notes on red slime(cynobacteria)

[tmz]

:eek1: There are a surprising number of posts this morning about problems with cynobacteria. I thought it would be usefull to respond in one place and invite your comments.

Cynobacteria is truly primordial slime. It created the oxygen in the oceans from CO2 and without it there would be no life on earth. Many believe it was the first life form on the planet and is essential to our existence.OK, somehow it still doesn't look good in a reef tank.

Cynobacteria consumes CO2 and creates oxygen in a very similar fashion to corals and algae. It only thrives when there is excess CO2 not readily consumed by the other organisms in the system. Increased nutrients conrtribute CO2 as they breakdown. CO2 injectors such as calcium reactors usually rasie the level of CO2 and their introduction to a system often sparks cynobacteria. Inadequate flow and/or poor surface water interaction with the air as in closed tanks can limit gas exchange and trap CO2 in the tank above the level of the surrounding air. Higher CO2 in the air itself will also cause higher CO2 in the tank( as might be the case in some of our homes at this time of year with less outside air circulating through via AC or open windows).

Aside from light depravation(cynobacteria is photosynthetic) controlling cynobacteria is about controlling CO2.The following is a summary some of the methods:

Control nutrients. Search for a dead animal and remove it. Rinse frozen food thoroughly with tap water to insure removal of the packing water and to control potential bacterial infections on the food. Skim aggressively.Clean out mechanical filters.Consider an upgade to your cleanup crew. Use an opposite photo period refugium with chaetomorpha or other macroalgae.( the macro algae consumes CO2and nutrients and produces oxygen in it's photosynthetic process). The reason for opposite photo period is to offset the process of other photosynthetic organisms in the sytem which consume CO2 during the day and produce oxygen while they "exhale" CO2 at night which causes the very familiar ph drop.

Increase CO2 expulsion and/or consumption.. Increase air exchange at the surface via increased flow,open water. Use a big bubbly skimmer. If your home is high in CO2 find a way to get fresh air to your system. Some actulaly pipe in fresh air to their skimmer intake.Increasing ph will put more ions in your system that will bind up CO2. Dosing kalkwasser at night will not only increase calcium ,alkalinity and ph,it will consume CO2 as the Calcium Hydroxide forms calcium carbonate. Manually export the mats. I use a turkey baster to suck it out.
I am sure there are methods I have overlooked and welcome additions.
Finally, as Mark Twain once said after writing a letter to a friend"I apologize for the length of this,if I had more time I would have written a post card."

 

[Gary Majchrzak]

good post, Tom.
It's often suggested that reactor effluent be dripped back into a system 5 or 6 inches above the water to facilitate blowing off any excess CO2.
I've come up with an additional way to help dissipate excess CO2... something I've never seen anybody else try, but it makes sense to me: I drip my effluent into my lit refugium filled with macroalgae. The macroalgae and DSB in my refugium do an excellent job of utilizing any CO2 and phosphates caused by running my calcium reactor while preventing any rapid changes of pH in my system as a whole.

Something else for everyone battling red slime to consider: red slime is your "friend". It's letting you know that nutrients have reached a critical level in your system and it's helping to reduce them. Cyano is a "red flag" of sorts telling you that your aquarium needs some attention.

 

[tmz]

Thanks Gary,

I'd try the refugium drip idea but mine are unfortunately upstream. I hadn't heard about 5 or 6 inches and have been running mine about threee out of the water. I'll raise it

 

[tmz]

A little more information on cynobacteria. It is ubiquitous and has been found in the harshest antartic environments, on mopuntain ranges and in polar bear coats. You can't erradicate it only controll it to a point where you may not see it.

It is autotrophic,thriving on the sugar it produces from water and CO2 releasing oxygen in the process(6molecules of water and 6 molecules of CO2 form 1 sugar molecule and 6 oxygen molecules).

As it grows it produces heterocyst which are anerobic sacks where oxygen cannot enter. In these sacks there is nitogenase (nitrogenase is severely inhibited by oxygen) which binds nitrogen from the air or water into biomass including amonia.nitrite and nitrate in sort of a reverse denitrifecation. In this way it fuels life including undesireable forms such as algae's and desireable forms like rice tor example where cyno cultures produce fertilizer.

So since free nirtrogen is pretty constant in the athmosphere and the tank the only variable limiting factor would be CO2,since without it the cyno can't complete the photosynthetic process. While there is always CO2 in your system , itis only when it rises above normal consumption levels by other autotrophs(corals,algae,etc.) that cyno will flourish untill the CO2 is consumed or blown off into air, if the air has a lower concentration of CO2 than the tank. It does not directly feed on nitrogenous waste but does produce it.