morphriz;13671 said:
I have seen no experimental data that high levels of NO3 limit the process of calcification, and I mean the chemical process itself.
I agree.
In the case of Macros the study you cited about macroalgae indicates that non calcifying macroalgae may outcompete calcifying when N and P is dosed. That again has nothing to do with the depositing of CaCO3 itself, only the relative competitiveness of the different algae.
I think, at least I would predict, a faster growth rate for the non CaCO3 macro.........although many can and do grow fast that have a CaCO3 deposit. Probably have to take a case by case approach for each species.
There is however significant experimental data that points to the fact that high levels of NO3 has negative effects on the coral as a whole.
In CA, USA, we have corals as well, but not reef building to the extent of the tropical types. We have massive growth of macro algae and some corals, the issue is whether it's inorganic derived NO3 or organic, most of the kelp forest all have cooler nutrient rich water. Same with tropical diatoms.
Theorized by some that nitrogen is used by the coral to manage its zooxanthellae. High levels of NO3 leading to zoox. overcrowding, coral browning, and also coral bleaching, coral ejecting it's zoox.. Stressed corals calcify less. Again, no direct connection between NO3 and calcification. Also there is the theory on CO2 limitation in the coral, reducing calcification, from higher zoox. activity as in your cited article Patrik.
All these are plausible hypothesis. I'm not nearly as privy to Corals as I am to plants and macros, but........I know when folks have not done experiments and what they often say and how they say it. It's as old as a broken record.
Do you again argue that high levels of NO3 does not affect a coral? Tom, your position?
How high is the question.
I take care of reef tank, some SPS's are present, large 200 gallon tank.
Refugium, lots of Caulpera, Chaeto, various reds.
I have about 5-10ppm of NO3 on average. There is a DBS.
I dose KNO3 into the sump weekly.
I really cannot say that much because I'm not a coral nut.
I am a fish nut and macrophyte nut.
So it's a bit outside of my particular area. I keep them and have no issues with color lost etc.
I do not have a coral tank to torture and experiment with, my interest lay with macro algae and some easier corals.
I suspect most reef folks do not have a spare tank to test out whether thigns are true or not.
You need enogh control growign both the macros and corals to make a realistic go. I can do both, but I do not have the time/space/$ to run it just yet.
It remains an unanswered question
I like stuff like that, I get bored redoing CO2 1001 times, so I need to think about what is the next step.
Fish and plant compatibilities are relatively easy to measure.
Coral and macro algae combos are another ball of wax.
Some are tempted to equate them, I'd caution against that.
When I discuss with other "reefers" on reef forums I argue that a higher nitrogen flux is necessary. In starved systems, heavily skimmed, that means holding a measurable nitrogen level. In "high-bio" systems, like the nanos of Lasse Forsberg or Eric Bornemans skimmerless tanks, that flux comes from organic nitrogen. Mostly from bacterial biomass. This also implies dosing may be necessary in some cases.
That's my arguement as well, the fraction that is used are different forms, organic vs some top off with inorganic.
I've stated this with FW plants as well.
I've found you simply do not get skimmate even with a well run skimmed system if you have a well run refugium.
So it's the plants that strip things out of the tank, not the skimmer when both are running on the tank. At least that's what I see.
No skimmate. Maybe I need a monster 500$ skimmer, but the Berlin Red sea thing does not make any with 500gph running through it, so what else am I to think that seems plausible?
You have also seen me argue in many places that NO3 may have to be dosed in starved reef systems using macroalgae as the primary export. This is to offset the relatively few N export paths in comparison with P export paths.
Exactly and well said, then you have both PO4 and NO3 well balanced. I think
if you drive one nutrient to a limitation, it's preferable to have it be PO4. Low NO3 as well makes things tough to grow, most plants will grow under PO4 limitatiosn much better than with low PO4.
The other issue with the recycled NH4 from within the organisms: you cannot test it for N or P, it gets used up and since it's a limiting nutrient (either of them can be) it is tough to get a handle for a test method to follow the amount of N through the system other than trace isotope fractionation.
You could never measure any NH4 but you know it's being used up rapidly without ever making it to NO3.
Also, how much is losted due to Denitrification. I really do not know for either, but there's some fairly straight forwards such as N2O measurement.
Again, nothing a hobbyists could do but something a research could rapidly figure out after a few weeks once the De NO3ers get established.
None of note is disputing your sound claims or trying to stop you from carrying out your interesting experiments. Several are arguing against your clearly incorrect claims. You have also, as I interpret your results, empirically proven some of your own claims to be false. Because we do not agree with you to 100% does not mean we disagree. In fact I'm still very much interested in your experiments.
//Mattias
I think we all learn by making mistakes and correcting them once we know better and try to improve our knowledge base. I know many things today and would rail on myself for suggesting things I did years ago.
CO2 measure would be one, yet I was able to eye ball things well a long time ago, still, that ignorance then helped me think better today and opened up other questions.
1. Coral growth in high-nutrient, low-pH seawater: a case study of corals cultured at the Waikiki Aquarium, Honolulu, Hawaii
SpringerLink - Journal Article
Okay that's what I pretty much expected to hear. But I reall think there something more to this paper: stability of those nutrient levels.
We can export/import Carbon easily.
Adding marine plants provides a good source of Carbon, this means not Carbon limitation(organic carbon, not CO2, that's a whole other issue).
I think many reefer keep their systems too clean and remove all the Organioc carbon, that stresses the algae/bacteria/corals to some degree.
The system becomes increasingly more sensitive/squirrley and some reef folks resort to draconian measures to control the PO4, strip the water with skimmers etc.
So one issue makes the next even harder in terms of management and complexity as well as cost.
Why forcue natural systems to be so rigid and set them up to have issues like this? I try and be practical about this.
I need to read the rest of the papers, not just the abstracts.
But..that will have to wait till after mid terms
Regards,
Tom Barr