Introducing co2 into saltwater tank to increase coral growth

[alexm2251]

hey everyone im a junior in high school and im in honors marine science. i have to do a independent study experiment. what i am thinking is if i can use co2 s a catalist for coral growth. so we all know about zoozanthelle. zoozanthelle turns co2 into oxygen which is supplied to the coral. another job of zoozanthelle is it creats amino acids,glucose, glycerol which in turn the coral uses these to make tissue proteins,fat,carbohydrates,and produce calcium carbonate. sooo if i dose the co2 will it exel the coral growth and health. thats what i am thinking about for the experiment. i need to find a method of adding disolved co2 to the water. i anyone has a product or method please let me know n the comments section. and feel free to add an suggestions. BTW i am aware that if i dose co2 the ph will change but i can fix that.

[xiaoxiy]

In the freshwater world, CO2 is routinely injected via a diffuser, or carbon can also be supplied via supplements such as Seachem Excel.

 

I wonder how much benefit CO2 injection would be in the saltwater world given that the environment we raise our organisms in have access to large amounts of carbon in the form of HCO3.

[HarryPotter]

How will you maintain pH? And how can you gauge coral growth- mass on a frag plug?

[alexm2251]

We will control ph by testing ph multiple times a day.meauserment we will either end up weighing or measuring length.

[spinycheek]

I'd recommend using soft corals for your test instead of hard corals so you won't have uncontrolled variables like interfering with carbonate deposition due to increased CO2 (i.e. acidification). Also soft corals are much hardier and make better experiment subjects.

 

Greenleafaquarium.com has a bunch of CO2 injecting supplies.

 

Keep in mind, the CO2-carbonate-pH connection is horrendously complex and it will take some considerable fore-thought to account for all the variables that could influence coral growth.

[alexm2251]

At my lab we are moe interested I using sps as test subjects because SpS is more relavent to the problem with the reefs dying off around the world. We are thinking about using other types of coral but idk anything we can fit multiple of in a small tank

We have 5 5 gallon tanks that are all connected except for one that is being used as the control

[spinycheek]

At my lab we are moe interested I using sps as test subjects because SpS is more relavent to the problem with the reefs dying off around the world. We are thinking about using other types of coral but idk anything we can fit multiple of in a small tank

We have 5 5 gallon tanks that are all connected except for one that is being used as the control

 

 

 

I see what you're saying, but the issue is that CO2 dissolves CaCO3 which will affect a stony coral's ability to grow. By using soft coral, you still see the results of CO2 on zooxanthellae, but don't have the confounding affects of corals not being able to grow a skeleton. You could test both groups, and maybe even a calcifying algae like Halimeda. At what point might CO2 stop helping growth and start dissolving skeletons, etc.

[R_MC]

Salt water van hold significantly more c02 than fresh and is likely already over saturated. C02 and the acidification of the oceans is partially why we're losing so many reef systems.

[alexm2251]

im realy interested because this is very contradictory. co2 is used by zoozanthelle to provide coral with the items it needs to grow. but on the other hand co2 will break down the calcium carbonate so im thinking if there is alot of calcium in the water i can provent the co2 breaking down the corals skeleton but at the same time keeping the zoozanthelle fed and providing needs for the coral... ???????

[jestep]

Interested to see how this plays out. I will say, you need to be careful in that you have to be able to control the experiment. Just sort of typing off the top of my head here so...

 

Dealing with CO2 is a bit of a trick because ph is altered by literally dozens if not hundreds of factors other than simply CO2, literally just open a window in the same room or turn on a ceiling fan and watch the PH go up... Introduction is fairly straightforward though, CO2 tank, regulator, diffuser or reactor, and ideally a solenoid controlled by a PH meter to prevent it from running away. If possible I would use a method of measuring and controlling CO2 concentration not based directly on measuring PH.

 

Also, the acidification of the tank water, thus the breakdown of CaCO3 in the tank is going add multiple variables including the potential release of PO4 and other macro and micro nutrients, bound in the rock and substrate. I'm not sure if there's a way to control this except using either pure CaCO3 or only using inert objects in the tank, ie: no substrate or actual rock.

 

I do think it's an interesting experiment, but I think by allowing breakdown of CaCO3, and measuring CO2 by PH, you run the risk of invalidating the experiment by creating too many uncontrollable variables into the equation. Anyway, just throwing some thoughts out there.

[alexm2251]

Hmmmm I'm interested and excited to do this. We will have a control tank. But I'm gonna bring up a way to test for co2 concentration in the tank. But we will also be ching ph with a probe multiple times a day just to make prime water conditions. The acidity of the water is just the ph dropping so I don't think it won't be that large of a problem just throw some ph+ is there when needed.we will also have some macro algae in each tank to try and deal with the po3 and show that there is co2 that can,be used in photosynthesis by the zoozanthelle and algae.

[alexm2251]

thoughts ????

[lobster876]

start with more easy sps before moving on to acros

[blasterman]

I'm already adding pH scrubbers to all my tanks to get every little decimal point I can to keep SPS healthy, and I can't think of a need for more. During the night cycle soft corals expel C02 and there's almost always too much of it. Even my softy tanks show a generous improvement in growth and health if I add calcium hydroxide directly and keeping pH no lower than 8.1.

 

C02 uptake in corals as I understand it is very little. It can increase under high light periods.

 

Calcium carbonate substrate in tanks, contrary to urban myth, does little to buffer pH or alk. Local acidity needs to get lower than 6.5 to begin to disolve calcium carbonate. However, at much higher pH levels coral calcification starts to stunt.

 

Might be an interesting experiment with zoas or softies.

[aquarium]

The only way that the zooxanthellae would get their co2 is through the tissues of the coral. levels of co2 in animal tissue remain stable until the outside conditions have a higher concentration of co2 than the tissue, and in such situations hypercapnia, or co2 poisoning, occurs. I think there would be difficulty in getting more co2 to the zooxanthellae without poisoning the coral, but I could easily be completely wrong. I am curious about what will happen, and would love to see your experimental results!

[alexm2251]

going to have the experiment set up when i get back from winter break so i will be posting pictures on this thread aswell some data.