# Weird alpha rarefaction curve
**URL:** https://forum.qiime2.org/t/weird-alpha-rarefaction-curve/31718
**Category:** User Support
**Tags:** alpha-rarefaction, dada2
**Created:** [October 24, 2024, 5:16am UTC](https://forum.qiime2.org/t/weird-alpha-rarefaction-curve/31718 "2024-10-24T05:16:41Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Shreeya\_qiime](https://forum.qiime2.org/u/Shreeya_qiime)
#### Post date: [October 24, 2024, 5:16am UTC](https://forum.qiime2.org/t/weird-alpha-rarefaction-curve/31718/1 "2024-10-24T05:16:41Z")
I got this weird alpha rarefaction curves when I ran it at a sequencing depth of 500, could anyone help me troubleshoot this? Can I go with this, or should I increase the depth?
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### Author:  [@salias](https://forum.qiime2.org/u/salias)
#### Post date: [October 24, 2024, 9:41am UTC](https://forum.qiime2.org/t/weird-alpha-rarefaction-curve/31718/2 "2024-10-24T09:41:22Z")
Hi @Shreeya_qiime and welcome to the :qiime2: forum!
It looks like Shannon values are declining, likely because as the sequencing depth increases, you're averaging over fewer samples (those with lower depth than the sequencing depth are excluded). You may want to generate curves by sample instead of aggregating them by metadata.
We addressed a similar issue [recently](https://forum.qiime2.org/t/strange-alpha-rarefaction-curve/31530), and in that case I redirected the user [here](https://forum.qiime2.org/t/alpha-rarefaction-plot-not-leveling-out/30962).
Hope that helps,
Sergio
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### Author:  [@system](https://forum.qiime2.org/u/system)
#### Post date: [November 24, 2024, 3:42pm UTC](https://forum.qiime2.org/t/weird-alpha-rarefaction-curve/31718/3 "2024-11-24T15:42:17Z")
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