Hi Darrel,
Nutrients alone will not trigger a bloom. Once the bloom occurs the nutrient concentration may be a factor in rate of growth, so that's where the "potential" would come in, and I'm not even sure that it does because I've seen some brutal algal blooms in nutrient starved tanks, which leads me to believe that algae don't even care that much about nutrient concentration even in the vegetative state. We've shown that they certainly don't care when they are in the spore state.
I think people don't pay enough attention to the transitive nature of algae and the existence of the two states. We've observed that plant health, more so than just plant growth, is a stronger factor in determining whether or not there is a bloom. The path to plant health lies in availability of those very same nutrients others decry.
In your tank, I'm fairly certain that despite your claim of low nutrients, that there would be plenty of nutrients in the sediment due to reclamation of plant biomass from decaying tissue, food and fish waste. There may even be nutrients in the tap you use for water changes as well, although I don't really know that, and of course that wouldn't be true if you're using RO. As you mention, the long term stability of the tank allows the plants to adapt to the lighting levels, to become better CO2 gatherers, and allow shading or other adaptations to the light energy. But I'm pretty sure that did not happen overnight.
It's a similar story with Viktors observations:
There's plenty of evidence that these plants don't need massive lighting, but that they definitely have a higher LCP than say, that of a fern, or a moss. As I always say, difficult plants are difficult because they require better flow and more CO2, not just because they have a higher LCP.
Cheers,
The problem with lumping all autotrophs together is that they each will have different mechanism. So it's easy to say that Growth Potential is increased for all with increasing nutrient concentration, but what we are saying is that the triggers are not the same for algae as they are for Macrophytes. The mechanisms are similar but not exactly the same. Algae have the spore and vegetative states. The only analog you could compare with Macrophytes would be stem and flower. It's really difficult to predict, for example under what conditions a submersed macrophyte would flower. Nutrients alone would not necessarily do it but may be part of the trigger equation. It appears to be a similar story with algal blooms, because they bloom from spores.dw1305 said:
Nutrients alone will not trigger a bloom. Once the bloom occurs the nutrient concentration may be a factor in rate of growth, so that's where the "potential" would come in, and I'm not even sure that it does because I've seen some brutal algal blooms in nutrient starved tanks, which leads me to believe that algae don't even care that much about nutrient concentration even in the vegetative state. We've shown that they certainly don't care when they are in the spore state.
I think people don't pay enough attention to the transitive nature of algae and the existence of the two states. We've observed that plant health, more so than just plant growth, is a stronger factor in determining whether or not there is a bloom. The path to plant health lies in availability of those very same nutrients others decry.
In your tank, I'm fairly certain that despite your claim of low nutrients, that there would be plenty of nutrients in the sediment due to reclamation of plant biomass from decaying tissue, food and fish waste. There may even be nutrients in the tap you use for water changes as well, although I don't really know that, and of course that wouldn't be true if you're using RO. As you mention, the long term stability of the tank allows the plants to adapt to the lighting levels, to become better CO2 gatherers, and allow shading or other adaptations to the light energy. But I'm pretty sure that did not happen overnight.
It's a similar story with Viktors observations:
Viktor I reckon a lot has to do with CO2/flow/distribution. It's easy to get good flow in a 30cm nano but not very easy to get good flow in a 240L behemoth. Here is D. diandra and P. stellata under a low light condition. The nutrient loading was, as usual for me, quite massive. Flow/distribution was excellent. Now, fair enough, I got bored and added huge levels of light, causing the stelleta to smother the diandra into oblivion.viktorlantos said:
There's plenty of evidence that these plants don't need massive lighting, but that they definitely have a higher LCP than say, that of a fern, or a moss. As I always say, difficult plants are difficult because they require better flow and more CO2, not just because they have a higher LCP.
Cheers,
