slime vs sapropel

slime and sapropel both are nouns.

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

As nouns, sapropel is a hyponym of slime; that is, sapropel is a word with a more specific, narrower meaning than slime:

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

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

slime (verb)	sapropel (verb)
cover or stain with slime