Phytofuge - For the biology nerds out there

Nice to hear. It is in a very exciting stage at the moment. The phytoplankton is growing very well and stably, supplying plenty of food. But I have no idea what will happen with the zooplankton. It seems like the large calanoid copepods are doing poorly. Most died the first days after introduction to the tank. But some are hanging in there after 3 weeks. But great blooms of benthic cyclopoids are developing, and I hope to get pelagic cyclopoids too. But so far it is in the open.
 
Here are two copepods that I caught in the water column in the zooplankton tank. One copepodite and one naupli. The body length of the adult is about one millimeter, not including antennae in the front or the long spines in the back. I believe the adult is a cyclopoid. If anyone can tell me something more about genus or other classification that would be great.
 

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Just a small update: 3 months now and no luck in growing planktonic copepods so far. They just die off at a steady rate, and produce little or no offspring. I don't really have any clear ideas what can be wrong. But I will try some small changes as I go along. Yesterday I did a restart of the whole system, except a small amount of water in the bottom of the phytoplankton aquarium so that the benthic pod populations wouldn't have to be reseeded. This time I won't dose silicon. I would like to try some other type of phytoplankton than diatoms. Diatoms have chemical defences agains copepods, so it may be worth a shot.

There has been some zooplankton reproduction though. There are lots of ciliates. And also some medusae of about 2 millimeter in diameter. The medusae are in numbers of 20 to 50 per litre. I am not sure if they are completely planktonic automedusae or if they are spawned out by some hydroids on the walls and bottom.
 

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norskfisk, this is an awesome experiment.
With the persisting problem of carpet algae, does anyone think an algae scrubber could help redirect where all that growth is blooming? or would that risk removing to many nutrients from the overall system? (I guess i'm asking if the azoox like slightly dirtier water like some LPS do.)
 
I used to grow phytoplankton on my kitchen table back in the 1980's. Your system is much better. I love this! Thank you so much for sharing. I really want to try this.
 
I am very interested in this project! I ran some experiments for a warm water 681 liter (180 gallon) NPS tank. I had no problem growing rotifers in tall tubes. I used a 6" inch diameter, 6 foot tall highly aerated tube that circulates 8 liters (2 or 3 gallons) per day, to and from the display tank. I fed it phyto paste. I have built a robot to feed six of these towers that are stacked along the wall in the garage with heaters in them.

As a side note, I also had no problems growing artemia in a 208 liter (55 gallon) closed system tank using filter feeder powdered food. All this of course is at a room temp environment.

I have been afraid of trying phytoplankton. The small bottles, constant cleaning and frequent crashes has made me avoid it for decades.

The longer term life between crashes, in a recirculating system sounds intriguing. Whether I can apply any of this process is a big question.

I have some 208 liter (55G) tanks and a 492 liter (130G) tank that I could use. Or maybe I could enlist some more towers. I also am building a Ca reactor that will be feeding about 30 to 50 milliliters per minute through it. I guess that I could use the effluent to work on phytoplankton.

I'm a designer, not a biologist so some of what is talked about goes over my head but I will tag along.
 
You talked about using CO2 for the phyto. Do you think that with it, the phytoplankton can out compete with the bacteria and therefore results in a longer lasting culture?

You mentioned that you use more CO2 than you would like. Could you try to put a cap on the tank and in order to recycle the CO2?
 
No, I don't think the CO2 has anything to do with competing with bacteria. It is just to make carbon available for the algae. I don't really think that bacteria are the cause of crashes.

I haven't experimented with putting a lid on the tank. I would prefer just adding more CO2 than trying to recycle it. That is more practical. In the current setup I don't add CO2 or even measure pH. I just let the algae grow to whatever concentration they can get to with minimum maintenance. I think that just setting up a bigger algae tank and not doing any measurements or controlling will always be the cheapest and easiest.
 
Well I have been reading all that I can about this idea. I don’t know enough to ask descend questions but this is a great set up. I have read it all a couple of times through. What do you think is the biggest threat for crashes?

I talked to a guy that simply put a white plastic 208 liter, 55 gallon drum in the sun light and put in some chicken fertilizer and it grew every time so the large volume is consistent with your idea in that respect. Of course it was not subjected to contaminants from being plumbed into a system but on the other hand he did no cleaning and I don’t think that he did any aeration either.

So …how long can you go without crashes now?
 
It is kind of unstable, one to 4 weeks typically between crashes. The crashes vary in intensity, and the concentrations and algae communities in between vary.
 
I haven't yet attempted your project yet, but I've done a lot of reading. I've read that some people think that copepods and rotifers living in the phyto culture can cause it to crash.

Here's a an article from a guy that's kept a phyto culture (separate from the tank) running for a long time.
 
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