What exactly causes BBA? Part 2 - Bacterial imbalance

[BruceF]

I think there is some process in the leaves of healthy plants that involves h202 and therefore keeps algae at bay. I've read about this but I am not sure of all the details.

 

[rebel]

Has anyone with the know-how started an experiment that can falsify the initial OPs hypothesis? I am guessing that you only need two tanks? One with and one without available B12.

Can anyone reliably grow BBA though?

Or am I way off the mark here?

 

[Guest]

Add ammonium and B12. If true, then a BBA outbreak should occur.

 

[AndyMcD]

Has anyone with the know-how started an experiment that can falsify the initial OPs hypothesis? I am guessing that you only need two tanks? One with and one without available B12.

Throughout this thread I've provided links to published papers (that must have been through a peer review process). Please take a look at the following abstract:
- Title speaks for itself
- Published in Nature - Well known scientific publication
- Written by University of Cambridge and University of Kent
- Published in 2005 (i.e. 10 years to disprove)

Algae acquire vitamin B12 through a symbiotic relationship with bacteria
http://www.nature.com/nature/journal/v438/n7064/full/nature04056.html

Before starting any experiment, it's recommended to determine what others have proved to narrow down what you are looking at. In the 'What exactly causes BBA?' thread there was discussion about a series of experiments to prove the causes of BBA outbreaks. However, there were so many suggested causes (apparently unrelated) that a properly controlled experiment would have been massive, requiring a big investment in time and money.

What I'd hope to do in this thread is propose a model based upon published scientific information, that seemed to fit the reported causes / suggested controls.

At some point I'll try and pull together an experiment to test this. However, I'm sure Cambridge University have done a better job than I ever could. If they're convinced enough to publish this, I'm not sure how you would go about disproving it!

However, if I was going to try growing BBA, I think I would:
- seed the tank with BBA algae
- add mature aquarium water / gravel / pebbles to transfer in heterotrophic bacteria. Alternatively, organics from the mechanical filter
- dechlorinate the water. Don't use glutaraldehyde
- provide a substrate to grow on with a high Carbon/Nitrogen ratio (C/N ratio), e.g. driftwood, damaged slow growing leaves, melting crypts.
- add a source of carbohydrate. There are shrimp farmers who cultivate heterotrophic bacteria for the shrimp to eat, who add carbohydrates to the water as an energy source for the bacteria (I think molasses was mentioned). They aimed for a C/N ratio > 10
- provide O2, CO2 (bicarbonates) and ammonia to feed the bacteria and grow the size of the population
- add vitamin B12 and / or switch off O2 for periods to stimulate B12 production
- provide CO2, ammonium and phosphate for algae growth
- add nutrients, to ensure no deficiencies
- consider adding limestone to buffer water, provide bicarbonate to prevent pH dropping too low
- keep temperature between 20 and 25 deg C
- provide light at between 50 and 70 PAR for 12 hours (found a paper, but still trying to figure what the results mean, but suggestion is that algae prefer lower light for longer)

 

[AndyMcD]

It's irrelevant which nutrient the plant is deficient in. It's got similar response whether it's iron, other micros, nitrogen or potassium, Co2, etc...,

Sciencefiction, I agree with this.

I suspect that this leads to the plants releasing organics, which feeds the heterotrophic bacteria.

I wonder if this increases with light intensity, with insufficient CO2.

I can't find much evidence that algae likes high light intensity. Autotrophic and heterotrophic bacteria don't need light.

 

[NC10]

No scientific reply from me, but I had BBA in my heavily fed but heavily filtered tank, in low light and in high light areas. Only thing in common with where the BBA grew was that it was a high flow area.

I either scraped the wood to remove it, or dosed the rocks with easycarbo to kill it and just reduced the flow significantly. A month on and no reappearance, job done.

 

[Yo-han]

High flow or close to the filter where B12 was produced

 

[AndyMcD]

I think there is some process in the leaves of healthy plants that involves h202 and therefore keeps algae at bay. I've read about this but I am not sure of all the details.

This paper discusses the role of H2O2 in plants, including when under stress "
The role of hydrogen peroxide in regulation of plant metabolism and cellular signalling in response to environmental stresses"

http://www.actabp.pl/pdf/1_2007/39.pdf

 

[BruceF]

I can’t say I understand all this but my limited understanding is that healthy plants have a number of defense mechanisms against algae. (PH is another one I believe) The point being that healthy plants don’t host algae.

I suspect that it is the o2 levels that affect the bacteria colonies and alter that balance that are the catalysts for most if not all algae problems. (More decay, less o2 perhaps more b12. )


The key thing being orp or redox or some other chemistry I don’t understand.

(I take large doses of b12 all the time for an anemia problem I have. So I have a ready supply. )

 

[sciencefiction]

I wonder if this increases with light intensity, with insufficient CO2

If we're talking about anubias, it obviously doesn't like high light. But it surely doesn't care about high CO2 much. And a tank never runs out of CO2 completely. Plus higher light doesn't always mean the plants run out of CO2. Higher light lowers the CO2 compensation point in some plants. Higher CO2 lowers the light compensation point. But neither can do anything about compensating for a nutrient deficiency.

Experience wise, when the sun starts blazing at my small tank next to the window(in the summer this happens until 10pm in the evening as it's still bright here at 11ppm on the longest days), I keep getting nitrogen deficiency on my stem plants and I also got green spot algae this summer on a few anubias leaves, which went away with a few generous feedings of actual fish food as I've got no phosphate. I've never got BBA in there. There isn't much stock in the tank, just shrimp and they aren't fed every day so the tank is low in organics as well I suppose. But for the most year the tank is spotless clean of any algae as it is right now. I just snapped off the green spot on the anubias leaves and haven't seen that algae since. What I am trying to say is that light doesn't trigger BBA, but more likely other nutrient related algae.

Green dust is also one of those that tends to appear when light is a bit too much but I think it's one of those algae types that likes higher nutrient content. I once put two containers on the window sill with floating plants(salvinia). I dosed one with all sorts of ferts and left the other with just tank water. In a few weeks the one with the ferts was covered in green dust algae and the one without had no algae at all but the floating plants in it weren't looking as good.

 

[AndyMcD]

Sciencefiction, thanks for the reply.

I went away on holiday and came back to some of my anubias covered in BBA.

Only in mid summer does the sun swing around far enough to shine on the tank. I'd had a little bit of a BBA issue before I went away, in the sunniest spot.

Before going away I'd applied neat Easycarbo, but didn't realise that I had burnt the leaves. It was the affected spots on the leaves where the BBA was worse. This made me wonder if the bacteria breaking down the damaged leaves could have a relationship with the growth of the algae.

However, I don't understand why brighter light causes algae issues, especially on anubias.

According to this paper, Rhodophyta algae prefer lower light intensities (65 vs 300 PAR), but longer photoperiods (16 hours vs 8 hours) and warmer temperatures (20 to 25 deg C).

http://www.researchgate.net/profile...in_culture/links/555ca06208ae6f4dcc8bc9a2.pdf

In mid summer, the uncontrolled light due to a brighter room could effectively be making the photoperiod a lot longer, which may help the photosynthesising algae.

The autotrophic bacteria on the leaves may not have liked the blue light / UV from the direct sunlight. If the autotrophic bacteria have become dormant or died, then the heterotrophic bacteria could have gained the surface area.

The heterotrophic bacteria doesn't care about light.

If the conditions were ideal for the algae, could they be creating more organics for the H. bacteria with the correct building blocks it needs to create vitamins. The sunlight may provide more energy to make this possible.

Sunlight may warm the water, which may be helping the algae grow. Henry's law may mean that the water can support less oxygen, favouring the H. bacteria and inhibiting the A. bacteria. A drop in oxygen may mean that the H. bacteria begun to act anaerobically and produced more vitamin B12.

However, what has any of this got to do with anubias leaves in particular? Why do anubias have to be in the shade? Why does the algae grow on the leaves and not the rocks?

As you say, anubias aren't massively dependent on CO2. They aren't fast growing.

I wondered if slow growing plants are more susceptible as biofilm is able to build up on them more easily, a fast growing expanding leaf stretches the biofilm.

Or do anubias leaves release organic carbons which the H. bacteria thrive on when they are stressed? Could the leaves be the perfect C/ N ratio for the H. Bacteria?

 

[sciencefiction]

However, what has any of this got to do with anubias leaves in particular? Why do anubias have to be in the shade? Why does the algae grow on the leaves and not the rocks?

I've got anubias with leaves that are probably 5 years old, as old as the plant. I'd presume that although they may seem fine to me visibly, they need to be removed because of being organic factory bombs. I am not sure why anubias does better in lower light. Perhaps it's not the light the problem but a combination of things. To keep several years old leaves healthy looking is a challenge, bigger than growing stem plants in a co2 injected tank. Because once anubias get riddled with algae, you need to wait all over again for ages for it to regrow even if you fix the cause. So it's just safer having it in a shaded place.

 

[sciencefiction]

Here's a picture of an anubias plant I've had for 5-6 years. It's in the tank next to the window. For an anubias plant, it gets enough light where the tank is, plus artificial. I chopped off half of it last year because it took over the entire substrate surface and my stem plants couldn't go through when I trimmed them. It absolutely started flourishing a couple of years back when I put soil underneath the sand. It has "wear and tear" but no algae, no BBA and the tank only has snails and shrimp as inhabitants so I doubt it there's much organics. On another hand another tank of mine at the same time for the same period of time had anubias riddled with BBA, overstocked tank as well, plus inert sand and anubias hanging from driftwood and stones and not planted in the substrate, except for one bunch. No direct sunlight there.

 

[AndyMcD]

I've got anubias with leaves that are probably 5 years old, as old as the plant. I'd presume that although they may seem fine to me visibly, they need to be removed because of being organic factory bombs.

This makes sense. Either:

- the leaves begin to signal (hormones / enzymes) that they're getting old (although they look fine) and the heterotrophic bacteria respond by building up a population on them. Keeping them shaded prevents this becoming an algae issue also, as there is less light energy for the algae spores to germinate and grow. Grazing clean up crew may keep the biofilm down and remove ungerminated spores

OR

- the leaves are able to stay on the plant longer because they're able to continuously replace the cells (this brush is ten years old - I've only replaced the head three times and the handle twice!), continually shedding old cells and replacing with new. The heterotrophic bacteria feed on the ejected old cells and respond by building up a population on them ... (as above).

There is definitely something fundamentally different about old leaves in comparison to new that the BBA responds to. I have crypts where one older leaf (but still OK looking) is riddled but new leaves are fine. As the heterotrophic bacteria are the organisms that break down the leaves eventually, are they just getting in early or do dying leaves just do a good impression of looking OK for a while. Maybe to keep on top of BBA, a ruthless attitude to pruning is essential.


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[AndyMcD]

The point being that healthy plants don’t host algae.

I suspect that it is the o2 levels that affect the bacteria colonies and alter that balance that are the catalysts for most if not all algae problems. (More decay, less o2 perhaps more b12. )

(I take large doses of b12 all the time for an anemia problem I have. So I have a ready supply. )

BruceF,

I agree with the points you made.

Since starting read about B12, I've become much more aware of how important to our health it is too.


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[AndyMcD]

I had BBA in my heavily fed but heavily filtered tank, in low light and in high light areas. Only thing in common with where the BBA grew was that it was a high flow area.

NC10,

In terms of BBA, flow seems to have the potential to be both a good and a bad thing.

In a clean and healthy tank, flow and distribution are essential for getting the CO2 and the nutrients in the water column to the plants. However, it may also be playing a role in terms of getting O2, ammonia, nitrite, bicarbonate to the autotrophic bacteria, not only in the filter but also on the surfaces and in the substrate.

However, I've also read on the forum that flow stirring up the substrate can cause issues.

The filter plays a role in capturing organics, which if they aren't removed by regular cleaning could mean that your filter becomes a heterotrophic bacteria factory. Yo-Han's suggested reading talks about this. As Yo-Han points out, particularly if the filter became clogged with organics, overwhelmed with heterotrophic bacteria and was becoming anaerobic, it could be spraying out vitamin B12 etc for the BBA to grow.

I can't quite remember, but I'm sure in one of the papers about producing vitamin B12 using Pseudomonas Denitrificans bacteria, they were mixing at 450 RPM.

The point is, if your water column is full of organics and oxygen (from photosynthesising plants) flow may also enable the heterotrophic bacteria population to flourish.

BBA in a high flow area has access to a greater quantity of passing nutrients.

Excessive flow may also damage plants.

Perhaps flow is an accelerator pedal.


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[AndyMcD]

Temperature could be another accelerator.


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[Guest]

So one thing I've observed is that when CO2 drops, non-filamentous algae grows on leaves of certain plants. If it's an issue with bacterial imbalance, why would this occur? Does this suggest that it's an issue with lower O2 levels? And why doesn't algae grow when plants are in a non-CO2-added tank?

 

[zozo]

If it's an issue with bacterial imbalance, why would this occur?

If its an imballance is debatable 🙂 but from what i understand of the whole story for short is: If there is to much or an excess of detritus (plant melt) there will be more bacteria pressent feasting on this. These bacteria secrete a stuff enzyme/vitamine which is a fert for algae.. I also observe that plant melt seems to induce algae growth.. I see algae on melting leaftips. I especialy noticed this on the potamogeton, first melt and than staghorn developing on those tips if not emediati;ly removed. 🙂 SO it looks like there's something to the story.. 🙂

 

[AndyMcD]

So one thing I've observed is that when CO2 drops, non-filamentous algae grows

This model is suggested for BBA. I don't think it will apply to all algae (although it may apply to some others). One of the papers referring to vitamin B12 dependency stated that it only applied to about 50% of the species of algae they had investigated.

algae grows on leaves of certain plants

Please read on as I've read another paper which I think may be of interest.

And why doesn't algae grow when plants are in a non-CO2-added tank?

I think it can, can't it? One of my tanks has a goldfish in it. I frequently buy it Elodea to munch on. I used to have active carbon in the filter, which I changed infrequently. I was getting BBA growing on the driftwood, particularly where the sun hit the driftwood at certain times of the day. I keep a spray bar rippling the surface at all times. High organics (decaying plant matter / clogged active carbon), high C/N ratio (driftwood), high(ish) ammonia (due to goldfish), high light (for short periods), O2 & CO2 (due to surface ripple). Since I replaced the active carbon with filter media, paid more attention to cleaning the filter foam, scrubbed the driftwood, the BBA has reduced.

If its an imballance is debatable 🙂

To fit all the anecdotal evidence, it seems necessary for the nitrifying bacteria to suffer (e.g. increased ammonia). To create the compounds (spermine / spermidine) that red algae need to reproduce, the Urea cycle seems to be the start of the process. If the nitrifying bacteria are working at full capacity, ammonia / urea should be converted to nitrates and there may be insufficient concentration for the algae to reproduce.

from what i understand of the whole story for short is: If there is to much or an excess of detritus (plant melt) there will be more bacteria pressent feasting on this. These bacteria secrete a stuff enzyme/vitamine which is a fert for algae.

Yes, that's about it.

I also observe that plant melt seems to induce algae growth.. I see algae on melting leaftips. I especialy noticed this on the potamogeton, first melt and than staghorn developing on those tips if not emediati;ly removed.

Please read on. Potamogeton is relevant.

Previously, I was discussing with ScienceFiction why anubias leaves are more susceptible to algae, especially in bright light. I did another Google search and found this paper, which I think is quite interesting:
"Photosynthetic HCO3- Utilization and OH- Excretion in Aquatic Angiosperms (Light-Induced pH Changes At The Leaf Surface)" http://www.plantphysiol.org/content/66/5/818.full.pdf

I hope the following sketch may help explain what they measured:


They measured what happened to the leaves of Potamogeton lucens, Elodea densa and Elodea Canadensis when light was shone onto them. These plants are able to use negatively charged bicarbonate ions (HCO3-) as their carbon source, splitting them into CO2 and an OH- ion (a negatively charged ion responsible for increasing pH).

They found that when the lights were on, there was a higher concentration of OH- ions released from / accumulating on the upper surface of the leaf, increasing the pH (+2.5 pH) and also creating a negative charge. On the under side of the leaf, there was a corresponding drop in the pH. This effect was most significant in Potamogeton lucens.

These effects were reversed when the lights were switched off.

I think this is of real interest in this discussion for the following reasons:

1. This effect would be greatest in plants that are able to utilise bicarbonate as well as CO2 as their carbon source (plants from hardwater environments). This effect would be greatest for those plants where there is a distance in the leaf between where the bicarbonate is drawn in and the OH- ions flow out. This would provide a fundamental difference between types of plants (as some are less able to utilise bicarbonate), which may mean some are more susceptible than others.

2. A separate paper stated that plants typically prefer to use CO2 rather than bicarbonate as their carbon source, as it requires less energy to fix the carbon. Therefore, when there is an excess of CO2 available in the water, this effect may be less (no OH- ions therefore no increase in pH or charge with CO2). However, if CO2 is reduced, these plants may go to the next best thing and absorb bicarbonates, causing this effect to occur.

3. This effect is dependant on light intensity. Increase the light and (providing there is sufficient bicarbonate available) this effect will increase. The following paper suggests that Audouinella Pygmaea and Audouinella Hermannii both prefer longer photoperiods (16 hours) and lower light (65 PAR), which suggests increasing the light intensity won't necessarily be optimum for the algae. Could this increase in light intensity effect the bacteria in some way?
http://onlinelibrary.wiley.com/doi/10.1046/j.1440-1835.2001.00230.x/abstract

4. The Wikipedia entry for Nitrosomonas (autotrophic bacteria) states that the optimum pH range is between a pH of 6.0 and 9.0. In this experiment, the pH on the Potamogeton leaves reached a pH of almost 11.0. Could such an increase lead to the autotrophic bacteria becoming dormant / stop nitrifying / being overrun by the heterotrophic bacteria? The autotrophic bacteria are a million times more efficient at producing nitrites and nitrates than the heterotrophic bacteria. On the microscopic scale, does this production of a high concentration of nitrites / nitrates provide a defence mechanism, allowing the autotrophic bacteria to defend a surface and stop themselves from being overrun by the heterotrophic bacteria? If the light intensity increased and hence the pH on certain types of leaves increased and pushed the autotrophic bacteria beyond their upper limit, could they be overrun? Even if the pH exceeded the upper limit for both types of bacteria, the heterotrophic bacteria are more able to re-colonise as their populations can increase in size much more quickly. Once they have colonised the surface, are they then better able to support the BBA?

5. A potential difference in charge was measured between the upper and lower surfaces of the leaf, with the upper surface being more negative. Does this imply that charged ions close to the surface of the leaf would experience a potential difference gradient. Would negatively charged ions (e.g. HCO3-, HPO4 2-) flow across the upper surface towards the edge? Would positively charged ions (e.g. NH4+) flow across the lower surface of the leaf towards the edge? Could the charged particles be accumulating at the edge of the leaf ... where algae grows the best?

I could not find evidence of similar experiments performed on anubias leaves. Could this effect be the reason why anubias leaves should be grown in the shade to avoid algae? They may be better able to utilise bicarbonates. Their leaves are thick and may offer a spatial separation between the upper and lower surfaces.