Similarities between tank care and lake restoration techniques

[Easternlethal]

I came across an article about lake restoration methods which I found useful when evaluating my own techniques.
http://www.unep.or.jp/ietc/Publications/techpublications/TechPub-11/6-11.asp

There are quite a few similarities when comparing the two:
Lake: precipitation used to remove phosphates. Tank:iron & phosphate precipitation is usually avoided with EI
Lake: sediment is removed to reduce unwanted nutrients. Tank: sediment disturbance by uprooting, substrate cleaning, use of bottom feeders and flow/filtration
Lake: algicides. But causes problems to certain forms of life. Tanks: ditto.
Lake: coverage of sediments by clay. Tank: Gravel is usually used. (Maybe clay gets into tank filters?)
Lake: shading by trees. Tank: duckweed and surface plants.
Lake: wetlands are used to remove excess nutrients. Tank: Ripariums.
Lake: aeration of the hypolimnion. ('Hypolimnion' is the bottom layer of water above the substrate). Tank: aerators, bubble walls etc, placement of intakes lower down and flow.
Lake: siphoning of the hypolimnion. Tank: Intake positioning.
Lake: biomanipulation. Tank: addition of snails, shrimps, algae eaters...

I never realised it but there are lots of lake restoration case studies on the web and I have a nice weekend reading through them. This one is pretty inspiring (even though it's really a marketing piece): http://www.vertexwaterfeatures.com/...-Case-Study-BDM-Lake-Restoration-051016_0.pdf

One thing that seems to be focused on more so than in our hobby is the importance of oxygen at lower levels and in the substrate, as well as the benefits of aeration for the removal of unwanted chemicals like hydrogen sulfide.

It also makes me start to think that maybe there's never a good reason to tear down a tank if it doesn't go your way.

 

[Chris Jackson]

Very interesting

It also makes me start to think that maybe there's never a good reason to tear down a tank if it doesn't go your way.

Definitely, there's no substitute for maturity...😉

I also think the importance of oxygenation tends to be overlooked. When a tank is running well then the plants are providing plenty of O2 but at times of melt down and algae plagues this is somewhat different. Then the received wisdom here is that all problems are down to insufficient CO2 so we see situations where a tank is pumped full of co2 with minimal surface disturbance so as not to lose the CO2 when really greater aeration and certainly night time aeration might actually be far more helpful.

 

[Easternlethal]

Another interesting comparison is to look at how lakes are normally categorised according to the amount of microbial activity (i.e. the trophic level).

http://rmbel.info/lake-trophic-states-2/

From this, it's clear that EI natural/ Walstad followers are actually trying to achieve some kind of mesotrophic condition in their tanks, i.e. oxygenated conditions at the higher levels and anoxic conditions at the lower levels and a high level of bacterial activity to produce required nutrients. I suppose this is what is meant by 'balanced' or 'mature' and supports the argument there should be lower flow and less disturbance of the substrate.

EI tanks on the other hand, I think, are actually oligotrophic with plants provided by an inorganic supply of nutrients. Looking at it this way I'm actually quite impressed by how innovative the EI approach actually is. These conditions are actually most ideal for fish.

 

[hard determinist]

From this, it's clear that EI natural/ Walstad followers are actually trying to achieve some kind of mesotrophic condition in their tanks ... EI tanks on the other hand, I think, are actually oligotrophic ...

As far as the nitrogen and phosphorus concentrations in EI tanks, it's clear that these belong rather to the "sewage water" category.

 

[Easternlethal]

Here is another fantastic resource. An entire book dedicated to the effects of plants and algae.

http://www.aquatics.org/bmp 3rd edition.pdf

I was surprised to read that eutrophic lakes actually have more aquatic plants in them than even mesotrophic lakes. Makes sense when I think about it.

Furthermore the appearance of algae can lead to more o2 being produced and more fish! The danger only comes when they die and bacteria take over, using up all the oxygen.

 

[Easternlethal]

Why then, do eutrophic lakes not teem with aquatic plants and give way to algae? The answer seems to be the natural advantage of free floating nature of algae to block light. A form of turbidity.

Here is another longish study about disappearing aquatic vegetation.
ftp://ftp.fao.org/docrep/fao/005/ac858e/AC858E00.pdf

Interesting discussion of turbidity and phytoplankton (algae):
https://www.researchgate.net/post/I...en_phytoplankton_bloom_and_turbidity_of_water

 

[Guest]

Nice thread, some interesting reading😉

 

[G H Nelson]

Yes indeed......good reading!
Thanks for posting.

 

[Easternlethal]

It's simply amazing what's out there once we learn a few simple scientific terms. If I google 'algae and plants' I get redirected to this forum 🙂 (just kidding!). But if I search for 'macrophytes and phytoplankton' I get this:

http://limno.fcien.edu.uy/pdf/fito2008/conf-m/Sondergaard-submergedmacrophytesPhytoplankton1997.pdf

Just pages of information about how plants and algae affect each other.. ( or display 'antagonistic forces' as the authors put it...)

One interesting tidbit is that plants themselves can affect the nitrification cycle without processing anything directly (i.e just by reducing flow around them to create layers of still water and hosting various bacteria and conditions within each layer - some of which might even be anoxic).

 

[Easternlethal]

Another book - this one is mainly on plants and how they interact with ecosystems. I never realized how diverse plants were. Apparently it's all in the 'morphology'. I'll have to bear that in mind when I'm ordering plants.

http://www.jlakes.org/ch/book/978-1-4020-5390-0.pdf

Perhaps some of you planted tank maestros looking for more exotic plant challenges can try your hand at growing some of those plants in Appendix I!

http://ec.europa.eu/environment/nat...edlist/downloads/European_vascular_plants.pdf

 

[Easternlethal]

It's not all about lakes because there are also rivers. And rivers differ because of 'hydrology' (i.e flow). Now God didn't invent flow just to help us suck up detritus into our intake. Apparently hydrology plays a big part in nutrient uptake as well. Who'd have thunk.....

http://wa.water.usgs.gov/neet/Mebane_macrophytes.pdf

For the biotope enthusiasts:

A brief description of different river types
http://rainforests.mongabay.com/0602.htm

whitewater vs blackwater environments:
http://link.springer.com/article/10.1007/s11273-015-9412-8

Now I wonder whether AGA will accept my high flow / heavily aerated EI tank as a biotope...?