Assertion: diatom | /r/CapableOf | migrate up before dawn
Facets:
value: down again
type: TEMPORAL
value: during the first hours of darkness
type: TEMPORAL
Source sentences:
text: Indeed, some diatoms living in sediments have been observed to migrate up to the surface before dawn and down again during the first hours of darkness or to move up and down according to the tides (38).