Hello, I hope you are well. I have some doubts regarding the rarefaction curves. I am working with soil samples. I would like to know if it is "normal" to get sample saturation with less than 10,000 sequences as shown in the image for some of my samples. Curiously, I observed that some samples that contained fewer readings also had a lower richness (observed features), why is this?
I will be attentive to your answers. Thanks for your help.
Hi @Wen,
Thanks for reaching out!
These look like normal rarefaction curves to me. By sample saturation, do you mean achieving a relatively stable metric (i.e. observed_features, faith's PD, etc) prior to a sequencing depth of 10,000? You can see another example these rarefaction curves in our Moving Pictures tutorial, which shows stability around 1,000:
It's hard to say why some of your samples had a lower number of observed features - the image you shared doesn't show what metadata category you've selected. This could be due to different metadata groupings, or due to some samples having less sequences than others. Ultimately, this is a great question to continue thinking about as you move forward with your analysis. 
Cheers 
