The ability of marine bacteria to utilize sunlight

As a Wallenberg Scholar, Jarone Pinhassi aims to produce new knowledge about how rhodopsins stimulate the efficiency of bacterial growth in light, where the ability to absorb various nutrients is particularly interesting. The project aims to provide crucial keys for understanding how marine ecosystems will respond to future environmental changes. 

Bacterial processes are significant for the marine ecosystem functioning. Yet only few studies are showing how energy from the light-sensitive protein rhodopsin stimulates and affects bacteria's ability to break down dissolved organic carbon in the ocean. 

Marine bacteria play a crucial role in the global cycles of carbon, nitrogen, and phosphorus. Rhodopsins in bacteria convert solar energy into chemical energy to grow better – not entirely unlike photosynthesis. The protein is related to the rhodopsins in our eye's retina that allow us to see. 

“These are fascinating, still unresolved, questions and we want to try to understand how bacteria contribute to the production of vitamins and other nutrients that are needed in the ocean's food chain as well as for human health" says Jarone Pinhassi. “It's an intriguing thought that we could potentially use this new knowledge to optimize the production of for example dietary supplements or to improve water purification processes.”

Pinhassi and his research group will investigate how bacteria's light utilization affects the composition of dissolved organic matter in the ocean. The researchers will also study during which seasons different bacteria use their rhodopsins and how gene expression varies in connection with algal blooms. They will measure which genes and proteins are used in light or darkness to understand how the light utilization is regulated. 

"On average, there are a billion bacteria in every liter of seawater, and bacteria grow actively and respire like other living organisms. Half of all photosynthesis on Earth is carried out by microscopic algae in the ocean, and bacteria process half of the organic material produced. This corresponds to an almost unimaginable amount of 72 million tons of carbon per day.”