Algal ORGANIC uptake of C,N,P in INORGANIC N&P limitation.

[Garf]

Like everyone else on here, I've been led to believe that algae (good and bad) only uptake inorganic forms of C,N&P.

This is wrong;


Discussion
It is clear from the experiments presented here that when concentrations of small, labile organic nitrogen compounds are sufficiently high, organic nitrogen has the potential to contribute a significant quantity of N to the overall N demand of estuarine macroalgae. The kinetic uptake parameters for urea and the various amino acids vary substantially between compounds, suggesting variable uptake mechanisms. The difference in uptake rates between species denotes that the importance of organic compounds may vary substantially between species of macroalgae, and may signify different adaptive strategies

http://www.vcrlter.virginia.edu/thesis/A_C_Tyler_Dissertation.pdf
page 141

[Garf]

Our data suggests that neutral amino acids may have the highest uptake rates in macroalgae, and that the potential for uptake is not necessarily proportional to the relative concentration of these amino acids in the environment (Chapter 3). The maximum uptake rate of amino acid N varies substantially between different types of amino acids, ranging from 0.1 to greater than 5 µmol g dw-1 h-1. We measured the highest maximum uptake rates for the two aliphatic neutral amino acids glycine and leucine; the lowest rate was also measured for an aliphatic neutral amino acid, aminobutyrate. Serine, an aliphatic hydroxy amino acid, was intermediate and the two acidic amino acids, aspartic and glutamic acids, had the lowest rates. As described further below, even among chemically similar molecules the mechanism for uptake appears to vary. Amino acid uptake rates for U. lactuca were higher than G. tikvahiae for all amino acids, as they were for urea
page 159/160


macroalgae are capable of utilizing many forms of dissolved nitrogen, even at low concentrations, but that there are distinct species-specific differences in organic nitrogen uptake kinetics. These differences may dictate the competitive dominance of individual species under conditions of variable inorganic and organic nitrogen supply

page 181 (same reference)

[Garf]

This one for Organic Phos removal


In an effort to assess the rate of organic P conversion or capture within an ATS™, HydroMentia conducted studies in which water samples were taken at intervals down an active floway at the S-154 MAPS facility. Noted in Figure 10 are these trends. From this data, it appears that organic P removal equals, and typically exceeds ortho P removal within the ATS™. The implication is that organic P hydrolysis, which generates ortho P, is occurring at a rate equal to or greater than ortho P uptake or precipitation. This provides strong indication that enzymatic activity is extensive within the ATS™. As this particular floway is harvested once weekly, it also appears that the enzyme-producing organisms are sustained on the actively managed floway. It is of course necessary to recognize that perhaps not all of the organic P removal may be associated with enzymatic activity, as particulate capture could also be involved. However, if there were no hydrolysis of organic P, it would be expected that ortho-P, not being replenished, would be reduced noticeably down the floway. This is not the case however, providing support to the probability that enzymatic activity is prevalent

http://www.hydromentia.com/Products-Services/Algal-Turf-Scrubber/Product-Documentation/Assets/2004_Stewart-Algal-Turf-Scrubber-History.pdf

[Ace25]

As always, I appreciate all the research and sharing you do. :)

My thoughts on your last post... I wonder how much bacteria is contributing to the organic P uptake. Since there is a symbiosis between algae and bacteria, and the study seems to be a 'real world' study, I am thinking the bacteria is actually the mechanism doing the majority of organic phosphate removal work. Now if they took strands of algae, killed off the bacteria in a lab environment and then did a true scientific study on the algae's abilities, I might think different.

[Garf]

I believe it's something to do with the way phosphates are recycled. If the boffins reckon its an enzyme release which extracts the phos from organics, that's good enough for me at this point. Whatever the actual mechanism, it's evident that screens DO remove organics under certain conditions and become net consumers and not producers. This would explain (to me anyway) why some people running skimmers notice a drop off in skimmate production.

[Garf]

Quick question regarding organics in an aquarium for all those seasoned scrubbers. It's about the disappearance of the dreaded yellow water symptoms that people used to get. Did the "elimination" of the yellowing compounds coincide with the reduction in screen size ? And perhaps denser growth ? Or purely from washing the screens at the sink, after harvest ?

[Ace25]

Honestly I think that has to do with better husbandry all around. In the 80's, it was crushed coral, lava rock, and undergravel filters with little water changes, and when water changes happened it was usually with tap water.

We now have much more complete ecosystems and understanding on how it works together. Obviously we don't know every aspect, but compared to the 80's, we have evolved from the stone age in just a few decades.

[Garf]

This ones a good one;
http://www.archive.org/stream/metabolismofalga00fogg/metabolismofalga00fogg_djvu.txt

It goes on to say that light deprived algae (after several regenerations) can adapt to low light by heterotrophic uptake of dissolved organics. It also says that some algae are not able to produce some of the essential amino acids and rely on external sources. Anyone with a strange "alien growth" screen willing to dose amino acids ?

[kotlec]

What are good indicators for lack of amino acids in tank in general ?

[Garf]

What are good indicators for lack of amino acids in tank in general ?

Thats what I've been trying to find out. Remember that until this thread, it was believed that algae didn't take up any organics (except for those biologists in the field researching this, and students). Tanks that are heavily fed may be immune to this shortage because apparently only tiny amounts of Aminos are required. Or tanks that have other organisms that produce the essential amino would be immune from sortage. However, if the growth on the screen initially takes up all the trace amounts of Aminos available, then the remaining growth may become totally heterotrophic with deficiencies in growth or even die. It is mentioned in the literature that heterotrophic growth of algae has only 1% of photosynthetic pigment (yellow or white) and grows at a rate of 60% of that of photosynthetic growth, so it's best to go green if possible :)

Of course, a drastic lack of light may also provide the same symptoms, in my view anyway ;)

[kotlec]

Do you have any rough idea what scenarios can be expected in various situations ?

[Garf]

I wish I did. Folks need to do a bit of experimentation unfortunately so we can build up a cause and effect picture. Theories are all well and good, but unles people try them were all none the wiser in the big wide world because obviously there could be some unforeseen flaws or inaccuracies, sorry.

[kotlec]

The only idea to check is to see if aminos would convert "alien" in to normal then ?

[Garf]

Certainly wouldn't do any harm to try it. Probably need to get the carbon out though.

[kotlec]

http://www.amazon.co.uk/Salifert-Coralline-Aminoacids-500ml/dp/B002TD1FY6

Have acces to this localy.

[Garf]

Looks good to me.

[sabbath]

What are good indicators for lack of amino acids in tank in general ?

If your corals overall are pale looking then I would try slowly adding amino's. If they are darker or brown then they have more then they need already.

[kotlec]

Some are brown (only tips blue) , some others are pale :)

[Garf]

From what i can tell, most of the wierd growth screens are associated with low feeding schedules. If its not associated with N and P limitation (which I find highly unlikely in aquariums), Aminos could be the key.

[kotlec]

Possibly this phenomena also has something to do with fact that N and P are barely measurable, but corals are brown and some algae in the DT feels very comfortable.

[Garf]

May just be because your screen isn't working right. Some exudates from algae can propagate other algae growth (as well as there own). There is lots of documented evidence that algae exudates can increase or reduce other types of algae growth. Have a look at my Allelopathy thread. The "Terms of engagement" will change if you can get green to grow. The Hydromentia horizontal systems report N and P in the 30parts per billion range, and algae just about persists, so the levels attainable in aquariums may be a bit of a red herring, so to speak.

[sabbath]

Some are brown (only tips blue) , some others are pale :)

Then I would look at the placement from your lights first. I find that brown is usually to many nutrients and or to little light. Pale is the opposite. Altho some corals can turn brown with to much trying to protect them selves from the light. So I would not add any aminos and look at your coral placements first.
Not sure but it might be a good thread to start to get better help with this.

[Garf]

Then I would look at the placement from your lights first. I find that brown is usually to many nutrients and or to little light. Pale is the opposite. Altho some corals can turn brown with to much trying to protect them selves from the light. So I would not add any aminos and look at your coral placements first.
Not sure but it might be a good thread to start to get better help with this.

Probably good info, but in Kotlecs case were trying to understand why his algae screen is wierd.

[sabbath]

Probably good info, but in Kotlecs case were trying to understand why his algae screen is wierd.

Do you think that amino's should be tried if the corals look like they are getting too much at the time?

[Garf]

Were only talking tiny amounts to get his algae going. Of course, this may have no relavence to his problem, I accept that. That's what experimentation is all about. :)

[kotlec]

Exactly.
I hang on every fresh idea with hope to solve my alien screen and overall tank problem. I have feeling that something is lacking or in excess , but cant find out what exactly. I had periods when nutrients where kept at extremely low levels , I had also period with reduced light with negative or no effect .
My feeling that those two (alien screen and pale - brown corals) are somehow related only goes stronger every day. I can very well be wrong though.

[Garf]

This seems to agree with me;
http://www.ecomii.com/science/encyclopedia/algae








Many photosynthetic algae are also able to use organic substances (such as hexose sugars and fatty acids) and thus can grow in the dark or in the absence of CO2. Colorless algae obtain both energy and carbon from a wide variety of organic compounds in a process called oxidative assimilation.










posted this on the wrong thread, sorry. Has relavence though :)