This scene comes from a series of wood-engraved illustrations based on Gustave Doré's drawings for Samuel Taylor Coleridge's poem, The Rime of the Ancient Mariner. The large folio edition featuring these illustrations was published in London in 1876.
This part is based on the moment in the poem when the sea seems to burn with ominous lights at night:
'About, about, in reel and rout
The death-fires danced at night;
The water, like a witch's oils,
Burnt green, and blue and white.'
The 'death-fires' imagery in the poem refers to St. Elmo's fire - a phenomenon that appears on pointed structures like ship masts during stormy weather and was often interpreted by sailors as a harbinger of doom. The depiction of the water burning green, blue, and white describes marine phosphorescence (bioluminescence) glowing in the dark. Coleridge blended these two distinct natural phenomena that sailors encountered in real life and attributed to supernatural forces.
Doré, too, doesn't depict this ambiguous display of light as a scene of scientific explanation. Instead, he transforms it into an image of dread featuring a winged humanoid figure, sea foam, the dark ocean, and tiny points of light.