The Reef Tank banner
1 - 20 of 88 Posts

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #1 ·
"Until your stony corals are well-established, you may need to consider removing the macroalgae from the tank, and concentrate on building a biotope that does not have competition via allelopathic mechanisms against stony corals. "

This is a quote from you/Tom in a different thread. I didn't want to hijack the thread, so I posted my question here.

I have studied this subject the best I can. Being just a hobbyist, my resources are limited.:( I can not find evidence that shows allelopathic substances from caulerpa have a negative effect on stony corals. I can find a ton of speculation. Mostly from aquarium writers.

I have read about the effects of allelopathy between different species of algae. Which makes sense to me. Why caulerpa would evolve a means to do chemical battle with stony corals does not. Caulerpa doesn't compete with stony corals for real estate. It simply grows over it. In fact caulerpa utilizes stony corals to anchor themselves in one place. In many cases it doesn't matter if the coral is alive or dead. Allelopathy from encrusting algae, like coraline, having an effect on stony corals, especially encrusting corals, would make sense, but no one suggests removing coraline from the system.

I have been keeping caulerpa for over two decades. In that time I have witnessed the effects of allelopathy on stony corals, from different species of soft coral, and what I believe was allelophathy between different caulerpas. I have never witnessed symptoms in stony corals that I could contribute to allelopathy from caulerpa. I have seen stony corals doing very well while surrounded by caulerpa, both in captivity and the ocean.

I guess my question is, sense you have access to better information than I do, can you post a link that discusses the effects of allelopathy from caulerpa on stony corals? This is a subject I would really like to study further.

Thanks
Darrell
 

·
Premium Member
Joined
·
34,435 Posts
Tom posted an article many years ago that talked about this. i tried to hunt it down but could not. if Tom does not see this thread in the next day or so i will PM him to get his attention.

i am not exactly sure that it was exactly a toxin released on purpose by the algae. it think it had more to do with the way the caleurpa grew. it is very leaky and it may have been the "leaked" compounds that had a negative affect on nearby stony corals. it may very well have been phosphates.

this was many years ago, and i may be wrong, but i hope Tom will still have the link to the article.

G~
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #3 ·
Thanks Geoff

While we're at it, and since you brought it up.....:funny:

Can anyone come up with a link to a study showing that caulerpa is "very leaky". All life forms, that I know of, could be considered "leaky". Even us. To pick one and say that it is "very leaky" implies (at least to me) that it is somehow more leaky than other life forms. We know that caulerpa is leaky. (as is every other life form) I guess one could say that caulerpa leaks oxygen into the water. It also "leaks" substances that are toxic to other caulerpas. Just try keeping several different types of caulerpa all intertwined together. Eventually you will end up with one type, as the others die off.

If caulerpa becomes overly "leaky", it will die. This is what happens when it crashes or "goes sexual". It simply leaks its internal fluids all at once. In order to survive it MUST maintain its internal fluids. Because it is so imperative that caulerpa retain its internal fluids, it has evolved mechanisms to keep these fluids intact. http://www.springerlink.com/index/L4K5J486MNMT4701.pdf
A quote from the link above.
" New wall formation began at 2 hours following wounding and was complete by 48 hours after wounding."
When was the last time any of us completely healed from a wound in 48 hours?

Caulerpa doesn't simply store nutrients like phosphates. They are utilized for growth and reproduction. This is a resource that they NEED for their survival. Nature isn't wasteful. In the natural environment where nutrients are usually limited, an organism that leaks almost as much of a vital nutrient as it uptakes, would simply not survive.

More to come after work:thumbup:
 

·
Premium Member
Joined
·
34,435 Posts
any excess phosphates are "leaked" out. they do not use all of the phosphates they uptake.

i am really hating the search function on this site. i know where these articles you are looking for, but i just can not limit my searches enough to get them for you without spending an insane amount of hours reading through entire threads.

G~
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #6 ·
it is very leaky and it may have been the "leaked" compounds that had a negative affect on nearby stony corals. it may very well have been phosphates.
G~
If it were the phosphates, it could not have been the caulerpa that caused the problem. Caulerpa does not manufacture phosphates, so they can not add phosphates to the system. Caulerpa utilizes phosphates for growth and reproduction, so there will always be a reduction in dissolved phosphate levels where caulerpa is growing. Especially where the older caulerpa is harvested and removed from the system.

any excess phosphates are "leaked" out. they do not use all of the phosphates they uptake.
G~
No organism is 100% efficient that I know of, but they are darn close.

I don't understand where all this "excess phosphate" is coming from. The nutrients needed for growth in caulerpa, like phosphates, are concentrated in the young, growing areas of the algae. When nutrient levels are high, they simply branch off creating new, young, growing tips that demand more phosphate, and phosphate uptake is increased. Caulerpa doesn't simply say, " I've done enough growing so I'll just spit this excess phosphate back".

Caulerpa doesn't live forever. It does have a life span. While most of the phosphate will be concentrated in the younger growing areas of the algae, there will be some throughout. As caulerpa ages and dies, it breaks down releasing, "leaking" its contents into the water. (including some phosphate) This is one of the reasons people like myself harvest the older caulerpa, leaving some of the younger to continue growing, and uptaking more phosphate.

Even if a minuscule amount of phosphate manages to escape the healthy caulerpa, it becomes irrelevant, when we realize that caulerpa will always cause a net reduction of phosphate in a system where it is growing.

All algae are not created equal. There are many forms of algae and they all have evolved methods to take advantage of particular aspects of the environment they live in. It's hard to make blanket statements like "algae are very leaky". "Leaky" is relative. "Leaky" will change with the age and type of algae. It's growth rate and impact on nutrient levels will also vary greatly with age and type of algae. Even within the different types of caulerpa, there can be drastic differences.
 

·
Premium Member
Joined
·
34,435 Posts
as long as the algae is harvested on time, then i could see there being a reduction in phosphates, but only after the harvesting. until that point the phosphates are still in the system. this is purely clarification.

i will PM/call Tom and get him in here, the article he posted explain a lot, actually let me see if Spanky posted the articles, one of them did. off to search hell. :(

G~
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #9 ·
as long as the algae is harvested on time, then i could see there being a reduction in phosphates, but only after the harvesting. until that point the phosphates are still in the system. this is purely clarification.

i will PM/call Tom and get him in here, the article he posted explain a lot, actually let me see if Spanky posted the articles, one of them did. off to search hell. :(

G~
:lol: You're right. Even a phosban reactor, or any of the phosphate medias, doesn't remove phosphates from the system. I should have worded it a little differently. How's this?

Phosphate concentrations in the water, where our pets live, will always be reduced when caulerpa is growing in the same water.
 

·
Premium Member
Joined
·
34,435 Posts
:lol: You're right. Even a phosban reactor, or any of the phosphate medias, doesn't remove phosphates from the system. I should have worded it a little differently. How's this?

Phosphate concentrations in the water, where our pets live, will always be reduced when caulerpa is growing in the same water.
that is only assuming the Caulerpa is getting the phosphates from the water column, instead of the substrate it is attached to. with Graciallara that can be free floating than it is probably getting the phosphates from the water, though in the areas these algae are generally kept the lower water flow allows the detritus to settle in these areas and rot then releasing the nutrients into the water column to be used by the algae.

just babbling that makes sense. :)

G~
 

·
Premium Member
Joined
·
8,278 Posts
that is only assuming the Caulerpa is getting the phosphates from the water column, instead of the substrate it is attached to. with Graciallara that can be free floating than it is probably getting the phosphates from the water, though in the areas these algae are generally kept the lower water flow allows the detritus to settle in these areas and rot then releasing the nutrients into the water column to be used by the algae.

just babbling that makes sense. :)

G~
That makes me wonder if a a rooted plant... maybe a mangrove could unbind a PO4 from a DSB that was full? I doubt most of us would want to let our tanks be periodically overtaken by any plant but it makes me wonder......
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #12 ·
that is only assuming the Caulerpa is getting the phosphates from the water column, instead of the substrate it is attached to. with Graciallara that can be free floating than it is probably getting the phosphates from the water, though in the areas these algae are generally kept the lower water flow allows the detritus to settle in these areas and rot then releasing the nutrients into the water column to be used by the algae.

just babbling that makes sense. :)

G~
For the longest time, it was believed that caulerpa pulled all its nutrients (other that photosynthesis products) from the water collumn. I have read one study that showed caulerpa could uptake at least some nutrients through its holdfasts. That study left me with questions. What percentage of the nutrients absorbed by an anchored strand of caulerpa can be contributed to the holdfasts?

Caulerpa doesn't break down detritus or liberate bound phosphate form calcium carbonate. It uptakes dissolved phosphate from the water it is in. In a well maintained aquarium, any phosphate the caulerpa can utilize would find its way into the open water column, regardless of where it got the phosphate from.
 

·
Premium Member
Joined
·
34,435 Posts
i agree, i must have been unclear. sorry. i was trying to say that the Caleurpa will be getting the nutrients from the water column, but just above where the detritus was collecting. as in as the detritus rots, the released nutrients are eagerly grabbed by the Caleurpa. the slower flow and the Caleurpa growth creates even slower flow which trap more detritus causing more nutrients to gather, and so on. i was wondering if the rhizomes of the Caleurpa were capable of nutrient uptake or not.

Jenglish- i would suspect that Mangroves or sea grasses would be able to uptake the phosphates in much the same way the Caleurpa does only with a root system they are able to get to the phosphate reserves deep in the substrate.

G~
 

·
Perfeshunal Hikk
Joined
·
8,887 Posts
Jenglish- i would suspect that Mangroves or sea grasses would be able to uptake the phosphates in much the same way the Caleurpa does only with a root system they are able to get to the phosphate reserves deep in the substrate.
If they can pull phosphates out of the depths of the sandbed, wouldn't that solve the issue of ever having a phosphate loaded sandbed if you keep some mangroves growing in it? I know you can't plant the entire system with it but phosphates wick across the sand so that if mangroves grew at the back of the tank and were removing phosphates from the back of the sand bed, the phosphates would tend to wick to the back - to be removed by the mangroves - by wanting to go to equilibrium.

Psst, you can't agree with me because that would mean DSB'es aren't doomed to crash :thumbup:
 

·
Premium Member
Joined
·
34,435 Posts
the problem is that the phosphates removed by the mangrove or the sea grass is so localized that it can not keep up with the amount of phosphates that the sand bed itself is able to absorb. the root systems for mangroves in the size that we are able to keep in our tanks is very small, they would only be able to remove phosphates very close the fine root structures. mangroves are very slow growing plants so the amount of phosphates they uptake is very small. this is why when people recommend using mangroves they say to put as many as you possibly can in their separate mangrove tank.

sea grasses on the other hand could have a better chance of doing what you say, but they are not very tank friendly and would make a very nice biotope display, but they will not work in a display that you would also want to keep corals and LR in.

the amount of food that we put into our systems is way more than a mangrove could uptake in a day. the rest of the food would still have a chance to settle and load up the sand bed in other areas.

sand beds are doomed. they are just like any other filter. they will need to be cleaned out every so often and restarted anew. sand beds are great phosphates sinks, as long as we use them for what they are and not try and pretend they are some magic area that makes matter/phosphates disappear forever.

not sure why Tom did not reply in this thread EC. my guess is that he is hunting references and soon we will be hit with an onslaught of HOMEWORK!!

G~
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #16 · (Edited)
i agree, i must have been unclear. sorry. i was trying to say that the Caleurpa will be getting the nutrients from the water column, but just above where the detritus was collecting. as in as the detritus rots, the released nutrients are eagerly grabbed by the Caleurpa. What detritus? the slower flow Who said anything about slower flow? and the Caleurpa growth creates even slower flow which trap more detritus causing more nutrients to gather, and so on. That's poor maintenance. Not a problem caused by caulerpa. Everything we place in the system restricts flow. It's part of good husbandry to design the system to deal with these issues. i was wondering if the rhizomes of the Caleurpa were capable of nutrient uptake or not.
G~
I understand that you are against the use of algae in any form to reduce nutrients in our systems, but now you are just getting back to the lack of basic husbandry and blaming the problems on caulerpa.

In our systems, where adequate flow is provided, the concentration of nutrients will be about equal throughout the water column. Caulerpa doesn't cause detritus unless you allow large quantities to die and rot in the system. (very poor husbandry) Caulerpa doesn't thrive in stagnant water. Your description sounds more like a settling tank than one designed to keep caulerpa. Any system where detritus is permitted to accumulate (even in LR and sand) is an example of a poorly maintained system, IMHO. It has nothing to do with caulerpa producing toxins, Leaking substances, or uptaking nutrients.

sand beds are doomed. they are just like any other filter. they will need to be cleaned out every so often and restarted anew. sand beds are great phosphates sinks, as long as we use them for what they are and not try and pretend they are some magic area that makes matter/phosphates disappear forever.
Again, I understand that you are totally against the use of sand beds. They are NOT "doomed", however. We have had several threads on this topic. ALL of the "evidence" or negative issues with sand beds presented, has been based on the assumption that detritus is permitted to accumulate to problem causing levels within the sand. There has not been a shred of evidence presented that would suggest that a clean sand bed is "doomed".

not sure why Tom did not reply in this thread EC. my guess is that he is hunting references and soon we will be hit with an onslaught of HOMEWORK!!

G~
I hope you are right. I have exhausted all of my resources, and can't find any evidence suggesting that caulerpa produces substances that are toxic to stony corals.
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #17 ·
While researching these issues, I came across this.
http://joi.jlc.jst.go.jp/JST.JSTAGE/cl/2005.1272?from=Google

Just as I suggested in my first post. It seems that coraline algae HAS evolved toxins to do battle with stony corals. I can understand this. They are in competition for the same realestate.
Caulerpa produces substances that are toxic to at least some fish when ingested. I can understand this. Caulerpa doesn't want to be eaten.
Caulerpa produces substances that may be toxic to other algae. Again, I can understand this.
I don't understand why caulerpa would produce substances that are toxic to stony corals. Some substances produced by organisms, to be toxic to a target organism, may also effect organisms that aren't the original target. Jelly fish venom and humans, for example. However, we can not make the leap that substances produced by caulerpa are toxic to stony corals simply because they may be toxic to their target organism.
 

·
Premium Member
Joined
·
34,435 Posts
i am not sure that it is a Toxin, as much as a growth inhibitor. i remember something "leaking" from the algae that interferes with the production of CO2 in the coral itself. i want to say phosphates, but without any references i can find, i am only so-so on my memory of this, and the fact that it seems every problem in our systems are caused by phosphates, so i am just playing the percentage game. :D

i was trying to say that anything you put in a water column will slow down the flow allowing more contact time and allowing a greater chance for anything in suspension to fall out of the water column. all of this will help the algae get nutrients, which is what it wants and what you are wanting it to do. sorry, i did not mean to imply that algae causes detritus. the detritus is in the water column. the algae just allows some of the detritus to fall out of suspension around it since it does slow the water column, even just a little.

a sand bed made of silica would not be "doomed" and need to be replaced. you can rinse/siphon it out and completely start over every now and then. it is inert to phosphates except for those bound by the bacteria living on the grains. this is different than calcium carbonate based sand. if there are phosphates at all in the water column then the calcium carbonate can uptake it. the detritus does not have to be sitting on the sand in order for this to occur, though resting detritus will max out the absorption ability of the sand bed in a hurry. at the very best it might be able to push them further down into the sand bed. which is basically what happens in nature. if you clean the sand bed very regularly you absolutely can increase the time it is viable. i do not have a problem with that at all. it actually binds phosphates you can siphon/rinse all you want, but it is unable to release the bound phosphates.

G~
 

·
Premium Member
Joined
·
17,355 Posts
Sorry to be such a slacker, I have a big project that is coming due on Monday that I have been researching for the school, so until that is finished; I probably will not be spending a lot of time on TRT... :(

Most of the info you folks are looking for can be found in one of three textbooks, I doubt there will be articles posted on the Internet that have relevance to this discussion in a broad sense (kind of like the basics for Phycology) and most of this research falls into proprietary realms:

Seaweed Ecology and Physiology , Christopher S. Lobban and Paul J Harrison; Cambridge University Press, 1997.

Algae, Linda E. Graham and Lee W. Wilcox; Prentice Hall, Upper Saddle River, NJ, 2000.

Algae: An Introduction to Phycology, C. Van Den Hoek, D. G. Mann, and H. M. Jahns; Cambridge University Press, 1995.

Seaweed ecology research has been mostly characterized by the development of a large body of theory and mathematical modeling centering around two main topics: trophic dynamics of the aquatic environment and competition theory. The origin of competition theory can be traced back to the 1934 work of G.F. Gause, "The Struggle for Existence": Williams and Wilkins (Dover Ed, 1971), Dover Publications, Minneola, NT, and is based totally on lab work involving the study of growth dynamics of bacterial colonies, still applicable to this day. His work led to the development of the competitive exclusion principle and the niche theory of population density changes in shared environments.

Graham and Wilcox said:
The basic idea is that biological interactions--not physical and chemical external factors--are paramount in community dynamics. Species are assumed to exist (at) close to their maximum density in the environment and to compete for scarce resources. If two species occupy the same niche, one must inevitably drive the other out through competitive displacement.
Algae and many photoautotrophic corals DO occupy the same niche in lagoonal biotopes in that physical space for light-gathering mechanisms is difficult to acquire and the competition for such space is quite intense. This competition extends to their mechanisms to gather inorganic sources of carbon (and in the Ocean, often nitrate and phosphate as well). However, If we assume that speciation is such that populations in a single milliliter of ocean water for phytoplankton are near their maximum density for the nutrients available, and the competitive exclusion theory is correct and in effect, then how can 50 to 100 species of phytoplankton coexist in that milliliter of water? This apparent paradox drives much of the experimental and theoretical research to this day, shaping the aquatic management practices of both fresh and marine preserves at this point in time.

I see many misconceptions being posted in the discussion so far, but I have got to finish this project, so I might be away for a few days (otherwise I'll end up joining the fray... :rolleyes: ) Keep in mind that the rules also change when moving from the study of one biotope to another, as the rules that might apply in a rocky intertidal seaweed community will definitely not apply when we discuss the algal ridge of a reef top stony coral community, even for the same species.

Geoff, can you refresh my memory more concerning what topic we were discussing when I posted the article? PM me if you'd like or give me a buzz, or I'll be at UNC Chapel Hill the weekend of April 24-26, and we can discuss it over a dark beer.
 

·
Premium Member
Joined
·
7,375 Posts
Discussion Starter · #20 ·
Thanks VERY much for taking the time to reply, Tom.

I just E-mailed Linda Graham. It may be wishful thinking that she may actually respond, but you never know. How cool would that be if she actually did?:thumbup:
 
1 - 20 of 88 Posts
Top