The Global Turbidity Current Pump and Its Implications for Organic Carbon Cycling

Area of Science:

• Geology
• Oceanography
• Climate Science

Background:

• Submarine turbidity currents are major sediment accumulators, but their role in global carbon cycles was underestimated.
• Previous assumptions suggested limited terrestrial organic carbon burial by turbidity currents (10-44%) and predominantly inactive systems.
• Turbidity currents were largely excluded from global carbon cycle models.

Purpose of the Study:

• To reassess the role of submarine turbidity currents in terrestrial organic carbon burial.
• To update global estimates of carbon mass flux and burial efficiency.
• To investigate the impact of turbidity currents on long-term atmospheric CO2 and climate.

Main Methods:

• Analysis of recent studies on turbidity current activity and organic carbon burial efficiency.
• Integration of new data into global carbon cycle models.
• Comparison of burial efficiencies across various marine settings.

Main Results:

• Terrestrial organic carbon burial by turbidity currents is highly efficient (>60-100%) in diverse settings.
• Global mass flux estimates revised to ~62-90 Mt C/year, with burial efficiency at ~31-45%.
• Turbidity current activity was significantly higher during past sea-level lowstands, with potentially underestimated burial fluxes.

Conclusions:

• Submarine turbidity currents play a crucial role in terrestrial organic carbon burial, contrary to previous beliefs.
• Revised estimates highlight a substantial contribution to marine carbon sequestration.
• Increased burial during sea-level lowstands suggests a significant influence on past atmospheric CO2 levels and climate regulation.