sapropel vs muck

sapropel and muck both are nouns.

Word	Noun	Adjective	Verb	Adverb
sapropel	Yes	No	No	No
muck	Yes	No	Yes	No

As nouns, muck is a hypernym of sapropel; that is, muck is a word with a broader meaning than sapropel:

sapropel: sludge (rich in organic matter) that accumulates at the bottom of lakes or oceans
muck: any thick, viscous matter

Other hypernyms of sapropel include goo, gook, goop, guck, gunk, ooze, slime, sludge.

sapropel (noun)	muck (noun)
sludge (rich in organic matter) that accumulates at the bottom of lakes or oceans	any thick, viscous matter
	fecal matter of animals

sapropel (verb)	muck (verb)
	remove muck, clear away muck, as in a mine
	soil with mud, muck, or mire
	spread manure, as for fertilization