I read the source

> Available evidence rules out natural phenomena as likely drivers, suggesting a large-scale pollution event and its associated mitigation measures most likely precipitated the declines...That the declines began shortly after the Deepwater Horizon oil spill points to that event as the most parsimonious explanation. These findings suggest that despite its immense size the deep-pelagic biome is vulnerable to human-induced disturbance and possesses limited resilience to facilitate recovery.

This means "the oil spill caused the declines". That is what this means in English.