What is a mature reef tank?

[Beuchat]

Reef aquarists frequently discuss the point at which an aquarium can be considered “mature.” It is, in many ways, an elusive concept. Experienced hobbyists intuitively understand what they mean when they use the term, yet the mechanisms underlying that perception are not always easy to define. A reef aquarium is a dynamic system of extraordinary biological, chemical, and ecological complexity, in which thousands of interactions occur simultaneously and evolve over time.

From a macroscopic perspective, a mature aquarium can be described as a stable system. Coral reef ecology teaches us that stability and biodiversity are mutually reinforcing states: stability promotes biodiversity, and biodiversity, in turn, promotes stability. However, stability in a reef aquarium involves far more than the absence of large fluctuations in parameters such as nutrient concentrations, salinity, or the chemical elements involved in coral calcification. It also implies the existence of a complex network of biological interactions capable of buffering disturbances and preventing any single population from dominating the ecosystem. Under these conditions, bacteria, cyanobacteria, dinoflagellates, algae, and zooplankton remain present, but their populations are regulated by multiple mechanisms acting simultaneously.

To understand this phenomenon, it is useful to turn to population ecology. In any ecosystem, including a reef aquarium, species pass through different phases of growth. When conditions are favorable, a population may enter an exponential growth phase characterized by rapid expansion, such as the dinoflagellate outbreaks or bacterial blooms that turn the water milky white. As competition, predation, and resource limitations increase, growth slows and eventually reaches a plateau. Finally, environmental and biological factors may trigger a period of decline and population reduction. This pattern can be observed in bacteria, algae, cyanobacteria, dinoflagellates, and zooplankton alike.

The survival and proliferation of any organism therefore depend on the balance between two broad categories of factors: those that promote growth and those that limit it. Growth-promoting factors include the species’ natural reproductive strategy, the availability of organic and inorganic nutrients, light intensity and photoperiod, and, in some cases, water movement. There is even evidence that certain organisms modify their reproductive strategies in response to chemical signals associated with the presence of predators. Limiting factors, on the other hand, include competition for space, grazing and predation pressure, hydrodynamic conditions, and inhibitory chemical signals produced by other organisms.

Bacteria form the invisible foundation of many of the biological processes that occur within the aquarium. Their greatest ecological advantage lies in their extraordinary reproductive capacity. Some heterotrophic bacterial species can double their populations within minutes or hours when a new source of organic carbon becomes available, whether from feeding, amino acid supplementation, or dissolved organic compounds. The availability of nitrate, phosphate, and organic matter further promotes bacterial growth. Adequate water circulation also enhances oxygenation and nutrient transport, creating favorable conditions for their development.

Yet bacterial populations are far from unrestricted. Competition among different strains, prior occupation of surfaces by established biofilms, predation by protozoans and zooplankton such as copepods and other microcrustaceans, as well as the production of natural antibiotics and inhibitory toxins, all contribute to preventing any single bacterial community from monopolizing the ecosystem.

Cyanobacteria are perhaps the quintessential example of an opportunistic organism. Their growth can be remarkably rapid when conditions are favorable, forming extensive mucous mats that spread across rocks and substrate. Excess phosphate combined with elevated concentrations of dissolved organic matter often encourages their proliferation. Some species are even capable of fixing atmospheric nitrogen, allowing them to thrive despite low nitrate levels. Areas of weak water flow tend to accumulate detritus and create ideal conditions for colonization. Cyanobacteria also utilize broader, whiter light spectra efficiently and often benefit from extended photoperiods.

Counteracting these advantages are several important limiting factors. Established coralline algae, corals, sponges, and biofilms significantly reduce the amount of available substrate. Strong water movement interferes with the formation of their characteristic mats, while grazing pressure and allelopathic compounds produced by corals and bacterial communities help keep cyanobacterial populations under control.

Dinoflagellates represent another particularly fascinating group because they often thrive precisely in biologically unbalanced systems. Many species alternate between benthic and planktonic stages and are capable of forming resistant cysts that can survive for extended periods. Unlike filamentous algae or cyanobacteria, dinoflagellates frequently emerge when nutrient levels become extremely low and biological competition is reduced.

Water movement facilitates their dispersal, while light is essential for many photosynthetic species. Their growth, however, can be limited by competition from diatoms, bacteria, algae, and cyanobacteria, as well as by the prior occupation of available surfaces. We now know that the use of external organic carbon sources can stimulate certain heterotrophic bacterial populations to produce allelopathic compounds capable of completely inhibiting dinoflagellate growth within the aquarium. Certain copepods and microcrustaceans also consume some dinoflagellate species. Furthermore, mature reef systems contain a complex network of biological and chemical interactions that makes successful colonization increasingly difficult. Indeed, dinoflagellate outbreaks often occur shortly after excessive intervention has removed much of the aquarium’s natural biological competition.

Filamentous algae are among the most visible organisms encountered by reef aquarists. Their growth is promoted by the availability of nitrate, phosphate, iron, dissolved organic matter, and abundant light. Water movement continuously delivers nutrients, allowing these algae to expand rapidly through fragmentation and spore production.

At the same time, filamentous algae are subject to several powerful control mechanisms. The occupation of surfaces by coralline algae, corals, sponges, and mature microbial biofilms significantly limits their ability to establish themselves. Herbivorous grazing is probably the most important regulating factor. Fish such as Zebrasoma, Ctenochaetus, and Salarias, together with sea urchins and numerous snail species, exert constant grazing pressure that restricts algal expansion. In addition, chemical compounds released by coralline algae and corals may inhibit the settlement of new spores.

Fig 1. In tanks set up with dry rock, algal outbreaks are usually much more common during the first months. The absence of the biodiversity found in live rock delays the ecological stabilization of the system, so aquarium maturation generally takes longer to occur.

Zooplankton, including copepods, amphipods, rotifers, and other microscopic organisms, plays a fundamental role in reef ecosystem dynamics. Their high reproductive capacity allows them to respond rapidly to increases in food availability. Bacteria, phytoplankton, detritus, and microalgae form the basis of their diet. Water movement facilitates both dispersal and access to resources, while light indirectly influences zooplankton populations through its effect on phytoplankton production.

Nevertheless, zooplankton populations are exposed to intense predation pressure. Mandarin dragonets, numerous wrasses, anthias, and a wide variety of filter-feeding corals continuously consume these organisms. Refuge availability and competition with other zooplankton species also contribute to regulating their abundance.

From this perspective, the hypothesis that reef aquarium maturity is linked to the establishment of a complex network of ecological interactions fits perfectly within the framework of community ecology. Young aquariums typically contain abundant unoccupied space, limited microbial diversity, little allelopathic activity, and numerous vacant ecological niches. As a result, it is common to observe a succession of opportunistic bacteria, diatoms, dinoflagellates, cyanobacteria, and filamentous algae.

As the system ages, ecological niches gradually become occupied, biodiversity increases, herbivore and predator communities become established, and corals begin to exert an increasingly significant chemical influence on their surroundings. For this reason, it is generally advisable to introduce a substantial coral population once the aquarium has completed its initial cycling process. These should, of course, be hardy species—most likely LPS corals—so that the available space becomes occupied by the organisms we ultimately wish to dominate the mature system.

Corals are net consumers of nutrients and therefore do not generally pose a significant risk of overwhelming the bacterial community. Fish, by contrast, are net producers of nutrients and should consequently be introduced at a more gradual pace.

The conclusion that emerges from these considerations, supported by the practical experience of countless aquarists, is that if coral introduction is delayed for too long, other opportunistic organisms such as cyanobacteria, dinoflagellates, and filamentous algae will have greater opportunities to colonize available surfaces and establish dominance. This dominance is not limited to physical space; it may also extend into the chemical environment of the aquarium, altering ecological conditions in ways that favor their continued success while making it increasingly difficult for desirable coral communities to become established.

The end result is that, in a mature reef aquarium, it becomes difficult for any population to enter an unchecked phase of exponential growth because multiple control mechanisms are operating simultaneously. Viewed in this way, reef aquarium maturity can be defined as the state in which competition for space and resources, predation, herbivory, and chemical signaling collectively keep all populations below their maximum growth potential, preventing any one of them from dominating the system.

Fig. 2. Once a stable coral community becomes established, it occupies the available ecological niches, limiting the ability of opportunistic species such as algae to gain a foothold and dominate the system.

This interpretation may also help explain why some highly mature aquariums appear to suffer when excessive amounts of activated carbon, ozone, or large-scale water changes are employed. While these techniques are valuable tools for maintaining water quality, they may also remove part of the complex network of dissolved organic compounds and chemical signals that contribute to biological stability. This is unlikely to be the primary factor governing aquarium maturity, but it represents an ecologically plausible hypothesis that remains largely unexplored within the reef aquarium hobby.

 

[Subsea]

Angel,
Great write up. I like this overview paragraph:

“The end result is that, in a mature reef aquarium, it becomes difficult for any population to enter an unchecked phase of exponential growth because multiple control mechanisms are operating simultaneously. Viewed in this way, reef aquarium maturity can be defined as the state in which competition for space and resources, predation, herbivory, and chemical signaling collectively keep all populations below their maximum growth potential, preventing any one of them from dominating the system.”

 

[Dan_P]

Reef aquarists frequently discuss the point at which an aquarium can be considered “mature.” It is, in many ways, an elusive concept. Experienced hobbyists intuitively understand what they mean when they use the term, yet the mechanisms underlying that perception are not always easy to define. A reef aquarium is a dynamic system of extraordinary biological, chemical, and ecological complexity, in which thousands of interactions occur simultaneously and evolve over time.

From a macroscopic perspective, a mature aquarium can be described as a stable system. Coral reef ecology teaches us that stability and biodiversity are mutually reinforcing states: stability promotes biodiversity, and biodiversity, in turn, promotes stability. However, stability in a reef aquarium involves far more than the absence of large fluctuations in parameters such as nutrient concentrations, salinity, or the chemical elements involved in coral calcification. It also implies the existence of a complex network of biological interactions capable of buffering disturbances and preventing any single population from dominating the ecosystem. Under these conditions, bacteria, cyanobacteria, dinoflagellates, algae, and zooplankton remain present, but their populations are regulated by multiple mechanisms acting simultaneously.

To understand this phenomenon, it is useful to turn to population ecology. In any ecosystem, including a reef aquarium, species pass through different phases of growth. When conditions are favorable, a population may enter an exponential growth phase characterized by rapid expansion, such as the dinoflagellate outbreaks or bacterial blooms that turn the water milky white. As competition, predation, and resource limitations increase, growth slows and eventually reaches a plateau. Finally, environmental and biological factors may trigger a period of decline and population reduction. This pattern can be observed in bacteria, algae, cyanobacteria, dinoflagellates, and zooplankton alike.

The survival and proliferation of any organism therefore depend on the balance between two broad categories of factors: those that promote growth and those that limit it. Growth-promoting factors include the species’ natural reproductive strategy, the availability of organic and inorganic nutrients, light intensity and photoperiod, and, in some cases, water movement. There is even evidence that certain organisms modify their reproductive strategies in response to chemical signals associated with the presence of predators. Limiting factors, on the other hand, include competition for space, grazing and predation pressure, hydrodynamic conditions, and inhibitory chemical signals produced by other organisms.

Bacteria form the invisible foundation of many of the biological processes that occur within the aquarium. Their greatest ecological advantage lies in their extraordinary reproductive capacity. Some heterotrophic bacterial species can double their populations within minutes or hours when a new source of organic carbon becomes available, whether from feeding, amino acid supplementation, or dissolved organic compounds. The availability of nitrate, phosphate, and organic matter further promotes bacterial growth. Adequate water circulation also enhances oxygenation and nutrient transport, creating favorable conditions for their development.

Yet bacterial populations are far from unrestricted. Competition among different strains, prior occupation of surfaces by established biofilms, predation by protozoans and zooplankton such as copepods and other microcrustaceans, as well as the production of natural antibiotics and inhibitory toxins, all contribute to preventing any single bacterial community from monopolizing the ecosystem.

Cyanobacteria are perhaps the quintessential example of an opportunistic organism. Their growth can be remarkably rapid when conditions are favorable, forming extensive mucous mats that spread across rocks and substrate. Excess phosphate combined with elevated concentrations of dissolved organic matter often encourages their proliferation. Some species are even capable of fixing atmospheric nitrogen, allowing them to thrive despite low nitrate levels. Areas of weak water flow tend to accumulate detritus and create ideal conditions for colonization. Cyanobacteria also utilize broader, whiter light spectra efficiently and often benefit from extended photoperiods.

Counteracting these advantages are several important limiting factors. Established coralline algae, corals, sponges, and biofilms significantly reduce the amount of available substrate. Strong water movement interferes with the formation of their characteristic mats, while grazing pressure and allelopathic compounds produced by corals and bacterial communities help keep cyanobacterial populations under control.

Dinoflagellates represent another particularly fascinating group because they often thrive precisely in biologically unbalanced systems. Many species alternate between benthic and planktonic stages and are capable of forming resistant cysts that can survive for extended periods. Unlike filamentous algae or cyanobacteria, dinoflagellates frequently emerge when nutrient levels become extremely low and biological competition is reduced.

Water movement facilitates their dispersal, while light is essential for many photosynthetic species. Their growth, however, can be limited by competition from diatoms, bacteria, algae, and cyanobacteria, as well as by the prior occupation of available surfaces. We now know that the use of external organic carbon sources can stimulate certain heterotrophic bacterial populations to produce allelopathic compounds capable of completely inhibiting dinoflagellate growth within the aquarium. Certain copepods and microcrustaceans also consume some dinoflagellate species. Furthermore, mature reef systems contain a complex network of biological and chemical interactions that makes successful colonization increasingly difficult. Indeed, dinoflagellate outbreaks often occur shortly after excessive intervention has removed much of the aquarium’s natural biological competition.

Filamentous algae are among the most visible organisms encountered by reef aquarists. Their growth is promoted by the availability of nitrate, phosphate, iron, dissolved organic matter, and abundant light. Water movement continuously delivers nutrients, allowing these algae to expand rapidly through fragmentation and spore production.

At the same time, filamentous algae are subject to several powerful control mechanisms. The occupation of surfaces by coralline algae, corals, sponges, and mature microbial biofilms significantly limits their ability to establish themselves. Herbivorous grazing is probably the most important regulating factor. Fish such as Zebrasoma, Ctenochaetus, and Salarias, together with sea urchins and numerous snail species, exert constant grazing pressure that restricts algal expansion. In addition, chemical compounds released by coralline algae and corals may inhibit the settlement of new spores.

Fig 1. In tanks set up with dry rock, algal outbreaks are usually much more common during the first months. The absence of the biodiversity found in live rock delays the ecological stabilization of the system, so aquarium maturation generally takes longer to occur.

Zooplankton, including copepods, amphipods, rotifers, and other microscopic organisms, plays a fundamental role in reef ecosystem dynamics. Their high reproductive capacity allows them to respond rapidly to increases in food availability. Bacteria, phytoplankton, detritus, and microalgae form the basis of their diet. Water movement facilitates both dispersal and access to resources, while light indirectly influences zooplankton populations through its effect on phytoplankton production.

Nevertheless, zooplankton populations are exposed to intense predation pressure. Mandarin dragonets, numerous wrasses, anthias, and a wide variety of filter-feeding corals continuously consume these organisms. Refuge availability and competition with other zooplankton species also contribute to regulating their abundance.

From this perspective, the hypothesis that reef aquarium maturity is linked to the establishment of a complex network of ecological interactions fits perfectly within the framework of community ecology. Young aquariums typically contain abundant unoccupied space, limited microbial diversity, little allelopathic activity, and numerous vacant ecological niches. As a result, it is common to observe a succession of opportunistic bacteria, diatoms, dinoflagellates, cyanobacteria, and filamentous algae.

As the system ages, ecological niches gradually become occupied, biodiversity increases, herbivore and predator communities become established, and corals begin to exert an increasingly significant chemical influence on their surroundings. For this reason, it is generally advisable to introduce a substantial coral population once the aquarium has completed its initial cycling process. These should, of course, be hardy species—most likely LPS corals—so that the available space becomes occupied by the organisms we ultimately wish to dominate the mature system.

Corals are net consumers of nutrients and therefore do not generally pose a significant risk of overwhelming the bacterial community. Fish, by contrast, are net producers of nutrients and should consequently be introduced at a more gradual pace.

The conclusion that emerges from these considerations, supported by the practical experience of countless aquarists, is that if coral introduction is delayed for too long, other opportunistic organisms such as cyanobacteria, dinoflagellates, and filamentous algae will have greater opportunities to colonize available surfaces and establish dominance. This dominance is not limited to physical space; it may also extend into the chemical environment of the aquarium, altering ecological conditions in ways that favor their continued success while making it increasingly difficult for desirable coral communities to become established.

The end result is that, in a mature reef aquarium, it becomes difficult for any population to enter an unchecked phase of exponential growth because multiple control mechanisms are operating simultaneously. Viewed in this way, reef aquarium maturity can be defined as the state in which competition for space and resources, predation, herbivory, and chemical signaling collectively keep all populations below their maximum growth potential, preventing any one of them from dominating the system.

Fig. 2. Once a stable coral community becomes established, it occupies the available ecological niches, limiting the ability of opportunistic species such as algae to gain a foothold and dominate the system.

This interpretation may also help explain why some highly mature aquariums appear to suffer when excessive amounts of activated carbon, ozone, or large-scale water changes are employed. While these techniques are valuable tools for maintaining water quality, they may also remove part of the complex network of dissolved organic compounds and chemical signals that contribute to biological stability. This is unlikely to be the primary factor governing aquarium maturity, but it represents an ecologically plausible hypothesis that remains largely unexplored within the reef aquarium hobby.

The amount of thought that went into this article is obvious. Your explanation is clear but likely incomplete as you make clear at the end of the article.

The biggest shortcoming in this hypothesis is the total neglect of the role of the aquarist in the aquarium ecology. I propose the aquarist likely plays the biggest role in determining whether an aquarium supports coral growth or is covered in hair algae. Until this role is better understood, explanations that are ecology based remain unconvincing.

The article’s value is diminished by refering to aquarium stability and diversity in broad sweeping terms. Stability in an aquarium is an intuitive feeling of an aquarist, and more likely an illusion that is not measurable, and therefore, not an attainable goal. Diversity is another popular smart sounding word that seems to convey meaning, but like stability is an illusion. In terms of being an objective, measurable goal for aquarium management. Further, diversity is not measurable nor has it (whatever “it” is) been linked to coral growth or visually appealing aquaria.

 

[Beuchat]

The amount of thought that went into this article is obvious. Your explanation is clear but likely incomplete as you make clear at the end of the article.

The biggest shortcoming in this hypothesis is the total neglect of the role of the aquarist in the aquarium ecology. I propose the aquarist likely plays the biggest role in determining whether an aquarium supports coral growth or is covered in hair algae. Until this role is better understood, explanations that are ecology based remain unconvincing.

The article’s value is diminished by refering to aquarium stability and diversity in broad sweeping terms. Stability in an aquarium is an intuitive feeling of an aquarist, and more likely an illusion that is not measurable, and therefore, not an attainable goal. Diversity is another popular smart sounding word that seems to convey meaning, but like stability is an illusion. In terms of being an objective, measurable goal for aquarium management. Further, diversity is not measurable nor has it (whatever “it” is) been linked to coral growth or visually appealing aquaria.

Hi Dan_P, thank you for your reply.

I do believe that both diversity and stability are objective concepts. Diversity implies the presence of a large number of organisms interacting with each other and with their environment, something that can be verified through sampling and genetic sequencing. Stability, beyond the absence of large fluctuations in water quality parameters, means that none of these organisms enters exponential growth and comes to dominate the rest of the system. This undoubtedly influences the health and growth of aquarium corals, since they are not being significantly affected by a pest outbreak.

Although diversity and stability are objective properties, they are not strictly reducible to chemical or biochemical interaction rules. Rather, they are qualities that emerge at higher levels of organization within the aquarium as a system. That does not make them an illusion or a fantasy.

I agree with you that the aquarist plays a fundamental role. That role can contribute both to the factors that facilitate the survival and proliferation of certain organisms in the aquarium and to the factors that limit them, depending on the consequences of maintenance practices and husbandry decisions. This role is not strictly mappable or reducible to low-level biochemical interactions either, but that does not make it a subjective assumption.

In my view, both the aquarist’s influence and the ecological properties of the system are real, measurable aspects of aquarium dynamics, even if they cannot always be fully explained through reductionist models alone.

 

[ReneReef]

Hi Dan_P, thank you for your reply.

I do believe that both diversity and stability are objective concepts. Diversity implies the presence of a large number of organisms interacting with each other and with their environment, something that can be verified through sampling and genetic sequencing. Stability, beyond the absence of large fluctuations in water quality parameters, means that none of these organisms enters exponential growth and comes to dominate the rest of the system. This undoubtedly influences the health and growth of aquarium corals, since they are not being significantly affected by a pest outbreak.

Although diversity and stability are objective properties, they are not strictly reducible to chemical or biochemical interaction rules. Rather, they are qualities that emerge at higher levels of organization within the aquarium as a system. That does not make them an illusion or a fantasy.

I agree with you that the aquarist plays a fundamental role. That role can contribute both to the factors that facilitate the survival and proliferation of certain organisms in the aquarium and to the factors that limit them, depending on the consequences of maintenance practices and husbandry decisions. This role is not strictly mappable or reducible to low-level biochemical interactions either, but that does not make it a subjective assumption.

In my view, both the aquarist’s influence and the ecological properties of the system are real, measurable aspects of aquarium dynamics, even if they cannot always be fully explained through reductionist models alone.

If stability and diversity are objective goals, then how do you propose to objectify them?

What is proper stability? What is enough stability? What is too little stability?
Is there a thing as too much stability?

Same goes for diversity. How does one tell if there is too little or too much of it? Does less diversity always lead to problems? Is there a thing as too much diversity?

Even if one could determine the is too little diversity or stability, how would you determine how to intervene???

The concept of a diverse ecosystem being generally more resilient to external influences is a fine concept. But it does not mean that more diversity is always desirable.

You say “the aquarist’s influence and the ecological properties of the system are real, measurable aspects of aquarium dynamics”.

What exact aquarium dynamics do we measure to say what exactly about what exact influence an aquarist has on the what exact ecological properties of the system? And what do these ecological properties of “the system” say about stability and diversity?

 

[Beuchat]

Hi Dan_P, I appreciate your interest in understanding the meaning of the article. Regarding your question:

f stability and diversity are objective goals, then how do you propose to objectify them?

What is proper stability? What is enough stability? What is too little stability?
Is there a thing as too much stability?

I believe that trying to objectify something that is already objective does not make much sense. However, if we are talking about quantification, it is important to point out that, although science often seeks to quantify everything, there are real properties whose quantification is problematic, incomplete, or dependent on convention.

For example, we know that a bacterium is less complex than a tropical rainforest, and that a tropical rainforest is less complex than the Earth's biosphere, yet there is no universally accepted unit of "complexity." We can measure genetic diversity, species richness, ecological connectivity, genomic information, and many other parameters, but none of them fully captures the complexity of the system, which is itself an irreducible property.

The same applies to the impossibility of universally quantifying the real properties of stability and diversity in an ecosystem.

I hope this helps to understand the meaning of the article

 

[Dan_P]

Hi Dan_P, thank you for your reply.

I do believe that both diversity and stability are objective concepts. Diversity implies the presence of a large number of organisms interacting with each other and with their environment, something that can be verified through sampling and genetic sequencing. Stability, beyond the absence of large fluctuations in water quality parameters, means that none of these organisms enters exponential growth and comes to dominate the rest of the system. This undoubtedly influences the health and growth of aquarium corals, since they are not being significantly affected by a pest outbreak.

Although diversity and stability are objective properties, they are not strictly reducible to chemical or biochemical interaction rules. Rather, they are qualities that emerge at higher levels of organization within the aquarium as a system. That does not make them an illusion or a fantasy.

I agree with you that the aquarist plays a fundamental role. That role can contribute both to the factors that facilitate the survival and proliferation of certain organisms in the aquarium and to the factors that limit them, depending on the consequences of maintenance practices and husbandry decisions. This role is not strictly mappable or reducible to low-level biochemical interactions either, but that does not make it a subjective assumption.

In my view, both the aquarist’s influence and the ecological properties of the system are real, measurable aspects of aquarium dynamics, even if they cannot always be fully explained through reductionist models alone.

As of today, only some water chemical parameters can be measured and might exhibit small variation, i.e., be stable. But that is it. Nothing else is measured and any claim of “stability” beyond the few water parameters that are measured is pure conjecture. The state of stability is an illusion. Also, given the erratic collection and trending of water parameters by the average aquarist, any claim of stable water chemistry must also be questioned.

You stated

Although diversity and stability are objective properties, they are not strictly reducible to chemical or biochemical interaction rules.

This makes no sense at all. Diversity and stability are descriptions of properties. Diversity is not a thing but a measure of something, such as, there are many species in a biofilm. That is why diversity without the “what” part is empty of meaning and cannot be a goal. The same applies for stability. Stability of what? With the .what” part never included there is no meaning.

As for “interaction rules”, I have no idea what this refers to. As far as being reducible to obeying the rules of chemistry, if they are not, then this article is fantasy.

You continue with

Rather, they are qualities that emerge at higher levels of organization within the aquarium as a system.

Since the article is vague about what actually is stable, it is a logical overreach to classify it as an emergent property. Stability is not described in terms of what is stabilized, it doesn’t actually follow the rules of chemistry and biochemistry, it is emergent. See why I can’t get the idea that what is being discussed in this article is like an illusion. The concepts are simply not testable.

 

[ReneReef]

Hi Dan_P, I appreciate your interest in understanding the meaning of the article. Regarding your question:



I believe that trying to objectify something that is already objective does not make much sense. However, if we are talking about quantification, it is important to point out that, although science often seeks to quantify everything, there are real properties whose quantification is problematic, incomplete, or dependent on convention.

For example, we know that a bacterium is less complex than a tropical rainforest, and that a tropical rainforest is less complex than the Earth's biosphere, yet there is no universally accepted unit of "complexity." We can measure genetic diversity, species richness, ecological connectivity, genomic information, and many other parameters, but none of them fully captures the complexity of the system, which is itself an irreducible property.

The same applies to the impossibility of universally quantifying the real properties of stability and diversity in an ecosystem.

I hope this helps to understand the meaning of the article

Yes this helps a lot.

You are unable to answer any of my very simple questions. So you can’t tell when there is a problem with stability or diversity. In stead, you argue the age old and always magnificent “but science always wants to quantify things” rhetoric.


If this paper past my desk for peer review I would return it to the editor with nothing more than those two words.

 

[Beuchat]

Yes this helps a lot.

You are unable to answer any of my very simple questions. So you can’t tell when there is a problem with stability or diversity. In stead, you argue the age old and always magnificent “but science always wants to quantify things” rhetoric.
You just started using fallacies and confirmed my initial assessment: Utter jibberish.

If this paper past my desk for peer review I would return it to the editor with nothing more than those two words.

Hello Renerref,

I can see that your intention is not to engage in a debate by presenting arguments, but rather to dismiss and belittle others through the use of vulgar and derogatory language. Such behavior only reveals your evident inability to engage in an honest intellectual discussion.

Unfortunately, this contributes nothing of value to the community of hobbyists who dedicate part of their time to learning how to maintain their aquariums in the best possible conditions.

You should be aware that I am not willing to tolerate being addressed in this manner. Please keep that in mind from now on.

 

[ReneReef]

Hello Renerref,

I can see that your intention is not to engage in a debate by presenting arguments, but rather to dismiss and belittle others through the use of vulgar and derogatory language. Such behavior only reveals your evident inability to engage in an honest intellectual discussion.

Unfortunately, this contributes nothing of value to the community of hobbyists who dedicate part of their time to learning how to maintain their aquariums in the best possible conditions.

You should be aware that I am not willing to tolerate being addressed in this manner. Please keep that in mind from now on.

Well you asked me a question, I answered.

Any beginning of a debate ended when you started using fallacies.

I asked you questions to convince me by telling me how you determine a tank has too little diversity and how you determine how to correct a lack of diversity. You responded with what was basically an ad hominem argument against all scientists…

If you can’t answer a question, just say so. Then we can discuss how to try and find the answers.

Anyway, I drew my conclusion from your response and gave my opinion about your article. Not about you personally.

 

[sixty_reefer]

Yes this helps a lot.

You are unable to answer any of my very simple questions. So you can’t tell when there is a problem with stability or diversity. In stead, you argue the age old and always magnificent “but science always wants to quantify things” rhetoric.
You just started using fallacies and confirmed my initial assessment: Utter jibberish.

If this paper past my desk for peer review I would return it to the editor with nothing more than those two words.

I think there is a step in your reasoning that I may be missing.

Your comments illustrates that the article does not provide sufficiently clear definitions to allow consistent measurement, prediction or intervention. That criticism seems straightforward.

What I do not see is how that leads to the conclusion that the article is meaningless rather than simply imprecisely defined.

In other words, where do you establish that a lack of operational definitions makes a framework invalid rather than incomplete?

Those seem to be different conclusions and I am not sure the second necessarily follows from the first.

Would you care to expand on why the absence of operational definitions is sufficient, in your view, to dismiss the entire article rather than conclude that the concepts require further refinement?

 

[BeanAnimal]

Subsea quoted what I think is actually the weakest paragraph in the article. "A mature tank is defined as one where control mechanisms prevent any population from dominating." My tank is decades old and nearly hands off. By that definition it qualifies. So let's examine if the logic holds.

I had dinoflagellates a few years back. The article uses dinos as an example of what mature biological complexity keeps in check. The biology didn't handle them. UV did.

Red discosoma are taking over the entire tank. I am the 20 year population control. If I ignore them they will take over every coral and every surface in the tank.

Two simple examples. So does my tank meet the definition or not? If yes, the definition isn't doing what it promises. If no, what does a decades old system need to qualify? I am arguably the stability, not the ecology.

The definition is also circular. A mature tank is stable because stability mechanisms are operating. You know the mechanisms are operating because the tank is stable. That's not a definition, it's a restatement in the abstract.

The author agrees with Dan that the aquarist plays a fundamental role, then immediately argues the ecological properties are real even if unmeasurable. It can't be both. If the aquarist is the one actually controlling outcomes and the ecology can't be measured or targeted, what is the framework telling you to do?

On diversity being measurable: measurable to what target? Genetic sequencing tells you what's there. It doesn't tell you what anything is doing, whether it's helping or hurting, or what to change when something goes wrong. Even "beneficial" depends entirely on systems and goals.

The rainforest argument answered a question nobody asked, it is a straw man for "diversity" that can't be defined to a target. ReneReef asked what an aquarist does when stability or diversity is insufficient. That question is still open.

The closing paragraph suggests that activated carbon, ozone, and large water changes may harm mature systems by removing dissolved organic compounds and chemical signals. That's plausible, but there is no mechanism and no evidence, and we are back in the same abstract space.

It's also a direct implication that standard, well supported interventions may be doing damage. That is the same unsupported unfalsifiable argument sixty_reefer has been running across multiple threads, chemistry bad, biology good, with the same absence of mechanism or evidence behind it.

This is a published R2R article. It needs more than "ecologically plausible" and abstract ideas to underpin it. The bar here should be higher.

A framework built on terms that can't be defined or targeted well enough to act on doesn't do any work other than to present ideas as settled interactions and science.

On sixty_reefer's post: the challenge was never that these concepts are philosophically invalid. It was that the framework doesn't tell you what to do. Those are different questions and this is defending the abstract with abstraction.