitrary.

 

It depends on what's important to you. If strong and resilient is of primary importance, then the obvious choice for a setup would be Aiptasia and algae. Now there's a care-free tank for you (don't laugh, I've seen plenty, the "FOAA tank").

 

The aesthetic of greater diversity is more appealing to me, because my interest is to have as close to a representation of a natural reef as possible, rather than keeping a certain species of anemone or fish. But that's simply my preference and it obviously will take more effort and consideration than an Aiptasia and algae tank. Remember I constantly mention preferences; others may have different goals.

 

However, I do think this aesthetic is functionally superior; diversity provides biological redundancy.

 

So what's "important" is whatever is most important to YOU.

 

That was by far the greatest detail write up I hhave read thanks alot and can I share it?

 

omg thanx, definitely.

 

 

Or do you feel it is equally as important to seek out diverse seeding sources for a new sand bed?

 

I've only given thought about this right now to live rock in relation to seeding dead rock... I mean, on the other extreme you can't KILL yourself getting a million different specimens of everything from all over the world, either. I'm not sure that it matters THAT much in all honesty. But you know what? I bet it can't hurt...

[Scott Riemer]

Mr. A, I've read your post and wonder, do you think there's any "down" side to mixing LR from different regions? ie. Could there potentially be different diverse organisms that should not be put together since they may not occur together naturally? Or, are we not biologically knowledgeable enough to guess? Notice I'm asking your opinion which I know you'll base on your knowledge.

[MrAnderson]

I was about to go there in my last post and deleted it.

 

I'm not sure, and the conflict would be on the microscopic scale where I'm not sure if studies have been done like that enough to know.

 

You now how some like to set up freshwater biotope tanks like "Amazon" or whatnot? I'm kind of like that. I'm not sure if there's any downside to mixing Caribbean stuff with Pacific, but I'm the type of freak that wouldn't do it because it would bother me, even if it works out fine, lol.

 

preference, preference, preference...

[Scott Riemer]

I'm not sure, and the conflict would be on the microscopic scale where I'm not sure if studies have been done like that enough to know.

That's sort of what I figured.

I'm not sure if there's any downside to mixing Caribbean stuff with Pacific, but I'm the type of freak that wouldn't do it because it would bother me, even if it works out fine, lol.

I completely understand where you're coming from there.

 

Thanks for the response.

[Tangman1218]

Okay Travis, I'll jump in here.

 

I agree with Mr A. on many points. As he has pointed out, Its not a matter of being right or wrong, but rather preference.

 

I personally seed LR. I did see certain flaws in his first post that I'll merely point out as my own opinion rather than a right or wrong.

 

First of all, whenever anything is taken from the ocean, it will have die off. I believe he made that point. Second, The shifts in current, temperature and even quick salinity changes in the oceans does the exact same thing, within itself. Let us not forget that things also die in the LR in the ocean itself. As to the differentiation, I'll leave that up to the Marine Biologists who sometimes have to merely make guesses at what happens with certain living creatures in the ocean.

 

Now to talk about seeding. I'll first start off by telling everyone here that I seed LR. I have LR that has been in my system for years as well the seeding tank. I even have people who want my seeded LR over LR they can get at the LFS. I consider my seeded rock to be of the same quality because of its source. Its a passdown of generations if you will. Survival of the fittest as someone pointed out.

 

Now, how can we consider LR to be of high quality when we get it from the LFS? We cant. It takes time to analyze rock of good quality. An hour to kill at the LFS looking at the rock wont make a hoot of difference. Sure , you can know the reputation of your LFS as a consideration. And you should. But as Travis pointed out, If we could have a tank full of LR that had corals originally growing on it, we could at least say that there is a "possibility" of it being of higher quality. Thats not always true either. The bottom line? We take what we can get and do the best we can. A casual observer would never know the diverse life in the rock. It takes many weeks, months and sometimes even years to finally recognize the incredible diversity.

 

Great topic Mr A

 

I do want to point out that the post made earlier about "why people fail at reefing" was not completely fair in its entirety for this thread. Every system has a different balance, and I mean every single one. There are simply to many variables to consider to say someone fails at reefing because they have seeded rock. If I understood the post incorrectly, sorry.

 

Tang

[rickjg]

Well thought out post Mr A

[MrAnderson]

Now to talk about seeding. I'll first start off by telling everyone here that I seed LR. I have LR that has been in my system for years as well the seeding tank. I even have people who want my seeded LR over LR they can get at the LFS. I consider my seeded rock to be of the same quality because of its source. Its a passdown of generations if you will. Survival of the fittest as someone pointed out.

 

Yeah, don't get me wrong, I don't think there's anything wrong with seeded rock at all. I've seen BEAUTIFUL seeded rock, and I'm not arguing against it at all.

 

You know when you first get some new, fresh off-the-boat LR and you look real close and there's like a freaking dozen different coralline algae evident? But then when it grows out there's only a few? I mean, survival of the fittest is going to occur regardless of what you do, because the tank's environment drives that and it can't be avoided. it's just that I PERSONALLY like the idea of starting off with that diversity even though my end product months/years down the road might be only three or four corallines eventually dominating. In the end the "true" LR ends up similar in diversity to "seeded" LR, so I'm not sure how much it really matters.

 

Get me? It's just a geeky biologist thing... It's what I find most interesting and challenging in reefkeeping, keeping the diversity going - my own little Darwinian experiment.

[kismetsh]

I think the greatest examples of rock that would have more diversity than normal in this fashion would be the aquacultured TBS liverock that is actually shipped in water straight out of the ocean and Dr. Mac's "pieces of the reef". Both would potentially offer more fragile life forms that may otherwise die from shipping.

 

Not necessarily. The Florida aquacultured rock may have greater diversity on the outside, but it is not nearly as porous as Pacific live rock so it may have much less diversity on the inside. I have read about people breaking open the aquacultured rock and they stated the life was mostly on the outside. Though I don't have solid "proof" to back me up I tend to think that the diveristy on the inside is probably more important. The article I posted by Dr Shimek does say that the small lifeforms inside the rock are responsible for the flow through the rock which is important for biological filtration.

 

KC

[kismetsh]

I was about to go there in my last post and deleted it.

 

I'm not sure, and the conflict would be on the microscopic scale where I'm not sure if studies have been done like that enough to know.

 

You now how some like to set up freshwater biotope tanks like "Amazon" or whatnot? I'm kind of like that. I'm not sure if there's any downside to mixing Caribbean stuff with Pacific, but I'm the type of freak that wouldn't do it because it would bother me, even if it works out fine, lol.

 

preference, preference, preference...

 

Yeah, most of the Caribbean rock I've seen hasn't appealed to me as much as the Pacific so I doubt I would mix that in. As you say, so much of it boils down to preference.

 

There is more than one way to skin a cat though...I think if someone wanted to go the biotope route they could still increase their potential diversity by buying all the same type of rock, but in different batches.

 

KC

[MrAnderson]

Not necessarily. The Florida aquacultured rock may have greater diversity on the outside, but it is not nearly as porous as Pacific live rock so it may have much less diversity on the inside.

 

Yeah, TBS rock doesn't really appeal to me either because of that reason. I believe they use actual "rock" meaning "stone" taken from land and dumped in the ocean. The structure is fundamentally different from "real" LR, since real LR is composed of coral skeleton and the internal structures are unique to that type of rock alone.

[smithcreek]

As a biologist I'm sure you are aware of the natural progression in a forest after a catastrophic event such as a fire or clear cutting. First the grasses and small plants populate the open field, next comes bushes and shrubs, then fast growing trees and ultimately the dominant species of after many years.

 

Another possibility is that dry rock is like a barren field waiting to be populated. Many organisms that have been outcompeted in large numbers still exist on/in live rock that you seed with, but in small numbers. The dry rock gives these "pioneer" species which may be very benficial a place to thrive for a long time until they are eventually outcompeted. In that case your biodiversity is increased.

 

Just a thought.

[kismetsh]

Another possibility is that dry rock is like a barren field waiting to be populated. Many organisms that have been outcompeted in large numbers still exist on/in live rock that you seed with, but in small numbers. The dry rock gives these "pioneer" species which may be very benficial a place to thrive for a long time until they are eventually outcompeted. In that case your biodiversity is increased.

 

No it isn't. An increase in the number of a species you already have isn't an increase in diversity, it is simply a population increase for that particular organism. In other words, "more of the same."