How do oceans absorb CO2?

1 Answer

Answer:

1) Differences in pressure between the air and the ocean cause carbon dioxide to be exchanged and 2) algae and phytoplankton absorb carbon dioxide.

Explanation:

The ocean can absorb carbon dioxide (#"CO"_2#) in 2 ways: diffusion from the atmosphere and through photosynthesis in plankton and algae.

http://www.pmel.noaa.gov/co2/file/Ocean+Carbon+Uptake+Image

Carbon dioxide moves between the atmosphere and the ocean by molecular diffusion: a difference between #"CO"_2# pressure in the atmosphere and ocean causes #"CO"_2# to be exchanged (source). The #"CO"_2# moves from the air to the water, when the atmospheric pressure of #"CO"_2# is higher. The #"CO"_2# is dissolved in the ocean because it is soluble.

The solubility of carbon dioxide varies based on salinity and temperature of the water and there is a finite amount that the water can absorb. The colder the water, the more #"CO"_2# can be dissolved.

The solubility of #"CO"_2# in water is demonstrated in the video below.

Another way in which the ocean absorbs #"CO"_2# is through some of its lifeforms. Phytoplankton and algae both photosynthesize in the ocean. They both consume #"CO"_2# using sunlight and release #"O"_2#.

For more information:

  1. The Ocean Carbon Cycle
  2. Carbon Dioxide in the Ocean and Atmosphere
  3. The Marine Carbon Cycle Video