Pyrosoma atlanticum is a pelagic species of marine colonial tunicate in the class Thaliacea found in temperate waters worldwide.

[2] The specific epithet atlanticum refers to the Atlantic Ocean, from where the first specimen of the species was collected for scientific description; it was described in 1804 by François Péron, a French naturalist.

The individual zooids are up to 8.5 mm (0.33 in) long and have a broad, rounded branchial sac with gill slits.

Plankton and other food particles are caught in mucus filters in the processes as the colony is propelled through the water.

This implies the species uses high biomass intake as a strategy, rather than investing in energy-conservation mechanisms.

The results of the study found that a possible source of bioluminescence in P. atlanticum is the abundance of Photobacterium in its microbiome.