Green boring algae?

[Davileet]

Purchased some sps frags at a swap today and curious to get thoughts from others on the forum. I think it’s rather curious that all the frags have this green hue on the underside and the base. One of the pics shows where I cut through the coral, seems the skeleton is green through and through.

Not sure the corals themselves are acting sickly, just wonder if it’s a matter of time though.

Vendor is saying it’s not green boring algae.

 

[Tahoe61]

https://www.reef2reef.com/threads/ostreobium-green-boring-algae-treatment.219648/

Your description stating the green hue went through the skeleton makes think you're correct.

 

[Davileet]

Yeah, saw this thread yesterday. Unsure if I should toss these frags in fear of it spreading or not. They were not cheap pieces.

 

[EnterName]

I'm not even sure we can keep this algae out of our tanks. It can also live on/in rocks as far as I know, so you probably already have it in your tank.

I can only assume that healthy corals have found a way to keep it out of their skeleton if it is actually damaging. Julian Sprung cites Schlichter et al. 1995 and Schlichter et al. 1997 in his booklet "Algae - A Problem Solver Guide". The 1995 article even points out potential benefits through the transfer of photoassimilates from this sort of algae to corals.

 

[Davileet]

I'm not even sure we can keep this algae out of our tanks. It can also live on/in rocks as far as I know, so you probably already have it in your tank.

I can only assume that healthy corals have found a way to keep it out of their skeleton if it is actually damaging. Julian Sprung cites Schlichter et al. 1995 and Schlichter et al. 1997 in his booklet "Algae - A Problem Solver Guide". The 1995 article even points out potential benefits through the transfer of photoassimilates from this sort of algae to corals.

Yeah, I agree that it is probably always present in our tanks. If healthy corals have mostly kept this out of their skeletons, I would argue that this is only beneficial in small amounts. Ostreobium at larger amounts seems to be detrimental.

Beneath the surface: community assembly and functions of the coral skeleton microbiome this study seems to read more on the subject too.

 

[EnterName]

Yeah, I agree that it is probably always present in our tanks. If healthy corals have mostly kept this out of their skeletons, I would argue that this is only beneficial in small amounts. Ostreobium at larger amounts seems to be detrimental.

Beneath the surface: community assembly and functions of the coral skeleton microbiome this study seems to read more on the subject too.

In that case you could keep the frags and simply see if they make it.

Thank you for the link! It's even an open access one

 

[Davileet]

Yes, will keep them and see what happens and report back at a later date.

For a frag to be this enveloped in boring algae, I would assume the mother colony would be dying off from the center. And I would like to think the vendor who has grown and sold this lineage for years wouldn't have fragged the tips off of a dying mother colony.

 

[EnterName]

Yes, will keep them and see what happens and report back at a later date.

For a frag to be this enveloped in boring algae, I would assume the mother colony would be dying off from the center. And I would like to think the vendor who has grown and sold this lineage for years wouldn't have fragged the tips off of a dying mother colony.

Maybe it's just a discoloration caused by the zooxanthellae reacting to the glue or a tissue-healing process caused by the cutting process. I think we are still looking at tissue not the open skeleton, so it doesn't necessarily has to be in the skeleton or an unwanted algae.

 

[Davileet]

Maybe it's just a discoloration caused by the zooxanthellae reacting to the glue or a tissue-healing process caused by the cutting process. I think we are still looking at tissue not the open skeleton, so it doesn't necessarily has to be in the skeleton or an unwanted algae.

The third image in the original post is a cross cutting of one of the corals.

Found this interesting from article.

"Many endolithic organisms including cyanobacteria, algae and fungi contribute to bioerosion of the coral skeleton [30, 82, 83], but the green alga Ostreobium is by far the most important agent of skeletal deterioration, responsible for 60–90% of microbial carbonate removal in coral skeleton [30, 65]. Most quantitative information on bioerosion comes from experiments on dead coral skeleton [30, 54], where microbial bioerosion rates are significant: up to 1.1 kg CaCO3 dissolution per m2 of exposed substrate area per year [26], corresponding to about 20% of the annual CaCO3 production in coral reefs. Much less knowledge is available for live corals, although it is known that less skeletal burrowing takes place in living corals than in dead carbonate skeletons. Nonetheless, microborers are present throughout the skeleton in living corals from very early developmental stages [44], and in the more densely populated areas of mature skeletons, more than 25% of the skeletal volume is occupied by microborers [26], implying substantial decalcification of live coral skeletons. Microbial bioerosion is known to increase at higher temperatures and lower pH, and it has been estimated that by the year 2100, coral endoliths will dissolve ca. 70% of the yearly reef CaCO3 production [54, 84], suggesting that this process will contribute to accelerated reef deterioration (and possibly coral fragility) in future ocean conditions [10, 84]."

 

[EnterName]

The third image in the original post is a cross cutting of one of the corals.

Oh sorry, I didn't catch that.

"Many endolithic organisms including cyanobacteria, algae and fungi contribute to bioerosion of the coral skeleton [30, 82, 83], but the green alga Ostreobium is by far the most important agent of skeletal deterioration, responsible for 60–90% of microbial carbonate removal in coral skeleton [30, 65]. Most quantitative information on bioerosion comes from experiments on dead coral skeleton [30, 54], where microbial bioerosion rates are significant: up to 1.1 kg CaCO3 dissolution per m2 of exposed substrate area per year [26], corresponding to about 20% of the annual CaCO3 production in coral reefs. Much less knowledge is available for live corals, although it is known that less skeletal burrowing takes place in living corals than in dead carbonate skeletons. Nonetheless, microborers are present throughout the skeleton in living corals from very early developmental stages [44], and in the more densely populated areas of mature skeletons, more than 25% of the skeletal volume is occupied by microborers [26], implying substantial decalcification of live coral skeletons. Microbial bioerosion is known to increase at higher temperatures and lower pH, and it has been estimated that by the year 2100, coral endoliths will dissolve ca. 70% of the yearly reef CaCO3 production [54, 84], suggesting that this process will contribute to accelerated reef deterioration (and possibly coral fragility) in future ocean conditions [10, 84]."

Would be interesting to know if this algae is actually causing significant trouble in reef tanks. We surely see it from time to time, but if there was no way for corals to deal with it you would just nuke your entire tank by introducing it. There has to be some nuance to this.