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Discussion Starter · #1 ·
Does Aquaculture actually clean water or just reduce water?

In other words, does it somehow have a way to filter out the dirt, ammonia, Nitrites,nitrates, trace elements etc.. from the water or does it rather just uptake whatever water happens to be its roots and evaporating it via the leaves reducing the water amount in the system which I assume get replaced with clean water giving the appearance of cleaning the water?

Please note I am talking about aquaculture( like hydroponics with fish) growing above water plants like Tomatoes,herbs,etc..

Thanks.
 

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Discussion Starter · #3 ·
Done correctly it does "clean" the water for simple terms. It is used in some places as a way to clean sewer waste water. Sprayed on cropland it is a very good way to clean the mess.

How would above water plant's roots clean the water?

They actual can attract and absorb the nutriments to the roots without just tanking in whatever water happens to be by the roots when it needs it or rather pull the nutriments without the water?

My understanding of hydroponics is that you usually need a large fan(if indoors) to get the plant to uptake more water and therefore nutriments.

So if you had a 100 gallon hydroponics system and the plants uptake 10 gallons of that solution, the nutriments won't just be reduced by 10%(10 gallons worth) but might actually take like 80% of the nutriments in the 100 gallon solution?

Please note that I'm not talking about spraying it on crops and that seem like it can be dangerous since people will throw very bad things in the sewer such as motor oil, batteries, chemicals used for dry cleaning,etc.... You can't guarantee its just organic waste like in a fish tank.

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I don't think the plants can separate out the solids and just use them. They will only take in liquids.
That is where they are handy in waste water treatment. They do not just flush the toilet into the field! It is a long complex series of treatment before it is then sprayed onto the crops. The solids are removed and used in other ways. The value is in letting the plants further deal with the waste rather than cleaning the water to a certain level and then releasing it into a body of water.
In place of millions of gallons of waste water going into a local river, thousands of tons of crop can be produced and sold. The solids which were separated first can then be sold for a variety of uses. One common use is spraying on fields or making compost. Some is used for food crops but much of it is likely to be used for non-food crops.
Since there is very little true "new" water, we might carry the thought through and say we are all part of a very large complicated aquaculture setup?
 

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In other words, does it somehow have a way to filter out the dirt, ammonia, Nitrites,nitrates, trace elements etc.. from the water or does it rather just uptake whatever water happens to be its roots and evaporating it via the leaves reducing the water amount in the system which I assume get replaced with clean water giving the appearance of cleaning the water?
terrestrial plants take in nitrates and use them to build amino acids. The nitrate molecules are transformed via chemical reactions that take place within the plant, that's how plants can make proteins and carbohydrates out of things like carbon dioxide, nitrates, ammonia, etc.

http://www.beslter.org/virtual_tour/Nitrate.html

The magic of plants! They're where all the protein and carbohydrates on earth originate!
 

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Aquaponics:
Plants can be so efficient at removing nitrogen from the water (ammonia, nitrite, nitrate) that the plants at the end of the line show nitrogen deficiencies. Plants use a lot of nitrogen when they are growing new leaves.

Sewage treatment:
Ditto PlantedRich: Aquatic plants (the green growing things) can be grown in treatment plants (the facility). When the plants are getting close to maturity, not growing so much, not taking in as much nitrogen, the plants are removed from the system and composted. New plants are added. The compost is blended with other things (such as the solids part of the waste) and sold. I have taken a tour of one waste treatment facility. They do the planted cleaning part of the system in a greenhouse for maximum growth rate of the plants in the winter. They use Water Hyacinth.
In a greenhouse there is indeed less evapotranspiration because of the high humidity, but the plants can actually do a small amount of pumping, not just depending on evaporation for move water and nutrients through their system. Also, the greenhouse is ventilated and this keeps the humidity lower than if it was a sealed greenhouse.

Land and aquatic plants take in all the nutrients they need when these nutrients are in simple form, small molecules, mostly. These are dissolved in water. Even land plants need their fertilizer dissolved in water. They do not take in solids. Plants (all sorts) are quite good at removing all the things they need from soil moisture or water in aquariums, aquaponics and hydroponics, and even can remove some things in excess, almost to the point of being toxic to the plants.

For a lot of pretty good info about this in aquariums read Diana Walstad's book, Ecology of the Planted Aquairum.
For info about land plants most of my information comes from Western Fertilizer Handbook and the soils class I took mumble... mumble... years ago.
There is a lot more info about hydroponics and aquaponics on line.
Ouroboros Farms | Commercial Aquaponic Farm | Organic Type Produce | Farm Stand | Half Moon Bay, San Mateo County, CA
 

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Discussion Starter · #7 ·
Aquaponics:
Plants can be so efficient at removing nitrogen from the water (ammonia, nitrite, nitrate) that the plants at the end of the line show nitrogen deficiencies. Plants use a lot of nitrogen when they are growing new leaves.

Sewage treatment:
Ditto PlantedRich: Aquatic plants (the green growing things) can be grown in treatment plants (the facility). When the plants are getting close to maturity, not growing so much, not taking in as much nitrogen, the plants are removed from the system and composted. New plants are added. The compost is blended with other things (such as the solids part of the waste) and sold. I have taken a tour of one waste treatment facility. They do the planted cleaning part of the system in a greenhouse for maximum growth rate of the plants in the winter. They use Water Hyacinth.
In a greenhouse there is indeed less evapotranspiration because of the high humidity, but the plants can actually do a small amount of pumping, not just depending on evaporation for move water and nutrients through their system. Also, the greenhouse is ventilated and this keeps the humidity lower than if it was a sealed greenhouse.

Land and aquatic plants take in all the nutrients they need when these nutrients are in simple form, small molecules, mostly. These are dissolved in water. Even land plants need their fertilizer dissolved in water. They do not take in solids. Plants (all sorts) are quite good at removing all the things they need from soil moisture or water in aquariums, aquaponics and hydroponics, and even can remove some things in excess, almost to the point of being toxic to the plants.

For a lot of pretty good info about this in aquariums read Diana Walstad's book, Ecology of the Planted Aquairum.
For info about land plants most of my information comes from Western Fertilizer Handbook and the soils class I took mumble... mumble... years ago.
There is a lot more info about hydroponics and aquaponics on line.
Ouroboros Farms | Commercial Aquaponic Farm | Organic Type Produce | Farm Stand | Half Moon Bay, San Mateo County, CA

Right....but what I'm after is if the plant root act like a nitrogen magnet to actually pull the nitrogen from the water or if they just happen to use nitrogen from water it takes in?

Lets say you have 100 gallon of aquaculture dirty water and your plants uptake 10 gallons(10%)

Will your nitrogen be reduced by 10% (just "cleaning"water it uptakes from the 10 gallons of water or like 80%(if they can somehow selectively uptake the nitrogen from the 100 gallon system)?

In other words, there is a water current passing by the roots. Do the roots just indiscriminately pull in water from its surroundings and then start to process whatever it happens to find in that water or does it somehow selectively target nitrogen from that water and decide to uptake only nitrogen from that water at a faster rate then just the water that is removed from the system?

Thanks.
 

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It just takes in the liquids that are around the roots. Whether that liquid has nitrogen or not , it takes the same liquid. If it is something that it needs, it may grow but if it is something toxic, it may die. How much of any particular element it will use depends on the plant. Some are nitrogen hogs and some not so much. Some need more iron and others not so much.
 

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Aquaponics:
For a lot of pretty good info about this in aquariums read Diana Walstad's book, Ecology of the Planted Aquairum.
For info about land plants most of my information comes from Western Fertilizer Handbook and the soils class I took mumble... mumble... years ago.
There is a lot more info about hydroponics and aquaponics on line.
Ouroboros Farms | Commercial Aquaponic Farm | Organic Type Produce | Farm Stand | Half Moon Bay, San Mateo County, CA
I'm reading through Diana Walstad's book and so far it's fantastic. It has plenty references to specific biochemical processes, yet casual enough for a layperson to get the general concepts and have enough material to follow up on to learn.

I also visited Ouroboros Farm, and I love it there. I'd like to do some volunteering there.

Right....but what I'm after is if the plant root act like a nitrogen magnet to actually pull the nitrogen from the water or if they just happen to use nitrogen from water it takes in?

Lets say you have 100 gallon of aquaculture dirty water and your plants uptake 10 gallons(10%)

Will your nitrogen be reduced by 10% (just "cleaning"water it uptakes from the 10 gallons of water or like 80%(if they can somehow selectively uptake the nitrogen from the 100 gallon system)?

In other words, there is a water current passing by the roots. Do the roots just indiscriminately pull in water from its surroundings and then start to process whatever it happens to find in that water or does it somehow selectively target nitrogen from that water and decide to uptake only nitrogen from that water at a faster rate then just the water that is removed from the system?

Thanks.
If I may reiterate your question to make sure I understand: does a plant take in water from its roots, after which it processes desired compounds from the water that is now contained within its cell walls, or does it take nutrients directly from the water?

With the caveat that I'm still learning, I believe the answer is that while both are possible (Diana mentions intake of water that is then transpired through the leaves I'm guessing), for aquatic plants it will mainly absorb nutrients directly from the water, just because it's already dissolved in water. And plants will intake some water for water's sake, and this is probably drastically less pronounced in submerged plants vs. terrestrial or even emersed.

To use your 100 gallon example, I think fairly little water volume will be actually used by the plants, especially when compared to evaporation. Assuming no nutrient deficiencies in the water and/or ambient air, the plants will take as much as it can get, and according to Diane Walstad, often much more than it needs. The ratio will depend on the plant type and the nutrient profile, since certain nutrients are more readily taken in than others. So back to your example, the plants will take way more of the nutrients available than the % of water volume it will use. In other words and for purposes of this example, nutrient uptake is not limited by the water volume the plant needs for itself. I'm sure a relationship exists, but they are probably not so linearly related.

Also, keep in mind that nutrient uptake is not only via the roots, but leaves as well (as in the case of submerged plants). And depending on the plant and nutrient, the leaves or roots can be the preferred method of transport.

Another cool example that I believe indicates direct uptake (and now I'm just showing off what I learned from reading Walstad :grin2:), is that plants can affect the water parameters directly around its roots (e.g. increase/decrease pH), so as to make certain elements more readily accepted/effective. If water uptake was a prerequisite to nutrient uptake, I imagine that the above mechanism wouldn't need to occur around the roots, if at all.

There are many others on here with deep knowledge and can provide a much more nuanced perspective, and maybe even call me out on any terrible representation of facts, lol.
 

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The nitrogen will be MORE reduced than the simple uptake of water would suggest. It is not simply a passive intake of the water and whatever is there. Plants can be selective, and take in the nutrients they need, and do not need to take in all the water around those molecules.

Example:
At Oroborous, their first set up, they had too few fish, not enough fish food (protein gets digested and enters the system as ammonia).
Plants in the growing troughs would remove 100% of the nitrogen, but not 100% of the water. Thus, the plants at the end of the line needed to have nitrogen added.

Within a very close range plants can affect the water surrounding their roots, so take in certain nutrients.
Since the water is moving through the troughs, all the water eventually comes close enough to the roots so that the nutrients in the water can be taken up by the plants.

Another way to put this (in reverse):
In a stagnant setting the plants have no magnet that will attract the nutrients from all over the tank.
Their 'magnet' works only at very close range. Water movement through soil, through an aquarium, through the hydroponic troughs is very important.
 

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Discussion Starter · #11 ·
The nitrogen will be MORE reduced than the simple uptake of water would suggest. It is not simply a passive intake of the water and whatever is there. Plants can be selective, and take in the nutrients they need, and do not need to take in all the water around those molecules.

Example:
At Oroborous, their first set up, they had too few fish, not enough fish food (protein gets digested and enters the system as ammonia).
Plants in the growing troughs would remove 100% of the nitrogen, but not 100% of the water. Thus, the plants at the end of the line needed to have nitrogen added.

Within a very close range plants can affect the water surrounding their roots, so take in certain nutrients.
Since the water is moving through the troughs, all the water eventually comes close enough to the roots so that the nutrients in the water can be taken up by the plants.

Another way to put this (in reverse):
In a stagnant setting the plants have no magnet that will attract the nutrients from all over the tank.
Their 'magnet' works only at very close range. Water movement through soil, through an aquarium, through the hydroponic troughs is very important.

That is very interesting and is an answer to my question. You must have really understanding what I was trying to get at with the whole magnet for minerals/nitrogen at close distances well as if the uptake just water in general or if it had a selection ability.

I liked your example of a aquarium having no more nitrogen while only a very little water was evaporated.

Perfect!
 
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