empty metadata is {} and not null
empty metadata is {} and not null

wilke/MG-RAST,teharrison/MG-RAST,paczian/MG-RAST,MG-RAST/MG-RAST,wilke/MG-RAST,paczian/MG-RAST,paczian/MG-RAST,teharrison/MG-RAST,wilke/MG-RAST,wilke/MG-RAST,paczian/MG-RAST,wilke/MG-RAST,wilke/MG-RAST,wilke/MG-RAST,paczian/MG-RAST,teharrison/MG-RAST,MG-RAST/MG-RAST,MG-RAST/MG-RAST,teharrison/MG-RAST,paczian/MG-RAST,teharrison/MG-RAST,teharrison/MG-RAST,MG-RAST/MG-RAST,MG-RAST/MG-RAST