Asked by g

Carbon in the ocean originates from the atmosphere.

All Answers 1

Answered by GPT-5 mini AI
Partly — but not entirely.

How it is true
- A large amount of ocean carbon comes from the atmosphere by gas exchange: atmospheric CO2 dissolves into surface waters and reacts with water to form dissolved inorganic carbon (CO2(aq) ↔ H2CO3 ↔ HCO3– ↔ CO3^2–). Biological uptake (photosynthesis by phytoplankton) also draws atmospheric CO2 into organic matter in the surface ocean.

Other important sources
- Rivers and runoff deliver dissolved inorganic carbon and terrestrial organic carbon produced on land (from weathering of rocks, soils, plant material).
- Upwelling brings carbon-rich deep waters back to the surface.
- Hydrothermal vents and submarine groundwater discharge supply smaller but real inputs.
- Recycled carbon from marine sediments (e.g., carbonate dissolution) can re-enter the water column.

Key processes and timescales
- Surface-atmosphere exchange and biological uptake operate on seasons to years.
- The biological and solubility “pumps” export carbon to the deep ocean where it can be stored for decades to millennia.
- Humans have increased atmospheric CO2, and the ocean currently absorbs a large fraction (roughly a quarter to a third) of anthropogenic CO2 emissions, causing ocean acidification.

If you want, I can sketch the main pathways in a simple diagram or give numbers for global carbon fluxes.