CONVERSION FACTORS


Numerous conversion factors for converting one unit of matter or energy into another are available in the literature. Generally we should use these factors only when we are not able to measure the required unit ourselves, because the relation between the different units is affected by taxon, season, region and many other parameters. I.e. each species in a particular study may be unique regarding the relation between the different units, and hence using conversion factors from the literature may be introduce a bias of unknown size.

The tables below summarise some conversion factors for converting wetmass (WM) to ashfree drymass (AFDM) from different taxa and with depth gradient. The data is taken from my diploma thesis (see contact) from Kongsfjorden, Brandal (78°56'N, 11°51'E) in June-August 2003.

 

Taxa WM –> AFDM
Mollusca 0.071
Bivalvia 0.080
Gastropoda 0.050
Polychaeta 0.143
Crustacea 0.106
Amphipoda 0.054
Isopoda 0.104
Echinodermata 0.102
Holothurioidea 0.112
Ophiuroidae 0.074
Taxa WM –> AFDM
5m depth
WM –> AFDM
10m-20m depth
WM –> AFDM
25m-30m depth
Mollusca 0.068
0.063
0.080
Polychaeta 0.077
0.120
0.138
Crustacea 0.043
0.084
0.149
Echinodermata -
0.102
0.074
  
Ciliatocardium ciliatum Crenella decussata Cryptonatica affinis Cuspidaria sp. Cylichna cf. arctica Cyrtodaria siliqua Dacrydium vitreum Dipolydora quadrilobata Eteone flava Ampharete cf. baltica