海洋 かいよう 酸素 さんそ事変 じへんなら
kaiyōmusansojihennara

Noun
Da Copula

The "-nara" conditional form ("if/when…") of 海洋無酸素事変

1. If/when the marine oxygen depletion incident…; In the event of the marine oxygen depletion incident…

Nara Conditional