Do Healthy Plants Release Organics?

jaypeecee

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Just an observation, Otos et al are often very busy on plant leaves that are strong, healthy and have no obvious algae.
Hi @Oldguy

This is something I've noticed many times and been intrigued by it. Yesterday, I was chatting with an ichthyologist who confirmed what I had long suspected, which is that Otos (and others) feed on something known as periphyton. Please take a look at:

https://en.wikipedia.org/wiki/Periphyton

We, as aquarists, would probably refer to this as biofilm. But, according to Wikipedia, biofilms can take many forms - including dental plaque! If interested, please see below:

https://en.wikipedia.org/wiki/Biofilm

And it's now an even wetter, rainy day. :(

JPC
 

Oldguy

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aquarists, would probably refer to this as biofilm
Good evening @jaypeecee, Thank you for your links, most interesting. Nothing in life is good or bad. I rely of biofilm [hopefully the good guys] in my wet/dry trickle filter which I modeled on a sewerage works treatment plant as a important part of my tank set up.

Complex films of chemicals, bacteria, protozoa, rotifers and fungi are intriguing. As a young lad I fell in love with rotifers and spent many hours looking into bird-bath films with a pocket microscope, much to the chagrin of some of my teachers and the wry support of my headteacher who could not make me out but gave much support.

Keeping fish in a planted tank brings all branches of science together with a wealth of practical observation and application. We learn new things every day, long may it continue.
 

dw1305

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jon32

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Hi, Interesting thread. I can rule out fish food as my 60X30X18 high tech tank always has surface film. The tank only has a few cherry shrimp and is heavily planted. I don't feed the shrimp I just leave alone to graze on the biofilm.
 

jaypeecee

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Hi Folks,

I very recently stumbled across this post:

https://www.ukaps.org/forum/threads...d-about-bacteria-in-filter.28795/#post-299821

Note the comment that "plants produce a LOT of waste, especially if the tank is enriched with CO2 via gas or liquid". So, does this not support the idea of continuously removing DOCs using suitable filtration media such as Seachem Purigen? Is this what other UKAPS members do?

JPC
 
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zozo

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Plants do release / respirate a lot of organics, think of smell for example :) to attract pollinators or to repel predators.

Think of the good-smelling essential oils, people extract from all kinds of plants and put it concentrated in a bottle.

It's this stuff that is a building block from the oily biofilm scum layer we sometimes see on the water surface in our aquariums.
 

dw1305

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Hi all,
Note the comment that "plants produce a LOT of waste, especially if the tank is enriched with CO2 via gas or liquid"
That is part of the reason for the big water change in EI and why people run surface skimmers, overflows etc. Marine reef aquarists use <"protein skimmers">, but these don't really work in freshwater.
So, does this not support the idea of continuously removing DOCs using suitable filtration media such as Seachem Purigen?
In terms of the "Purigen" it is back to the <"size of the particles"> it removes. In terms of large non-dissolved particles and fine mechanical filtration, you just need to ensure that you change the filter media over really frequently to avoid clogging.

The answer to a lot of these questions is really to do with oxygen, natural systems low in DOC tend to be <"nutrient poor, highly oxygenated and with alkaline water">. As you move away from these scenarios (or look at the wider picture) then the situation becomes <"more complicated">.

In terms of DOC generally, it is an entirely natural component of all aquatic systems, just in differing amounts. Is there any advantage to its complete removal, I'm pretty sure that answer is "no", and that if you could get water entirely devoid of DOC it would impinge on fish health. There is quite a lot of <"scientific research in this area">, although @jaypeecee may not like the <"shades of grey"> aspect to it.

Personally I think that the <"BOD concept"> is more useful, which is why you <"can have tanks full of structural leaf litter and dead wood">, but with very high water quality.

cheers Darrel
 

jaypeecee

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In terms of the "Purigen" it is back to the <"size of the particles"> it removes.
Hi Darrel,

My concern is not about particulate matter - that's easy to remove with mechanical filtration. Let's go back to the start - surface film. As surface film appears to be caused by dissolved organics, then how do we remove these organics? Isn't this what products like Purigen are supposed to do? And, if the likes of Purigen are effective, why do we not hear mention of this on UKAPS? Do you know of anyone that uses Purigen or similar materials?

Edit: I do realize that some organics, e.g. humic substances, are beneficial. So, perhaps the only solution to the surface film problem is the surface skimmer. Although I have an Eheim skim350, I have found it difficult to get it to work reliably and it's another unwelcome piece of kit in an 125l tank.

JPC
 
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jaypeecee

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Hi Folks,

I was reading Diana Walstad's book* today and she was discussing allelopathy. She says "Aquatic plants probably release large amounts of allelochemicals, for they are leaky when they're alive...". This supports what @dw1305 has previously mentioned. That made me think. Is this why we sometimes see BBA growing along the edges of leaves? Is it from here that plants are leaking nutrients/organic compounds into the water column?

* Ecology of the Planted Aquarium

JPC
 
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