Bacteria eat sunlight.
A scientist in marine microbiology at Linnaeus University, Sweden, is part of a Swedish and Spanish group that has found, contrary to previous beliefs, that considerably many bacteria living in the ocean possess a gene that activates a pigment called proteorhodopsin which harvests light as a nutritional source when conventional food becomes scarce.

"It was long thought that phytoplankton were the only organisms in the sea that could harvest the energy from sunlight for growth," says Dr. Jarone Pinhassi, scientist in marine microbiology at Linnaeus University, Sweden. These microscopic planktonic organisms carry out the same chlorophyll driven photosynthesis process as green plants on land.

Related to the pigment in the retina that enables human vision in less intense light, proteorhodopsin in these bacteria fulfills a crucial role in the global carbon cycle by determining oceanic production of carbon dioxide through respiration and determining how the fluxes of energy that are fixed by photosynthesis are channeled through marine food chains.

Reported in late April, the findings provide an understanding of mechanisms for marine bacteria to efficiently use solar energy, and hints at further applications and research, especially if one considers that a quart of seawater on average contains around a billion bacteria.

Resource: Public Library of Science