# study & questions 2



## Flear (Oct 5, 2012)

took forever to get back into this, ... Caffeine, how i despise thee, how i cannot study without thee, i hate you i love you ... 

if this is to be screened out by moderators, damn, that would really suck 
http://www.google.ca/url?sa=t&rct=j...viyRXDfYaaQW9wH5A&sig2=RXIWeZuZQ_JCoIHRValxhQ
hopefully that link works (looks like a power point presentation from some school/university class - i dono, i'm not taking that course)

anyway, ... was looking up sponges yesterday (yes for aquariums, freshwater mind you 

there was mention that much of the structure of sponges involves silica, ... :/ isn't that also the body of diatomes as well ?, ... wasn't really looking into raising diatoms for self-sustaining, ... might have to include that on my list of things to get, ...

... doesn't silica have an even slower cycle than sulfur ??? i dono, so i looked for what i could find, ... found the power point presentation above (if it's allowed to be posted) and thankful i am studying again (got boring before)

what i am looking for at this point, ... aside from general knowledge of nutrient cycles is time of cycle and how to compensate for what nutrient quantities to provide enough in the substrate so there are no deficiencies ... either i'm searching for the wrong info (and don't know what to search for for these answers) or the information i am searching for is very difficult to find and not listed in laymans terms for ease of reference - going to have to inquire on this with another person in another forum to see what (if anything) can be done on the substrate mix.

but all/most of the above is my ramblings.

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questions  yay, i knew this was going somewhere 

where do i find information on nutrient cycling ?, not stages, but time and quantities ?

sulfur is expected to have a very slow cycle, so more is needed to compensate
from the sounds of it silica is the same, maybe more-so, and despite low concentrations in any of the critters (including microscopic) much higher levels are going to be needed to provide sufficient levels to ensure a nutrient deficiency doesn't reach 'zero' and the critters that require this for survival all die off, ... or worse, a crash of the whole system due to nutrient deficiencies.
-*where/what information is there that would give some kind of timeline on events that would cycle nutrients instead of a process ?*, ... a process doesn't need a time to complete, it's just a logical after X is Z, after A is B, but no idea how long to expect any of these to go through a cycle (not counting being consumed and used as biological structure of the plants and organisms (i guess counting bacterial, but i dono, i'm rather lost with this

i'm still stuck on iron as it relates to redox, mostly because i can't wrap my head around Fe(II) vs Fe(III) as it relates to both redox & pH... initially that was my concern but i am also realizing this is more of a concern that just iron as redox may make one nutrient abundant or limited while pH says otherwise.
-iron is a big concern as it sounds like the conversion between Fe(II) & Fe(III) in the water is chemical instead of organic, one is soluble, one isn't, and pH gives a gradient of available iron
-*the whole pH vs Redox is confusing, ... each one alone i could follow but how they interact i'm confused and farther reading isn't helping me out here *

sorry about bouncing around i tried to make it short and stick to the points that were really concerning me.


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## Flear (Oct 5, 2012)

*Theory*

if i took a sediment sample from a local stream (while trying to preserve any layers in the sediment that may have developed to obtain the bacterial species from said sample (from surface to anoxic) and (dono how yet) without disturbing this sample (no mixing in any way) inserted this into the aquarium substrate with the hope of safely transplanting the bacteria. ...

could i expect the bacteria to survive the transition ???

how lethal is O2 to anoxic bacteria ?

these and related questions are crossing my mind.

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concerns of introducing parasites are not on my mind, first thing is first, ... is this a viable way to introduce species of bacteria into a tank that may not otherwise appear in the substrate?
-i would worry about parasites and other organisms later.


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## Mikaila31 (Dec 18, 2008)

You will be hard pressed to find a standardized 'timeline' from an aquatic system. They are subject to many conditions and limitations. Example: Temperate lakes and rivers where I live are going to cycle much differently then the amazon river or african rivers with wet and dry seasons. Yearly cycles effect the nutrient cycles. Even within a region lakes are different. Eutrophic lakes are typically shallower with a greater amount of nutrient cycling. Then we also have ogliotrohpic and mesotrophic lakes, ogliotrophic being similar to the great lakes, including the african rift lakes, and many northern lakes here. The water is clear and their overall ability to sustain life is low. Ogliotrophic lake has little to no plants and the nutrient cycling will be different then a eutrophic lake. Simply put there is no timeline. Here in Minnesota our natural waters are subject to 6 months of ice and darkness and below freezing temps, the cycles slow down to the point of almost stopping. This never happens in a tropical setting.

Nature isn't perfect either, if you are thinking cycles never become limiting you are wrong. Something is always limiting. Fairly often in the midwest phosphate is the most limiting nutrient and changing this can result in massive algae blooms and fish kills, to the degree that agricultural fertilizers are limited in there phosphate amounts so that the run off does not damage our lakes and rivers. 

Silica is generally abundant and one of the few cycles I would worry about. Ye.s it is a large part in the make up of diatoms and 'sponges'. Naturally rain and runoff bring silicates in from leaching soil as well as groundwater input from underwater or above ground springs. As far as FW 'sponges' I am well aware of them, if you can find someone who has successfully kept them in an aquarium I would be very interested. I have found wild FW bryozoans before, they are very interesting tho but not something that I have heard being kept successfully. Silica is the last issue IMO, they are very sensitive in light, water circulation, waste build-up, and available food. I've never heard of any suppliers/sources online for tropical species. 

As far as Fe+2 and Fe+3 this is a chemical change and most are, it is little different then the ammonia to ammonium interaction. Yes one precipitates out when conditions favor that but it will redissolve when conditions change and it becomes more soluble.

The toxicity of O2 to anerobic bacteria varies greatly. To strict anaerobes it is often most toxic. Bacteria are not strictly aerobic or anerobic, many can do one or the other as the environment changes. Typically they are better at one metabolism then the other. Facculative anerobe being the designation for this. There is a whole classification system on bacteria and their metabolism and O2 dependency. So yes in a soil transfer bacteria will survive even if anoxic conditions are lost, you may loose some or all of the oxygen intolerant bacteria tho. Changes in environment pH, temp, ect may cause others to die off if it is unsuitable or they are out competed for resources. 

All I can suggest to you is to continue with reading dodds, much of this is explained in there. What I am saying is a very brief overview of that. You can always come back to nutrient cycling and it will likely make more sense a second time through after you look at the larger picture. There are quite a few areas of the ecosystem you are still not considering at all. What is also important to realize in your digging is that FW ecology was nonexistent less then 50 years ago. A swamp or wetland use to be unusable land, best for filling and farming, something that is now protected against by law. It is still a very young and unexplored science.


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## Flear (Oct 5, 2012)

so a nutrient cycle of any particular nutrient, as it rises and falls, ... a low will become a limiting nutrient, ... which when you said that i thought well just increase it, ... then a moment later, ... but when conditions change it will rise, and could go from high to toxic, ...

so far better to have the high point of the cycle safe and the low point limiting than the low point safe and the high point toxic.

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as you mention it, i can now understand and accept lengths of cycles are in flux, for the reasons you said too, temp, ph, i'm sure nutrient availability plays with other nutrient cycles too.

but ...

not having a clue vs. having even vague generalizations ... i'd rather at least have a place to start

guessing/suggesting (thinking about it at the moment here), we're most familiar with the nitrogen cycle right ? (at least till it becomes nitrates), could that be used as a starting point to base generalizations with ?
-is iron about the same ?
-is sulfur 4x longer, or 6-10x longer (as it varies)

i have heard mention before that the substrate shouldn't be considered one big area, ... but a bunch of smaller sections, as fluxes in pH change in each, so to does each change it's ability for nutrients to remain potentially bound to minerals in the substrate, or are they completely freed to be released into the water column. i don't know how large these areas would be, but at the time it was enough of an eye opener to give me pause to rethink what goes on in the substrate.

Mikaila, despite having these questions, you're probably right, i'm not ready for the answers yet
off to continue reading 

and the hard part of reading, ... so boring , but if i don't get through it, i won't understand it, and going through it again to understand better ... well i wouldn't have finished it the first time


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## Flear (Oct 5, 2012)

*Greenwater crash in main tank*

i have a theory on the greenwater issue that was plaguing me before.

from one source i came across mentioned phytoplankton releasing chelating chemicals into the water. which makes sense, to ensure nutrients stay available for it's own survival.

from another source, that these chemicals when having released the nutrient they are holding onto, aren't necessarily broken down or otherwise used, but may be free to grab another nutrient.

i am guessing over time enough were released to cause an imbalance as the majority held onto a particular nutrient instead of a wide range of a variety of nutrients. ... causing an imbalance of what would be available to the phytoplankton floating/swimming in the water, ... then starving due to deficiency of whatever key nutrient.

and ultimately greenwater crashing

over time i would continue to add more greenwater not knowing why, and the water would clear up within a couple days, i didn't know (even now this is but a theory)

a couple weeks ago i did a massive water change ... what amounted to 75% over the course of a week, ... i have added greenwater and now it's holding and currently stable in the tank.

i am expecting it to crash again, :/ dono when though.

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for what i have recently assumed to be a sulfur deficiency in the plants, ... i cannot tell (honestly the water isn't clear to tell) but from what i am seeing, or imagining, the younger leaves do seem to be regaining a more green color ... i won't know till the greenwater crashes though.


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