Caulerpa Toxicity in perspective

[NaH2O]

jlehigh - no apologies necessary! We are all trying to learn something on this thread. I don't know if my post contributed much for the discussion, but I wanted to make a few points that came in my head. Quite possible I'm wrong, quite possible I don't make sense, and it is quite possible no one cares.

 

[cwcross]

Urchin larvae study!! Everybody run! (Had to add that, Mike )

Yea, ha ha..!! I'm glad you brought that up. I let him go on that one . I can't believe Mike is using urchin studies to back up his arguments. That's a good one...LOL.

I'll get to your posts, Nikki and Mike, later today. I largely agree with what you are saying. That is what I meant by "what experts?". This is one problem with this hobby. Much speculation and little study. That is the nature of the beast though. However, a healthy discussion never hurts.

Sincerely...Collin

 

[cwcross]

I think this thread is great for the mere point of getting people to search, read, and try to understand. For many hobbyists, myself included, trying to find studies (and for some interpretting them) can prove to be quite a task. Some people may not know where to look, know if the study is good, or if the study was put out by a reliable source. You posed a list of questions early in the thread, and question one: What Experts? I feel this needs definition, as in this hobby there are many "Experts", but what type of credentials does one need to be considered an expert? Someone that has kept successful and beautiful reef tanks for 20+ years, or someone with Ph.D. after their name....perhaps both. I have read one article put out by a so-called "expert" (so named by hobbyists, I guess) that I had a good laugh at. Do we, as aquarists, have a published peer reviewed scientific journal specific to closed systems? I can't think of any, but there may be one or more for that matter. For me, I have to go on studies available on the web, and try to imagine what effect it would have on a closed environment.

Experts are Experts. It does not matter how much education one has. Give me a 20 year veteran over a green Ph.D. any day. However, Ph.D's, if nothing else, have been trained in two things. How to find and read literature and educate themselves quickly. And two, how to use a theoretical framework but build new thoughts on. A Ph.D. with 20 years experience in an industry is likely a good expert if worth his salt.

All I have access to is the web. I do not have a library stocked with the correct journals to search this topic. Mostly I can find only abstracts. However, they are out there. Problem is that scientific articles are filled with Jargon. Many people are not familiar with the language and so reading such an paper loses thier interest quickly. Also, it is often difficult to discern nuances of the methodolgy used and how it is relevant. This frequently leads to mis-interpretation by lay audiences. Most people have heard the phrase "enough information to be dangerous". It is easy to take things out of context if not careful in a technical paper.

Believe it or not, often (but not always) 20 year veterans can be poor sources of innovation or acceptance of new ways or things they are not familiar with. Being in an industry too long lead to "inbreeding". People can literally get so comfortable in a position that they lost the fire to forge ahead. These people can great consultants for past events or history, but frequently poor at inducing or embracing change. This is a pitfall of experience I believe we should all try to overcome.

I see this point, and although it is hard to apply to the issue at hand, it did bring up a thought for me. I have an allergy to a specific medication. The concentration doesn't matter....I simply can't have any medications that contain the allergen.

Toxicity can take many forms. The nature of the effect depends upon many variables. This is why I am challenging this topic (plus I like to play the devils advocate sometimes ). In the case of certain neurotoxins, a toxin can cause what is called a "cascade reaction". This means that a single molecule can start a chain of events leading to many-many more problem molecules. Imagine a single molecule catalyzing 20 more different molecules which each them catalyze 20 more molecules. In this case, you get a geometrical form of amplification to the original foreign molecule. Extreme allergies also can fall into the category, where the toxin starts a cascade of hormones that basically cause the body to run wild. The adrenaline response also uses cascade reactions to get an extreme response in very little time, although this is not caused by a toxin.

A second form would be long term buildup. In this case, the offending species must reach a "critical dosage" before harm is done. This is the most complicated case because it depends upon the rate the toxin is introduced to the organism compared to the rate of elimination through either oil or water solubility in the tissues and thier excretion coupled with metabolic degredation. If something is eliminated quickly and introduced slowly, you will never reach a toxic dose, even if the material is itself toxic. The other extreme of that is if it is eliminated very slowly and introduced rapidly. In this case it will build up to a toxic level very quickly. Intermediate cases are more complicated, expecially in a random environment, such as an aquarium, where a toxin can be periodically introduced at varying levels, but elimination via metabolism or excretion is relatively constant.

Then there is hypersensitivity. In this case, when first introduced to a toxin, organisms are very immune and even un-affected. Then though over time with continuous exposure, the sensitivity to the toxin grows greater and greater. At some point then even a miniscule amount can have drastic effects. Latex gloves as worn by nurses and such are frequently cause of "hypersensitization".


The point of all this is that toxicity is a complicated subject. One animals toxin is another animals food source. It is not appropriate to make an inductive leap that because mullusks, crustacea and polycheates are affected by a toxin that a coral will be. The two organisms have completely different physiology and internal defense strategies. Every organism has defense stratgies. Immune systems, nucleases to scavange foreign DNA/RNA nuclear material, elimination etc. An example is simple bug spray...raid for instance. The active ingredients in these formulations are powerful neurotoxins to insects. However, they have absolution no effect on mammals. You can spray some right in your mouth if you want. I don't suggest it. You will get sick, but not from neurotoxicity. I think it is the mongoose that is immune from cobra venom for the most part? Or maybe I am getting confused. Point is that just because one thing is toxic to one family does not mean it is toxic to another. This is a simple fact and not subject to debate.

Are corals affected by herbivore toxins? I still haven't seen anything to convince me of that. Stunted growth is a very subjective terminology. How is this determined? Compared to what? How do you get a control sample? Corals grow pretty slowly. How long did these measurements take? Even if growth was stunded, could anything else have caused it, like shade or CO2 depletion, oxygen saturation etc. Do you want to let Caulerpa grow next to your corals or take over your main tank? No. Surely not! Are they poisoning something? That is another story.

So, does it matter to the SPS the concentration of toxin? Perhaps being continuosly bombarded with a low concentration of toxin is enough to hinder their growth or coloration. Maybe the friend you pointed out would see an increase in SPS growth and coloration if the algae was removed from the system? Maybe not. A lot of variables. I could be way off base, and if so, I hope someone corrects me.

No, I think these are valid questions. The answer is one of relativity. First, his corals and reefs look great. First class tanks. One is a 300 gallon custom cube that sits in this really rich guys bedroom floor. You can walk all the way around it. It is filled with SPS. It runs on ecosystem and has C. prolifera in it and has had for a long time. He has another about 40 gallon cube in his daughters bedroom that has both softies and sps under T5's at the top. You can nearly see them growing.

If one is happy with color and growth rates, does it really matter if it grows faster or could have a little more color? Personally, I have a few corals I wish would slow down some. My colt coral and frogspawn for instance. They are both outgrowing my tank right now and I'm going to have to split them up and get rid of most of it in the near future. I can't image the caulerpa is slowing them down any. Maybe I need more of it, or to plant some right by them .

I will get to Mikes post tomorrow. I'm getting tired.

Urchin larvae study!! Everybody run! (Had to add that, Mike )

Ha Ha...I love it!

 

[wrightme43]

I have been following and enjoying this post. Some (well more than that) is over my head. LOL. I am enjoying it though. Here is one thing I know, if you take grape calupera and let it sit in a collection cup overnight with only the water that came off of it, and smell it in the morning. It will make you dizzy and light headed and kind of sick feeling. Well maybe not you but it sure did me. Is that the toxins? Or just my imagination? Here is a photo of a tank that uses calupera, grape and racemoesa its in a 55 gal refugium attached to the sump.

 

[wrightme43]

The corals seem to grow very well. Hope this helps. Steve

 

[FishyinKy]

Okay okay I just had to stick my two cents in. Mike, you made a point earlier about how there are no caulerpas on a reef. BUT there are grasses and caulerpas on lagoons. My point is pretty simple and one that I think most people are missing. The ocean is made up of all its parts. When we do a tank we are trying to stimulate a part of the ocean. I think as we become more sophisticated we try to add more parts to this "simulation". I personally think that's why refugiums work so well, because they are another "part" to the system. (And yes Mike I know you might disagree about refugiums working so well lol).
I'm lovin this thread, and for the record Mike I think when these threads go over peoples heads it just stimulates them to get busy learning.

 

[NaH2O]

When we do a tank we are trying to stimulate a part of the ocean. I think as we become more sophisticated we try to add more parts to this "simulation".

Trying to simulate a biotope is fine, IMO. When you start adding things like caulerpas to a SPS closed system reef, you are not simulating that particular biotope. You indicated in your post that caulerpas and sea grasses are present in lagoons.....so, simulate that biotope with corals that grow in the lagoon. Adding more parts isn't always good.....as it adds to Mike's house of cards scenario.

 

[FishyinKy]

I agree to a point Nikki, its just that each biotope is a part of the whole. I'm not advocating growing the grasses within the tank but instead its the idea of a separate refugium that like a lagoon feeds the other parts of the ocean. Hey its just a thought.

 

[NaH2O]

its just that each biotope is a part of the whole.

I don't agree.....IMO, each tank is the whole biotope. Trying to mix biotopes in the same tank is rough....again, IMO.

 

[mojoreef]

Hiya Mac

Okay okay I just had to stick my two cents in. Mike, you made a point earlier about how there are no caulerpas on a reef. BUT there are grasses and caulerpas on lagoons. My point is pretty simple and one that I think most people are missing.The ocean is made up of all its parts. When we do a tank we are trying to stimulate a part of the ocean.

Sure in the wild we a reef, and a few hundred miles away a huge lagoon and a few hundred miles from that some beaches. The only thing you cant simulate is the billions of gallons of water inbetween them and around them.

I think as we become more sophisticated we try to add more parts to this "simulation".

See I look at that as a step backwards. What you end up doing is building a house of cards in which when one card falls it brings down the next and so on and so on.

Their is nothing wrong with running a refugium if you so decide. People that run high nutrient tanks (dsb/no skimmer :eek2: ) have no choice when tyring to reduce nutrients. What I am saying is that when you design one and want to use some form of vegetation that you match it up with the type of corals you are keeping. If you are keeping softies/gorgs/and some kinds of LPS you have a much broader range of vegetation that you can choose from safely. If you are keeping more delicate corals such as sps you can still do it, but it would be wise and safe to choose a less toxic form of vegetation.
Now if you want to do it the opposite go for it!! I am not here to tell folks how to run Their tanks, just make suggestions and share what I have learned over the years.

Mike

 

[mojoreef]

Yea, ha ha..!! I'm glad you brought that up. I let him go on that one . I can't believe Mike is using urchin studies to back up his arguments. That's a good one...LOL.

It was hard Collin it was hard. At least these ones were done properly and not in some ones garage after a night with his little friend

 

[cwcross]

I have been following and enjoying this post. Some (well more than that) is over my head. LOL. I am enjoying it though. Here is one thing I know, if you take grape calupera and let it sit in a collection cup overnight with only the water that came off of it, and smell it in the morning. It will make you dizzy and light headed and kind of sick feeling. Well maybe not you but it sure did me. Is that the toxins? Or just my imagination? Here is a photo of a tank that uses calupera, grape and racemoesa its in a 55 gal refugium attached to the sump.

Wow, I like that tank!

Well the dizziness could be you are just sniffing to hard and hyperventilating...just kidding.

I guess it would depend upon how volatile the toxins are. If they can evaporate, you might get some. However, if this was the case then they really wouldn't last long in water. Who knows. I've never heard of it or tried it...Collin

 

[cwcross]

Okay okay I just had to stick my two cents in. Mike, you made a point earlier about how there are no caulerpas on a reef. BUT there are grasses and caulerpas on lagoons. My point is pretty simple and one that I think most people are missing. The ocean is made up of all its parts. When we do a tank we are trying to stimulate a part of the ocean. I think as we become more sophisticated we try to add more parts to this "simulation". I personally think that's why refugiums work so well, because they are another "part" to the system. (And yes Mike I know you might disagree about refugiums working so well lol).
I'm lovin this thread, and for the record Mike I think when these threads go over peoples heads it just stimulates them to get busy learning.

I agree with you wholeheartedly. My system seems to work very well. Also, it is chock full of swarms of pods and stuff I don't even know what it is. Also, a lot of stuff grows right on the caulerpa leaves. All of it lives under the leaves. It can't be too poison for sure...C

 

[cwcross]

Trying to simulate a biotope is fine, IMO. When you start adding things like caulerpas to a SPS closed system reef, you are not simulating that particular biotope. You indicated in your post that caulerpas and sea grasses are present in lagoons.....so, simulate that biotope with corals that grow in the lagoon. Adding more parts isn't always good.....as it adds to Mike's house of cards scenario.

There have been numerous studies showing how lagoons near reefs, coupled with tidal and wave action help to process nutrients from the reef.

Here is an excerpt from a review, illustrating the point:

The description of nutrient flow (flux) over a coral reef is complex and not entirely known. However, a brief description is necessary. In the simplest scenario, upwellings and currents bring plankton rich water across a coral reef. There, the incredible array of life strips the water of its "food." Much of the energy from this food is recycled and conserved within the reef habitat though the food chain within the reef community. The primary production of food by sunlight, creating and sustaining plants and algae which are in turn eaten by progressively higher consumers, is not considered here. As waves and currents wash over the reef, waste, mucus, sediment, and particulate organic matter (detritus) is carried across the reef and deposited into near shore communties. These communities depend to some degree on the organic input of the coral reef community to fuel their own growth and productivity. To some degree, like the reef, they are self sufficient. Nonetheless, the flow of nutrients does foster and influence these adjacent communties (Hansen1987, Johnstone, 1990 et. al.).

Bottom sediments and their accompanying flora and fauna are among the most important ways of recycling organic reef material (Sorokin 1981). The coral reef and its adjacent communties are very effective in absorbing nutrients and recycling them within the community, preventing loss of such energy sources back to the ocean, and therefore allowing the vast complex web of species to exist (Crossland, Barnes 1983). They are largely dependent upon each other. Kinsey (1985) states that, "gross production and calcification in coral reefs are, nevertheless, clearly dominated by benthic processes..." To further illustrate their importance, Ogden (1988) states, "Mangrove and seagrass systems are sinks, trapping and accumulating organic and inorganic material and permitting the growth of coral reefs offshore (while) coral reefs buffer the physical influence of the ocean and permit the development...of lagoon and sedimentary environments suitable for mangroves and seagrasses."

Even if the system is not realistic, I don't think it matters to me.

 

[mojoreef]

Bottom sediments and their accompanying flora and fauna are among the most important ways of recycling organic reef material (Sorokin 1981).

Ahhh here ya go.. the key is in this statement "Reef Material" !!!! thats the source.

As waves and currents wash over the reef, waste, mucus, sediment, and particulate organic matter (detritus) is carried across the reef and deposited into near shore communties

Ahhh old thoughts.. you need to look at some more new ones. Same waves pull the same material off the reef and deposit it in abyasal (or simular) you can see this on almost every deep dive off shore of a reef...its like a white out.

These communities depend to some degree on the organic input of the coral reef community to fuel their own growth and productivity

yep they are relient on it for sure and must be feed just as much as you would feed your fish. they are a bioload and organism unto themselfs. Great for folks that wish to try to recreate this type of system in thier home. My interest however dweel more to the keeping of corals and such.

To some degree, like the reef, they are self sufficient. Nonetheless, the flow of nutrients does foster and influence these adjacent communties (Hansen1987, Johnstone, 1990 et. al.).

Yep again the reef sure does foster life in adjacent communities

Kinsey (1985) states that, "gross production and calcification in coral reefs are, nevertheless, clearly dominated by benthic processes..."

that one I would like to have clearified. No wonder they pulled his permit and wont allow him to operate in florida anymore

Ogden (1988) states, "Mangrove and seagrass systems are sinks, trapping and accumulating organic and inorganic material and permitting the growth of coral reefs offshore (while) coral reefs buffer the physical influence of the ocean and permit the development...of lagoon and sedimentary environments suitable for mangroves and seagrasses."

Ogden did most of his work in Florida Bay. What he is talking about is that the mangrove swamps and sea grass fields have the everglades plugged, and with that decades of pollutants and nutrients that are stored with in it. If you disturb that sink/blockade you can kiss all life (ecept for algae) good by.


Hey Collin thier is a great old reefer in your neck of the woods. Her name is Sue Truet (awesome reef). She had a MM refugium set up by your maintenance company friend. You should shoot her an email. Just a side note thing..no biggie and off topic.

Hey do you have any pics of your reef my friend?? I would love to see it.


Mike

 

[NaH2O]

Here is a post by Sue (I'm not trying to get this anymore off topic), but I thought it may help, at least to get in touch with her, if you are interested, Collin: SueT - Single Post, Filtration Concept

 

[cwcross]

Collin you are comparing Racemose with the most toxic form of Caulerpa out their, so the 80X looks pretty good, but perhaps we should just look at the amount released by the caulerpas we are talking about.

Yes, exactly. Many studies have been done on the amount of toxin contained by C. taxifolia and then studies were done to ascertain how toxic the CYN isolated from the taxifolia extract is. Racemose has 80x less CYN than taxifolia and Prolifera even less than that. By doing this we can, to at least some degree extrapolate the relative toxicity by comparison. It would be expected to be about 80 times less.

On the studies they were not all related to organisms that were eating the caulerpa. various forms of larva and planktonic life forms has nothing to do with eating, just general vicinity. The toxin is definalty released as a defensive measure, but the breaking of the plant is not required, it leaches all on its own. Remember caulerpas are competitors and very aggressive at doing so.

Yes, the toxin is released from the leaves even without being broken. However, some of the studies you referenced to me showed that the toxin concentration is at a maximum (called 100%) at the very border of the leaf. The concentration then falls off rapidly such that within a very short distance, it falls to zero. The CYN toxin is very shortlived in seawater. Kinetic studies were performed to understand it breakdown. The rate study showed nearly perfect 1st order kinetic laws. From this we can understand how long it takes the toxin to degrade by being exposed to naked sea water.

So. Here is a few graphs to illustrate, taken from some of the references you quoted:

So, lets do some back of the envelope calculations. C. Taxifolia has, at max at the height of its toxin in Autum I believe, 2% by dry weight CYN. Lets assume that a regufium has about 1 oz or 1/16 of a lb of prolifica in it. Lets also assume a 100 gallon aquarium with seawater at 8 lbs/gallon. So, if the taxifolia released ALL of its toxin instantaneously the concentration in the water would be:

(1/16)*0.02/(100*8)= 0.0625/800=0.000078 = 1.6 ppm

Now Racemosa has 80x less so this would equate to about:

0.02 ppm or 20 ppb of CYN if all was Racemose CYN was released instantaneously into a 100 gallon tank.

Now lets refer to the chart above. Growth rates do not become negative until being soaked for 2 weeks at 250 ug/ml which is 250 ppm. At 0.02 ppm, we are right next to the control. Thus we are far from the rate at which growth rates are affected significantly. Now, that being said the caulerpas so have other toxins other than CYN, so lets multiply by 100 just to be safe. Even then we are at only 2 ppm. I think this is very conservative, or in other words...overkill.

So the next argument is probably, but we are in a closed system so it will buildup over time and get higher? Let's address that. To re-interate, even if everything was released instantaneously (which is far from correct) we are nowhere near toxic levels. However, lets even assume that something like 1% of this amount is released on some continuous basis.

Now, another set of charts:

please look at the upper left hand chart. This is a chart of the time decay of the toxin in seawater that I refered to earlier that exhibits nearly perfect 1st order kinetics. From this chart we can see that a given concentration of CYN will degrade to effectively zero within 24 hours. From these two sets of data, I could actually calculate the equilibrium steady state concentration of CYN in the aquarium. I have done such pharmokinetic calculations many times in my career. Such calculations are beyond the scope of this discussion, however, suffice it to say that the equilibrium concentration will not come close to exceeding that of an instantaneous release of all the toxins at once. It will be more like 5% of that number of ballpark around 0.1 ppm which is 100 ppb...very very low.

Thus it can be seen that prolifera or racemosa will not provide enough toxin into the tank to stunt growth at steady state or even the instantaneous release of all toxin. Now if a caulerpa continually brushes up on a coral, I might buy that it is somewhat affected (but I'll barely buy that).

So, I have done what you suggested. Roughly quantified the amount of CYN capable of being introduced, in a worst case scenario, into at reef tank and compared it to published toxicology information.

Now, I am even more convinced that my theoretical rambling is in the ballpark.

Also just some trivia, vitamin A is necessary for us to live. However, at too high of a dose it is toxic. This shows that at low levels, some "toxins" can either be beneficial or a non-event.

Similarly, qur drinking water if full of "toxins" however, the EPA regulates the amounts that can be present such that our metabolisms can handle them without problem. I find it hard to believe that low levels of CYN can really be a problem. Like I said. My Prolifera is FULL of life. Stuff even grows right on the fronds themselves.

Nope not really, its more to do with enviromental conditions. Every critter from corals to algae with thrive if the conditions are correct. So if you have a pristine reef with low nutrients and thriving corals that is all of a sudden subjected to a nutrient load the enviroment has been skewed and now it is more to the liking of algaes.

again, a chicken and egg. If the corals get nutrient loaded water for a long enough time, they are sick anyway. At that point the algea will invade. However, they are likely already in decline. However, I agree. Caulerpa does not belong next to corals in a mini-reef or real reef.

I would say the most common was nutrient fluxes. High original fluxes allowed for excellerated growth and over population. Once the food source was greatly deprecated the caulerpa crashed. Second most common was lighting. Not so much the 24/7 as much as the caulerpa that was under the canopy of caulerpa crashed. there are a lot of reasons, some more common then others

OK, why were the nutrient fluxes so high for a long enough time to let the caulerpa overgrow to such an extent without being pruned? This sounds like poor husbandry. We have to understand the needs of the organisms in the tank. If we don't feed our fish for a month, they will probably die also and poision the tank.

Absolutely!! but the caulerpa crash was but one more in the house of cards that multiplied the severeness of the crash. Kinda like a tank with a DSB, If you build a system like it was a house of cards, it tends to have harder crashes and less chance of surviving events. Thats where a good skimmer can save your tank.

I don't buy the house of cards argument. If a tank crashes it crashes. Who can say it would survive with or without the algea. How can we make this conculsion?

mute point, although 24/7 lighting seems to be the safest bet, coupled with constant harvesting.

I agree completely.

In the case of an event it was just more fuel to the fire. In the case of close proximity it was stunted growth, not really any damage up to the point where the coral just bleached out.

So this doesn't sound so severe really.

Mostly racemose, feather was another big one.

Racmose, as you pointed out, is nearly as aggressive as taxifolia from a growth rate perspective and has a much larger tendency for going sexual than prolifera.

Agreed for sure. When a person is selecting an algae to use as an export medium they should take alot of things into consideration. Amount exported, toxicity, potentcal for going sexual and so on. If they are just looking for a pure bulk remover I would suggest cyanobacter as it uptakes 500x more then your best caulerpa, hairs is also better, xynia is way up their to. Oh and I wouldn't keep a cucumber either, just got to much invested in the tank and my luck really sucks.

Again it becomes a why bother when their are better alternatives???

I'm just not convinced prolifera is a bad alternative. Maybe racemosa or some others are a little worse but still not an avalanche.

It shows that toxins are released with out any damage being done to the caulerpa.

Yes this is considered a fact.

ok try this one Lemée et al., 1997. heres a quote


all these studies were on the toxins that are shared amongst most all caulerpas

I don't think any of it is an exageration. Its just the other side of a particular method. One can still use caulerpas as a great nutrient absorber all we are saying is that their is a risk or a possibility that it may hurt your inhabitants. The choice is always the individuals. The risk goes up when the tank is full of more delicate species such as sps (who's defence against these toxins are not thier) and the risk lowers when the tanks is full os softies and lps that have a greater defence mechanism against simular chemicals thats all.
Cheato is a far better choice, so is Ulva (pods love nest).

take care


Mike

I just don't see that the caulerpas stack up that poorly. And also, the main point of all this is that there is no data showing that corals are even affected by this toxin. I'd say that there is a good chance if the concentration is high enough, but I just don't see how it could get to that stage unless you have A LOT of caulerpa and don't take proper care of it.

Best Regards...Collin

 

[cwcross]

Hey do you have any pics of your reef my friend?? I would love to see it.


Mike

I do. I will get them uploaded sometime in the not toooo distant future. My current reef is just about a year old and is just starting come to life really. Its nothing like yours but I enjoy it.

....C

 

[mojoreef]

Collin you are calculating under the premise of taxifolia being 80x more toxic in regards to cyn. When in the wild with out competition it is closer to 25x. Also if their is no competition it can increase its cyn output by 42% This will change the numbers a tad. You are also comparing a freak aquarium version of Taxifolia to a native racemosa, Can it be assumed that the racemosa has not morphed in our aquariums exactly like the taxifolia has??Also we can assume that in a refugium its going to be non competitive and perfect light and heat conditions, Prime for the production of CYN.
Regardless Collin, IMHO if a person wants to run a refugium and they are choosing a macro algae to use in it. When choosing you have to take a number of things into consideration, including secondary chemicals, possibility of sexual, growth rates and so on. Here is a table of the growth rates of a few algaes
Halimeda: ~4% / day (20-40 mg/g/d)
Dictyota: ~ 10% (50-100 mg/g/d)
Padina: ~ 10% (75-100 mg/g/d)
Caulerpa: ~ 10% (50-100 mg/g/d)
Thalassia: ~1.5% (10-15 mg/g/d)
Palmaria: ~25% (tripled in 1 week)
Enteromorpha: 20% (7 fold increase in 1 month)
Gracilaria: 10% / day
Cheleto: 15% (5 fold increase in 1 month)
cyanobactor: 35% (300-400 mg/g/d)

Now when you look at these and say eliminate the most toxic (caulerpa, dictyota and Padina), then eliminate cyano because it is gross and tough to harvest, you are left with several great exporters, that are easy to grow and harvest, have a low sexual rate and you dont have a problem with toxins. Now if you still wish to use caulerpa, by all means


Mike

 

[cwcross]

Collin you are calculating under the premise of taxifolia being 80x more toxic in regards to cyn. When in the wild with out competition it is closer to 25x. Also if their is no competition it can increase its cyn output by 42% This will change the numbers a tad. You are also comparing a freak aquarium version of Taxifolia to a native racemosa, Can it be assumed that the racemosa has not morphed in our aquariums exactly like the taxifolia has??Also we can assume that in a refugium its going to be non competitive and perfect light and heat conditions, Prime for the production of CYN.

Yes, all this is true. I this most likely accounts for about a factor of 2-5X. I multiplied by factor of 100X to take such things into account conservatively. Thus the actual numbers I calculated are 100 times less than than what I wrote down. Also, according to what I read, I would think that being in an aquarium would cause LESS toxicity than in the wild having 24/7 lighting, being thinned frequently, and having hair algea growing over the top, as long as it doesn't cover it all up. Competing with other algeas for light was shown to reduce toxicity as more energy is shunted to leaf growth.

Regardless Collin, IMHO if a person wants to run a refugium and they are choosing a macro algae to use in it. When choosing you have to take a number of things into consideration, including secondary chemicals, possibility of sexual, growth rates and so on. Here is a table of the growth rates of a few algaes
Halimeda: ~4% / day (20-40 mg/g/d)
Dictyota: ~ 10% (50-100 mg/g/d)
Padina: ~ 10% (75-100 mg/g/d)
Caulerpa: ~ 10% (50-100 mg/g/d)
Thalassia: ~1.5% (10-15 mg/g/d)
Palmaria: ~25% (tripled in 1 week)
Enteromorpha: 20% (7 fold increase in 1 month)
Gracilaria: 10% / day
Cheleto: 15% (5 fold increase in 1 month)
cyanobactor: 35% (300-400 mg/g/d)

Now when you look at these and say eliminate the most toxic (caulerpa, dictyota and Padina), then eliminate cyano because it is gross and tough to harvest, you are left with several great exporters, that are easy to grow and harvest, have a low sexual rate and you dont have a problem with toxins. Now if you still wish to use caulerpa, by all means

Mike

I agree with all this. I am not trying recommend that people use caulerpa's. Your data clearly shows that there are better algeas out there to achieve the goal of nutrient export. I am not debating that point.

My goal is to illustrate why I believe that the perception of caulerpas being toxic is overexagerated. I firmly believe this is true. There is an argument, you and others have stated that "any" toxicity is bad. This is an easy argument to accept. I do not necessarily agree with it for reasons I have stated earlier in the thread. However, I do agree with you that there are other better algeas to use so why not use them instead. I have no problem with that and it is good advice.

I just don't want people to run screaming when they hear of someone using caulerpa, or find that they are using it when they hear the news about toxicity.

If you have C. Taxifolia in your tank. Then maybe drastic action should be taken.

So, I will summarize my opinion on Caulerpa:

I think the reports of Caulerpa toxicity, although true, are mostly overexagerated,excepting C. taxifolia.

There are more effective algeas to use than Caulerpa

Amoung Caulerpas, prolifica is safer than racemosa. Also, racemose is a very aggressive grower and has a greater tendency to go sexual than prolifica.

If one keeps caulerpa, one should make sure to thin it relatively frequently but pulling the whole plant out and not breaking or cutting it. Also, hair algea or other algeas (even itself) should not be allowed to completely obstruct the light.

Don't keep caulerpa in your main tank, especially next to delicate corals, especially SPS.

Caulerpa toxicity for Prolifica and Racemosa, is very mild at worst, to the extent that steady state levels of toxins in a closed system are practically non-existent if the algea is kept to reasonable levels and not allowed to get out of control or fill the refugium.

Thanks for everybodies input. I will be happy to continue the thread if anybody is intersted but can't think of anything else to add right now.

Best Regards...Collin