The zooxanthellae feed the organic nutrients present in water?

[frank88]

The zooxanthellae feed on organic nutrients present in water?
feed the organic material or
only inorganic?

[HighlandReefer]

The complete paper is at the link & I have only noted the Abstract. ;)

ON THE FEEDING OF SOME SCLERACTINIAN
CORALS WITH BACTERIA AND DISSOLVED
ORGANIC MATTER
www.aslo.org/lo/toc/vol_18/issue_3/0380.pdf

Yu. I. Sorokin
Institute of Biology of Inland Waters, Academy of Sciences USSR,
Borok, Jaroslavl, USSR


ABSTRACT

Feeding experirnents were carried out with 6 species of common scleractinian reef-building corals from reefs of the Bismarck Archipelago. Their ability to utilize planktonic bacteria and dissolved organic matter (protein hydrolyzate) as food was demonstrated by using radiocarbon, The amount of organic carbon assimilated per day by animals given labeled food at concentrations approaching those found in situ was equivalent to 10-20s of the carbon content of the polyp’s body. The rate of consumption and assimilation of some planktonic algae by corals was much lower. Corals could consume organic phosphorus bound in the cells of planktonic bacteria more actively than inorganic phosphate at the same concentration (several ,ug liter-l), The rate of consumption of phosphorus was 3 pg g-l day-l.

[bertoni]

They will feed on inorganic carbon. They will need fixed nitrogen and phosphorus from the water column. I'm not sure which forms they can take up, though. I think they have some flexibility, but they can take up phosphate and nitrate directly, as well as ammonia.

[frank88]

The complete paper is at the link & I have only noted the Abstract. ;)

ON THE FEEDING OF SOME SCLERACTINIAN
CORALS WITH BACTERIA AND DISSOLVED
ORGANIC MATTER
www.aslo.org/lo/toc/vol_18/issue_3/0380.pdf

Yu. I. Sorokin
Institute of Biology of Inland Waters, Academy of Sciences USSR,
Borok, Jaroslavl, USSR


ABSTRACT

Feeding experirnents were carried out with 6 species of common scleractinian reef-building corals from reefs of the Bismarck Archipelago. Their ability to utilize planktonic bacteria and dissolved organic matter (protein hydrolyzate) as food was demonstrated by using radiocarbon, The amount of organic carbon assimilated per day by animals given labeled food at concentrations approaching those found in situ was equivalent to 10-20s of the carbon content of the polyp’s body. The rate of consumption and assimilation of some planktonic algae by corals was much lower. Corals could consume organic phosphorus bound in the cells of planktonic bacteria more actively than inorganic phosphate at the same concentration (several ,ug liter-l), The rate of consumption of phosphorus was 3 pg g-l day-l.

thanks :rolleyes:

my question (I do not speak very good English) is:
zooxanthellae algae feed on dissolved organic matter in the water?

here in Italy many are convinced that the zooxanthellae are fed only inorganic ...

[frank88]

They will feed on inorganic carbon. They will need fixed nitrogen and phosphorus from the water column. I'm not sure which forms they can take up, though. I think they have some flexibility, but they can take up phosphate and nitrate directly, as well as ammonia.

then nothing organic in their food?

[HighlandReefer]

There is scientific documentation that has demonstrated that coral will use both dissolved organics and suspended organics as a food source. The primary coral food is derived from photosynthesis within the symbiotic dinos which are shared with the coral itself. Proteins, some amino acids......etc can be derived from the tank water. Bacteria, algae and a few other micro-organisms can be consumed and their nutrients can be utilized. ;)

FWIW, there needs to be more research in this area as they don't completely understand how all the different dissolved organics may be used. :)

You also need to take into consideration the bacteria in the mucal layer excreted by the coral by using organics produced by photosynthesis. The bacteria can utilize both dissolved organics, perhaps suspended organics and the inorganic nutrients in the surround water, which can be shared with the coral. This aspect is not completely understood either. ;)