Dealing with marine algae

[pachy-pleuro-whatnot-odon]

Hello everyone,

 

I found the below ichthyosaur vertebra on the beach at Wimereux two weeks ago. It had obviously been lying there for some time, as it was covered in green algae and barnacles. Based on the advise of various friends and the fact this rock seems to hard and massive to work through using just my Dremel, I'll be leaving the fossil in its matrix. However, I do want to clean it up from the algae and barnacles.

 

 

As such, I used a 1:2 dilution of 14° household cleaning vinegar and a couple of sturdy brushes to remove most of the algae (dipping the brushes in the solution between brushings) and soaked it in soapy hot water. Areas with tougher algae were treated using the undiluted vinegar. Today removed the remaining barnacles using wooden toothpicks, following it with another soak in hot soapy water and another rinse.

 

 

Although I think this got rid of all the barnacles, and the piece is no longer entirely coated in green algae, there are still various green spots on the rock (and a slight green sheen on the vertebra itself) that haven't come out with the treatment. (Also the "dead fish smell" still lingers) This makes me wonder about the following things:

 

1. Can the algae regrow, given enough light and moisture in the air?

2. Has anyone ever experienced algae spreading in their collection after failing to remove all traces of algae (I mean, fungi will spread between books and, as I understand, algae can transmit their spores by air)?

3. Is there a way I can get rid of the remaining algae on the rock? E.g. exposure to sun/UV light?

4. Is there a way something can be done about the slight lingering smell, or is this just something that needs to dissipate over time?

 

Now I read some of you prefer using diluted bleach to remove algae growth from fossils (as mentioned in the post below), but I'm not sure I feel comfortable playing around with such aggressive agents yet...

 

 

[pachy-pleuro-whatnot-odon]

So, I guess I may have overreacted when I read a comment in the above quoted thread (since no longer accessible?) that suggested bleach is a much more aggressive acid than vinegar. Though this might be the case, everybody I asked seemed to suggest this as the way to go. So, properly protected by goggles and gloves (and some plastic across table and clothing), I finally set out to remove the last remnants of green algae from my fossil today. I'll have another look tomorrow, but it seems to have worked a charm, as I did not spot any more green algae after my cleaning session today.

 

For those interested, I applied the same approach as with the vinegar - i.e., slightly diluted the bleach, then dipped in a toothbrush and started scrubbing those parts that were still green. Rinsed thoroughly after. And now that there don't seem to be any algae left, I can proceed properly desalination the piece too

 

Other suggestions I've had, though, is to abrade off the remaining algae, either using air abrasion, sand paper, or even a Dremel...

[sjaak]

Ah, and I missed this topic, so we’re even!

Glad it worked out. 

[sjaak]

The vertebra is in a good state of preservation for this area. You were just in time. If you were there a little bit later you would have found this:

[pachy-pleuro-whatnot-odon]

Yeah, as I didn't get any responses here, I decided to post it on Paleontica as well. My reasoning was there'd be a lot more people there collecting from marine contexts, thus with experience with this issue

 

Anyway, seems to have worked out fine, though I did go over it one more time today...

 

And, yes, if you compare it to just the imprint of an ichthyosaur vertebra, then my vertebra is definitely not a bad find at all Still, sauropod bone is not bad either - and that's just me having a preference for marine reptile  But in all honesty, by the looks of it, not sure if I'd have spotted it the condition it was in. Remains an amazing find!

 

 

[crabfossilsteve]

Nice prep on your vert.  For what its worth, I often leave barnacles in place on the matrix (if they don't interfere with the prep of the main attraction) because it represents both modern and ancient life on one rock which I think is kind of cool.  .

[pachy-pleuro-whatnot-odon]

Thanks! It didn't take a lot of time or effort, but definitely looks better this way. Also, I wouldn't necessarily have removed the barnacles either (though I think I prefer my fossils without) were it not for the fact that they started to smell. And though I realise this would've passed, I'm not a big fan of fish and sea food. So the smell of rotting sea live seem particularly gruesome to me