Hey Inka,

Maybe magnetic seperation could help? Depending on your clastic material, of course.. Probably wont give a perfect seperation, but might be a useful additional step.

Cheers, Jana

The clastic material is mainly of volcanic origin and aeolian dust. Not sure if that has enough signal, but I will look into it. Thanks, Ariana!

Hi Stefan,

that's the one I use as well and I also do several separation steps. I get like half of the diatoms out but since the percentage of the clastics is so low, it is still a lot.

Thank you, Stefan!

I'm sorry I can't answer you.

I don't have much knowledge of diatoms.

But I work on bacterial resistance and the dissemination of bacteria.

Best regards.

Dear Inka,

I suggest you get in contact with François Demory who's is currently in the Cerege at Aix-en-Provence ([email protected]). We worked together on sediments from the Lake Baikal and experienced this problem. He was doing his PhD, so most of the work... Cheers to the Ghent colleagues, incl. Tist. Alain T.

Dear Alain,

thanks for the tip, I will certainly contact him! Thanks a lot!

Petra Zahajská , thanks foryour answer. I do know the size of the clastic fraction and also of the diatoms, which are quite big. However, their structure is very slim and elongated, so I am not sure if sieving works. But I will check on this anyhow. Merci, Inka

Freezing might help seperate valves from clastics, but won't break diatoms (except perhaps for very lightly silicified species). Seperation could help with your density sep though - I would try sonication, it might help seperate stubborn valves from your fines and any other clusters.

If you're interested in the GSD of your seds, sonication might not be the best idea for material with weaker physical properties.