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Discussion Starter · #1 ·
1) Macros don't out-compete hair algae. Never did, never will. See Adey...
Example, my 40g breeder crashed. Nothing alive. Added macros. Got hair algae all over it - no micro-grazers there! (Fe didn't help)
I cleaned it out. Set it up again, added macros, lots of pods. Hair algae free now - cause the pods maintain the macros...

2) Why would you need them if you have a denitrification filter, aka DSB/sandbed?

3) Oh, phospate...no sir, now everyone with DSB/refugia are using Phosban, Rowaphos, in addition, 'cause they still get nuisance algae etc.

conclusion - they are okay for feeding your fish with, but don't expect them to clean your tank.
 

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1)If used properly Macros can outcompete hair algae provided you have a way to deal with both.

2) because the DSB or LR will only handle the Ammonia, nitrites and nitrates. They do very litle for phosphates and other water column contained nutrients that feed algae.


3) Not everyone tries to use a "chemical" solution to fix a problem. Especially since most of them do nothing other than to mask the problem not fix it. In order to solve the problem/symptoms you ned to find the cause of the problem. Hair alhae is not a "problem" but a visible symptom of another problem such as poor husbandry or over feeding. Chemicals might get rid of the sumptom, hair algae, buit they definately won't solve the problem.

I wouldn't expect anything to clean and maintain my tank. If you want a maintanence free tank where you have to do nothing other than watch it, get a screensaver...
 

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cyberchef said:
1)If used properly Macros can outcompete hair algae provided you have a way to deal with both... ... Hair alhae is not a "problem" but a visible symptom of another problem such as poor husbandry or over feeding. Chemicals might get rid of the sumptom, hair algae, buit they definately won't solve the problem.
thank you Don.

Although I like much of what Dr. Adey has presented in Dynamic Aquaria, much of what he has presented there doe not include more recent developments in closed systems (check out some of his more current statements in the lit.)
 

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Discussion Starter · #4 ·
So you guys still think that hair algae results from high nutrients, eh? Not what Adey report, nor Little, nor any of the new literature.
Hair algae thrive in a low nutrient environment.
Hair algae are controlled by grazing.

Take the grazers away - e.g. pods - get hair algae.

All these refugia that are maintaining macroalgae are being grazed heavily by pods. Pods don't affect the macros to a visible degree, but they do eat the hair/micro algae, and it appears that the refugia are working to lower nutrients.

I don't believe it.
 

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Discussion Starter · #6 ·
I don't believe the oft-stated claim that you can get rid of hair algae by using refugia/macro filters.

As a source of food for your system, sure they can be handy.
 

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I would rather have "hair algae" in the sump than the main system. If it is isolated to the refuge, then it seems to me that you are winning the battle.
 

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I think the common problem is that people go into reef keeping with MAYBE a basic hint of the bio processes involved. Get impatient and go to fast, stock to heavy and feed to much, then expect instant cures when imbalances occur.
People tend to forget that replicating a reef environment is to try and duplicate one of the most complex, diverse ecosystems on the planet, compounded by the limitations of doing it in a drop of water compared to the vastness of the ocean.
Its possible to have trouble free pieces of said environment without a degree in marine bio or he related disciplines, but I think as a rule those that do and have not those qualifications usually plan out in advance, go slowly and sort through the myraid of info out there and pick methods that work for a lot of people when followed conscientiously.
The trend to try every new miracle method or substance that comes along seems doomed to failure as the system never gets a chance to settle down and function to the best of its inherent ability.
I think if one starts with good quality source water, setsup the tank with good live rock and sand, makes sure that you have a diverse population of detrivore and herbivores, stock light and slow, change water faithfully and keep water params in check, you will prolly be OK.
Expect major phases the first year and learn, learn, learn. Above all have a shipload of patience, its not going to happen overnight.
 

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mad_coder said:
So you guys still think that hair algae results from high nutrients, eh? Not what Adey report, nor Little, nor any of the new literature. ...Hair algae thrive in a low nutrient environment.
Hair algae are controlled by grazing. ... I don't believe it.
I agree with the part about grazing control, not too much with you on the rest of the info. How about some specific references to the Adey or Loveland or Little info/papers/pubs? The basic biology still doesn't change when going to a cvlosed system. Although the closed systems as we have then don't really reflect the ocean well, succession of speciation still occurs, with more efficient competitors for resources (nutrients and light and real estate) replacing those that are either less efficient or more slowly growing. The Basic biology does not change. The water column does not demo a large dissolvbed nutrient level because these substances are usually locked up in biomass. With cyanobacteria, nitrates in the watercolumn will show zero or near zero at hobbyist testing levels, but will rise during the dark as biomass disintegrates to release the locked up nutrients back to the water column. the hair algae/Derbasia/batphoria, chlorophyta micro's in general tend to lock up dissolve nutrients pretty much permanently, and therefore will not show a diunral rise and fall.. If you're referring to the article by the Little's at this site, there is little to compare with using the seagrasses vs using macroalgal competition to mimic biotope succession, not really apples to apples, although there are many resources from Dr Adey and company at the Smithsonian to suggest otherwise as well.

I also looked through a good number of Dr. Adey's recently published articles to see if there was a change in his POV, but none of the abstracts in the following artlcles support that:


  • Adey, W. H. , A. Athanasiadis and P. Lebednik. 2001. Leptophytum laeve: taxonomy and biogeography of the genera Leptophytum and Phymatolithon (Corallinales, Rhodophyta). Eur. J. Phy. 36: 191 - 203

    .Adey, W. and R. Steneck. 2001. Thermogeography over time creates biogeographic regions: a temperature/space/time integrated model and an abundance-weighted test for benthic marine algae. J.Phycology 37: 1-22.

    Adey, W. 2000. Coral reef ecosystems and human health, biodiversity counts. Ecosystem Health 6: 227 - 236.

    Adey, W., T. McConnaughey, A. Small and D. Spoon. 2000. Coral Reefs: Endangered, Biodiverse, Genetic Resources. Pp. Chapter 109: pp. 33 - 42. In: Charles R.C. Shepherd (Ed.). Seas at the Millenium: An Environmental Evaluation. Elsevier Press , Amsterdam.

    Adey, W. 1999. Algal-controlled ecosystems in oligotrophic seas: keys to coral reef evolution and degradation. 16th International Botanical Congress 19.10.1: 236. (Abstract).

    Finn M., P. Kangas and W. Adey. 1999. Mangrove Ecosystem Development in Biosphere II. Ecological Engineering 13: 173-178.

    Adey, W. 1998. Coral Reefs: algal structured and mediated ecosystems in shallow, turbulent alkaline waters. J. Phycology 34: 393-406. [Review Article]

    Adey, W. 1998. Coral Reefs, conservation by valuation and the utilization of pharmaceutical potential. Pp. 72-75. In:. Coral Reefs: Challenges and Opportunities for Sustainable Development. 5th Annual World Bank Conference on Environmentally and Socially Sustainable Development, Washington,D.C.

    Adey, W. 1998. Algal Turf Water Purification Method (Phosphorous and heavy metal precipitation in algal cell walls). United States Patent 5,851, 398. 10pp, six drawings.

    Adey, W. and K. Loveland. 1998. Dynamic Aquaria. Academic Press, San Diego. 498 pp. [Revised and expanded 2nd Edition; graduate text for living systems modeling]

    Small, A., W. Adey and D. Spoon. 1998. Are current estimates of coral reef biodiversity too low? The view through the window of a microcosm. Atoll Research Bulletin 458: 1-20.

    Adey, W., M. Finn, P. Kangas, L. Lange, C. Luckett and D. Spoon. 1996. A Florida Everglades Mesocosm - model veracity after four years of self organization. Ecological Engineering 6(1-3): 171-224.

    Adey, W., C. Luckett and M. Smith. 1996. Purification of industrially-contaminated ground waters using controlled ecosystems. Ecological Engineering 7: 191-212.

    Kangas, P. and W. Adey. 1996. Mesocosms and ecological engineering. Special Issue of Ecological Engineering. Ecological Engineering 6(1-3): 1-6.

    Luckett, C., W. Adey, J. Morrissey and D. Spoon. 1996. Coral reef mesocosms and microcosms - Successes, problems and the future of laboratory models. Ecological Engineering 6(1-3): 57-73.

    Adey, W. 1995. Cost effective wastewater remediation for the protection of coral reef environments. Env. Sustainable Dev. Proc. Ser. 9: 46-47. (Abstract). [Abstract- World Bank]

    Adey, W. 1995. An algal solution to large scale wastewater amelioration. Ecological Soc.Am. Ann. Meeting 76(2): 1. (Abstract).

    Adey, W. 1995. Controlled Ecologies. P. 6 pp, 5 figs. In: W.A. Nierenburg (Ed.). Encyclopedia of Environmental Biology. Academic Press, San Diego.

    Craggs, R., W. Adey, K. Jensen, M. St.John, F. Green and W. Oswald. 1995. Phosphorous removal from wastewater using an algal turf scrubber. In:. Proc. Int. Assoc. Water Quality(March)26: 11pp.

    Adey, W. 1994. Algal turf scrubbers and model ecosystems - a continuing dialog. Aquarium Frontiers Spring: 1-7.

    Adey, W., C. Luckett and K. Jensen. 1993. Phosphorous removal from natural waters using controlled algal production. Restoration Ecology 1: 1-11.

    Adey, W. 1992. Ecosystem Encounters: Lessons in Synthetic Ecology. The Science Teacher 59(6): 22-27.

    Adey, W. 1992. Water purification system and apparatus - microcosm system integration with ATS. U.S. patent no. 5,097,795.

Although it is apparent that Dr. Adey prefers the use of microalgae as the means of removing dissolved nutrients from the water column in closed systems (hence his prediliction for algal turf scrubbers and his patents for these algal-based water purificatioin systems), I do not see him making the statement that the macroalgae are not part of the natural succession of more effective nutrient acquisitions in closed systems. On the contrary, his statements support the need for increasing biodiversity to maintain stability in closed systems, including the flora as well as fauna of the systems.

Speaking of the fauna, I did find a good abstract supporting the view of top down competition for nutrients and control of microalgaal overgrowths (as well as worm and copepod consumption as you have described for the refugiums:

Faust, M.A. and R.A. Gulledge. 1996
Associations of microalgae and meiofauna in floating detritus at a mangrove island, Twin Cays, Belize.
Journal of Experimental Marine Biology and Ecology197: 159-175.

Associations of microalgae were examined in detritus from a shallow mangrove ecosystem. Detritus originates through the decomposition of mangrove leaves in warm tropical waters. Floating detritus exhibits a diurnal movement: it rises to the surface via oxygen bubbles generated by attached microalgae at sunrise and sinks down at sunset. In floating mangrove detritus, dinoflagellates were present in highest proportion (50-90%), followed by diatoms (5-15%), cyanobacteria (3-25%) and dinoflagellate cysts (1-7%). The vertical distributions of microalgal taxa in detritus were different with depth and time. Microalgal densities correlated significantly with dissolved oxygen concentrations, depth and time (r²=0.902). In floating detritus, nematodes, ciliates, copepods and crustacean larvae were the most numerous, whereas, in bottom detritus, nematodes and ciliates were the dominant heterotrophic taxa. Nematodes and ciliates were the major consumers of dinoflagellates in the aggregates.
Truly stable systems without microalgal overgrowths are the result of species succession as closed systems mature, especially in closed systems. A portion of the same diversity of organisms that drive open/oceanic reef systems stability have found some means of surviving to produce food chains that consume (graze) the growth that does occur, and competition by many macroalgae for the nutients that drive the original blooms control the initial growth. Lots of documentation for this, both in th ocean and in closed systems.

I agree with the info on the grazers being a major part of microalgal nuisance blooms, but competition for the limited nutrients in the water column on oceanic reefs has made the macroalgae much more successful than microalgae at competng for these same nutrients that drive growth, giving them a role in controllling microalgal growth. Nitrates, phosphates, and in some cases silicates are all necessities to growth in Chlorophyta (and some other problem algae). Growth may occur in nutrient poor waters, but explosive blooms require these substances in large amounts. Macroalgal competion is one means of controlling these blooms in addition to limiting inputs, controlling lights, and increasing herbivore pressures.

Sorry for the long post, I had most of the info here already (for the DSB research I am undertaking), so it was relatively easy to hammer together.

HTH
 

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Discussion Starter · #10 ·
Oops. I'll make sure I load up my next reply with tons of references...Not! :funny:

I've seen it for myself, with my own tank(yes, it's a small-n-design!):

  • micrograzers absent: hair algae outcompetes macro algae.
  • micrograzers present: macro algae seems to outcompete micro algae.

("seems to" because I suspect that the microalgae are there, but are being grazed down to invisibility by the pods.)

In 'Dynamic Aquaria', Adey was pretty adamant about clearing out the pods in his scrubbers, otherwise their efficiency deteriorated. Not so, proponents of Refugia.

All your "real world" examples of succession were in the presence of grazers.

Fine, I'll try to drag up the experimental studies on grazing vs. algae:rolleyes:
 

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mad_coder said:
Oops. I'll make sure I load up my next reply with tons of references...Not! :funny:

I've seen it for myself, with my own tank(yes, it's a small-n-design!):

  • micrograzers absent: hair algae outcompetes macro algae.
  • micrograzers present: macro algae seems to outcompete micro algae.
I was just curious, when you say "absent", do you mean none at all?
Steve
 

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mad_coder said:
I've seen it for myself, with my own tank(yes, it's a small-n-design!):

  • micrograzers absent: hair algae outcompetes macro algae.
  • micrograzers present: macro algae seems to outcompete micro algae.
yup! That is pretty much the whole idea, the use of macroalgae is just one facet of a multipronged approach to controlling blooms of microalgae. The macroalgae on a gram per gram basis well outcompete the microalgae under the same circumstances, they have greater surface area to gather light, they have better active transport as a means of gathering nutrients (think about the excessive absorption and storage of phosphate for example, just this ability by itself gives macros the ability to endure periods when low water column phosphates are the rate limiting factor in colonial growth), they can qand do overgrow areas of substrate on which many micro and benthic microalgae depend for areas to gather light. Macros by themselves will not stop a microalgal bloom, but they are indeed part of the solution. Microalgae, on the otherhand, have numbers on their side, as they have prodigeous primary production in the top 2 cm of sandbeds alone, providing for the incredible amount of carbon production associated with the benthos. This is what Dr Adey uses as the driving principle behind the algal turf scrubbers, it is the numbers per unit volume that makes them so effective, not their overall ability to outcompete macroalgae. It is the ability to pack a lot of water processing punch in a small volume that makes the algal systems so effective, and even then, there are problems with the leaking of organic byproducts from the algal mats. I DON'T dispute the fact that these systems are quite effective, and that based on the application to algal turf scrubbers, the systems prolly can absorb much more total nutrients than a similar vol of macroalgal organisms, but this has nothing to do with the efficiency of these systems, only the sheer numbers of the microalgal organisms in a small space. This is why Dr Adey doesn't want benthic grazers in his filters, they reduce the total number of cells available to absorb these water column nutrients and release them back into the water column.

As far as your nano system and algal blooms, I would not be surprised at this. Under the right conditions, even shallow bays become eutrophic and fill with algal mats. Parts of the Caribbean have problems with increases in nitrogen and sediments due to runoff and other anthropomorphic changes there (and the loss of primary grazers like Diadema urchins) that have lead to the widespread growth of microalgae. With conditions as such, this can most certainly happen, but it requires the right set of conditions. God forbid that this should come to pass for the entire Caribbean... ...What would the Spankster do for a living? count algal colonies??? :rolleyes:

Think of it this way. Developments in succession via darwinian selection provided for the evolution of the different autotrophs of the extant spp. we now know of, had each one of these developments not had some competative edge over the other lower but similar spp, selection would not have favored the newly evolving specie. Some were capable of exploiting a particular niche, others were just plain better at doing what they do, either by better growth, better absorption, better reproduction, or better resistance to being consumed. Had the microalgae been so much more successful than each new variant that would lead to the higher autotrophs, then there would have been no "drive" for the evolution of new species, and the world would be one big happy mass of microalgae now.:eek:

but then again, I digress... :rolleyes:

..."but Tom, isn't Oregon one big mass of microalgae???"
 

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mad_coder said:
  • micrograzers absent: hair algae outcompetes macro algae.
  • micrograzers present: macro algae seems to outcompete micro algae.
("seems to" because I suspect that the microalgae are there, but are being grazed down to invisibility by the pods.)
Steve had a point about the grazers never being absent.
You furthermore seem to ignore that your "microalgae" (?) are virtually ALWAYS present, and that it is merely a question of supression.
Supression of "microalgae" (let's just call 'em hair, mmm'kay?) can be accomplished by herbivorous pressure, yes, but given sufficient nutrients, there are too many captive situations where your "micrograzers" will be unable to keep up.

In a nutrient-dump episode, the population spike of grazers will fall far behind the spurt in algal growth. Insofar as long 'hair' algae in weak current become an inviting site for epiphytization by filmers, the odds are short that you'll obtain an autotrophic engine gone eutrophic under that goop, pushing the nutrient spike along.
In 'Dynamic Aquaria', Adey was pretty adamant about clearing out the pods in his scrubbers, otherwise their efficiency deteriorated. Not so, proponents of Refugia.
:)
Refugia? What are refugia? What do they have to do with scrubbing DIN/DON and CO2, and supressing "hair"?

If you are going to twirl Doc Walter around like that, it might be better to stick to HIS first definition of a refugium: simply, a refuge for potentially beneficial populations of organisms that might otherwise be pressured by predation into insignificance. That aside...

The pods in the good doctor's scrubbers were keeping the nutrient in-system, rather than leaving them in exportable algal tissue. The reason macroalgal-scrubber enthusiasts don't bother dissing pods is that they chow not so much on the macro's as on the tiny epiphytes present. While this once again returns nutrient into play as pod metabolites, it at least helps maintain macroalgal efficiency by keeping macroalgae clear of fouling epiphytes. Possibly a zero-sum, so no clear alarum, hein?

Furthermore, the scrubber algae described in Adey & Loveland are NOT the hair algae that aquarists treat as problems nor what you seem to refer to as 'hair' algae. What Adey & Loveland sought to employ were caespitose red and brown algae, and those behave differently from the caespitose greens the hobby generally shuns and you seem to be referring to.

The raison d'etre of a macroalgal scrubber is to steal resources from blooming problem algae. There is no question that they lust for the same resources, and if macros consume any of it, it constitutes pressure on other algae.

Bottom line: simple filamentous greens have easier bodies to construct, hence they grow faster than most more-complex macros. That's a no brainer. Both macros and 'hairs' consume pretty much the same nutrient resources, and thus are largely in direct competition for the same fuel.

Macroalgal filters are presently and properly relegated to topping-out an already sufficient conventional setup for dealing with DIN/DON and other algal treats. After all, macroalgae are even slower on the curve for catching up to a nutrient-dump episode than 'hair', so you can't use them as the bedrock of waste management unless you can devote significant real estate to harvestable macroalgal biomass.

Macroalgal filters are supposed to be amped via preferential lighting intensity/period and water current. What's left is making sure the macroalgal filter site does not become an engine and silo for nutrients ITSELF, ...and the way certain merchants' so-called "refugia" (blechhh) are set up, duplexed with de facto DSB's, they can too-easily turn into such silos and engines.

I suspect that many a system that is not benefitting from macroalgal scrubbing of DIN/DON has very basic structural problems in the display: animal stocking levels, feeding regime, ad nauseam, ...coupled with basic structural problems in the macroalgal scrubber used: complexing with contradictory agencies like siltbeds.

:fish:
 

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I had to look this word up, and just thought I would share with anyone else that didn't know its definition:) :

What are epiphytes?
Epiphytes are plants which grow above the ground surface, using other plants or objects for support. They are not rooted in the soil nor are they parasitic (ie they do not directly harm the other plant). By growing on other plants, the epiphytes can reach positions where the light is better or where they can avoid competition for light. Many mosses and lichens are epiphytes, as are approximately 10 per cent of all seed plants and ferns. Epiphytes are particularly common in some groups of plants, such as ferns, bromeliads (members of the pineapple family, Bromeliaceae) and orchids: over half of the 20,000 species of orchids are epiphytic


Steve
 

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Would it be simplistic to assume then, that when I hooked up a 20L to my 70 main tank and put oolitic sand and a rock of turtle grass in it that the sudden bloom of cyano in the 20 and a small hair algae episode in the main was a result of some nutrient dump, presumably in the sand?
 

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Discussion Starter · #17 ·
dark horge said:

Supression of "microalgae" (let's just call 'em hair, mmm'kay?) can be accomplished by herbivorous pressure, yes, but given sufficient nutrients, there are too many captive situations where your "micrograzers" will be unable to keep up.

In a nutrient-dump episode, the population spike of grazers will fall far behind the spurt in algal growth. Insofar as long 'hair' algae in weak current become an inviting site for epiphytization by filmers, the odds are short that you'll obtain an autotrophic engine gone eutrophic under that goop, pushing the nutrient spike along.

Macroalgal filters are presently and properly relegated to topping-out an already sufficient conventional setup for dealing with DIN/DON and other algal treats. After all, macroalgae are even slower on the curve for catching up to a nutrient-dump episode than 'hair', so you can't use them as the bedrock of waste management unless you can devote significant real estate to harvestable macroalgal biomass.

Macroalgal filters are supposed to be amped via preferential lighting intensity/period and water current. What's left is making sure the macroalgal filter site does not become an engine and silo for nutrients ITSELF, ...and the way certain merchants' so-called "refugia" (blechhh) are set up, duplexed with de facto DSB's, they can too-easily turn into such silos and engines.

I suspect that many a system that is not benefitting from macroalgal scrubbing of DIN/DON has very basic structural problems in the display: animal stocking levels, feeding regime, ad nauseam, ...coupled with basic structural problems in the macroalgal scrubber used: complexing with contradictory agencies like siltbeds.

:fish:
well said, it's nice we're in such agreement! ;)
 

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Steve,
Thanks for pointing that out :)
I'm certainly NOT taking this out on you nor on Eric, but am addressing it to a phantom hobbyist, a composite of several others who IMO have taken Miller et al. out further in aquaristic discussion than is sensible ;)

So everyone understands...
Eric was merely summarizing and commenting on
Miller, M. W., M. E. Hay, S. L. Miller, D. Malone, E. E. Soka, and A. M. Szmant. 1999. Effects of nutrients versus herbivores on reef algae: A new method for manipulating nutrients on coral reefs. Limnol. Oceanogr 44: 1847-1861. It is reckoned a fairly well-designed gig, albeit burdened by "natural experiment" vulnerabilities

Miller et al. used commercial plant-food sticks partially wrapped in wax, and then placed in certain cinder-block compartments as the nutrient source, and different schemes of wire cage enclosures to effect degrees of herbivore exclusion. Eric summarized:
Algal response to elevated nutrients with exclusion of large herbivores showed that only one type of cyanobacteria increased in response to enriched nutrients
We already know, least of all from aquaristic experience, that the most primitive organism is the fastest to exploit a resource bonanza, and will often act to supress competitors.

I'd earlier (it is apparently quoted in the post preceding this one) pointed out that filming epiphytes will party on in a nutrient dump episode. A slow-burn release of nutrients would make them just as happy, although there's more time for slower-growing competitors to try and put up a fight. Anyway...

Even top-down adherents will admit Miller et al.'s data is NOT as clean-cut as Eric's summary might imply. Besides a cyano bloom is STILL bad news in an aquarium, last time I checked. If such are nutrient limited (duh!), then that's argument enough to temper nutrient levels.

Regarding Miller et al.'s reported lack of other-algal growth acceleration, it might be good to note that many algae can sometimes respond to a nutrient bonanza and a lack of herbivorous presssure via reproductive investment rather than visible vegetative investment ---the profit from added nutrient would then show up somewhere else downstream, where spores/zygotes wind up, away from the study area.

Anyways... Eric continues to summarize:
However, herbivore exclusion treatments had large effects. Turf algae and frondose macroalgae both increased when herbivores were excluded, and coralline algae decreased.
Well certainly, if you are going to exclude herbivores, then the fastest growing algae will dominate, (Like, what an epiphany!! Stop the presses!!! :funny: ) and then leaked secondary metabolites, photodeprivation, and denial of circulating water will put the squeeze on slower growing algae below.

Eric then goes on regarding the INCLUSION of herbivores:
"It was found that increasing nutrients did not cause more algae to grow, but resulted in more nutrient-rich algae that were, incidentally, grazed at a faster rate (thought to be a result of them being more nutritious to herbivores preferentially seeking and requiring nitrogen rich material). It appeared, from this article, that algae are not nutrient limited on coral reefs and the primary control of algae on reefs is herbivory, not nutrients."
Yep. Indeedy-doody-pie.
As already stressed in my last post, there is a difference between algal presence (guaranteed) and appearance (determined largely by herbivory).

As a sidenote: the local presence of herbivores --particularly piscine-- will fluctuate BASED ON AVAILABILITY AND QUALITY OF FODDER. Without trotting out 'nutrient enrichment of the turf tissue', simply increasing the biomass of grazable turf will attract more herbivorous attention from all corners, and one might wonder just how well the study was able to guard against accelerated herbivory masking algal growth. Setting aside an exclusion control isn't enough: grazing can actually increase algal productivity. Lower forms of herbivorous life may not come in from neighboring regions, but they can reproductively exploit a bonanza of food, and they tend to have a quicker reproductive turnaround than fish.

Build it and they will come. From all corners, because the reef is open. Can't really happen in an aquarium, because the corners are only a foot or less away. ---and that's where the rubber meets our aquaristic road.

Eric points out that other papers (like Aronson & Precht, 2000), have since come to support Miller et. al. which is itself a support to Hughes & Szmant (1999). I might note that yet other papers have similarly come to 'support' Lapointe, B. E. 1997. (Nutrient thresholds for bottom-up control of macroalgal blooms on coral reefs in Jamaica and southeast Florida. Limnol. Oceanogr. 42: 1119-1131.), because...

Both herbivory and nutrient availability affect algal dominance in a reef ecosystem, and yet remain just two factors out of about a dozen that come to my mind. This top-down vs. bottom-up argument is a steaming pile of, of... nutrient, if you ask me, and it's fuelling the accelerated growth of practically useless, resource-draining argument, particularly for the field of aquaristics.

For us aquarists:
Why 'choose sides'?
TMAM, nothing in Miller et al. diminishes the aquaristic importance of guarding nutrient availability to problem algae, especially since the herbivore profiles in typical hobbyist aquaria are shamefully poor. Woefully lacking. Pitifully inadequate. Heart-wrenchingly...
Well, okay, you get the idea.

It might be fair to say that since aquaria are so impoverished of herbivores, they constitute an herbivore-exclusion sample. So, take Miller et al.'s exclusion sample as your guide: with such herbivores excluded, turfs and frondose algae will almost always tend to go gangbusters.

Be realistic. How many herbivores can visit their voraciousness on a square foot of algal meadow in the wild? You'd be drafting from several thousand square feet for fishes, and several hundred feet for many crustaceans and molluscs. A tank with a square foot of algal meadow usually has only one square foot of territory to draft any herbivores from.

The real-reef ace of herbivory is largely out of our aquaristic reach.
So we play a lower deck, discount herbivore card.
What else are we left to play with, to strengthen our hand?
The lower-deck card of nutrient management.
It's no ace, but it's not as inutile as the study might lead one to believe.

If you like, take a page right out of Miller et al: try stockpiling plant-food sticks in your reeftank and find out if that added nutrient "won't cause more algae to grow".
:idea:

Then, come back to me and maybe I'll tell you how to really handcuff unwanted algae in an aquarium. I could fill three to four hundred pages describing practical, yet seemingly contradictory strategies towards it... virtually all of them tried, tested, idiot simple, dirt cheap and --yeppers-- massively unpopular with the aquarium trade.

Or maybe I could just yell "top-down!" or "bottom-up!", as if it's contention --preferably personal and yet camouflaged by truckloads of citations, that people really get off on.

:dance:
horge:
 

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dark horge said:
The opposing view regarding nutrients and algal growth is presented in Lapointe, B. E. 1997. Nutrient thresholds for bottom-up control of macroalgal blooms on coral reefs in Jamaica and southeast Florida. Limnol. Oceanogr. 42: 1119-1131.
well heck! I was posting something along the same line at the same time, but I will defer this to Horge's post, as the thought process and at least one article is the same.

Given these studies were not done in closed systems, they still reflect the current discussion in terms of nutrient driven blooms vs predation by herbivores (top down vs. bottom up) It all still comes back to the fact that the macroalgal filter by itself (refugium?) is not enough to control nutrient dumps, the growth is too slow. Even if the macros were capable of this rapid growth and absorption of nutrients, controlling nutrients is not enough to prevent nuisance algal blooms by itself. Under the conditions present in most closed systems (constant input of nitrogen and primary production of the benthos) nitrogen/nutrients in general are not growth limiting factors. Controlling/exporting them is part of the solution as is herbivory (jeeze I like that word :D ). For most of us, both the top down and bottom up approach is needed to gain the upper hand in controlling nuisance algal blooms (which is what I think mad_coder has most of his complaint centered on, correct me if I missed the point).

Thanks for the input Horge, still waiting for part two of the algal opus.;)
 

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Well, I had to recompose the whole lot, Tom. I didn't think anyone was still awake on that side of the Pacific, and thought I could safely compose/recompose on-thread without anyone seeing.
:D

Re-reading what I had first typed, I saw that I was sometimes coming off saying the exact opposite of what I wanted. I was too hyper, maybe, and this top-down vs bottom-up argument has sometimes been a PITA for me personally, sort of like those nature vs. nurture arguments regarding criminal behavior. :eek:
 
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