General Oceanography: Biogeochemistry and Carbon Dioxide

What is Advection?

transport in water water mass deriving from elsewhere (horizontal current flow, mixing, waves). Supplies oxygen-rich waters to deep ocean.

What is the Oxygen Minimum Zone?

typically at depth of pycnocline. Oxygen demand by respiration is greater than supply through advection, mixing and photosynthesis

What are stable isotopes?

difference in number of neutrons, giving it a different atomic weight without altering the charge.

_____ isotopes with more neutrons react more ____ leading to fractionation between reactant and product

heavier, slowly

____ more readily taken up by phytoplankton than ¹³C

¹²C

How is ¹³C of benthic foraminifera used?

¹²C is released during remineralization and picked up by water masses as they age. So, old bottom water has ¹²C rich water for foraminifera to construct their CaCO₃ tests

CaCO₃ tests have isotopically light C as they grow old in _____ bottom water; and heavier isotopic composition if grown in ____ bottom water

old, younger

Major sources of carbon dioxide are ______

respiration and decay

Major sinks of carbon dioxide are _______

photosynthesis and construction of carbonate shells

Surface water is ____ in CO₂ due to photosynthesis

lower

Bottom water is ____ in CO₂ due to respiration and decomposition

high

What are the differences in CO₂, Nutrients, and O₂ between Deep Pacific and Deep Atlantic?

Pacific: more CO₂, less O₂, and more nutrients

Atlantic: less CO₂, more O₂, and less nutrients

DIC in water acts as a ____ preventing large shifts in pH

buffer

____ H⁺ in a solution results in lowered pH (acidic)

more

CO₂ combines with the water to produce ______ which releases H⁺ ions (lowers pH)

carbonic acid