Marine Allelopathy

[Garf]

An article which demonstrates the complicated interactions between living things in the ocean and how some of these interactions are good, some bad.

http://webs.uvigo.es/thalassas/Thalassas%2023(1)/T23(1)_04_%20Rodr%EDguez-Ramos%20et%20al.pdf

[SantaMonica]

Is mostly about phyto, so is more of a general interest than specific to using macro for filtering.

[Garf]

How scrubbers REALLY get rid of display algae (mostly). Due to the effects of Allelopathy on nutrient uptake on the target species, it's effect is amplified by competition for nutrients. Doesn't always work though, especially if the display outbreak is large enough to "poison" the screen first.

http://www.academicjournals.org/AJPS/PDF/Pdf2012/Jul/Addisie%20and%20Medell%C3%ADn.pdf

[SantaMonica]

That paper was for microalgae.

[Garf]

That paper was for microalgae.

Yes, and this ones about Hair Algae on phyto;
http://www.researchgate.net/publication/230067290_Filamentous_green_algae_inhibit_phytopla nkton_with_enhanced_effects_when_lakes_get_warmer
can you see a theme developing here ?

[Garf]

Oh, yeah, there's this one;


Chemicals contributed by the alga can affect (1) other algae in its vicinity, (2) its own growth (i.e., autotoxicity), (3) microbes associated with it, (4) higher plants in its vicinity, and (5) accumulation and availability of nutrient ions which can influence the distribution, growth and establishment of other algae, microorganisms, and plants

http://www.mendeley.com/research/algal-allelopathy/

[Ace25]

Good stuff, thanks for sharing. I do believe some of that relates to how my ATS is working on my 75G (ie, never worked in regards to removing algae from the display). I always pull out more algae from the display than from the screen each week even though to me seems like the screen is working fantastic going off of the amount of algae I scrape each week, and this is going on close to 4 years now. Meanwhile my 60G system that only has an ATS and never grew much on the screen has never had an algae problem in the display. I always suspected having the screen work 'too well' was contributing to my failure but could never pinpoint why exactly, but those articles shed a little light onto why that may be.

I also wondered how much cleaning the screen contributed to the issues. There was a documentary I watched recently that showed how plants give off chemicals when threatened in order to warn other plants of danger which in turn makes the other plants go into protection mode, close up, and stop growing. It is the plants way of communicating with each other, which I found absolutely fascinating. I have no idea if that related to macro algae, the documentary was on land plants and what happens when animals eat the leaves. Just google 'plants communicate' to read up on it.

[SantaMonica]

If macros could inhibit other macros, displays would not fill up with algae.

[Ace25]

Anyway Garf, as always, I appreciate all the research you do and share with us.

4 Days growth on my 75G ATS

http://www.youtube.com/watch?feature=player_detailpage&v=34RyusDLg3o

[Garf]

If macros could inhibit other macros, displays would not fill up with algae.
Your not really getting the point here SM. This is how I see it so far, secondary metabolites can either inhibit OR promote OR have zero effect on the growth of other organisms. This explains why Caulerpa species can be killed off in a scrubber system, even though Caulerpas (reef macros) have a lower growth rate and higher affinity for N & P, which means they are capable of survival at mega low dissolved inorganic levels. It also explains why some screens just will not start up and are always a screen full of mush "autotoxification". It also explains why display algae can die off, shortly after starting a scrubber, even though nutrients are far from limiting. It also explains why sometimes as in Aces case, the scrubber can grow great, but unfortunately so does the display algae. It also explains the "clamping" issue that has been observed in corals. Basically this one theory encompasses every problem related to running a scrubber tank. I think it's worth your time, not to just dismiss this.

[cdm2012]

Garf, I agree with you that this is worth the time and research. I found this write up: http://www.algone.com/articles/aquarium-basics/aquarium-algae

"It also needs to be noted that some algae types can avoid other species to grow. Pithophora (Green Hair Algae) for example produces allelochemicals that suppress the growth of planctonic Euglena (Green Water). Cyanobacteria is also known to compete against green algae, which by the means of succession means that cyano follows green algae."

[SantaMonica]

No, unfortunately it does not explain these things. But fortunately what does matter is that some people get the results they want.

[Ace25]

And some people don't get the results... and that is the point, figuring out WHY people like me don't have success on one system but do on another. There is something we are not fully understanding, and Garf is doing the most on this forum to help try and solve that puzzle. I will be an ATS user for life because I believe in the concept, so I am not an 'ATS basher' obviously, but I don't just put blind faith in anything, especially when I know there is something to it none of us are fully understanding. If a properly working ATS was as simple as the concept makes it sound, we would all have 100% success, but we are far from that. Sure, there are systems where they work fantastic, and systems where they don't work at all, same as Bio-pellets, trying to figure out why that happens is the puzzle I believe Garf is attempting to figure out.

[druckle]

This open minded search for solutions to problems is what has made science successful. We all need open minds and a deep sense of curiosity if we're going to make progress.

[kotlec]

And some people don't get the results... and that is the point, figuring out WHY people like me don't have success on one system but do on another. There is something we are not fully understanding, and Garf is doing the most on this forum to help try and solve that puzzle. I will be an ATS user for life because I believe in the concept, so I am not an 'ATS basher' obviously, but I don't just put blind faith in anything, especially when I know there is something to it none of us are fully understanding. If a properly working ATS was as simple as the concept makes it sound, we would all have 100% success, but we are far from that. Sure, there are systems where they work fantastic, and systems where they don't work at all, same as Bio-pellets, trying to figure out why that happens is the puzzle I believe Garf is attempting to figure out.

Cant say better

[cdm2012]

Could running a protein skimmer or activated carbon for a short while rid a tank of allelochemicals? I read somewhere that it can. So, maybe someone that is having poor growth, should try running a skimmer for a few days and then shut it off and see if growth occurs. If it doesn't, then allelopathy may not be the answer. But I'm no expert like SM, Floyd, Garf, or Ace. I'm learning!!! :)

[Nick28]

Bacteria in the sand bed and rock break these chemicals down. maybe not fast enough in some cases.

bacteria produce these chemicals too. But algae, corals, bacteria, etc.., also produce beneficial compounds as well. In the wild you usually have coral dominated reefs or algae dominated zones (not totally though).

Some corals or algae are more tolerant than others and produce more harmful chemicals than others (caulerpa!). My guess is they don't last long either by being consumed, oxidized or dispersed to low concentrations.

[Ace25]

My tank that has issues with the ATS (which doesn't appear growth related) does run a quasi skimmer and 2 canisters of carbon and GFO. Tank that is doing good only runs an ATS, BUT that tank also has super high phosphates, but they don't seem to negatively effect the corals even though according to the experts I shouldn't be able to grow SPS corals with phosphate as high as they are. To this day I have had the best luck running a tank when I used Caulerpa as my macro algae filtration, never once had an issue with it, but I no longer have that and in California it is illegal to buy (for good reason).

Lately I am leaning more and more to the 'set it and forget it' side of things. The more I try and control parameters to how I would like them, the worse the tank does. When I let the tank do whatever it wants and find its own balance, things seem to thrive.

Still, that is a very generalized view of my tanks and I know there are scientific reasons to why my tanks behave the way they do, which is why I appreciate all the research Garf does because it is like picking up new puzzle pieces to a 1000 piece puzzle and seeing if that piece fits into what I am working on.

[Garf]

Well, what can I say. I'm humbled by the responses so far. Just like Ace, I don't want to bash the scrubber, for crying out loud, I'm running one. What I can't stomach is the "your scrubber is weak" generic phrase to any problems. This is obviously not the case in most scenarios. There are other problems afoot here. We need to find a reason for these failures. If anyone has pertinent information regarding this problem, please declare it. The most obvious (although not scientically proved) to me, are secondary metabolites that are formed in algae and then exuded through natural processes. Together, we can get to the bottom of this.

[cdm2012]

My tank that has issues with the ATS (which doesn't appear growth related) does run a quasi skimmer and 2 canisters of carbon and GFO. Tank that is doing good only runs an ATS, BUT that tank also has super high phosphates, but they don't seem to negatively effect the corals even though according to the experts I shouldn't be able to grow SPS corals with phosphate as high as they are. To this day I have had the best luck running a tank when I used Caulerpa as my macro algae filtration, never once had an issue with it, but I no longer have that and in California it is illegal to buy (for good reason).

Lately I am leaning more and more to the 'set it and forget it' side of things. The more I try and control parameters to how I would like them, the worse the tank does. When I let the tank do whatever it wants and find its own balance, things seem to thrive.

Still, that is a very generalized view of my tanks and I know there are scientific reasons to why my tanks behave the way they do, which is why I appreciate all the research Garf does because it is like picking up new puzzle pieces to a 1000 piece puzzle and seeing if that piece fits into what I am working on.

Interesting!

It's given that higher phosphates can promote algae growth in the display tank on tanks that don't run algae scrubbers. Maybe it's the algae growing all in the tank that is causing the corals to suffer and not necessarily the phosphates. But because a tank that is filtered by an algae scrubber has the algae growing away from the corals in the DT, maybe the phosphates don't impact the corals as much as people think they do. Maybe trying to get phosphates to low levels is a problem with a scrubber. It's a possibility that just allowing the scrubber to do it's job without worrying about phosphates is the answer? What do you think? Or am I way off on this?!?

[kotlec]

What I can't stomach is the "your scrubber is weak" generic phrase to any problems. This is obviously not the case in most scenarios.

I have hard times to stomach that as well.
My friend has tank with no scrubber at all. Not a surprise his P and N is always low but measurable. But he has seen some algae only during cycle and then forgot how it looks forever. And his corals are all colorful and nice.
Others including me have scrubber with P at zero most of the time. But never my tank was 100% free of pest algae. It seems like algae will dye off soon , but that day never comes. New tuft appears instead.
Go figure.
Scrubber is invaluable reducing N and P no question though.

[Ace25]

Interesting!

It's given that higher phosphates can promote algae growth in the display tank on tanks that don't run algae scrubbers. Maybe it's the algae growing all in the tank that is causing the corals to suffer and not necessarily the phosphates. But because a tank that is filtered by an algae scrubber has the algae growing away from the corals in the DT, maybe the phosphates don't impact the corals as much as people think they do. Maybe trying to get phosphates to low levels is a problem with a scrubber. It's a possibility that just allowing the scrubber to do it's job without worrying about phosphates is the answer? What do you think? Or am I way off on this?!?

Well, it is a good theory. We all know algae and corals in the same location do not work together as algae releases chemicals that kills corals. That effect has been documented to death so I don't think there is any debate about that. I don't think running a scrubber and not worrying about parameters at all is the right answer though, I think I just got lucky on my 'ats only' tank that the phosphate levels stopped rising at a certain point, if they had continued to rise I do think my SPS corals would have died. I believe around .5 phosphates is the upper limit for phosphates with SPS corals and even then it wouldn't be a level I would recommend anyone else running on purpose. I am still coming back to 2 theories myself, 1. hair algae isn't that good of a macro algae filter and I think there is room to find alternate types of algae that would still work in an ATS environment that has a better C:N:P absorption ratio and 2. getting a better understanding on bacteria and how to maintain and grow the correct strains to best compliment the algae. Again, I believe it comes back to finding a balance in the tank above all else, screw trying to get certain parameters to fall within the experts rules (.003-.03 phosphates) because by manually trying to keep certain parameters within a abnormal range, you just end up fighting the natural filtration in your tank. You can't have it both ways, use nature to filter your tank then interact and change parameters to your liking because it then falls outside of what the tank likes in some tanks. Then again, other tanks may function fine if you keep your hands wet and always tweak it because the algae then adapts over time to your levels, but if you slack off in maintaining levels for just 1 week it could cause the tank to start into a nose dive. This is not an easy question/answer, but the more we discuss things the more we may understand it better, so everyone's opinions no matter how different they may sound is valuable in this type of thread.

[SantaMonica]

Study shows that corals prefer to grow touching algae:
http://algaescrubber.net/forums/showthread.php?1539-Study-shows-that-corals-prefer-to-grow-touching-turf&highlight=touching

[C-Horse]

Interesting discussion.

As I understand it, an algae scrubber is designed to provide a space more favorable for growing most type of algae than the DT.

Now allelopathy may play a part in determining which species of algae dominant over which and where. If so, how can we eliminate this factor, so that the algae species in the scrubber is dominant over the ones in the DT?

From what I read, light spectrum is also a factor in favoring one algae species
over another. So if the light spectrum in the DT is perfect for a particular species of algae, wouldn't the DT be a better space for this algae than the scrubber?

[Ace25]

Study shows that corals prefer to grow touching algae:
http://algaescrubber.net/forums/showthread.php?1539-Study-shows-that-corals-prefer-to-grow-touching-turf&highlight=touching

Ummm... your link is about turf algae, I am speaking about hair algae, which is the most common problem in displays. I will agree with you that turf algae doesn't seem to negatively impact corals as I have 1 rock that has a giant montipora surrounded by turf algae, been that way for years, and as the monti grows it just kills off the turf, albeit very very slowly.
http://www.advancedaquarist.com/blog/corals-attacked-by-toxic-seaweed-use-chemical-911-signals-to-summon-help-from-fish

[SantaMonica]

Apparently they don't much signaling, since the majority of corals prefer, and do, live next to and touching algae.

[cdm2012]

Can the overgrowth of GHA next to, or top of, some corals prevent it from extending and getting light and nutrients?

[cdm2012]

Interesting discussion.

As I understand it, an algae scrubber is designed to provide a space more favorable for growing most type of algae than the DT.

Now allelopathy may play a part in determining which species of algae dominant over which and where. If so, how can we eliminate this factor, so that the algae species in the scrubber is dominant over the ones in the DT?

From what I read, light spectrum is also a factor in favoring one algae species
over another. So if the light spectrum in the DT is perfect for a particular species of algae, wouldn't the DT be a better space for this algae than the scrubber?

That's a fair question. Could that be an issue? Maybe another scrubber could be ran with the same spectrum as the DT lights.

[Doompie]

What I still believe (and see in my tank) is that when the algae (types) in the scrubber has a faster growth ability then the ones in the DT, the DT algae will eventually die-off and vanish.

I have done many tests on my tank the past year to try to get a better understanding about what is going on, and certain effects.
Because of some tests, I "suffered" a lot of different algae in the DT. The worst period I had No3 to 100+ which was a result of 2 months only cleaning once and continuous feeding. (also noticeable: I never been able to measure Po4 >0,02)
All these tests have led to Cyano, red marco algae, cheato, caulerpa, bubble algae, and lots more which I 'wasn't even able to identify.
Though the biggest finding I had by all this is the folowing:

The type of algae growing in the scrubber varied a LOT. It seems that the species in the scrubber adjust to the available nutrients, the feeding given, the light period and the flow rate.
What I also found is that it doesn't really matter what species grow there.. It's hard to control any way, but the scrubber always knows best (!!)
When you stick to the cleaning routine (7-10 days) the algae in the scrubber will (always in my case) out compete the algae in the display tank. Certain types like bubbles, and red macro's take longer to vanish from the DT, but in the end they will.

Very important is HOW you have set-up the DT and stocking, and how many changes to the biota you do.
When you give opportunity for wastes to build, you will end-up with some algae because the source distance is just that much shorter, and since corals house algae (symbiosis), it's not more then logic that algae are always able to grow in the DT..

I have to admit: The best results in my case I get from combining LED on one-side and T5 (3000k) on the other side of the scrubber, lights on for 16 hours and 8 hours darkness.. The types on my T5 side differ from the ones on the LED side..

As the scrubber matured over time, I got a combination (many types) of green hair and green turfs which pulled out the nutrients from 100+ to <1 within 2 months.

Another finding is that 10% water changes per month have a lot of benefit. I haven't done a water change for a year, and only added kalkwasser with vinegar. But started picking up PWC since november last year. Certain minerals just seem to wear out over time and it's VERY hard to guess which. The structure and dependencies in the reef biota is complex as we know.

What I also found is that the biota, especially the worm's, snails (which I have MANY different who all by it self) and "snake-stars" (also grew out of live-rock) and a lot more which are hard to see/identify have a very important function in that respect.
They are able to breakdown wastes (DOC's) (which really just build-up) better then any device available.
No skimmer can do what these animals do. Because of that, the turn-over from particle to nutrient is quite high, which again thrives the algae growth in the scrubber.

My advice: Don't try to steer, set-up and forget I get the best results with the scrubber.. As always, nature knows best. Even though it's nature in a glass box..

The holy grail for me is: http://www.coralscience.org/main/articles/climate-a-ecology-16/coral-reef-ecology

Decomposers are VERY VERY VERY VERY VERY VERY VERY important in ATS systems.. In my case it took over 10 months for them to become in numbers strong enough to coop with the waste numbers in my tank. And every addition of higher life means I see an adjustment In those too..

just my 2-cents..

[SantaMonica]

Can the overgrowth of GHA next to, or top of, some corals prevent it from extending and getting light and nutrients?

Of course. That's why we want the growth in a separate box.


What I still believe (and see in my tank) is that when the algae (types) in the scrubber has a faster growth ability then the ones in the DT, the DT algae will eventually die-off and vanish.

Yes, and this is what most people find, on most forums.


Because of some tests, I "suffered" a lot of different algae in the DT.

Let me tell you about some display suffering :)


also noticeable: I never been able to measure Po4 >0,02

That's what I usually find: about half the people have higher N, and half have higher P. In the end, if the scrubber is made stronger, both N and P go away. The question is, how to make them stronger without more size or wattage.

[Garf]

That's what I usually find: about half the people have higher N, and half have higher P. In the end, if the scrubber is made stronger, both N and P go away. The question is, how to make them stronger without more size or wattage.

Manipulating pH perhaps ?

http://algaescrubber.net/forums/showthread.php?2611-Photosynthetically-Induced-Phosphate-Precipitation

[Garf]

Ok, let's put this one to bed;


ABSTRACT: Allelopathy in aquatic environments may provide a competitive advantage to angiosperms, algae, or cyanobacteria in their interaction with other primary producers. Allelopathy can influence the competition between different photoautotrophs for resources and change the succession of species, for exarnple, in phytoplank- ton cornmunities. Field evidence and laboratory studies indicate that allelopathy occurs in all aquatic habitats (marine and freshwater), and that ail prirnary producing organisms (cyanobacteria, micro- and macroalgae as well as angiospenns) are capable of producing and releasing allelopathically active compounds. Although allelopathy also includes positive (stimulating) interactions, the majority of studies describe the inhibitory activity of ailelopathicaily active compounds. Different mechanisms operate depending on whether allelopathy takes place in the Open water (pelagic zone) or is Substrate associated (benthic habitats). Allelopathical interactions are especiaily common in fully aquatic species, such as submersed macrophytes or benthic algae and cyanobacteria. The prevention of shading by epiphytic and planktonic primary producers and the competition for space may be the ultimate cause for allelopathical interactions. Aquatic ailelochemicals often target multiple physiological processes. The inhibition of photosynthesis of competing primary producers seems tobe a frequent mode of action. Multiple biotic and abiotic factors determine the strength of allelopathic interactions. Bacteria associated with the donor or target organism can metabolize excreted aiielochemicals. Frequently, the impact of surplus or limiting nutrients has been shown to affect the overail production of allelochemicals and their effect on target species. Similarities and differences of ailelopathic interactions in marine and freshwater habitats as well as between the different types of producing organisms are discussed

http://www.jlakes.org/web/Allelopathy_aquatic-autotrophs-CRPS2003.pdf

[Floyd R Turbo]

I haven't read all of this thread, just what I can from time to time, and certainly not all of the articles, maybe someday. This last one though is very intriguing. Aside from the rampant typos, from the quote above, a few big things I see:

- bacteria are involved in processing of allelochemicals meaning adaptation to each other's form of warfare happens. This makes sense, and might explain why certain species of coral seem to "not like" scrubbers. Like my Zoas, that just do not last, and green birdsnest, along with hammers and frogspawn.

- this warfare may not happen when limitation is not occurring. this mean that if the scrubber is balanced properly with the system, and NPK and whatever else the algae needs is present, you may not have problems with the above corals. So there may be a factor involved in preventing algae from "declaring war". This may mean that there is much more to the screen sizing decision that thought before. In the same breath, they say that "surplus or limiting nutrients" affects the production of chemicals. So much to learn.

- the inhibition of growth due to allelopathy (from cyanobacteria) is likely the reason one scrubber I am running has produced only minimal amounts of algae in 4 months (1/4 cup total). Worth noting that it has improved in growth rate, and that under LEDs all of it is green, but still no where near effective filtration (high nutrient tank). This further grounds my decision to tear the tank down and start over.

- bacteria are associated with the algae. I know several people who are testing the theory that the bacterial biofilms that grow on algae mats are symbiotic and have a parallel function/concept to Zeovit type systems. It is also worth noting that I am learning that certain types of carbon dosing do not necessarily compete with algal growth but rather seem to enhance it.

Sooooo much uncharted territory here. Someone really needs to get me a big fat juicy grant so I can quit my job and study this stuff.

[Garf]

Sorry for the typos, it was transferred to Adobe reader on iPad before copying and pasting. To me it also explains why some people just cannot get a scrubber to grow, and also why I don't get algae growing on my display glass. There are multiple problems and benefits associated with this single theory such as nutrient uptake, growth of bacteria and algae etc, etc.

[Floyd R Turbo]

Seems like also a good argument for running carbon if you are having problems getting growth. Absorbing the alleopathic chemicals might allow different species to coexist until one overpowers the others due to environment/location (scrubber being favorable growth environment)

[Garf]

Seems like also a good argument for running carbon if you are having problems getting growth. Absorbing the alleopathic chemicals might allow different species to coexist until one overpowers the others due to environment/location (scrubber being favorable growth environment)

http://i1269.photobucket.com/albums/jj597/Garf1971/33cb01e764bd53fbcb15b0b2556331ad_zpsd53728e2.jpg

[Garf]

So, now we've gone from algae exudates and soft corals to hard corals also;

http://www.advancedaquarist.com/2002/11/corals

Seems as though most things in the ocean has a chemical defence, attack mode. Luckily it seems these can be skimmed out or adsorbed to activated carbon.


Grozinger (1983) found a biologically active compound in Madracis mirabilis that is also found in nudibranchs and sponges. Stony corals can also inhibit growth of marine algae (De Ruyter van Steveninck 1988). Finally, Sheppard (1979) concluded that non-contact necrosis between nearby stony coral colonies resulted from allelopathic chemicals produced by the stony corals.


Various effects may result, from reactions by other organisms that range from acute toxicity, to a general "failure to thrive," to no visible effects (even though there may be very significant effects that are simply not visible to the aquarist, such as changes in respiration or photosynthesis rates). There may also be cumulative effects, with low levels produced increasing over time so that levels that initially had no effects begin being expressed over time on various organisms, perhaps in various ways. Such a progressive increase of metabolite concentrations could help explain the "old tank syndrome"


Many of the more toxic compounds studied across terrestrial and marine systems occur in the polar aqueous fractions of extracted tissues. This is not to say that nonpolar compounds with deleterious effects do not exist, but that the majority seems to be polar. As such, they may be more likely to be removed by foam fractionation.


I would also suggest that the use of activated carbon maybe among the more effective ways of dealing with such secondary compounds, as it has been found to be effective in the absorption of similar compounds from terrestrial plants.

[Garf]

A bit more general Allelopathy related stuff. Seems everything is at it!http://www.international-allelopathy-society.org/main/home/down/1275822225.pdf
166. Significance of Algal Allelochemicals in Naturaland Agroecosystem A.S. AhluwaliaDepartment of Botany, Panjab University, Chandigarh,160014, India Algae and cyanobacteria are known to employallelochemicals in the offensive and defensive interactionsamong themselves and with higher plants, which play animportant role in structuring the aquatic community. We,however, witness little progress in better understandingthe role of algal chemicals in aquatic and wetland ecology.Demonstrating allelopathic activities in aquatic system, forexample, is considered difficult because of dispersion ofallelochemicals due to continuous movement of water andless chances of lack of contact between competingorganisms and chemicals. This talk will discuss thesignificance of well-replicated field studies from differentgeographical locations in appreciating algal allelopathy.To understand wetland and aquatic ecology, bloomformation, lake succession, algal invasion and dominanceof certain algae in a given ecosystem, more research isneeded on chemical warfare between and among algae andcyanobacteria.

5th World Congress on Allelopathy

[Garf]

Now I've got a bit of time to look into this, there's lots of interweb stuff on allelopathy. Eric Borneman writes;

http://www.reefkeeping.com/issues/2003-12/eb/index.php


Myth 8: The statement, "but my water quality checks out fine."

In his articles here (and elsewhere), as well as in his forum on Reef Central called The Reef Chemistry Forum, Randy Holmes-Farley provides extensive information on the nature of common (and sometimes uncommon) chemicals in reef aquaria. Ron Shimek, and others, have also covered various topics in chemistry and biochemistry over time frames spanning ten years and more. Until relatively recently, only a few chemicals were generally considered in reef aquaria, and the ability to accurately measure those parameters has frequently been called into question.


My point above is that aquarists routinely check a variably complete set of a handful of chemical parameters in variably accurate ways to make the oft-repeated statement, "my water quality checks out fine." As has been discussed elsewhere, there are many difficulties of being assured that such statements are true, and the more recent information concerning more exotic and toxic chemical species including various metals and organometallics virtually ensure that there might be many reasons to suspect that one's water quality might not be "fine," despite routine testing for common parameters.


To take this issue a step further, one must necessarily include the bounty of organic chemicals produced by organisms in aquariums called secondary metabolites. I am both pleased and troubled that the word "allelopathy" has become a regular word in many aquarists' vocabulary. It is almost impossible to describe how varied the products of metabolism can be in the marine environment. In short, virtually every organism in the tank has them, produces them, and releases them. The effects of secondary metabolite chemistry are significant enough to cause real and sometimes dramatic effects in the wild where dilution effects are vast. So common and numerous are these compounds that conferences, books, and journals are devoted entirely to the subject. I would urge readers to look through a copy of the Journal of Natural Products to see the scope of this topic (it is only one of many sources of such information). Each issue consists of several hundred pages (often filled with 1-2 paragraph descriptions) of metabolites derived and isolated from natural sources (organisms) and, sometimes, a brief description of potential effects (usually based on chemical structures similar to those of known function). In any given issue, about 20-50 percent of the chemicals are from marine organisms, and many are from tropical marine organisms. For example, here are the relative feature articles from the past two issues alone:


Novel Oxylipin Metabolites from the Brown Alga Eisenia bicyclis


Isolation and Structure Determination of Lyngbyastatin 3, a Lyngbyastatin 1 Homologue from the Marine Cyanobacterium Lyngbya majuscula. Determination of the Configuration of the 4-Amino-2,2-dimethyl-3-oxopentanoic Acid Unit in Majusculamide C, Dolastatin 12, Lyngbyastatin 1, and Lyngbyastatin 3 from Cyanobacteria


Semiplenamides A-G, Fatty Acid Amides from a Papua New Guinea Collection of the Marine Cyanobacterium Lyngbya semiplena


Komodoquinone A, a Novel Neuritogenic Anthracycline, from Marine Streptomyces sp. KS3


Placidenes C-F, Novel -Pyrone Propionates from the Mediterranean Sacoglossan Placida dendritica


Plakortides M and N, Bioactive Polyketide Endoperoxides from the Caribbean Marine Sponge Plakortis halichondrioides.


New Polyhydroxy Sterols: Proteasome Inhibitors from a Marine Sponge Acanthodendrilla sp.
New Brominated Labdane Diterpenes from the Red Alga Laurencia obtusa


Briaexcavatolides S-V, Four New Briaranes from a Formosan Gorgonian Briareum excavatum


The Synthesis of SO-3, a Conopeptide with High Analgesic Activity Derived from Conus striatus


New Cembrane Diterpenes of the Marine Octocoral Eunicea tourniforti from the Eastern Caribbean


Isolation and Structure Determination of an Antimicrobial Ester from a Marine Sediment-Derived Bacterium


Identification of New Okadaic Acid Derivatives from Laboratory Cultures of Prorocentrum lima


One can imagine what twenty years worth of this type of research has produced. In the feature articles of the past two issues of a single journal, we see novel chemicals derived from sponges, soft corals, dinoflagellates, bacteria, algae, cyanobacteria and mollusks. These are, of course, in addition to those already known from these organisms. Some sponges, algae, and soft corals have been identified that produce in excess of 40 separate chemical compounds.


They are termed "secondary metabolites" because in many cases these compounds do not seem to have a function in basic metabolism. However, many are extremely bioactive, and have diverse effects on other organisms, including being lethal. Of course, the effects are largely unknown and many of these chemicals are not produced to have an effect on organisms that would not ordinarily be encountered by the producer of the compound. Other compounds may have an unintentional effect. Furthermore, various compounds may be very specific in the species they affect, and in how they affect those species. In almost all cases, pairwise tests of one species on another have not been done for any effects. There is little to no information as to what the ultimate fate or reactivity of these organics products might be in any environment, much less in aquaria. Finally, these bioactive compounds are highly concentrated in the closed small water volumes of our aquaria. For some examples of the scope of secondary metabolite chemistry from coral reef organisms, see the boxes below which I have derived from various primary and secondary literature over the years. The listings in the boxes are by no means exhaustive.


I hesitate to make such seemingly alarming statements, for I am concerned that such "unknowns" may become the fuel for more myths. It would be comparatively easy for such information to be used as an excuse on which to blame the death or failure to thrive of various tank inhabitants. However, the fact that virtually every inhabitant in our aquaria is producing variable amounts of novel, uncharacterized, and well-known bioactive secondary metabolites of mostly unknown effects, and may be reactive with a host of other largely unknown organic and inorganic compounds present in our tanks, makes our water a complex soup with no two tanks being alike - or predictable.


The take-home message of this myth is that it is practically not possible to say "my water tests fine." All we can do is recognize certain facts, and act accordingly. In my opinion and experience, the most pragmatic solution is dilution and absorption by the use of water changes, protein skimming, and activated carbon. I fully realize the many issues that might stem from this simple advice, especially in light of the materials provided by authors as mentioned above. However, if nothing else, it seems to potentially simplify the many potential chemical interactions that might be occurring.


Potential: Innocuous to lethal. I believe many inexplicable problems in the survival of aquarium species may be due to secondary metabolites. Some are well known to occur, others are purely speculative. However, there remains the incontrovertible fact that there are effects, and that every reef aquarium has organisms producing a pharmacopoeia of bioactive compounds.


Distribution: Ubiquitous. Every day, aquarists around the world use hobby test kits to measure the levels of perhaps 1-6 variables for which tests are available. There are no tests available for the 4-Amino-2,2-dimethyl-3-oxopentanoic acid unit in Majusculamide C, Dolastatin 12, Lyngbyastatin 1, and Lyngbyastatin 3 from Cyanobacteria that were discovered last month. For all we know, this unit causes 100% mortality in Trachyphyllia geoffroyi. Then again, it might not.

[Bilk]

Seems like also a good argument for running carbon if you are having problems getting growth. Absorbing the alleopathic chemicals might allow different species to coexist until one overpowers the others due to environment/location (scrubber being favorable growth environment)
This may have some validity. I just installed a carbon reactor and the growth of algae on the screen has developed exponentially from what it was prior. I will clean the screen tomorrow, which will be 11 days from the last cleaning and take pics. It's thick and green, which is very cool :)

[Garf]

Excellent, a bit of field evidence :)

[Bilk]

Excellent, a bit of field evidence :)

Not sure of that is in reply to my post, but this is the growth I got after the carbon reactor addition and raising the ph of the system with kalwasser.

http://i116.photobucket.com/albums/o34/bilk22/Reef%20Tank/Reef%20Tank/DSC00182.jpg


This was prior to those changes.

http://i116.photobucket.com/albums/o34/bilk22/Reef%20Tank/Reef%20Tank/31313atscleaning.jpg

Realize though, my system is very young. Only just cycled or still in a bit of it. * I'm awaiting delivery of new test kits as I noticed the Elos kits I have, expired a few months ago. Not sure how accurate the tests are at this point, so not sure on where the cycle is exactly. I realized this when the NH3 tests were giving very strange results. Colorimetric readings were odd. Color didn't relate to anything on the chart. The current tank inhabitants - half dozen crabs and lots of different species of snails, are all doing fine, so the NH3 is surely not an issue any more.

[Garf]

Seems as though running a bit of UV light on a screen could also destroy some of these toxic compounds;


Toxic Organics Combined with solar ultraviolet, ATS systems with high oxygen supersaturation break down entrained hydrocarbons. There is an extensive general research literature on this process, and a single ATS research study in the late 1990’s demonstrated that when combined with artificial ultraviolet, ATS systems have considerable capability of breaking down a variety of chlorinated hydrocarbons. Additional research is necessary in this area, as a single study, even with a considerable laboratory support, cannot provide the basis for systems engineering; however, it is likely that if ATS is carried out at very large scale to produce bioenergy, it will significantly reduce toxic hydrocarbons in aquatic environments and ultimately the ocean

http://www.physicsegypt.org/epc08/epc823.pdf