Lecture 22- Marine Chemistry II Flashcards
conservative consituents
- only varied by physical exchange processes at the sea surface (or by mixing with other water masses at depth)
once the water leaves the surface, these properties are conserved
- salinity
- temperature
- inert gas concentration
nonconservative constituents
- altered by chemical or biological processes that occur in the water column
examples of nonconservative constituents
- Biological uptake and recycling (eg., nutrient uptake and remineralization)
- Geochemical processes (eg., radioactive decay)
- Nutrients, oxygen, carbon dioxide
- Sources, sinks, transports, chemical reactions
plant nutrient source
through bacterial remineralization
Atlantic Ocean plant nutrients can vary greatly from place to place due to
horizontal advection
biological sources and sinks
- photosynthesis and vertical diffusion across air sea interface: produce oxygen
- respiration and horizontal advection: consume oxygen
ocean models predict a global O2 inventory decline of — by 2100
1-7%
direct observations recently published show a global O2 decline of
2% since 1960 with some regions exceeding 4% decline
O2 decline has been caused by
- Decline in oxygen solubility in the surface layer
- Enhanced surface layer buoyancy leading to reduced subduction into the thermocline (500m), reduced vertical mixing
- Reduced deep convection (>1000m)
- Biological consumption
coastal upwelling and acidity
brings deep water that is cold and rich in CO2 (and therefore more acidic) up to the surface in coastal regions
ocean has taken up – of all the CO2 we have emitted since the start of the industrial era
30% but acidity has increased by 26%
affects of acidity
- ability of the ocean to take up more CO2 in the future will go down with increases in acidity
- Cold waters take up more CO2 and so high latitude regions are acidifying faster than lower latitudes- polar seas are at great risk
