Boat encounter with the 2019 Java bioluminescent milky sea: Views from on-deck confirm satellite detection

Abstract

“Milky seas” are massive swaths of uniformly and steadily glowing ocean seen at night. The phenomenon is thought to be caused by luminous bacteria, but details of milky sea composition, structure, cause, and implications in nature remain largely uncertain. Between late July and early September 2019, specialized low-light satellite sensors detected a possible bioluminescent milky sea south of Java, Indonesia, spanning >100,000 km 2 . Upon learning of these findings, crew members of the yacht Ganesha reached out to confirm and share details of their personal encounter with this same event. Here, we document Ganesha ’s experience as recalled by the crew, compare their course to satellite data, and assess their photography of this milky sea.