My 40B keeps breaking out with cyanobacteria. What would cause this over and over? I've got an Eheim 2217, co2, medium lighting. Only thing that is different in this tank is that I use ada Amazonia as a substrate.
High phosphates are the primary cause, but high nitrates also contribute. Cyanobacteria do not need much light.My 40B keeps breaking out with cyanobacteria. What would cause this over and over? I've got an Eheim 2217, co2, medium lighting. Only thing that is different in this tank is that I use ada Amazonia as a substrate.
Poorly applied literature references tells a story, but does not support your claim. Was there shallow dense submersed vegetation in each study? No.......Doesn't really matter whether ya believe me or not, Plantbrain. The literature tells the story.
I have 3-7 ppm as PO4 at all times. Clearly quite non limiting to any and all BGA and any and all algae. This is NOT something new either, I've had high PO4 and have suggested folks to dose it since 1996 in articles.I'd hafta say ya don't have phosphates in excess of what yer plants are using.
Plants(macrophytes, this will include Chara and Nitella) are not competing with algae or BGA for nutrients. Light perhaps, but not CO2 or nutrients. The point where P becomes limiting is roughly 3ppb for most algae and BGA, for submersed plants, it's around 50ppb. This is over an order of maginitude.Yer plants are well-established and ya have enough light to keep growth at a pace that keeps algae and cyanobacteria blooms under control. If yer also dosing CO2, then the plants have enough carbon to use up the phosphates, leaving nothing or little left to promote a cyanobacteria bloom.
It is talking about total phosphorous, and not phosphates, though.Box 8.2 Thresholds for phosphorus control of different cyanobacterial ecostrategists
Knowledge of the prevalent ecotypes in a given water body leads to the following consequences for total phosphorus management:
• If scum-forming ecostrategists prevail (such as Microcystis spp. or Anabaena spp.) cell numbers
and biomass are likely to decline if total phosphorus concentrations can be brought well below 50
μg I-1 P. This will also reduce scum formation, because less cells and colonies will be available to
concentrate into scums. Nonetheless, some scums will probably continue to occur until
phosphorus limitation becomes so severe that cell density (and therefore turbidity) decreases to
the point where the depth of light penetration is as deep as the depth of large areas of the water
body (Zeu = Zm). Under these conditions, vertical migration of these taxa is less effective because
their buoyancy regulating mechanism requires some time in the dark (see section 2.2). Therefore,
they lose their competitive advantage over other phytoplankton.
• If dispersed ecostrategists prevail (such as the filamentous species Planktothrix agardhii,
formerly named Oscillatoria agardhii) very pronounced "switches" may be expected. As
phosphorus limitation reduces filament density, and thus turbidity, to the point where the
relationship of the depth of light penetration to the depth of the mixed layer (Zeu/Zm) is greater
than 0.4, these species are likely to disappear quite abruptly, and turbidity will increase even
further, thus stabilising the result.
• If metalimnetic ecostrategists prevail (such as Planktothrix rubescens), the water layer above
these cells is usually quite clear. Very low concentrations of total phosphorus (often below 10 μg
I-1 P) are necessary to decrease turbidity further and thus increase light intensity down to the
depth inhabited by these species. If this can be achieved, metalimnetic ecotypes may disappear.
If not, hydrophysical measures may be more successful in controlling their density.
• If nitrogen fixing ecotypes prevail (such as Anabaena spp.), reduction of total phosphorus down
to concentrations effectively limiting biomass will cause dissolved nitrogen concentrations in
excess of uptake by phytoplankton. Nitrogen fixation is then no longer an advantage in
competition over other cyanobacteria and algae. This may induce disappearance of the nitrogen
fixing species.
Interesting tidbit on the 2002 article mentioned above:The term total phosphorus is preferable to the term total phosphate, because results are reported
in terms of phosphorus rather than phosphate. This is important because the weight of the PO4
molecule is about three times that of its central P atom, and lack of specification in reporting
results as to whether they refer to μg PO4 or μg P has caused considerable confusion in the
literature.
In treatments where carbon limitation slowed down the growth of heterotrophic bacteria, picophytoplankton became abundant and these organisms showed a positive response to P in combination with a negative response to glucose.
Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. Section 2.2.4Because cyanobacterial blooms often develop in eutrophic lakes, it was originally
assumed that they required high phosphorus and nitrogen concentrations. This
assumption was maintained even though cyanobacterial blooms often occurred when
concentrations of dissolved phosphate were lowest. Experimental data have shown that
the affinity of many cyanobacteria for nitrogen or phosphorus is higher than for many
other photosynthetic organisms. This means that they can out-compete other
phytoplankton organisms under conditions of phosphorus or nitrogen limitation.
I agree that BGA will have a lower threshold of limitation for P and N than algae or plants. This makes biological sense. There are some larger BGA's and then some really small phytoplankton algae, so you might have some crossover if you went to extremes.Good point, Canuck. However, it DOES NOT state that high phosphates DO NOT contribute to cyanobacteria blooms. It states that cyanobacteria in nutrient-deficient conditions will out-compete other organisms for available phosphorous, and no where have I stated that high phosphorous concentrations were required. There are any number of examples in the scientific literature that support my assertion that high phosphates in a body of water triggers cyanobacteria blooms, with run-off from agriculture being the primary cause. This is a world-wide problem.
So perhaps it has little to do with PO4 after all:tongue:Even in nutrient-deficient situations it is not as simple as saying “the cyanobacteria get all the available phosphorous”. There are too many other factors affecting uptake: photoperiod, pH, alkalinity, temperature, etc.
I agree, so why fight it, embrace the plant's needs and focus on what makes them thrive, algae are rarely an issue if this is done. Why that is.....is another matter, but where plants grow well/best, they have ample ferts, ample CO2, ample light. If their growth suffers, then epiphytic algae can attack and cover the plants.The real failing in this as an argument to my point is that an aquarium is a closed system and nutrient-deficient aquariums are seldom the rule, no matter how hard we strive for that state.
So why do my tanks after close to 20 years grow like mad, 300-400 species all thrive, grow as healthy if not more healthy than the best examples in the hobby?I realized several posts back I should have used "excess" rather than high, or “excess and /or high”. Regardless of wording, the end deduction is the same: phosphates must be available to promote cyanobacteria growth. If all the available phosphorous in the aquarium is not being used by plants or algae, the cyanobacteria has a foothold for growth. Limit the source of the phosphates and ya limit the cyanobacteria.
Cheers,
WYite
Well, a little offended, Mr. Barr? Misapplied references do not offer support, eh? Well the reference you supplied isn't an aquarium either, and is just as misapplied then. My sources focused on the biology of cyanobacteria, which will be consistent in any environment.
http://www.thetropicaltank.co.uk/algae.htm#blue-read the section on BGA.
http://www.who.int/water_sanitation_health/resourcesquality/toxcyanchap8.pdf - read the section about limiting cyanobacteria growth through phosphorous control, and the very first paragraph about competition with aquatic plants.
I'll quote this again:
"Phosphorous is the major nutrient controlling the occurence of water blooms of cyanobacteria in many regions of the world, although nitrogen compounds are sometimes relevant in determining the amount of cyanobacteria present. However, in contrast to planktonic algae, some cyanobacteria are able to escape nitrogen limitation by fixing atmospheric nitrogen.. The lack of nitrate or ammonia, therefore, favors the dominance of these species. Thus, the availability of nitrate or ammonia is an important factor in determining which species are present.”
Toxic Cyanobacteria in Water: A Guide to Their Public Health Consequences, Monitoring and Management; World Health Organization; edited by Chorus and Bartram, 1999. p. 6.
Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that. This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.
The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that. But cyanobacteria blooms do occur when there is excess phosphorous. Disprove that. That it hasn't happened in your tank does not prove that excess phosphates and excess nitrates are not the cause of cyanobacteria blooms. Thats like saying that I drive above the speed limit and haven't had an accident, so no one who drives above the speed limit can have an accident. Your references to overdosing do not falsify my "claim". And please quote your source that BGA does not compete with plants for nutrients. Anytime two species utilize the same resource, they compete (also see above link.)
The problem stated by the OP was continual cyanobacteria blooms. I didn't offer speculation that it could be low O2 or some other cause. I offered actual conditions that are conducive to cyanobacteria blooms and suggested remediation. What was your reply? Something along the lines of we can't be sure what causes that.
I'm done with this topic. I've obviously upset the apple cart and offended the "in-crowd" and it seems some people aren't willing to keep an open-mind or willing to accept somebody else may have something different to contribute.
Cheers,
WYite
This is my tank right now. The substrate is Akadama Double-Red. I have zero ppm of phosphate. I dose nothing right now except for a very minimal amount of N and K. I am currently experiencing a cyano outbreak that's on just about everything. So, it is absolutely possible for cyano to thrive without the presence of phosphates.Bottom line is cyanobacteria are phosphorous dependent. Period. No one is yet to dispute that. This is not a hypothesis, nor a theory. This is clearly stated in the literature, in more than one source. Quote your source stating cyanobacteria aren't phosphorous dependent or drop it. Seriously.
The presence of excess phosphorous doesn't guarantee that a cyanobacteria bloom will occur, I never stated that. But cyanobacteria blooms do occur when there is excess phosphorous. Disprove that.