Refugiums don't export nutrients?

[Reefin Dude]

Perhaps you are not familiar with Nano tanks, but many deploy a small army of herbivores/omnivores. Hermit crabs, amphipods, snails, some small blennies, etc. Any of these will eat various types of micro algae and/or various types of macro algae.

 

I'm not referring to any particular article at this point, just elaborating on a theme you have continuously mentioned that a ULNS tank should have no algae if detritus is removed regularly, thus negating the need for Macro algae in a refugium. I agree with you, but I am also pointing out that algae is processed in any tank that has organisms that consume it, to a lesser or greater extent, and the PO4 is then removed via detritus removal.

 

In a system that maintains a higher nutrient level, then additional macro algae harvesting can be a beneficial tool.

 

This was fun and I hope everyone enjoys their nano reefs...whatever type they are

 

Ok, but what organisms do we want? Do the organisms that eat the algae a part of the system we need, or are they just something we think we want?

 

First off no one here has made any claim that refugiums can provide 100% filtration for a thriving reef aquarium. Certainly using a skimmer is beneficial in many ways and good luck with your tank. The problem with some of the posts that have been made about macroalgae not being a method for nutrient export have been continually made without any substantial evidence to back them up. This has led to some comments that may seem more hostile, but are merely just the frustrations of those participating.

 

Its still seems that ReefingDude is taking some leaps of faith and writing them off under bioindicators. An increase in biomass in an aquarium is the goal isn't it? We want our pets to thrive and watching them grow is one of the best "bioindicators" of this. No one has claimed that refugiums somehow negate the need for aquarium maintenance, they are a piece of the puzzle and in many cases, a beneficial one. So what do you mean exactly by increasing biomass?

 

The claim that small polyp stonies can't survive long term in an environment with higher nutrient levels has also been made without any proof other than personal testimony. There are many long term success stories of SPS dominated systems, and the goal of NSW concentrations of nutrients is a unicorn. In the following link take a quick stroll down to photos 1 and 2 http://www.reefkeeping.com/issues/2002-07/eb/index.php. Photo 1 is of the typical outer reef crest where nutrients are at there lowest. But photo 2 shows an area of the inner reef where nutrients are much higher, micro algae are turning the water green and SPS are thriving. To say we have to maintain our systems as close to NSW levels as possible is certainly a no-brainer, but you're putting the cart before the horse. Why these regions of the reef so nutrient poor is because of the severe competition for these nutrients not because they are nutrient deserts.

 

Stating that Calcium Carbonate is a sink for phosphates is also well known in the hobby. Turkey basting your rocks routinely to remove detritus isn't a guarded secret. Once again it is suggested routine maintenance given in most beginners tutorials I have personally read. But you're beating around the bush again, are you suggesting we don't use Calcium Carbonate rock for reef structure? are you suggesting less live rock per volume? what is your point?

 

Your also making assumptions that algae can't survive in lower nutrients again without proof. We know from our own experience that this isn't the case. Hardy macro algae can survive in these conditions within our enclosed environments. Just because these aren't the environments they are typically found in nature, doesn't mean that its impossible. Further the abundance of herbivores on the reef crest is most certainly a "bioindicator" that algae can and will grow in these environments. Once again the fact that macroalgae isn't abundant in that environment doesn't mean it can't grow, its such a treasured commodity that it remains trimmed back and competition for every little bit is fierce.

 

Again, what have I not provided references for? What references have you provided for this conversation? All I hear is prove this, prove that, which I have tried my best to provide the references for why I think the way I do. All I ask is the same in return. Nobody can make an informed decision about anything unless they have all of the information that can be gleaned about the subject being discussed. I am bringing my cards to the table. Lets see yours.

 

I have never said that a "refugium" negates the need for maintenance. I have been saying that the way the function is not exactly the way we have been taught and that they give a false sense of security that all is going well. I have also never said anything about not using calcium carbonate based LR in our systems. I would suggest that we should always use it. It has the ability to bind phosphates when Pi levels go up in a system for some reason, yet it also has the ability to purge them when Pi levels go back down. Something that a substrate is not able to do without added work for the aquarist. Can a "refugium" be beneficial, sure, if the organisms that are kept in the "refugium" match the environment that the organisms in the display also need. I would like you to find a reference for me showing that the algae that are commonly kept in "refugiums" are the same algae that are found on the outer reefs, the same places that we find the SPS that we keep.

 

Looking at those pictures that you are referencing it is important to know that the GBR experiences seasonal nutrient upwellings during the year. It would be interesting to know what time of year those pictures were taken. If the inner reef pic was taken during a seasonal upwelling event. Are the corals thriving? hard to tell in that pic. Would you want to look at that tank day in and day out? Do you really think that a tank that looks like that is healthy? I do not believe that pictured was altered, I do believe the picture was taken out of context and to know the entire story we would need to know when those pictures were taken.

 

 

Upwelling as a Source of Nutrients for the Great Barrier Reef Ecosystems: A Solution to Darwin's Question?

 

Again. We need to define what low nutrient is. What you all consider low nutrient is not really what low nutrient is. You are relying on kits that are looking at a very specific small aspect of what makes an environment nutrient rich or poor. Please find a reference showing that the algae that is commonly found in "refuigiums" is found in a healthy outer reef biotope. Did you see the references I posted earlier about how one of the first signs of an unhealthy reef (one suffering from eutrophication) is the presence of algae. I believe you may also have issues with putting the cart before the horse. Is it really the algae that comes first or is it the herbivores? I would put money on the algae being there first.

 

Yes, you are correct. I would suggest a lot less LR is needed than what we put into our systems. What does adding more LR do? How can it add more bacteria? If we build more houses in a desert, does that mean more people will live there? The resources needed for the survival of the organism also have to be there in order for their to be more organisms. When it comes to bacteria, more room is very seldom a limiting factor for growth. I think that the more LR the less efficient the bacteria become. They are more spread out making their access to certain resources more limited. The less LR also allows easier turkey basting of the LR. If you can get to all of the LR with a turkey baster you are more likely to get more of it out of the system. The less that is likely to hide either behind the aquascaping and in and amongst it.

 

For a previous comment on hold fasts not being used for nutrient transfer in algae. This is part of the basic definition between roots and holdfasts is the ability to absorb nutrients.

 

Holdfasts from Wikipedia.

 

I do not mind posting references, but i was hoping that someone that disagrees, would do some homework first to double check that maybe they have may have missed something. I would hope that this forum is all about exchanging information.

 

G~

[Subsea]

Your reference to a definition from Wekipedia does not constitute scientific evidence. Please lay more cards on the table.

[Griever]

At any moment in time, the excretion is small. Over time (days and weeks) the total excretion is actually greater than the amount thrown away from harvest.

 

This is the part I'm having a very hard time grasping. How can algae excrete more over time than it absorbs, while increasing it's biomass? I'm having a hard time picturing how this would work from a fundamental science perspective.

 

You can't excrete more than you absorb as an organism, especially if you're using those basic compounds to increase your biomass. Is there something I'm missing?

[Subsea]

Your reference to a definition from Wekipedia does not constitute scientific evidence. Please lay more cards on the table.

 

I can appreciate your science point of view. I am a marine engineer and use scientific principals to make math models and design things. I have been in the hobby for 40 years. No internet in those days. While working as a project manager with Fortune 500 companies, I learned how to communicate with many different type of personalities. Reefer Dude, your personality is very much like mine. You are a Sherman Tank. When others on this thead presented different points of view, in most cases, you totally disregarded there post to continue making your point. You should not be surprised by the responses that you have gotton on this thread. If you want to make this a meaningful discussion, then consider that others may have something meaningful to contribute. There are some smart people here. Instead of preaching to the choir, let us discuss a little bit more. A point of example. You choose to come back on this thread with an attitude it is us against you. I have been posting here less than two weeks. After making several post on this thread, I made one solitare post about vacuming red cynobacteria to remove phosphates. This was in agreement that phosphate is the issue. However, there are more than one way to skin the cat. Give others credit for seeing the big picture. We may see it different than you, but we have that right.

Ease up a little bit on your agenda. We may all learn something.

 

Patrick Castille

Mgr, AquacultureRanch

[Reefin Dude]

This is the part I'm having a very hard time grasping. How can algae excrete more over time than it absorbs, while increasing it's biomass? I'm having a hard time picturing how this would work from a fundamental science perspective.

 

You can't excrete more than you absorb as an organism, especially if you're using those basic compounds to increase your biomass. Is there something I'm missing?

 

This is unfortunately basic biology. Think about the amount of food you take in during your life. Do you increase in mass that even comes close to the amount of food you bring in? You excrete a huge amount of material. Other organisms are the same. Organisms are not nearly as efficient as we think they are.

 

I can appreciate your science point of view. I am a marine engineer and use scientific principals to make math models and design things. I have been in the hobby for 40 years. No internet in those days. While working as a project manager with Fortune 500 companies, I learned how to communicate with many different type of personalities. Reefer Dude, your personality is very much like mine. You are a Sherman Tank. When others on this thead presented different points of view, in most cases, you totally disregarded there post to continue making your point. You should not be surprised by the responses that you have gotton on this thread. If you want to make this a meaningful discussion, then consider that others may have something meaningful to contribute. There are some smart people here. Instead of preaching to the choir, let us discuss a little bit more. A point of example. You choose to come back on this thread with an attitude it is us against you. I have been posting here less than two weeks. After making several post on this thread, I made one solitare post about vacuming red cynobacteria to remove phosphates. This was in agreement that phosphate is the issue. However, there are more than one way to skin the cat. Give others credit for seeing the big picture. We may see it different than you, but we have that right.

Ease up a little bit on your agenda. We may all learn something.

 

Patrick Castille

Mgr, AquacultureRanch

 

I do. I have been reading all of the posts and I have been trying to respond to them. I am not trying to ignore them. I have also noticed that my questions back to several of the members have been ignored also. Mainly showing anything that shows that the algae we keep in our systems is found anywhere near the corals we are trying to keep. I would also like to know your all thoughts on how corals are symbiotic and what that means to what we are discussing.

 

If I came on thinking that this was all against me, then I am sorry. I just came on to discuss what I have found through my personal research over the 25+ years of reefkeeping. I think I have been very civil through all of this despite the hostility of some here.

 

The hobby is full of smart people. There are people from every profession, though I wish we had some pathobiologists right now. I would also expect people to have adult conversations. When someone posts something that goes against what I think is going on I try and look that up to see if I can figure out how they came up with that thinking. It is very likely that i could have missed something. Reading through the algae thread on TRT that was posted on here several times is eye opening about what we think about what goes on in algae and how P is used. We obviously do not know all of the answers. All I want to put forward is that if what we are doing is correct, then why do we have algae problems and why do we kill far more organisms than we are able to keep alive in this trade. This seems like a pretty decent sign that what we have been doing is not very effective. Why? How can we make it better? Can we really bring this hobby back to the absolute basics in a way to push the hobby forward.

 

What do I need to post to show that one of the basic definition differences between a hold fast and a true root is the ability to absorb nutrients?

 

Differences between Algae and Plants.

 

If you are able to find another definition for holdfast that shows that nutrient absorption takes place through them, then please post them. Algae do not move nutrients systemically through the organisms. There is no reason for them to take in nutrients through the holdfasts. They get all they can through the water column.

 

G~

[danimal1211]

What do I need to post to show that one of the basic definition differences between a hold fast and a true root is the ability to absorb nutrients?

 

Differences between Algae and Plants.

.

Maybe start with better reading comprehension

 

"Algae do not absorb nutrients from the substrate through the hold fast, but they are autotrophs"

 

 

[Subsea]

In this discussion, I note that you call algae a problem. I see it as the solution. What you call increasing nutrient, I call increasing biomass, which includes our coral. Coral would die without its relationship to algae.

 

I will produce no one article that addresses cynobacteria mats or macro nutrient holdfast uptake. . I assure you that enzyme action produces much chemical/biological reactions that are more complicated then I can discuss. Because I can not break it down to the scientific language, does not mean that the processes are not happening.

 

What is the point to all of this discussion? You choose a nutrient deficient method of reefkeeping to maintain the SPS that you care far. Good for you. I am glad that you know the difference being inorganic and organic phosphate. Most of us reading this thread, already know that. I choose to use macro as my bioindicator for system health. When I feed too much, then biomass of macro increases. If the bioindicator is some gorgeous display quality macro in my display tank, why would you find fault in this method of reefikeeping?

[Griever]

This is unfortunately basic biology. Think about the amount of food you take in during your life. Do you increase in mass that even comes close to the amount of food you bring in? You excrete a huge amount of material. Other organisms are the same. Organisms are not nearly as efficient as we think they are.

 

This is an extreme over simplification. If we look at the human intake of hydrocarbons for example, there's no way you could tell me that I excrete more hydrocarbons than I utilize. Most of that energy is lost as heat, and the C and H is expelled as CO2 gas and water vapor.

 

Now lets expand this to a colony of humans (which would be a better comparison as a single mature human is a terrible one), ones that were reproducing and growing, than the net import of nutrients would be less than the exports, because their biomass is increasing. Even if they're 99% inefficient at using a type of nutrient, the net excrete is less than the intake due to mass lost as heat and kinetic energy. Not to mention elements of the growth limiting nutrient being used in making new cells.

 

Algae is limited by phosphates and nitrates in the aquarium (simplification of course), so by definition they need these compounds to grow and reproduce. A percentage of those compounds are put into new cell growth. Even if 99% of the phosphates they come into contact with are excreted, and only 1% are used to create new cells, it's still a net reduction once those cells are removed from the system.

 

I'm still having an extremely difficult time understanding the claim that algae could possibly attribute to a net increase in phosphate due to excretion against having no algae at all. That's just not possible.

 

If I'm wrong, please enlighten me. Maybe I'm not understanding the context to your remarks, or an alternative source of phosphate that's somehow being taken from a source external to what we put in as food.

[xerophyte_nyc]

 

I'm still having an extremely difficult time understanding the claim that algae could possibly attribute to a net increase in phosphate due to excretion against having no algae at all. That's just not possible.

 

You are right, it is not possible. It's not that algae is contributing to the net phosphorus in the tank. The point being made is that as the algae grows it is not assimilating enough phosphorus for there to be a net system export at the time it is harvested, because during the period it has been growing, more phosphorus enters the algae to be excreted, than enters the algae towards biomass. It's like having a 5 gallon bucket and you keep adding more and more water, there could be 100 gallons that spilled but when you check the bucket it is only 5 gallons even though you poured much more than 5 gallons. The only way for this to work would be to dump the bucket each time before it fills up.

 

However, when you take into consideration that some of this phosphorus that leaves the algae then contributes another food source for the system's bacteria, which in turn make more food for the algae, you then see how it can indeed be detrimental to keep the algae, if the goal is to reduce phosphorus appreciably. It is actually more work to try and remove organic phosphorus this way. If algae were eliminated completely, you are also cutting off a bacterial food source and thereby making it easier to lower P in the tank because you can try to get it all before it gets converted to Pi.

 

It's really about controlling the bacteria. If you could wipe out all the bacteria with a systemic antibiotic, you would see all the algae die because they can't get Pi from anywhere. But if you could kill all the algae in one shot, bacteria can still use P that is bound to the rock. It is harder to control bacteria. If you want a LNS, then don't feed the bacteria any more than is necessary.

[danimal1211]

But if this were true of what's actually happening, bacteria would be converting organic phosphates to inorganic phosphates at a rate that would be measurable by hobbyists test kits and Nitrates would noticeably decrease. Algae would continue to grow. It hasn't been shown that a rate below this would be in anyway detrimental to stony corals.

[danimal1211]

You are right, it is not possible. It's not that algae is contributing to the net phosphorus in the tank. The point being made is that as the algae grows it is not assimilating enough phosphorus for there to be a net system export at the time it is harvested, because during the period it has been growing, more phosphorus enters the algae to be excreted, than enters the algae towards biomass. It's like having a 5 gallon bucket and you keep adding more and more water, there could be 100 gallons that spilled but when you check the bucket it is only 5 gallons even though you poured much more than 5 gallons. The only way for this to work would be to dump the bucket each time before it fills up.

 

 

But if the maintenance remained the same and the algae weren't in there, there would be less decrease in overall phosphates because an additional sink that's actually controllable isn't available. As the algae grows you remove the growth. It may not be 100% removal, but it's better than not having it. There is the increase when the algae is originally added but as long as the excess growth is trimmed off you absolutely will have a decrease in nutrients. No one will ever be able to remove 100% of all detritus before it can be broken down. The algae is there as a redundancy.

 

 

However, when you take into consideration that some of this phosphorus that leaves the algae then contributes another food source for the system's bacteria, which in turn make more food for the algae, you then see how it can indeed be detrimental to keep the algae, if the goal is to reduce phosphorus appreciably. It is actually more work to try and remove organic phosphorus this way. If algae were eliminated completely, you are also cutting off a bacterial food source and thereby making it easier to lower P in the tank because you can try to get it all before it gets converted to Pi.

 

 

You're not removing organic phosphates, your removing inorganic phosphates, and according to a loosely associated paper written in 1976 about zooplankton, at least most of it before it's converted back to organic phosphates.

 

 

 

It's really about controlling the bacteria. If you could wipe out all the bacteria with a systemic antibiotic, you would see all the algae die because they can't get Pi from anywhere. But if you could kill all the algae in one shot, bacteria can still use P that is bound to the rock. It is harder to control bacteria. If you want a LNS, then don't feed the bacteria any more than is necessary.

You would also see the rest of your tank die along with it. Bacteria is not only the source of nitrogen processing but is also a food source for many of our tanks inhabitants.

[xerophyte_nyc]

But if this were true of what's actually happening, bacteria would be converting organic phosphates to inorganic phosphates at a rate that would be measurable by hobbyists test kits and Nitrates would noticeably decrease. Algae would continue to grow. It hasn't been shown that a rate below this would be in anyway detrimental to stony corals.

 

What you have to realize is that even a "high" phosphate level is still a tiny amount. Our test kits are simply not that accurate. I wish they were. I test zero all the time on my Salifert but I have an ATS so clearly there is lots of Pi there. A couple explanations: 1) Pi is used up very quickly as it is being made, thereby bypassing a test. 2) Pi is liberated by bacteria locally (right on the rock) and is then quickly used by nearby algae, also bypassing a test.

[xerophyte_nyc]

But if the maintenance remained the same and the algae weren't in there, there would be less decrease in overall phosphates because an additional sink that's actually controllable isn't available. As the algae grows you remove the growth. It may not be 100% removal, but it's better than not having it.

 

Maybe, maybe not. Since nobody tests for Po regularly we don't really know exactly what is happening. We are at best making educated guesses based on research and based on observation. Maybe when algae is removed you knock down overall P a few % points, but how much was added that week as the algae was growing? I don't know exactly. I do know this: if algae were so good at removing P, we would all see it shrinking every week. Based on my own observation, it seems at best algae keeps things steady, like a buffer.

 

 

There is the increase when the algae is originally added but as long as the excess growth is trimmed off you absolutely will have a decrease in nutrients. No one will ever be able to remove 100% of all detritus before it can be broken down. The algae is there as a redundancy.

 

We are all chasing our tails it seems. Some chase faster than others

 

You're not removing organic phosphates, your removing inorganic phosphates, and according to a loosely associated paper written in 1976 about zooplankton, at least most of it before it's converted back to organic phosphates.

 

I'm not sure I understand what you're getting at...

 

 

You would also see the rest of your tank die along with it. Bacteria is not only the source of nitrogen processing but is also a food source for many of our tanks inhabitants.

 

I never said we should eliminate bacteria. Without them none of us would have any success. But if you want a LNS, the goal is to limit organic P, which would indirectly keep the bacteria a little hungry, so to speak. The presence of algae in a tank means that bacteria are well fed. They are the primary source of Pi. In some tanks there is so much Pi that other nutrients become limiting.

 

FYI, I do not have a LNS tank, nor do I even want to do the work to have one. I'm just trying to help others understand some of these concepts, the way I see them. I'm far, far from an expert. I'm not pushing an agenda. I don't know Reefin' Dude or Future Doc, in fact I was pretty aggressive against them earlier in this thread. I just want to understand as best I can what is happening in my tank so that I can approach success.

[danimal1211]

I'm not sure I understand what you're getting at...

The original refference paper given in this thread was a study conducted in 1976 on zooplankton discussing the excretion of organic phosphates vs. the uptake of inorganic phosphates. I consider it loosely related as from what I could read (I don't have access to the entire document) it dealt with zooplankton and not macro algae.

 

 

Maybe, maybe not. Since nobody tests for Po regularly we don't really know exactly what is happening. We are at best making educated guesses based on research and based on observation. Maybe when algae is removed you knock down overall P a few % points, but how much was added that week as the algae was growing? I don't know exactly. I do know this: if algae were so good at removing P, we would all see it shrinking every week. Based on my own observation, it seems at best algae keeps things steady, like a buffer.

 

A good point, we don't know exactly whats going on, but it seems to me that when I trim my chaeto or you trim your turf algae, there is phosphates bound within it. If it is new growth, then we are removing at least some of what we had put in our systems. We are all chasing our tails to whatever degree we can or are willing to do. I have a very small tank so maintenance isn't difficult or time consuming, and I keep up with it weekly yet my chaeto still grows a bit. I like redundancies and this one seems to be working just fine for me.

 

BTW, sorry to read about your tank crashing due to Sandy, good luck with the new system.

[Reefin Dude]

.

Maybe start with better reading comprehension

 

"Algae do not absorb nutrients from the substrate through the hold fast, but they are autotrophs"

 

 

 

 

 

I am confused at what you are saying. All I have said is that algae is not able to uptake Pi from the substrate. They are not. Of course they are able to uptake Pi from the water itself. If they were not, then they would not be alive. If hold fasts were able to uptake Pi from the substrate then we would have an export mechanism for some of the Pi building up in the substrate. Since this does not occur; because they are hold fasts and not true roots; we are back to the same problem being that P builds up in a substrate. Algae is not helpful in removing P from a substrate. They are right there if any is released from the decomposition of detritus in that area, but they are not able to migrate P out of the substrate using their hold fasts.

 

Sorry, I am not sure how I need to work on my reading comprehension? What was quoted was correct.

 

But if this were true of what's actually happening, bacteria would be converting organic phosphates to inorganic phosphates at a rate that would be measurable by hobbyists test kits and Nitrates would noticeably decrease. Algae would continue to grow. It hasn't been shown that a rate below this would be in anyway detrimental to stony corals.

 

The problem is that there are a lot of other organisms and even the calcium carbonate itself that is also very interested in this released Pi from the bacteria. In order to have any readable Pi there must be more than what these other organisms/calcium carbonate can use. Our test kits are just not accurate enough to catch this rapidly exchanging Pi.

 

Not exactly sure why nitrates were put in that sentence. Could you please elaborate? Are you talking about the bacterials use of Po in order to process nitrates or another process?

 

Pi becomes detrimental to SPS coral health because it changes the balance of power in the coral. The coral takes in food. During normal metabolic functions it creates wastes. These wastes feed the zoax. Provide the Pi, CO2, and nitrates necessary for the zoax. In return the zoax provide simple sugars and O2 back to the corals. There is a tightly bound P cycle within the corals because of the lack of available nutrients in the water column. They work together. When there is a lot of Pi in the water column, this balance of power gets disrupted. The corals are not getting enough nutrition. They are getting Frosted Flakes all of the time instead of a well balanced meal. The zoax are just providing the simple sugars because they are not relying on the corals to provide the resources they need. We as aquarist stop feeding the tank because our corals are turning brown. To much Pi in the water column. Thus starving the corals even more.

 

G~

[xerophyte_nyc]

I have a very small tank so maintenance isn't difficult or time consuming, and I keep up with it weekly yet my chaeto still grows a bit. I like redundancies and this one seems to be working just fine for me.

Nothing wrong with redundancy. I like it too. It's like having a diverse stock portfolio. My new tank is still in its early stages. Mandarin is fat and happy. Still working out the sand and aquascape, and I am nearing the end of my LED build. Thank you for the well wishes. Sandy really devastated a lot of people, my loss is nothing.

[xerophyte_nyc]

They are getting Frosted Flakes all of the time instead of a well balanced meal.

 

You mean Frosted Flakes are not part of a complete breakfast along with my toast and OJ? Are you calling Tony the Tiger a liar?

[Subsea]

Reefer Dude,

To further make the point of macro algae uptake of phosphate with a net loss of total phosphate when macro is exported, I say this. If inorganic phosphate in substrate is converted to organic phosphate in the water column and is then assimilated in macro algae biomass, when the macro is prunned and removed what form of phosphate left the system. You would probably say organic phosphate left the system. I am an engineer. The fact that inorganic phosphate in substrate has decreased thru bacteria or macro enzyme action means that total inorganic phosphate is less. When I remove macro, would you concur that the total phosphate has been decreased? I would. You have consistently railed against macro as a phosphate export mechanism. In the above sceanario, please explain how macro is not a phosphate export method. Remember, no bs.

Patrick

[danimal1211]

Looking at those pictures that you are referencing it is important to know that the GBR experiences seasonal nutrient upwellings during the year. It would be interesting to know what time of year those pictures were taken. If the inner reef pic was taken during a seasonal upwelling event. Are the corals thriving? hard to tell in that pic. Would you want to look at that tank day in and day out? Do you really think that a tank that looks like that is healthy? I do not believe that pictured was altered, I do believe the picture was taken out of context and to know the entire story we would need to know when those pictures were taken.

The inner reef zone is characterized as having higher levels of nutrients due to its proximity to land and fresh water run off, again not ground breaking information. The photo was of the inner reef, those corals live and have lived for milliions of years in those conditions. No it's not a close up picture to see what their colors look like, but the density of stony corals should be more than enough evidence that they are thriving in that environment. If you think the integrity of the photo is somehow in question, I can't help you there. I didn't take it, and can't for the life of me think why borneman would falsify it. I'm at work I'll try and post more later.

[Subsea]

Reefer Dude,

To further make the point of macro algae uptake of phosphate with a net loss of total phosphate when macro is exported, I say this. If inorganic phosphate in substrate is converted to organic phosphate in the water column and is then assimilated in macro algae biomass, when the macro is prunned and removed what form of phosphate left the system. You would probably say organic phosphate left the system. I am an engineer. The fact that inorganic phosphate in substrate has decreased thru bacteria or macro enzyme action means that total inorganic phosphate is less. When I remove macro, would you concur that the total phosphate has been decreased? I would. You have consistently railed against macro as a phosphate export mechanism. In the above sceanario, please explain how macro is not a phosphate export method. Remember, no bs.

Patrick

In summation of some of the logic that has been offered, I feel like the discussion has evolved to Clarance Darrel and Willian Jennings Bryon. Let us assume that the holdfast part of the macro has no assimilation of nutrients from the water in the sediments. Just because the conversion of inorganic to organic occured in the sediments and transferred to water in sediments does not mean that this same dissolved organic phosphate does not migrate to the water column to be acted on by macro algae.

 

If the only point was that macroalgae cannot directly assimilate inorganic phosphate that is bound in the substrate. You have a valid point. I do not look at things in the micro. I see macroalgae that exports nutrients including organic phosphate directly from the water column and inorganic phosphate from the substrate. Just because the process in the substrate took three steps using bacteria enzyne biochemistry, water migration from substate interpore spaces and macroalgae assimilation of phosphate as a nutrient from the water column. It is an export of phosphate.

[xerophyte_nyc]

If inorganic phosphate in substrate is converted to organic phosphate in the water column and is then assimilated in macro algae biomass, when the macro is prunned and removed what form of phosphate left the system. You would probably say organic phosphate left the system. I am an engineer. The fact that inorganic phosphate in substrate has decreased thru bacteria or macro enzyme action means that total inorganic phosphate is less. When I remove macro, would you concur that the total phosphate has been decreased?

 

When there is enough algal biomass in a system, the Po that it leaks is preferentially used by the bacteria instead of the Po bound to rock. The Po-calcium bond is a strong one. Bacteria have to upregulate enzymes to facilitate this reaction. It costs them less, energetically, to utilize other sources of Po.

 

An oversimplified explanation of the situation you describe where bacteria are cleaving the calcium bonds, is one in which there is minimal Po in the system to begin with. In this state there is a smaller bacterial biomass so there is not that much Pi being made - just enough to perhaps feed some small amounts of nuisance algae, or coralline algae.

[xerophyte_nyc]

Just because the process in the substrate took three steps using bacteria enzyne biochemistry, water migration from substate interpore spaces and macroalgae assimilation of phosphate as a nutrient from the water column. It is an export of phosphate.

 

Yes it is an export of phosphate - just not that much. Not enough to appreciably reduce phosphorus in a reef tank. If it was a strong and effective means of export, we would be seeing the macroalgae naturally shrink in mass week to week as nutrients are theoretically being depleted. But that doesn't really happen. The macro is always there, ready for us to prune. Other methods of P export need to be implemented to see a real or more pronounced effect (water changes, skimmers, etc.)

[Subsea]

Yes it is an export of phosphate - just not that much. Not enough to appreciably reduce phosphorus in a reef tank. If it was a strong and effective means of export, we would be seeing the macroalgae naturally shrink in mass week to week as nutrients are theoretically being depleted. But that doesn't really happen. The macro is always there, ready for us to prune. Other methods of P export need to be implemented to see a real or more pronounced effect (water changes, skimmers, etc.)

I hear your words. You have shown me no proof.

[Subsea]

I hear your words. You have shown me no proof.

I puposely add nutrients to my system to grow more macro. I both eat it and I sell it. What you offer as a proof that macro is ineffective at removing phosphate is my proof that it is effective at removig all nutrients. To say that it is ineffective, otherwise it would starve itself ignores the fact that we as reefkeeper add nutrients continually to fuel growth.

[xerophyte_nyc]

I hear your words. You have shown me no proof.

www.pnas.org/content/106/50/21013.full

 

www.pnas.org/content/106/50/21219.full

 

Heterotrophic marine bacteria assimilate organic P directly. They have more metabolic machinery to do this, compared to alkaline phosphatase which is needed to get P from rock. Alk p-ase assays underestimate the nutrient levels in the water.

 

Want more proof? Just look through the numerous FTS on this forum. Lots of nice looking macro. If nutrients were low, the macro would not grow. Yes we continually feed, and the macro continually exports a small amount. But it does not export what you import. An earlier referenced study demonstrates that unequivocally, where in a 4 hour period algae excreted P equivalent to 8% of bacterial P biomass. In a couple of days, the algae could supply all the bacterial P needs (in reality that would never happen, some sort of equilibrium would be established first).

 

Nobody here is suggesting that macro be abandoned as a means of export. We just need to understand that it is not terribly good at it. No organism assimilate nutrients well. It takes 6 pounds of high quality grain to give you 1 pound of beef. Not efficient at all. Algae is not different than other life on earth. There is waste being produced during growth. In the ocean this waste is washed away and P is buried into the ocean floor. Our reef tanks do not have those things so we have to do it ourselves.