Assertion: dolphin's sound | /r/CreatedBy | navy sonar
Facets:
value: usually
type: TEMPORAL
Source sentences:
text: Other notable threats to the population of this species include anthropogenic sounds, usually produced by navy sonar or seismic exploration: these sounds, which resonate through the ocean, are extremely dangerous for dolphins, causing gas-bubble disease, which, in turn, leads to high number of mortality among this species.