Sugar OD?
- Thread starter akwtampa
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MCsaxmaster
New member
Please, everyone, I don't mean to seem as though I'm picking on anyone, but I think it important to be rigorous when we consider what's going on with our tanks...
Yes, they will take up organic carbon and fixed nitrogen (ammonia or, secondarily, nitrate). They also produce organic carbon, and substantially faster than they take it up. The net effect is a loss of organic carbon. They're leaking the stuff at a pretty prodigious rate. Increased water column DOC at the kinds of concentrations we're talking about couldn't have a substantial effect--they'd still be leaking it out into solution a heck of a lot faster than they suck it up from solution. As for the nitrogen, they only go to the trouble of reducing N2 to NH3 if they are low on N. This is a very energetically costly pathway, and the energy is not wasted unless it is needed.
I should give counterevidence to a point that is far from demonstrated and defies basic biology?
But, how do you know that one led to the other? You suggest yourself that the conditions were not appropriate to reach such conclusions. Please just consider two points: 1) correlation does not prove causation--I put on my shoes yesterday morning and the sun rose today; putting on my shoes did not cause the sun to rise; 2) anything can happen once (or even a few times); without sufficient replication, how do we know that this correlation (if there is one...) wasn't a 'fluke'?
Let's consider possible indirect pathways. What did you use as a C source? How pure was it? What else was in it? How much of those other things? Do we have any way of knowing?
What literature and which hobbyists? Why would gorgonians be any more sensitive than other corals to cyanobacterial blooms???
Best,
Chris
Yes, they will take up organic carbon and fixed nitrogen (ammonia or, secondarily, nitrate). They also produce organic carbon, and substantially faster than they take it up. The net effect is a loss of organic carbon. They're leaking the stuff at a pretty prodigious rate. Increased water column DOC at the kinds of concentrations we're talking about couldn't have a substantial effect--they'd still be leaking it out into solution a heck of a lot faster than they suck it up from solution. As for the nitrogen, they only go to the trouble of reducing N2 to NH3 if they are low on N. This is a very energetically costly pathway, and the energy is not wasted unless it is needed.
I should give counterevidence to a point that is far from demonstrated and defies basic biology?
But, how do you know that one led to the other? You suggest yourself that the conditions were not appropriate to reach such conclusions. Please just consider two points: 1) correlation does not prove causation--I put on my shoes yesterday morning and the sun rose today; putting on my shoes did not cause the sun to rise; 2) anything can happen once (or even a few times); without sufficient replication, how do we know that this correlation (if there is one...) wasn't a 'fluke'?
Let's consider possible indirect pathways. What did you use as a C source? How pure was it? What else was in it? How much of those other things? Do we have any way of knowing?
What literature and which hobbyists? Why would gorgonians be any more sensitive than other corals to cyanobacterial blooms???
Best,
Chris
glassbox-design
New member
MCsax...since you are certain, let's eliminate C dosing as causing cyano growth. in low nutrient tanks....what might cause this? tanks with .o2 po4 and 0 No3 are experiencing this.
and if there is none, or very little available?
can you provide a link to some studies on this? i'd like to read up on it.
no uptake of organic nitrogen?
eric
and if there is none, or very little available?
can you provide a link to some studies on this? i'd like to read up on it.
no uptake of organic nitrogen?
eric
MCsaxmaster
New member
Never say never, but we should NEVER think of a nutrient concentration as "0" or "none." A zero concentration of whatever nutrient simply does not exist in nature, and perhaps even with the best water purification systems available. For nutrient analyses in the lab one must go to something like 18 megaohm or better quality freshwater, and even that will have some tiiiiiiiiiny, completely immesurable concentation of nutrients.
Now, a "0" reading for nitrate in an aquarium and 0.02 ppm reading for phosphate isn't necessarily "low nutrient" in the context of the natural world anyway. The lowest concentration we can measure for nitrate and phosphate given aquarium test kits is about 0.2 and 0.03 ppm, respectively. Compared to the water surging over a typical coral reef, that would be very high for nitrate and on the higher side for phosphate. In the best of scenarios most aquariums can approach middle-of-the road or 'high' in terms of ambient nutrient concentration compared to coral reefs.
Cyanobacteria grow on reefs. They bloom on reefs occasionally. They can form huge, disgusting mats at times, and then just diappear after awhile. All of this can and does occur without any change in ambient nutrient concentrations (although elevated nutrients, such as from coastal runoff/sewage can sure get the ball rolling...). If cyanobacteria occasionally bloom on reefs despite low nutrients, why would they NOT bloom in tanks on occasion given somewhat high nutrients?
Actually, the research that has been done has found little correlation (sometimes positive, sometimes negative, sometimes none) between ambient nutrient concentration and the coverage of cyanobacteria on reefs. Sometimes they just spring up here and there, and for reasons that still aren't understood (probably ecology at work, just not explained yet...)
Try googlescholar with terms like 'fate of phytoplankton DOC' or 'phytoplankton production'...hopefully that will point in the right direction. I'd try to give you a better lead, but unfortunately just don't have the time at the moment (and won't for at least a few weeks). I type this as a water sample aerates....
Ha, you never asked
Sure they do, as does pretty much everything in the ocean that lakes a hollow dorsal nerve cord.cj
RichConley
New member
Every single sugar dosing situation where I've seen cyano pop up, its been someone who was dosing sugar to deal with a really undersized skimmer.
I agree with MXSaxmaster here, sugar isnt going to cause cyano. Its just typical bad maintenance doing this.
As to gorgonians, I can't see sugar bothering them, but I CAN see real low nutrients bothering them, and sugar can cause that.
I agree with MXSaxmaster here, sugar isnt going to cause cyano. Its just typical bad maintenance doing this.
As to gorgonians, I can't see sugar bothering them, but I CAN see real low nutrients bothering them, and sugar can cause that.
MCsaxmaster
New member
Playing devil's advocate:
Nutrient concentrations in nature are as low or lower (sometimes MUCH lower) than in tanks yet they do very well out there....hmmmm..... Worth pondering I think.
Also, sugar probably couldn't and wouldn't bother most corals at any but outrageous concentrations (they've got little glycerol machines in them, afterall), but a bacterial bloom or increased microbial growth or increased growth of particular microbes might present some problems...
cj
Nutrient concentrations in nature are as low or lower (sometimes MUCH lower) than in tanks yet they do very well out there....hmmmm..... Worth pondering I think.
Also, sugar probably couldn't and wouldn't bother most corals at any but outrageous concentrations (they've got little glycerol machines in them, afterall), but a bacterial bloom or increased microbial growth or increased growth of particular microbes might present some problems...
cj
glassbox-design
New member
cj i appreciate your input. but to compare our tiny systems to the ocean is difficult to do. as you mentioned tides... their water can change in a heart beat, low nutrient-high nutrient...hardly the case with most captive reefs.
as for low nutrient in our systems, i agree....but any lower than .o2 and mosts will find their colors growth stunted and colors fade (sps). again this is low nutrient in our systems because we do not have the luxury of daily 100%+ wc's bringing in fresh nitrogen and food. we also dont have the diversity of nutrient reducing organisms.
that is why "nutrients" can be so low in the wild. they have a constant source of compounds and elements that usually limit our growth in captive systems. we're stuck playing the feed enough to nourish, but not pollute game.
as i mentioned before the importance of skimming. i believe in those general cases it is from lake of export, of the biomass created by the c dosing. as the bac population crashes it then "pollutes" the water....but there are cases of large efficient skimmers and well maintained tanks and cyano still pops up with C dosing. who knows :rollface:
anyone know the scientific name of the cyano we speak of interms of captive reefs? it's difficult to not blur the line of wild vs captive and the various types of phytoplankton (are lableing cyano as phyto? if so what type of cyano?)...i'd like to try and maintain focus.
jmo.
as for low nutrient in our systems, i agree....but any lower than .o2 and mosts will find their colors growth stunted and colors fade (sps). again this is low nutrient in our systems because we do not have the luxury of daily 100%+ wc's bringing in fresh nitrogen and food. we also dont have the diversity of nutrient reducing organisms.
that is why "nutrients" can be so low in the wild. they have a constant source of compounds and elements that usually limit our growth in captive systems. we're stuck playing the feed enough to nourish, but not pollute game.
as i mentioned before the importance of skimming. i believe in those general cases it is from lake of export, of the biomass created by the c dosing. as the bac population crashes it then "pollutes" the water....but there are cases of large efficient skimmers and well maintained tanks and cyano still pops up with C dosing. who knows :rollface:
anyone know the scientific name of the cyano we speak of interms of captive reefs? it's difficult to not blur the line of wild vs captive and the various types of phytoplankton (are lableing cyano as phyto? if so what type of cyano?)...i'd like to try and maintain focus.
jmo.
MCsaxmaster
New member
Huh? Ingoing or outgoing tides bring nutrient rich water???
Why would a concentration lower that 0.02 ppm of nitrate or phosphate (not sure which you mean, or both?) cause stunted growth and fading colors in captivity? There are a lot of tanks in private hands and public aquaria that have lower nutrient concentrations than this and their corals are fantastic. The corals in nature aren't too shabby either
No, we generally don't have the luxury of short water dwell times in our reefs. Can we not simply feed the critters in the tanks though? Isn't that what we do normally. No, we don't have the kind of diversity seen on reefs in our tanks, but high biodiversity is not required to maintain low nutrient concentrations...
Ok, so feed the critters in the tank, but don't grossly overdo it. Also, have sufficient filtration (nutrient uptake) in place to deal with the waste produced. It's a balance, no doubt about it. There are a lot of folks nowadays that seem to strike the balance of feeding well but maintaing low dissolved inorganic nutrients.
Ok, but that still leads me to ask what was dosed and what else was dosed (unintentionally) with the organic C?
There are quite a number that show up...
Also, have a look here. They looked at the relative importance of herbivory vs. nutrient enrichment in controlling cyanobacterial cover and species composition. Nutrient enrichment had little effect on cyanobacterial cover but herbivore exlusion did (favoring macroalgae):
http://www.springerlink.com/content/dnk1amt37jq9ru71/fulltext.pdf
cj
glassbox-design
New member
i apologize, wrong term used, fresh elements. also their is a constant source of nitrogen from fish urine and waste. what i am getting at is in the wild corals can feed, without being subject to rising po4 and no3 that happens in our systems.
i know of very few and those are generally plagued with algae causing in accurate testing or using bacterioplankton systems that again cause the same problem, please enlighten us if you know of any that accurately have tested their po4 and have lower po4 with bright and bold colors and good growth. research this topic and you will see that po4 limitation is a real problem with todays low nutrient systems.
sounds simple doesnt it? but boy is it tricky. ask most sps keepers and besides alk/cal balance i'm sure this is up their on their list. to keep the tank low nutrient enough that algae is not a problem and colors can shine, but feed enough that nitrogen limitation is not a problem. hence the rise of new n supplements such as aa's. for most people this is not a proble, for the neat freaks and perfectionists like myself, it is. my sps colors can change ever few days just based on what i feed...
besides some "contamination" of sugar or vodka, which would not have a noticable effect...nothing.
thanks for the link, i just glanced at it but it looks like a good read.
eric
MCsaxmaster
New member
But why does feeding the corals in captivity inherently lead to rising, unhealthy nutrient concentrations? It doesn't necessarily, and shouldn't if the tank is properly established and well cared for.
There a lots of people with < 0.02 ppm phosphate with great looking corals. Last week I ran nurient samples for the seawater system here at the lab. Nitrate was about 0.29 uM and phosphate about 0.06 uM, or about 0.017 and 0.006 ppm respectively. Our corals look fine, I'd say. We feed them twice a week with Artemia nauplii. They've got published low nutrients typical of reef water in the culture systems at the Waikiki aquarium. I know lots of people with phosphate undetectable on hobbyist grade kits. I'm suprised this isn't common knowledge?
Sure, sure no one said it was an inherently easy thing to keep things going well. It requires pretty constant diligence
So, whatever sort of contaminiation might be in the sugar, vodka or whatever won't and can't have a noticable effect???
I must respectfully disagree.cj
glassbox-design
New member
cj,
obviously you have access to lab grade test, i myself and many others do not. but using a hanna photometer .oo2 is certainly the range many shoot for. i would sya this is the sps keepers ideal way of po4 measurement.... this would show up as zero on all hobby po4 tests except for possibly deltec/merc. i'd say it's not common knowledge that 0 po4 isnt wanted or always a good thing. as you know a true level of zero po4 would be very bad for the animals we try to keep.
again some people running bacterioplankton as well as the ocean are different stories. that po4 is being used up quicker than it can be tested for because of the diverese organisms within. the same is true with algae infested tanks... :lol:
the waiki aquarium isnt exactly a far comparison, fresh sw is certainly a plus.
again easier said for then done. this is why the craze to run gfo as of late. but again that does not remove no3... hence the reason people are dosing carbon to begin with, to lower nutrients. for most advance aquarists it's keeping the nutrient levels elevated, by the input of food because their export is so good....they will tell you the effect of too low nutrient.
OT, how are the sps responding to freshly hatched artemia? also do you dose any enzymes or nitrogen specific supplements?
eric
obviously you have access to lab grade test, i myself and many others do not. but using a hanna photometer .oo2 is certainly the range many shoot for. i would sya this is the sps keepers ideal way of po4 measurement.... this would show up as zero on all hobby po4 tests except for possibly deltec/merc. i'd say it's not common knowledge that 0 po4 isnt wanted or always a good thing. as you know a true level of zero po4 would be very bad for the animals we try to keep.
again some people running bacterioplankton as well as the ocean are different stories. that po4 is being used up quicker than it can be tested for because of the diverese organisms within. the same is true with algae infested tanks... :lol:
the waiki aquarium isnt exactly a far comparison, fresh sw is certainly a plus.
again easier said for then done. this is why the craze to run gfo as of late. but again that does not remove no3... hence the reason people are dosing carbon to begin with, to lower nutrients. for most advance aquarists it's keeping the nutrient levels elevated, by the input of food because their export is so good....they will tell you the effect of too low nutrient.
OT, how are the sps responding to freshly hatched artemia? also do you dose any enzymes or nitrogen specific supplements?
eric
MCsaxmaster
New member
Yup, we've got a big, expensive (~$60,000, I think???) autoanalyzer (not sure of the specifics as I'm really not a nutrient guy) in the lab next door/our co-lab that is used to run nutrient samples for just about anybody that needs to through the university (I'm a marine bio. MS candidate). The hanna photometer, what are the units on that 0.002 reading? I'd suspect that they are giving you ppm PO4-P (parts per million of phosphate phosphorus) and not PO4, which gives deceptively low readings. At very low nutrient levels it's hard to detect the signals, requireing pretty good equipment.
I'm not sure that corals "need" any dissolved orthophosphate, but they'll certainly use it if it's available. Usually, due to the good waterflow on most reefs, they can take up some phosphate at even really low concentrations. Dissolved, inorganic nutrients are much less important in providing nutrients than things like zooplankton to corals in nature, but every bit helps. If it's there, they'll use it.
But, that's why there are low nutrients in the ocean in the first place. Organisms suck them up as quickly as they become available, and there are a lot of pathways that keep them in 'solid' form instead of being broken down into inorganic nutrients. This works essentially the same whether in a tank or ocean.
Ha, well I should point out that they use seawater from a well, not directly from the ocean. This water is pretty high in nutrients--much, much higher than what's in the ocean, and much higher than what is typical of their tanks. The critters in the tank just suck the nutrients up as fast as possible, leaving low dissolved inorganic nutrients in the water--just like in the ocean.
Sure, sure, coral reefs are not low nutrient systems. This has been misunderstood and debated in the scientific community since at least the 30's (and still is being debated). Reefs are huge storehouses of nutrients, but definition, as they are full of organic material (live and dead). They are poor in dissolved, inorganic nutrients, but not nutrients in general. Corals are used to very low DIN and DIP levels but pretty high zooplankton and bacterioplankton densities. That is normal for them.
They respond well enough, I guess? I mean, I just pipette them into their tentacles and they stuff themselves until I run out of brine shrimp. We only have a few species of coral--about 6--but they all seem to like the brine pretty much equally. Newly hatched brine is a pretty underrated food for reefs IMHO. No, we don't dose any enzymes or anything like that. The corals get light, brine shrimp, and occasional spikes of nutrients when we do water changes (using intracoastal water which has ~5 - 10 uM nitrate and ~0.3 uM phosphate--about 0.3 - 0.6 ppm and 0.03 ppm, respectively). What else would we give them? They seem to do fine though. We received just this week F2 planulae from Favia fragum that we have in culture. The original broodstock were collected about 2 years ago, some of their early progeny are about 1.5 years old (produced, settled and grown in captivity) and these progeny have just released planulae which we've also settled. Fingers crossed to getting to F3!
Chris
RichConley
New member
Sugar dosing is no more risky than calcium dosing.
People just aren't nearly as careful with it, because its "just sugar".
You wouldnt just dump a scoop of baking soda in your tank without knowing how much you need, right? Well, thats exactly what most people do with sugar.
MCsaxmaster
New member
Rich
Hmmm, I'm not sure I'd necessarily agree, but point well taken. If folks were as careful dosing sugar as to calculate the final concentration (and increase in microbial biomass and potential increase in BOD from such an increase) similar to what they do if, say, dosing calcium chloride, this would be a much safer practice. I still don't feel it would be safe on par with dosing calcium or alkalinity or something like that though.
Best,
Chris
Hmmm, I'm not sure I'd necessarily agree, but point well taken. If folks were as careful dosing sugar as to calculate the final concentration (and increase in microbial biomass and potential increase in BOD from such an increase) similar to what they do if, say, dosing calcium chloride, this would be a much safer practice. I still don't feel it would be safe on par with dosing calcium or alkalinity or something like that though.
Best,
Chris
