Table 1.

Mantel test results comparing data layers generated for the EMP500 samples

Dataset 1	Dataset 2	n	Spearman rho	P value
LC–MS/MS	GC–MS	401	0.13	0.001
	Metagenomics (taxa)	454	0.43	0.001
	Metagenomics (function)	440	0.32	0.001
	16S	477	0.27	0.001
	18S	340	0.07	0.2
	ITS	373	0.07	0.006
	full-length rRNA operon	181	0.34	0.001
GC–MS	Metagenomics (taxa)	331	0.07	0.002
	Metagenomics (function)	327	0.11	0.001
	16S	349	0.22	0.001
	18S	280	0.08	0.004
	ITS	269	0.09	0.001
	full-length rRNA operon	168	0.11	0.001
Metagenomics (taxa)	Metagenomics (function)	564	0.53	0.001
	16S	538	0.51	0.001
	18S	363	−0.002	0.9
	ITS	423	0.16	0.001
	full-length rRNA operon	235	0.48	0.001
Metagenomics (function)	16S	538	0.58	0.001
	18S	375	−0.02	0.4
	ITS	413	0.22	0.001
	full-length rRNA operon	239	0.55	0.001
16S	18S	414	0.09	0.001
	ITS	463	0.09	0.001
	full-length rRNA operon	215	0.51	0.001
18S	ITS	385	−0.05	0.1
	full-length rRNA operon	173	0.006	0.8
ITS	full-length rRNA operon	171	0.02	0.6

Note the strong relationships between the metabolomics data (that is, LC–MS/MS and GC–MS) and the sequence data from Bacteria and Archaea (that is, shotgun metagenomics, 16S and full-length rRNA operon) as compared to relationships between metabolomics data and sequence data from eukaryotes (that is, 18S and ITS). There are also strong relationships between difference sequence data from Bacteria and Archaea (rho > 0.2 in bolded font; >0.4 in bolded italics; >0.5 additionally underlined).