Coral Holibiont

[Subsea]

I would really like it if nobody ever mentioned old tank syndrome ever again. The term is ambiguous and it does not apply. When people cannot figure something out, they just go to "old tank."

The original old tank syndrome, to me, was when people thought that their tanks and 3 or 4 years would start to leach phosphates from out of nowhere. One of the sayings was that sand beds were phosphate factories - like they can manufacturer po4 out of nowhere. Of course, this is just their misunderstanding, but it was one of the first internet reef tank misconceptions. Of course, it was that they did not understand that the aragonite was masking their lack of phosphate mantenace for a long time... and maybe that they did not understand the difference between binding/unbinding vs absorb/leach.

Also, getting old is undefeated. You cannot just simply change a thing (like add carbon) and fix an issue with being old. Most issues with old things are chronic.

Most of these issues likely should be just called what they are. For example, if Abe thinks that his tank was carbon deficient, then just call it that. It was not because the tank was old.

@jda
I might be sensitive about my age, which sparked my initial comments. For that, I apologize to you.

Nevertheless, I am fatigued with some of the instant gratification mindset of too many American Reefers that use short term vision and I asked a knowledgeable friend from Sweden to join this conversation to bring other points of view. @Lasse & I had similar starting out careers as: Municipal Waste Water Superintendents. He really knows how to stir IT UP.

AGAIN, I apologize for blunt/harsh words. Not to make excuses for impoliteness, my Zen has been challenged and I faltered:

two weeks ago, I experienced a heart attack that resulted in three stents placed in my heart on December 6 at 4pm. I walked out of the hospital on December 7 at 11am. I have had 14 days to think about my mortality and at times, the process is difficult.

So as to change the mood, I should add that a favorite short book is written by humorist Erma Bombeck, “If Life is a Bowl of Cherries, Why am I Always in the Pits”

 

[jimk60]

Great thread! I took started long before the Internet and Martin Moe was my go to guy and I still have all his books. Seems like all my reefs hit a wall at around seven years with slow coral growth and slow decline of previously flourishing colonies. I always attributed this to "old tank syndrome" which usually results in a tear down to reset. I am currently around that age but looking good. Thanks for new ideas on how to prevent this

 

[Subsea]

Becatse Erma is a very insightful author, she wrote a book for @Lasse & I to read!

The Grass Is Always Greener over the Septic Tank Paperback – March 1, 1995​

by Erma Bombeck (Author)


“[Erma Bombeck] is marvelously funny, direct as a hypodermic, a virtuoso in the field of suburban living.”—Vogue

It’s the exposé to end all exposés—the truth about the suburbs: where they planted trees and crabgrass came up, where they planted the schools and taxes came up, where they died of old age trying to merge onto the freeway and where they finally got sex out of the schools and back into the gutters

 

[Subsea]

Great thread! I took started long before the Internet and Martin Moe was my go to guy and I still have all his books. Seems like all my reefs hit a wall at around seven years with slow coral growth and slow decline of previously flourishing colonies. I always attributed this to "old tank syndrome" which usually results in a tear down to reset. I am currently around that age but looking good. Thanks for new ideas on how to prevent this

Thank you for kind words,

I just moved a 3 yr mature 55G dual tank stand from living room to alcove in dining room. As part of the process, I moved all mature live rock/corals into other mature systems in order to install reverse flow ug filter. I copied RIP clean by lightly washing in fresh water. I have mixed results with lightly washed in fresh water:
Pros:
I saved much micro biodiversity

Cons:
The initial reason I disassembled this tank is because
Red Planaria have survived two treatments of 500% dosage. And one week layer, I am not confident I eliminated all as I watch developing larvae,

Tale of Two Cities or Phoenix Rises

Pardon my use of classic literature in the title of this thread. It comes with my age at 75 years young. I have operated marine aquariums for 51 years, thus a companion thread “Nutrient Management by Old School Reefer”...

www.reef2reef.com

 

[Subsea]

They also might not understand and trust too much. Some of it is instant gratification, some is laziness and some is also that people who are honestly trying to help might just be doing the wrong things, and it propagates. Some have to quantify mostly out of doubt, so a number on a test kit is absolute and what their eyes and other senses tell them about what is in their tank is forsaken - you have seen folks get crushed when they find out that test kits of ICP are really not all that great, right?

In the example of adding the algaecide which makes a huge hole in the ecosystem, some posters and internet folks mean well because the algaecide worked for them, but they are just a few weeks away from it and have not experienced the full impact yet. Sure, there are folks who cautioned not to take this approach, but who knows how many heed the advice - many of those that did likely disappear into nevermind because they did not come back and post about the issues in a month or two.

@jda
I am no sure how old you are, I guessed < 30yrs with more degrees than a thermometer.

After rereading this post, I see much more wisdom & maturity. I will not guess your age anymore.

 

[jda]

My current reef is more than 20 years old. No signs of slowing. Like I said before, if you relied on your sand and rock (unknowingly or not) to manage po4 for you, it cannot do this forever. If you have sand, it might be a good time to slowly clean it out - I do 25% a quarter every 4 yeas. While the gunk that is in there is mostly benign since the ecosystem will have used every bit of energy or building blocks, it can gum up the works and not allow water to flow through there correctly nor for the sand critters to live well. I like to get this gunk out of there. You have to do this slowly so that the oxic and anoxic zones can rebuild before you move on. You can see the sand critters flock to the fresh areas.

Other than the above, the rest is about treating the acute issues as they arise.

@Subsea - I am glad that you are on the mend. I was born in mid 70s... in time to meet most of the authors and pioneers of the hobby and among the first on the internet. Been keeping saltwater before i could drive. I have fish that are older than some of my kids that are in college - purple and yellow tang.

 

[Subsea]

I have no phosphate problems that I know of.

Let’s talk to the holibiont.

With respect to flushing out old sand-beds, I say, “Not on My Watch.”

With reverse flow ug, nothing needs flushing!

It’s aerobic. Slow down and smell the roses,

 

[jda]

I want all of my sand beds to remove nitrate. No UGF for me - besides, if I had a time machine to go back and put a UGF in, I would use it to play the lottery, buy amazon stock, see the last White Stripes or Radiohead concert or get a bunch of BitCoin. Dr Ron and I talked about this years ago and he agreed that he did not write enough about inert gunk but also wanted to perform some tests over a few years - he was 6 inches deep and I like 3 inch sand beds and he thought that he had more time with the extra depth. Probably true.

The phosphate buffering on the low side, the sand critters and denitrification are too important to me. I will never have an ecosystem without 3 inches of sand. I just don't want to work hard enough to do these things in other ways. I love that I don't have to worry about there not being a trace of po4, nor no3 every getting above 1.0 ppm.

This is like the foundation of my ecosystem, or larger holobiont.

On a different topic, Lasse posted some stuff that I was reading and went to the references and read through those. The coral host also can store building blocks for use later - this particular article that I was reading talked about metaphosphate and how most hosts prefer metaphosphate (to ortho) for this reason and also to use the other things bound in the structure to attach waste to expel... kinda like trash cans. Hosts can also recycle building blocks and energy for their symbionts.

 

[Subsea]

I want all of my sand beds to remove nitrate. No UGF for me - besides, if I had a time machine to go back and put a UGF in, I would use it to play the lottery, buy amazon stock, see the last White Stripes or Radiohead concert or get a bunch of BitCoin. Dr Ron and I talked about this years ago and he agreed that he did not write enough about inert gunk but also wanted to perform some tests over a few years - he was 6 inches deep and I like 3 inch sand beds and he thought that he had more time with the extra depth. Probably true.

The phosphate buffering on the low side, the sand critters and denitrification are too important to me. I will never have an ecosystem without 3 inches of sand. I just don't want to work hard enough to do these things in other ways. I love that I don't have to worry about there not being a trace of po4, nor no3 every getting above 1.0 ppm.

This is like the foundation of my ecosystem, or larger holobiont.

On a different topic, Lasse posted some stuff that I was reading and went to the references and read through those. The coral host also can store building blocks for use later - this particular article that I was reading talked about metaphosphate and how most hosts prefer metaphosphate (to ortho) for this reason and also to use the other things bound in the structure to attach waste to expel... kinda like trash cans. Hosts can also recycle building blocks and energy for their symbionts.

Your nitrate messages are old. I see you have them in storage,

I dose nh4. Nitrate is a waste product.

 

[Subsea]

@Beuchat said:

The concept of tank maturity

The disappearance of algae pests is related to the concept of "mature and stable aquarium". Since I started in the hobby more than 25 years ago, I have heard these two terms all the time, and have always wondered what they really mean. Tank maturity and stability is an emerging quality that has very complex chemical, biological and ecological underpinnings. We can say that aquarium stability is closely related to the stability of the typical parameters that we usually measure, i.e.: concentrations of calcium, magnesium, alkalinity, nitrate, phosphate, potassium, trace elements, etc., but there is something that goes beyond such parameter stability and has a lot to do with the interspecific competition between species of microorganisms and macroscopic organisms that inhabit the aquarium.

When we speak of these "emergent" qualities it is convenient to emphasize that they are based on innumerable chemical and biochemical processes that sustain the metabolism of the organisms that are part of the microcosm. There is absorption and release of nutrients into the water, birth, growth, reproduction, predation and death. Algae, protists and bacteria constitute the first levels of the trophic web, taking care of the recycling of organic and inorganic nutrients in the water column, all of them interacting with each other and with the environment where they live (as an ecosystem itself).

In reference to the concept of maturity I want to propose a hypothesis, which by definition is something that must be demonstrated to be taken as true. The intention of this article is to generate a debate about it. The hypothesis can be expressed as a series of "requirements" for the attainment of the state of maturity, namely:

- Stability of chemical parameters, as mentioned.

- Stability in light intensity and spectrum.

- Diversity of microorganisms: phytoplankton, zooplankton (copepods, for example), autotrophic and heterotrophic bacteria. Diversity is one of the consequences of
stability, as occurs in coral reefs.

- Sufficient" concentrations of nitrate and phosphate in the water so that all species have "food" so that none of them can take advantage due to their metabolism
adapted to "extreme" situations, for example, cyanobacteria that are able to take advantage of the nitrogen dissolved in the water, without the need to directly assimilate
ammonia.

- Real competition between all aquarium organisms, especially microorganisms: bacteria, phytoplankton and zooplankton. This competition could be summarized in several
types:


o Competition for space. This is probably one of the most relevant. Once a surface (live rock, substrate, etc.) is colonized by one species, it becomes more difficult
for another to occupy that spot (therefore newly set up aquariums are so prone to algae pests).

o Competition for inorganic nutrients. The availability of ammonia, nitrate, phosphate, CO2 and trace elements in the water is variable and depends on
consumption and release by organisms. For example, a functional heterotrophic bacterial biofilm will remove nitrate and phosphate on its surface, made
more difficult for algae to assimilate.

o Grazing and predation. Algae are subjected to grazing by zooplankton, for example, copepods feeding on dinoflagellates. Surgeonfish grazing at diatoms and
hair algae on the rocks or tank walls limit their growth.

o Chemical interaction between organisms. I will elaborate on this point in more detail in the next paragraph for clarity. I am convinced that it is the most
relevant factor of them all.

 

[Subsea]

@Beuchat said”

“Dilution of allelopathy compounds that inhibit the growth of dinoflagellates and cyanobacteria. It is striking the fact that a bloom of dinos, cyano and even
hair algae, are initiated in a "synchronized" way at different spots of the tank, at exactly at the same time. This suggests the existence of "chemical signals" or, at
least, significant changes in the water concentration of certain inhibitory compounds released by competing species. It is relatively easy to find scientific papers“

I brought this up again as it highlights the holistic nature of how holibionts function to enance their enviroment with cross talk between microbes: gene expression.

 

[Subsea]

@Beuchat said in support of coral holibiont in this paragraph:

“Organic carbon dosing is very effective in controlling dinoflagellates such as Ostreopsis, Prorocentrum and Amphidinium, provided that nitrate and phosphate are not allowed
to drop to undetectable values during treatment. Heterotrophic bacteria generate natural algaecide compounds that inhibit dinoflagellate growth.

- The use of "miracle" products such as commercial chemical algaecides (e.g., heavy metals), can eradicate the pest, but often make a big hole in the food web, so that another
invasive species is able to occupy the available niche after the death of the previous one. In this way, pests follow one after another in the tank: cyanobacteria,
dinoflagellates,filamentous, etc.

 

[Subsea]

@Beuchat

Angel,
Thank you for a very interesting article & hypothesis. I like it so much that I bought your book.

“Reefkeeping Fundamentals is a book that raises the standard of what a hobbyist can achieve. The author deep dives into the science and technology behind the creation of a complete ecosystem within our home. Fundamental issues are reviewed, dispelling myths and providing a rigorous, useful and innovative view.
The guide explores aspects such as coral classification, aquarium type, water circulation, lighting, aquascaping, feeding, fish and coral quarantine, seawater composition and algae pests. The reader will find the information needed to achieve a mature and stable system, correctly establish the food web and consolidate an optimal nutrient flow. An excellent guide with best practices recommendations to get to the next level.
The volume includes numerous underwater photographs of fish, corals and invertebrates in their natural habitat, as well as technical descriptions of some reference set ups, as inspiration for each personal project. A YouTube channel, accessed via QR codes within the book, shows microscopic organisms that inhabit reef aquariums, explanations of specific equipment, and personal interviews with leading hobbyists. A high value proposition, never before included in a single book.”

Table of Contents:
1- Biology and Nutrients
2- Corals in the Reef Aquarium
3- Acclimation, Quarantine and Health
4- The Project Start-Up
5- Parameters and Ranges
6- Seawater
7- The Food Web in the Reef Aquarium
8- Nutrient Flow
9- Nutrient Reduction, Export and Import of Techniques
10- Calcium, Magnesium and Alkalinity Maintenance
11- Oxidation Reduction Potential and Ozone
12- Reef Aquarium Portfolio
Read less


Beuchat ends this artcle with a challenge to discuss:

Conclusion for discussion.

The hypothesis presented is that the chemical interaction between the organisms that inhabit a reef tank is probably the most important factor that allows the ecosystem to "self-regulate" its algae populations, so that the probability of a single species taking advantage of the others is quite low. This would therefore be the most determining factor in terms of the robustness of an aquarium. Almost all algae species are desired. What is undesired by the hobbyist is a pest of any one of them. I am convinced that this chemical interaction plays a decisive factor in determining the concept of "mature aquarium". One question would be: What percentage of the total "maturity" of the tank could be attributed to this factor if any?

 

[Subsea]

As an avid outdoorsman, I see a Climax Forest similarly as Old Tank Syndrome. In land as in the sea, the top competitors dominate at the expense of weaker species. LOSS OF DIVERSITY

Suggestions for combatting OTS amount to introducing biodiversity of micro fauna & fauna, which provides multiple nutrient pathways and thinning out old colonies.

In my experiences, diver collected live rock is the best way to bring in diversity.

Gulf Live Rock.com

gulfliverock.com

Gulf Live Rock.com

gulfliverock.com

 

[Beuchat]

Hi @Subsea , thank you very much for acquiring the book.

In my early years in the hobby, when researching in books and on the internet, I would come across articles dealing with aspects of reef aquarium physics, chemistry and biology (Delbeck & Sprung, Borneman, Bingman, Wilkens, etc.). Topics were treated independently (nitrification, denitrification, coral calcification, lighting, etc.). Over time you realize that all these processes are treated separately simply for the sake of simplicity of understanding them.

To me, they are all the same process and are nothing more than nature's ability to transfer matter and energy and stay alive. Everything is utilized without exception. Chemical compounds are used simultaneously as nutrients and waste products, light as an input of energy (which is then transformed into food in zooxanthellae, for example) and also as an output (bioluminescence, fluorescence). And so on. It is a gigantic and endless loop that maintains the existence of all living things.

The holobiont coral is an example. Scientists consider zooxanthellae, the coral itself and all associated microorganisms (bacteria, archaea, unicellular algae other than zooxanthellae living in their tissues) as an evolutionary unit. The stability (homeostasis) of the holobiont is sustained by the association of all of them. But the level of association also depends on external conditions (temperature, light intensity, concentration of organic and inorganic nutrients in the water, etc.), so that an abrupt variation in one or more of them may imply a change from cooperation to competition.

For example, a coral deprived of light, zooxanthellae stop translocating organic compounds and become parasites of the host, so they are expelled. Similarly, when faced with an excessive increase in light radiation, the coral expels the zooxanthellae so as not to be intoxicated by the excess of superoxide radicals produced by them.

The dosage of organic carbon also alters these conditions outside the holobiont. The heterotrophic bacteria that lodge inside the coral tissues have much more food than before, so their metabolic rate and reproduction increases, taking more nitrogen, phosphorus and trace elements from their surroundings, which, in excess, leads to the collapse of homeostasis and the coral dies. The holobiont disintegrates because the collaboration/competition equilibrium has been broken).

An example of this situation is the cases of RTN that occur in some aquariums when the alkalinity maintenance system is abruptly changed from traditional inorganic methods (Balling) to organic methods (e.g. Tropic Marin's "all for reefs", which uses calcium formate).

 

[Subsea]

@Beuchat

I am looking forward to reading your book. Your ability to go back & forth from micro to macro cosmos with ease while clearly explaining the sophistication of the process is stellar.
A Cajun Aggie,
Patrick

PS: For clarity

Cosmos often simply means "universe". But the word is generally used to suggest an orderly or harmonious universe, as it was originally used by Pythagoras in the 6th century B.C. Thus, a religious mystic may help put us in touch with the cosmos, and so may a physicist.

 

[Subsea]

jda said:

“IMO, too much emphasis is put on bacteria as tanks mature. In the beginning, you need and want bacteria but as tanks get more and more corals, algae, micro critters who can use and process fish waste directly for the benefit of themselves and the whole ecosystem, bacteria fall by the wayside still existing but performing a less important function. What was once a danger is now a savior (ammonia). I think that many researchers miss this. Most hobbyists do.“


@jda

Bacteria are the microbial overlords that drive biochemistry. Initially during new tank startups with dry sand and dry rock, bottled bacteria are nitrification & denitrification only. This is a very small representation for bacteria in a healthy mature reef. Then as ecosystem matures, enhance the word bacteria with the word microbes:

“The term “marine microbe” covers a diversity of microorganisms, including microalgae, bacteria and archaea, protozoa fungi and viruses(Photo 1 to 5). These can be prokaryotes (i.e., organisms whose cells lack membrane-encased nuclei) and eukaryotes (i.e., organisms with true nuclei).“

PS:
As I view this list of microbes from the point of view of the Coral Holibiont, I say food in the form, of the Microbial Loop.

 

[Subsea]

Marine Microbial Diversity: The Key to Earth's Habitability - NCBI Bookshelf

Marine microbes are uniquely important to life as we know it. Since life most likely began in the oceans, marine microorganisms are the closest living descendants of the original forms of life. They are also major pillars of the biosphere. Their unique metabolisms allow marine microbes to carry...

www.ncbi.nlm.nih.gov

Marine Microbial Diversity: The Key to Earth's Habitability​

This report is based on a colloquium, sponsored by the American Academy of Microbiology, held April 8–10, 2005, in San Francisco, California.
Jennie Hunter-Cevera, David Karl, and Merry Buckley.

Washington (DC): American Society for Microbiology; 2005.

• Copyright and Permissions

 

[Lasse]

Sorry for late entrance

First - my standpoint according to the coral holibiont in reef-building corals differ in some way from the most accepted theories (at least in the hobby). And I have had this point of view from the beginning of my reefing experiences. Lately my believe in this point of view have been strengthen a lot by a scientific papers done by Jörg Wiedenmann, Cecilia D’Angelo, M. Loreto Mardones et al. Jörg Wiedenmann and Cecilia D’Angelo has also help to debunk another myth among aquarists - summarized here. These findings is from 2013-2014. Here is an excellent review of the scientific paper from 2023

My standpoint is - and have always been that the relationship between the animal and the holibiont is in the form of the farmer and his/hers crop - shortly - the animal farm the holibiont and eat the produced surplus holibionts. I have always based this on the main theorems of thermodynamics and some biological principles as reproduction and maximum energy utilization (with this I mean that biological life strives towards conserving energy within the organism and release as little as possible to the outside as waste) All other explanations for the basic principles of food-intake of the main actor in a successful ecosystem as the coral reef is for me impossible from an evolutionary standpoint. It will also solve Darwin's paradox. The paper of Jörg Wiedenmann et al show this with a rather beautiful experiment. I also want to emphasize that Jörg Wiedenmann has been an aquarist since childhood and he also point out this as an advantage in his research."This childhood hobby developed into an important skill set: I am one of the few people in the field who can maintain long-term coral collections and use them as experimental models in an aquarium."

This article - that´s a comment on another research paper is also interesting. It is from 2018 and you maybe can see the paper from 2023 as an answer on the questions raised in this paper.

I know about the theories of feeding photosynthetic corals because of their polyps. Yes - I believe that photosynthetic reef building corals can utilize prey of both zoo and phytoplankton but that is not the main use for the polyps, And I do not either think it is mandatory for them to catch prey.

I also believe that when they show their polyps during the day when they photosynthesize - then the polyps have a different function - namely to increase the surface area towards the water and in that way optimize the diffusion of produced oxygen out to the water. I think this also applies to soft corals that "inflate" themselves while photosynthesis is taking place.

For stony corals that not use photosynthesis (and non-photosynthetic soft corals) prey is essential and they use their polyps in order to catch the pray IMO. But I seldom see these corals showing polyps (if it is not a known "feeding" time) when the lights are on.

My system is a system without any mechanical cleaning - the main reason for this was from the beginning that I believe that my corals could take benefit from small organic particles and bacteria. I´m not so convinced of this any longer. However my sponges and other filtrating animals love it.

However - I have notice that aiptasia is one of the best in order to switch between photosynthesis and prey feeding. I had a heavy growth of aiptasia in one special place in my aquarium. It was in a construction that serve as wavemaker - open in the top - letting light coming in. It was a place there both aiptasia and yellow tubastrea thrive. The aiptasia was on its way to take over, hence I put a light shield over the opening. Still feeding there every day. The aiptasia growth slow down but - it still reproduce itself. The tubastrea (not a photosynthetic hard coral) grow as it did before. I stop feeding in that spot and today some months later - no sign of aiptasia and the tubastrea colony is much smaller. Have start to feed that spot again. But the particles in the water was not enough for the aiptasia and the tubastrea did not get enough either but seems to utilize the particles and bacteria better.

I think that some carbon comes from alk too. Dana Riddle has written about this. It could be either or both... neither are scarce in most situations (if they are, you are in trouble) so it never really mattered to me.

High co2 means low pH and that is not all that good for stony corals, so co2 at atmospheric levels of 400ish appears plenty fine.

Right but I want use "some" - I would use "most" in normal aquariums. Consider that - higher pH - lesser CO2 content in water. The photosynthesis will rise the pH (because CO2 is consumed) but in HCO3 rich water (like salt water and some alkalinity high fresh water-system (read the great lakes of east Africa and some fresh water system in Central America) the photosynthesis continue and produce higher pH. In low alkalinity freshwater system - like Amazonas and west Africa - the photosynthesis stops or slow down if it drive the pH to high. However - I think that this is mostly valid for normal systems. Fresh water aquarist use CO2 addition in order to withhold a lower pH during photosynthesis (hence more CO2 dissolved) and I think that if someone start to add CO2 in a reef aquarium and stabilize pH during photosynthesis to around 8.2 - it should result in better growth. I base even this on energy balance - it cost more internal energy to convert HCO3 into CO2 just outside or inside the cell compared with using CO2 directly from the water (if available) In the cell processes CO2 is mandatory - outside HCO3 have to be converted into CO2 in one or another way in order to be available for the cell processes. And it cost energy

I would really like it if nobody ever mentioned old tank syndrome ever again. The term is ambiguous and it does not apply. When people cannot figure something out, they just go to "old tank."

I agree

The initial reason I disassembled this tank is because
Red Planaria have survived two treatments of 500% dosage. And one week layer, I am not confident I eliminated all as I watch developing larvae,

Have you ever heard about scooter blenny (Synchiropus ocellatus) - its an excellent red planaria eater.



Sincerely Lasse

 

[Subsea]

My friend, thank you for the farmer analogy. I will suggest, replace farmer with God, using the dna code as Intelligent Design & the Laws of Nature that conduct their symphony: Coral Holibiont.

Sustainable farming means Environmental Steward. That’s a good platform to discuss from.

As a nature lover who has lived in forest and marshes, I see an analogy between old tank syndrome and climax forest, yet, so as not to muddy the water, I will not talk ots.

Lasse,
You have more degrees in your thermometer than I.

As an Engineer, I can address The first & second Laws of Thermodynamics and if need be we can go there. However, I like this better and let’s replace the farmer with environmental steward, who uses systems engineering.

Systems engineering is an interdisciplinary field of engineering and engineering management that focuses on how to design, integrate, and manage complex systems over their life cycles. At its core, systems engineering utilizes systems thinking principles to organize this body of knowledge. The individual outcome of such efforts, an engineered system, can be defined as a combination of components that work in synergy to collectively perform a useful function