In a new study published in Science Advances, oceans researchers say that just 0.001% of the deep seafloor has been visually observed. The findings highlight the potential for a lack of understanding of ocean biodiversity.

Across Earth's deep oceans, explorers have taken a look at an area roughly the size of Rhode Island, which isn't saying much. That works out to about 0.001% of the deep sea, according to a study published Wednesday in Science Advances.