| adapters | optional |
| alkalinity | optional |
| alkyl diethers | optional |
| aminopeptidase activity | optional |
| ammonium | optional |
| amount or size of sample collected | optional |
| annotation source | optional |
| atmospheric data | optional |
| bacterial carbon production | optional |
| bacterial production | optional |
| bacterial respiration | optional |
| biomass | optional |
| bishomohopanol | optional |
| broad-scale environmental context | mandatory |
| bromide | optional |
| calcium | optional |
| carbon/nitrogen ratio | optional |
| chemical administration | optional |
| chimera check | optional |
| chloride | optional |
| chlorophyll | optional |
| conductivity | optional |
| density | optional |
| diether lipids | optional |
| dissolved carbon dioxide | optional |
| dissolved hydrogen | optional |
| dissolved inorganic carbon | optional |
| dissolved inorganic nitrogen | optional |
| dissolved inorganic phosphorus | optional |
| dissolved organic carbon | optional |
| dissolved organic nitrogen | optional |
| dissolved oxygen | optional |
| downward PAR | optional |
| encoded traits | optional |
| environmental medium | mandatory |
| estimated size | optional |
| experimental factor | optional |
| extrachromosomal elements | optional |
| finishing strategy | optional |
| fluorescence | optional |
| geographic location (altitude) | optional |
| geographic location (depth) | mandatory |
| geographic location (elevation) | optional |
| geographic location (latitude) | mandatory |
| geographic location (longitude) | mandatory |
| geographic location (region and locality) | optional |
| glucosidase activity | optional |
| health or disease status of specific host | optional |
| investigation type | ignore |
| isolation and growth condition | optional |
| known pathogenicity | optional |
| library construction method | optional |
| library reads sequenced | optional |
| library screening strategy | optional |
| library size | optional |
| library vector | optional |
| light intensity | optional |
| local environmental context | mandatory |
| magnesium | optional |
| mean friction velocity | optional |
| mean peak friction velocity | optional |
| miscellaneous parameter | optional |
| multiplex identifiers | optional |
| n-alkanes | optional |
| nitrate | optional |
| nitrite | optional |
| nitrogen | optional |
| nucleic acid amplification | optional |
| nucleic acid extraction | optional |
| number of replicons | optional |
| observed biotic relationship | optional |
| organic carbon | optional |
| organic matter | optional |
| organic nitrogen | optional |
| organism count | optional |
| oxygenation status of sample | optional |
| particulate organic carbon | optional |
| particulate organic nitrogen | optional |
| pcr conditions | optional |
| pcr primers | optional |
| perturbation | optional |
| petroleum hydrocarbon | optional |
| pH | optional |
| phaeopigments | optional |
| phosphate | optional |
| phospholipid fatty acid | optional |
| photon flux | optional |
| ploidy | optional |
| potassium | optional |
| pressure | optional |
| primary production | optional |
| project name | ignore |
| propagation | optional |
| redox potential | optional |
| reference for biomaterial | optional |
| relationship to oxygen | optional |
| relevant electronic resources | optional |
| relevant standard operating procedures | optional |
| sample collection device or method | optional |
| sample material processing | optional |
| sample storage duration | optional |
| sample storage location | optional |
| sample storage temperature | optional |
| sample volume or weight for DNA extraction | optional |
| sequence quality check | optional |
| sequencing method | ignore |
| silicate | optional |
| sodium | optional |
| soluble reactive phosphorus | optional |
| source material identifiers | optional |
| specific host | optional |
| subspecific genetic lineage | optional |
| sulfate | optional |
| sulfide | optional |
| suspended particulate matter | optional |
| target gene | optional |
| temperature | optional |
| tidal stage | optional |
| total depth of water column | optional |
| total dissolved nitrogen | optional |
| total inorganic nitrogen | optional |
| total nitrogen | optional |
| total particulate carbon | optional |
| total phosphorus | optional |
| trophic level | optional |
| water current | optional |
