algae growth and carbon uptake

[TbyZ]

In the article 'Photosynthesis and the Reef Aquarium, Part I: Carbon Sources' by Randy Holmes Farley, he describes how various species of photosynthiesising organisms use various mechanisms to obtain carbon other than directly from CO2.

Is there a mechanism whereby a marine algae could obtain carbon, for photosynthesis, from the dissolved organic carbon in the aquarium water.

 

[Cory]

heres a good article

http://onlinelibrary.wiley.com/doi/10.2307/1932984/full

 

[TbyZ]

thanks cory for the reply.

Unfortunately the study was testing bacteria & algae uptake in fresh water& cannot be compared to marine algae.

From Randy's article -"Freshwater algae, on the other hand, can sometimes obtain all of their required carbon dioxide by passive uptake.3 While a review of such literature is unnecessary in this article, I'll give one example. The freshwater chrysophyte alga, Mallomonas papillosa, has been shown to have none of the more sophisticated mechanisms for carbon dioxide uptake that are described later in this article, and it relies on simple passive uptake. For this reason it has been shown to photosynthesize most effectively where carbon dioxide concentrations are high, at pH 5-7.4"
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the concentration of CO2 in seawater, at a pH of 8.2, is almost nonexistant. This is why marine algae need to get carbon for photosynthesis from other sources.

 

[TbyZ]

question:-

can marine photosynthesising organisms obtain CO2 from the carbon in dissolved organic compounds in an aquarium where pH is above 8 and alkalinity is low?

some feedback from Mr Holmes Farley would be greatly appreciated