How do marine microorganisms drive the global carbon cycle?

Marine microorganisms, which make up a vast majority of the ocean's biomass, play a foundational role in the global carbon cycle. Through metabolic processes, photosynthesis, and decomposition, these microscopic organisms consume and produce vast quantities of organic matter. They sequester large amounts of carbon and regulate nutrient exchanges across the world's oceans.

What we know

• Marine microorganisms are estimated to make up between 70 and 90 percent of the biomass in the ocean. [2]
• Marine microorganisms are responsible for nearly all photosynthesis occurring in the ocean and participate in global element cycling. [2]
• Microbial marine systems produce and consume about half of all organic matter generated on the planet every year. [2]
• Biological processes in biogeochemical cycles rely heavily on microorganisms as critical drivers of nutrient and chemical cycling. [4]

Still open

• Microscopic life in the oceans is still poorly understood, and the specific role of viruses in marine ecosystems has barely been explored.

Where to go next

• the bigger pictureWhat are marine prokaryotes and their biomass?
• what caused itHow do biogeochemical cycles function globally?
• a case in pointWhat are marine biogeochemical cycles?
• how it workedHow do metabolic processes drive element cycling?
• whenHow does the last universal common ancestor connect to marine life?
• an unexpected connectionHow does bacterial biomass compare to total human biomass?Bacteria collectively possess over 1000 times the biomass of all humans combined on the planet.

Sources

• [1]Marine microorganism (Wikidata Q28000814) · CC0 1.0
• [2]Marine microorganisms · CC BY-SA 4.0
• [3]Marine prokaryotes · CC BY-SA 4.0
• [4]Biogeochemical cycle · CC BY-SA 4.0
• [5]Marine biogeochemical cycles · CC BY-SA 4.0