Studies:

Scope: all

Type: string with fixed values

Note: On the Metalog website, negative controls and mock samples are not shown, as they only serve as controls for the sampling and sequencing process, but do not have meaningful metadata associated with them. They are, however, contained in the download files. At any rate, if you are analysing data, you are advised to consider if the artificial column has an impact on your results. If you are looking for "unperturbed" samples, you will want to take only those samples into account where this field is empty.

Allowed values:

• mock (any defined artificial mixture, e.g. ZymoBIOMICS Microbial Community Standards)
• negative control (e.g. sequencing blank test tubes with only water to test the sampling/sequencing kit)
• spike-in (spike-in of known quantities of DNA for absolute quantification)
• cultivation (the original sample was kept in a medium for a while to allow bacteria to grow)
• enrichment (enrichment for specific prokaryotic phyla e.g. by centrifugation -- will distort the relative abundances)
• virome enrichment (enrichment for viruses, for example by iron flocculation -- will distort the relative abundances)
• sorted cells (enrichment for specific species by cell sorting prior to sequencing -- will distort the relative abundances)
• mesocosm (like cultivation, but in a mesocosm)
• paleosample (the subject died a long time ago)
• post-mortem (the subject died a short time ago)

Description: Empty in case of natural, non-modified sample. Otherwise, this field has been set to alert users to the fact that the relative abundances of the species in this sample may not reflect the underlying sample due to technical modifications or passage of time.