Phosphate content of phytoplankton preparations

[Sk8r]

Curious whether phyto dosing is adding significant phosphate to the tank.

[bertoni]

It will add phosphate from the phytoplankton itself, which could be very significant. The growing media might be a source, too, depending on how well the packaging is done.

[Sk8r]

Suspected so. Thank you, Bertoni.

[CJO]

Doesn't it matter whether it is live phytoplankton or dead? I would think that live phyto, in itself, would add as much phosphate as any algae (0) while it is alive.

From what I've read, most commercial phytoplankton makers separate the live phyto from the growth medium and bottle it with sterilized sea water, so that wouldn't contribute phosphate either.

Please correct me if I'm wrong.

Thanks,
CJ

[bertoni]

All living organisms contain phosphorus, so live phytoplankton is going to contain some. The death of the organism won't affect the phosphorus content directly.

[CJO]

Sorry, I was speaking of available phosphorus :)

CJ

[bertoni]

I'm not sure what you mean by "available" in this case. All of the phosphorus in algae can end up in the water column via consumption or decay. It should be easy to verify that algae will release phosphorus: just soak some in a cup of RO/DI water for a while and test the total phosphorus content. Testing for phosphate might be good enough.

[CJO]

I meant available to nuisance algae. Fish are also full of phosphorous, which could end up in the water column via consumption or decay and probably show up fairly quickly if you soak them in a cup of RO/DI water as well, no?

Now you have me wondering. I've always assumed that live phytoplankton introduces very little free phosphorous into the water column. I'll have to test some to see.

CJ

[tmz]

It's not just potential orthophosphate( PO4 species ); nitrogen and organic carbon are potential pollutants as well. Not sure of the life cycle period for phyto plankton but I suspect it is not very long in a reef tank and the phosphorous, nitrogen and organic carbon not converted to tissue mass by an organism consuming it will show up in the water.

[bertoni]

At least some of the phytoplankton will die or be consumed by organisms that produce waste. Either case can feed nuisance algae. Also, the media in which the algae were cultured can contain a lot of nutrients, and some vendors might be more careful about removing the media before shipping than others. I don't know how significant that might be, though.

I agree that any food is likely to show a lot of phosphorus when soaked in some water. They all can feed algae fairly directly.

[CJO]

Some other thoughts:
http://www.reefcentral.com/forums/showthread.php?t=1728396

CJ

[CJO]

And some more:
http://www.reefnutrition.com/phytofeast_faq.html

CJ

[HighlandReefer]

Curious whether phyto dosing is adding significant phosphate to the tank.

Phytoplankton nutrient limitation and food quality for Daphnia
http://www.jstor.org/pss/2837927

[tmz]

Thanks for the links: CJO and Cliff.
Even the vendor phyto vendor post admits phyto contains N and P but notes in their product none are added.

It's just the nature of things.Living things contain carbon, nitrogen and phosphate.So adding them adds these nutrients. There is no free lunch in terms of nutrient additions. Whatever is not retained in tissue mass or exported from the tank is freed up as organic waste which breaks down to dissolved organic carbon, and inorganic nitrate and phosphate.

One post in the first link notes phtyo reduces NO3 an PO4 in a tank. While live phyoplankton might do that in the short run as live phyto will take up some nitrate and phosphate as and if it it grows in a tank or culturing vessel, it will put it all back when it dies or is consumed by other organisms which will use some of the phosphate and nitrate and expel excess as waste or in turn put it all back when the consuming organism dies and decays.
While the nitrogen and phosphate are bound organically they may be more susceptible to skimming and removal by adsorbents like granulated activated carbon than they would as NO3 or PO4.

Dosing some live phyto might be a good idea for some tanks but all in all ,live or dead it adds C,N and P to the nutrient load. Many who culture phyto and pods do so in a separate culturing tank and use them for controlled feeding.

[UVvis]

As mentioned above, you also have to put the phosphorus number into context.

Take the Redfield ratio, of 106:16:1 for Carbon, Nitrogen, and Phosphorus, respectively, in marine phytoplankton, and some other marine organic substances. For reef aquariums, the carbon value isn't always as important, as alkalinity adjustments add inorganic carbon to the system, of which some can be pulled out by primary productivity. The Nitrogen and Phosphorus numbers are somewhat important in foods, as keeping them in balance for a marine system represents that you have pretty much all the raw chemical resources to build organic matter.

What I'm meaning is that balanced foods help keep the ratios in check, and you generally want that. Adding C, N, or P to the tank shouldn't be a concern as long as you are doing it in a balanced way. C and N have additional import/export cycles that the P does not.

Like TMZ said, it's easier to remove and export a larger balanced item like a cell or protein, than it is raw NO3, or orthophos. That's the concept behind carbon dosing and certain batch treatments.

[tmz]

The Redfield ratio is a ratio for marine plankton and varies from organism to organism. It offers a good perspective on CNP content in marine life.

For another perspective;, surface sea water levels are: C (organic carbon) 0.7 to 1.1ppm;NO3 < 1ppm and PO4 a scant .005ppm. These levels are higher by 5 to 10x in deeper waters and areas with turbid water Some corals may benefit from the higher levels.Note, we usually don't know the C level in our tanks because measurement tools are not readily available to hobbyists.
Concentrated bioload in the relatively small space of the aquarium usually leads to excess nutrients . Primary productivity( mostly photosynthesis, perhaps a bit of chemosynthesis) in high bioload tanks often seems to provide less organic carbon(from CO2) relative to N and P over time . Thus allowing inorganic N an P levels to rise as heterotrophic bacteria wax and wane relative to available C as well as N and P. So limiting P and N and C input overall lessens the need for mechanical and biological filtration .
Over the past few years biological filtration strategies involving the use of organic carbon dosing(vodka, vinegar, Vitamin C, etc) ) to increase the available organic C to favor heterotrophic bacteria which take up the organic C and inorganic forms of N and P, nitrate and orthophosphate. As a result the NO3 and PO4 become organic and are more exportable by skimming and gac. With carbon dosing it's common to see tanks with very low N an P and I think more attention to feeding is required in these anemic conditions as the consumption of the bacteria by certain organisms to the extent it occurs at all may not be enough to meet the nutritional needs of many corals . Coral natural habitats have copious amounts of zooplankton but are also low in inorganic nutrients due to continous and copious water changes with the surrounding sea.

Getting that balance in a tiny by comparison closed system is elusive at best.



Overall, I think some phyto pkankton is a good component to have in establishing a nice food web in a system. Many filter feeders benefit directly from phtyo. Certainly most corals will benefit from zooplankton which will benefit from phytoplankton.Although it might be easier to raise zooplankton in separate culturing tanks.

When considering phytopankton or other foods in the context of controlling phosphate levels of it might be helpful to look at some protein to phosphate ratios. Algaes in general don't seem to have higher phosphate to protein ratios than other foods. Foods containing bony material give the most phopshate.

The post by Randy Holmes Farely in this thread may be of interest even though it doesn't give a specific ratio for phytoplankton:

http://www.reefcentral.com/forums/showthread.php?t=1799201&highlight=phopshate+protein+ratios