▁support ▁both ▁sul fur ▁reducing ▁b acter ia ▁and ▁m eth ane ▁producing ▁arch ae a , ▁leading ▁to ▁the ▁conclusion ▁that ▁the ▁area ▁is ▁not ▁electron ▁don or ▁limited , ▁and / or ▁there ▁is ▁minimal ▁or ▁no ▁competition ▁for ▁suitable ▁substr ate . ▁Con cent r ation ▁grad ients ▁of ▁both ▁sul f ide ▁and ▁m eth ane ▁can ▁be ▁found ▁around ▁wh ale ▁falls , ▁with ▁the ▁highest ▁concentration ▁coming ▁within ▁one ▁meter ▁of ▁the ▁car c ass , ▁which ▁is ▁several ▁orders ▁of ▁magnitude ▁higher ▁than ▁the ▁surrounding ▁sed iment ▁concentr ations . ▁M eth an ogen esis ▁appears ▁to ▁only ▁occur ▁in ▁sed iments ▁as ▁opposed ▁to ▁sul fur ▁reduction , ▁which ▁occurs ▁both ▁in ▁sed iments ▁and ▁on ▁the ▁b ones ▁of ▁the ▁car c ass . ▁The ▁addition ▁of ▁sul fur ▁reduction ▁in ▁both ▁sed iments ▁and ▁high ▁li pid ▁wh ale ▁b ones ▁is ▁a ▁key ▁factor ▁for ▁why ▁wh ale ▁falls ▁are ▁able ▁to ▁sust ain ▁deep - se a ▁communities ▁for ▁extended ▁periods ▁of ▁time . ▁ ▁Pale ont ology ▁ ▁Wh ale ▁fall ▁foss ils ▁from ▁the ▁late ▁E oc ene ▁and ▁O lig oc ene ▁( 3 4 – 2 3 ▁MY A ) ▁in ▁Washington ▁and ▁from ▁the ▁P li oc ene ▁in ▁Italy ▁include ▁cl ams ▁that ▁also ▁inhab ited ▁non - chem os yn th etic ▁environments . ▁Chem os yn th etic - only ▁animals ▁do ▁not ▁appear ▁until ▁the ▁Mi oc ene ▁( 2 3 –