Scientific Research

[David_M]

Hey...


i kind of need help to choose a topic for a big huge research project i have at school.... My project is going to be about fishkeeping (FW, SW, etc...) but i need to do some sort of experiment, i just can't collect info and expose it like that i need something good....


soo there is were you guys come in and try to help me i need some ideas that can really really really get me to think and do an experiment about that or to prove something wrong or right..... some examples of ideas are in the scientific discussion (its pinned) on this forum.......

for u to get an idea how big is the project, I'm in 11 grade (Spain) and the project its soooo big and important that i need to start know to present it next ear in 12 grade and its a BIG major grade for me to go to college...

please and thanks oh and i don't actually want help on the project (don't wanna cheat) its only ideas i want thanks........

 

[Mr Bliss]

What kinds of experiments would you be able to do, ie. could you set up two or more tanks to make controlled comparisons between environments?

One experiment that would be interesting and valuable, as well as somewhat simple to carry out, would be to compare the effect of pH and alkalinity (KH) on the nitrification rate of a typical aquarium biofilter. You wouldn't necessarily even need a tank for this, just one or more big buckets and (possibly self made) filters, a bottle of ammonia and test kits. Water with a KH of 0 (so you can set it at a desired level with bicarbonate) can easily be produced by boiling.

It's often said that nitrifying bacteria don't perform well at low pH, and people often observe slow or stalling fishless cycles at low pH, but in nature efficient nitrification happens in soils with a pH of 4 so there has to be more to the story (carbon dioxide concentration might be a factor here). Ideally you could compare both the time to cycle, as well as the peak nitrification rates of fully cycled filters. You could also test the significance of heterotrophic nitrifiers by adding controlled amounts of organic carbon (e.g. glucose) into the water.

 

[Bignose]

Water with a KH of 0 (so you can set it at a desired level with bicarbonate) can easily be produced by boiling.

The low KH from boiling is only temporary. The minerals in the water change when they are exposed to high heat.

calcium carbonate + carbon dioxide dissovled in the water + water <---> calcium ions + 2 carbonic acids
CaCO3 + CO2 + H2O <--> Ca(2+) + 2HCO3(-)

The above reaction occurs in equilibrium. That is, the left hand side is constantly changing the the right hands side and vice versa. The equilibrium happens when the rates of the left and right hand side of the reaction are equal.

When you boil, you drive out a large amount of the dissolved carbon dioxide in the water. Because there is only a small amount of CO2, the left hand side of the reaction cannot occur. The calcium carbonate can precipitate out. KH is a measure of how much calcium carbonate is in the water, so with the precipitate out, it looks like KH is lowered. To make the change permanent, however, you have to remove that precipitate, because once the water cools and CO2 begins redissolving back into the water, the KH will rise again.

 

[Jonathangerous]

It doesn't matter how much organic carbon you add to an aquarium system because:

1) it is always available in excess, as long as you have fish present.

2) heterotrophic nitrification, if it is even a major factor in microbial aquarium ecosystematics, is going to be limited by autotrophic nitrosomonas.

 

[Mr Bliss]

It doesn't matter how much organic carbon you add to an aquarium system because:

1) it is always available in excess, as long as you have fish present.

2) heterotrophic nitrification, if it is even a major factor in microbial aquarium ecosystematics, is going to be limited by autotrophic nitrosomonas.

Yes, but the suggestion was to do the testing basically in fishless cycling conditions.

 

[Jonathangerous]

my second point still applies.