▁of ▁o xygen , ▁they ▁reduce ▁dissol ved ▁sul f ate ▁() ▁and ▁ex crete ▁hydro gen ▁sul f ide . ▁Due ▁to ▁the ▁to x icity ▁of ▁, ▁only ▁resist ant ▁chem os yn th etic ▁b acter ia ▁surv ive . ▁The ▁b acter ial ▁m ats ▁provide ▁n our ishment ▁for ▁muss els , ▁cl ams , ▁lim p ets ▁and ▁sea ▁sn ails . ▁As ▁wh ale ▁b ones ▁are ▁rich ▁in ▁lip ids , ▁representing ▁ 4 – 6 % ▁of ▁its ▁body ▁weight , ▁the ▁final ▁dig estion ▁stage ▁can ▁last ▁between ▁ 5 0 ▁and ▁possibly ▁ 1 0 0 ▁years . ▁ ▁Stage ▁ 4 ▁ ▁Some ▁scient ists ▁post ulate ▁a ▁fourth ▁stage ▁of ▁e colog ical ▁succession ▁at ▁wh ale ▁fall ▁sites , ▁called ▁the ▁" ree f ▁stage ." ▁A ▁wh ale ▁fall ▁enters ▁this ▁stage ▁once ▁the ▁organ ic ▁comp ounds ▁have ▁been ▁exha usted ▁and ▁only ▁min er als ▁remain ▁in ▁the ▁b ones , ▁which ▁provide ▁a ▁hard ▁substr ate ▁for ▁susp ension ▁and ▁filter ▁feed ers . ▁ ▁M eth an ogen esis ▁ ▁A ▁process ▁called ▁m eth an ogen esis ▁can ▁also ▁occur ▁around ▁wh ale ▁falls . ▁Arch ae a ▁that ▁produce ▁m eth ane ▁can ▁be ▁abund ant ▁in ▁an ox ic ▁sed iment , ▁but ▁are ▁typically ▁not ▁found ▁in ▁co - occ urrence ▁with ▁the ▁sul fur ▁reducing ▁b acter ia ▁found ▁at ▁wh ale ▁falls . ▁Wh ale ▁falls ▁do ▁however