Dinoflagellates.

[crashmushroom]

Cool cheers for the help. What does the vinegar do?

[crashmushroom]

and am i reading that right do you mean the growth on your screen reaches 6 inches?

[Floyd R Turbo]

I think he means 6" longer than nthe screen. He posted a pic a while back of his growth hanging off the bottom of the screen

[kerry]

The vinegar makes the Ca count more because it does not precipitate out as much. Here is a pic of the growth.

[Garf]

Trying to tie up a few things i have learned recently.

Apologies for dragging up an oldish topic but considering cyano and dinos ( in the wild ) thrive in areas where the natural balance of phos and nitrate is skewed by land run off water, is it not safe to assume that ;

A). Algae outcompetes dino and cyano for nutrients when the nutrients are roughly balanced.
B). Algae exudate feeds the bacteria which in turn restricts further the nutrient availability for cyano and dino's.
C). In the event that phos and nitrate levels in an aquarium become severely skewed, the cyano and dino's get the upper hand due to the algae being unable to grow properly which also affects the availability of bacterial sugars, which further promotes cyano etc.

I know (C) is a bit questionable but seems to tie in with what I have seen generally. Lower the levels are, the more the difference in ratios are affected.

I guess what I am saying in essence that maybe the "ratio" is a lot more important than has previously been assumed, especially when nutrient levels are low.

[SantaMonica]

where the natural balance of phos and nitrate is skewed by land run off water

Why this assumption?

Algae outcompetes dino and cyano for nutrients when the nutrients are roughly balanced.

Depends.

In the event that phos and nitrate levels in an aquarium become severely skewed

Which way?

due to the algae being unable to grow properly

Algae grows fine in almost any combination of N and P, since the algae alter their assimilation ratios.

[Floyd R Turbo]

Why this assumption?

It wasn't an assumption, he was saying if the area has skewed N and P due to runoff, not assuming that all runoff skews N and P

Algae grows fine in almost any combination of N and P, since the algae alter their assimilation ratios.

I would contend that difference algaes assimilate at different rates/ratios. One particular strain/species of algae I would not think could "change" it's uptake rate. So a mixed bed of different strains would result in an effect by which growth of one strain over another would depend on the nutrients available, however once a nutrient is limited, all growth would be limited by the lack of availability of that nutrient.

So most algae would not be able to grow very well, if at all, if the combination of N and P was either one being zero.

[Garf]

Found this just because I wasn't expecting that response from SM to be honest. You gotta read all this to show the latest thinking. Especially with regard to co2 levels. A quick skim over did the trick for me;
http://www.epa.gov/cyano_habs_sympos...graph/Ch33.pdf

This discussion relates back to a paper by Smith (1983)that suggested low TN:TP ratios are responsible for cyanobacteria domi-nance under eutrophic conditions. This hypothesis is consistent with re-source ratio theory and was supported by observations from some temper-ate lakes with varying ratios of TN:TP. Since that time, certainobservational and experimental studies have shown that cyanobacteria be-come increasingly dominant at low TN:TP

Going by SM's recent posts relaying the fact that denitrifying bacteria do not consume phosphate, this leads to more evidence. This would imply a phosphate gradient within the sand bed. Where does cyano normally occur ? Yes, on the sandbed !!!

[Garf]

This may not only apply to this topic but others where nutrient skewed effects are noticed. The algae requiring LOWEST nutrients become dominant. Therefore algae doing the LEAST filtering become dominant.

http://www.public.iastate.edu/~kmolo...eRatio.htm#two

I will probably take a bit of beating over this but if this theory is correct then nitrate limited screens probably started out as high ratio screens which then became PHOSPHATE limited. This starved out the normal ratio algae and low nitrate : phos ratio algae took over the screen. This new algae could use more nitrate than phos, leading into a skewing of the filtration balance leaving more phos in the water column. This low ratio algae could also assimilate ammonia faster to supplement the nitrate limitation that it has caused. Hence the rise in phos. If anyone can prove this theory wrong I am happy to hear about it, after all it contradicts the teachings so far and I am not here to cause upset, just to help improve this technology if I can.

[SantaMonica]

I would not think could "change" it's uptake rate.

You'd be surprised. I should have saved the studies that followed the uptake rates. The ratios change based on what proteins the algae manufacture.

So most algae would not be able to grow very well, if at all, if the combination of N and P was either one being zero.

But of course they are not zero. GHA will grow pretty well when test kits measure zero, if there is a flux of nutrients from feeding.

cyanobacteria become increasingly dominant at low TN:TP

Makes sense, since they fix N.

This would imply a phosphate gradient within the sand bed. Where does cyano normally occur ? Yes, on the sandbed

Their certainly is a fluxing gradient on the bed, when external P filtering is high. However when external P filtering is low, the flux and gradient of P on the bed is reversed, as the P going back into the sand. Same with rocks.

However I think the "cyano on the sand bed" thing has been shown to just be settled food particles, which supply C directly. A powerhead takes care of this.