Aquatic Plant Forum banner
41 - 60 of 129 Posts

·
Registered
Joined
·
137 Posts
I am intrigued by the amount of knowledge that Tom has.

I do have a few specific questions for him:

I was reading a post by Adrvark in the "New to aquarium plants" forum under the "Fertilizers and chemicals that you dose?" thread and it once again got me thinking back to limnology days again. Ardvark referenced Tom in his quote:

"According to plantbrain optimum algae environment includes high light, moderate-to-high NH4, low NO3, varying CO2 and just about low everything else."

So initially I thought this might make sense most algal blooms in newhampshire occur between late spring-early fall. I initiall thought this was due to the cycling of nutrients as the thermoclines change and the water mixes. I then began to think maybe this could be due to the fact it is summer (high light) and during this time the farmers in the area are fertilizing their crops (run-off into the local ponds and estuaries may lead to eutrophication).

Then I remembered a post somewhere someone saying that you should not use terestrial platn fertilizers in aquarium tanks because the N source is usually from ammonia and may kill the fish. If the farmers are fertilizing with ammonia based fertilizers this would lead to the mid to high levels of NH3 required by algae. So there you have two of the factors that cause algae blooms or eutrophication.

My only hesitance to this statement is an experiment I remember seeing in my limnology book. Now keep in mind I haven't seen my book in about 5 years so the facts may be skewed (correct me if I am mistaken). In the experiment they divided a pond/lake into two sections with a plastic divider. To one half of the lake they added a source of nitrogen. To the second half of the pond/lake they added a source of nitrogen and a source phosphate.

Only the side with added phosphate had an outbreak of algae. This, I believe, was the main experiment leading scientists/environmentalists to charge phosphate as the cause of algae outbreaks. If I remember correctly the outbreak was actually BGA so this experiment may hold no validity.

So Tom, do you know what the factors are that actually lead to eutrophication of lakes/ponds? Do algae outbreaks coincide with lake cycling? Does the classic experiment with adding nitrogen and phoshporus hold any water?

Thank you in advance for any information you may have :)

Ken Takeuchi
 

·
Registered
Joined
·
46 Posts
I have a really dumb question, what is the ei and pps system and where would I read about them?
 

·
Registered
Joined
·
13 Posts
Inorganic vs. Organics

I've been gone some time, but I've been lurking. And since this thread is interesting...

The more I experiment, the more I think the algae equation is based at least partly on whether nutrients are organic or inorganic. For the most part, plants can't uptake organics directly, they need bacteria or something to breakdown organics into inorganics. Algae, and especially cyano, can use (simple) organics directly.

My guess is that tanks with low organics (e.g., fish waste, decaying plants) will have less algae. This is what happens in clean, established tanks. Adding mulm helps because it hastens the process.

Dosing inorganics (e.g., PO4, NO3, K+, etc.) will not give algae a benefit over not dosing inorganics. Why? Because you can't nutrient limit algae. I've read algae can prosper with PO4 in ppb range, and it is not feasible to get it into this range (unless you want to run "reef" style). So, you might as well add inorganics to help out the plants.

In addition, some organics, like urea, break down into NH4 quite rapidly. Tom has already said that NH4 has some positive correlation with algae growth. I guess that would be another topic, though.

For reference, my tank is "old school" no water column fertilizing (see <http://www.aquaticplantcentral.com/forumapc/showthread.php?t=2063> where some of the current topic was also discussed).
Peace,
 

·
Registered
Joined
·
298 Posts
Your post, McFinn, summarize exactly my own thoughts. Mostly based on my own tanks running on EI and Walstad and all the info Tom Barr gives us.

This also explains why tanks relying completely on the substrate to mineralize organic nutrients have times of "inexplainable" low growth: Mineralization is inactive due to any number of billion reasons.

EI removing substrate from the whole equation is, to me, why EI is superior compared to any other regieme where one has to rely upon substrate mineralized organic bound nutrients.
 

·
Registered
Joined
·
4,700 Posts
I have seen that, when N and P are at very low or undetectible levels, various kinds of algae get going almost secretly because they are yillowish or brownish colored. When N and P are added the algae greens up and suddenly become much more visible. When N and P are very low, snails decline even when the soft, surface-coating types of algae are on the increase. When things green up, the snails start growing and multiplying again. I would like to advance the hypothesis that snails play an important part in the control of soft alage---not hair algae---and that when N and P are low, the algae is so low in nutritive value that the snails starve to death eating it. With N and P high, the algae is nutritious, allowing the snails to multiply and eventually eat it all up.
 

·
Registered
Joined
·
13 Posts
Edward said:
How to explain algae free aquariums with no water changes, inert substrate and high light? Where is the organics negative impact?
Hi Edward,
There are no organics entering in the setup you just described. This is kind of like buying 1 gallon of drinking water, adding some inert gravel and some inorganic nutrients, and then placing it under high light. Result: No algae.

Overload the tank with fish and no filtration, and then you will start getting organics and then algae (I think). Under light load and properly established filters, the organic fraction will quickly deteriorate into inorganics.

Think about this simple experiment: Add a tablespoon of an organic fertilizer, like steel manure, to say a 5 gallon tank. In another tank, add 1 tablespoon of the theoretical equivalent amount of inorganic NO3, K+, PO4, TE, etc. Which tank would get more algae?

Just to be clear, I am not saying that organics are the only reason for algae.

Peace,
 

·
Premium Member
Joined
·
2,035 Posts
McFinn K. said:
Hi Edward,
There are no organics entering in the setup you just described.
Yes there is fish and snails that I feed beef heart. Additionally, there is no filtration, just one air stone.

This is kind of like buying 1 gallon of drinking water, adding some inert gravel and some inorganic nutrients, and then placing it under high light. Result: No algae.
Actually I tried it and the water turned green.

Think about this simple experiment: Add a tablespoon of an organic fertilizer, like steel manure, to say a 5 gallon tank. In another tank, add 1 tablespoon of the theoretical equivalent amount of inorganic NO3, K+, PO4, TE, etc. Which tank would get more algae?
I would expect the manure tank developing algae first; however there may be the benefit of insect and microorganism infestation that will consume the algae turning the water clear.

What do you think?

Edward
 

·
Registered
Joined
·
2,173 Posts
plantbrain said:
NH4+ is worth more and is a good signal for a successful bloom in natural systems than other parameters, it tells the algae spore that no one(no other autotrophs) else is around.
I'd like to add to this statement. One of the things I found most interesting in a class I recently took was the concept that NH4+/NH3 are actually toxic to plants, even though it is less energy intensive to finally use than NO3-. Since NH4+ is toxic, but nutritious, plants act quickly to sequester it in their cellular vacuoles until such times as they can synthesize it into proteins.

I'm a firm believer in NH4+/NH3 = algae bloom. I just had a load of native plants drop their emersed leaves in one of my tanks while at the same time they didn't grow submersed leaves too well. All that decay = NH4+/NH3 + high light + CO2 => lots of algae

I also did a little experiment outside in some buckets that I'm using for emersed culture. Both containers were right next to eachother so light and temperature equality weren't issues. One had old tank substrate, the other didn't have any, and both had a high biomass. At first I was using my normal aquarium fertilization regimen on the buckets (Stump remover, enema, and the like). I got good growth from this routine. After a month I added a 1/2 tsp of MiracleGro Rose Food (Urea/NH4+ based) to each container which immediately resulted in algae.

The container with the substrate exhibited significantly less algae than did the water only container. This was only a secondary observation but it seems to support the mulm-seeding hypothesis.

For a long time experienced and knowledgable aquarists have said that well growing plants = little/no algae. That's because healthy plants act quickly to remove NH4+/NH3 from the water. Just like Tom asserts, low NH4+/NH3 = "Something else is living there, stay dormant and wait for a better opportunity." = little visible algae.

What about cyanobacteria? At this point I feel it has to do more with O2 content and organic compound concentration with preference for organic compound concentration. 99% of the time when I have a problem with BGA it is in areas where lots of mulm has accumulated and there is little water circulation. That poor/no circulation allows a microclimate that gets hypoxic/anoxic quickly from the respiration of decomposing bacteria. Once that happens anaerobic bacteria such as BGA are able to colonize and thrive. Once the area is aerated again and/or the mulm is removed BGA no longer do well and die off/move to another area.

I've observed a lack of BGA even in dense stands of well growing stemplants where there is little current and decent mulm accumulation, but high available oxygen from healthy growth and photosynthesis at the lower levels. I also saw a lack of BGA in one of my early tanks where the growth wasn't as good, but there was a spraybar along the entire bottom portion of the tank right at substrate level keeping the area oxygenated.

My two-bit hypotheses,
Phil
 

·
Premium Member
Joined
·
2,309 Posts
Great post Phil!

What you say re NH4 makes perfect sense and is well explained.

It leads me to the question of organic build-up and mulm in tanks. Is the goal to keep the substrate (at least the top couple of cms) free of build-up? I can understand this for open areas of the substrate but even for planted areas?

When I do water changes, I usually run the hose lightly over the surface of the substrate to get the most obvious build-ups but never paid that much attention to build-up in the heavily planted areas. However I constantly hear of people doing their water changes by just draining and filling (Tom B mentions this often when he's talking about how little time it takes him to do water changes); no vacuuming at all. Maybe they just vacuum once a month or so?

Also I had no idea BGA was anaerobic. That could explain some things...
 

·
Registered
Joined
·
2,173 Posts
I don't know if the aquarium species is the same as the terrestrial types, but it's cyanobacteria that are responsible for nitrogen fixation in a number of ecosystems. I think BGA are the organisms that innoculate legumes as well. I'll have to check on that.

I say all this about BGA while I have a major problem with it in my 20g. That stuff loves bare FloraBase! :( Does anyone have any available fast growing carpet plants? I'm getting sick of the stuff and the beautiful Saggitaria PK sent isn't growing fast enough.

Regards,
Phil
 

·
Registered
Joined
·
2,173 Posts
plantbrain said:
I'm not sure it's the presence of these, but rather the loading rate.
If the loading raste exceeds the bacteria break down of these, then you'll get BGA or BBA I think also.
That makes sense, I've got a significant problem with both types in the tank right now. On the up side, my filter hardware and heater are less obtrusive because they're "planted" with BBA now.

I enjoyed Phys. It's strenuous to take as a summer course, but it was fun.
 
41 - 60 of 129 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top