IMS W6 Chemistry Flashcards
Salinity
Salinity is relative to the conductivity of a standard KCl solution at a given temperature and pressure
Sea water composition(8)
Water, chloride, sodium, sulfate, magnesium, bicarbonate, calcium, potassium
Cations
(+)
Anions
(-)
Conservative ions
Concentrations are not affected by processes other than precipitation and evaporation.
Atlantic more saline
More river input in the Pacific
Deep water formation
Cold and salt water. At the poles.
Effect of compression
Due to the change in pressure the temperature changes. Potential temperature takes this into account.
Alkalinity CBA
Due to a difference in cations and anions the CBA will make up the electroneutrality of the water. Seawater is NOT river water.
Ocean more Cl- and Na+
Rivers more Ca+, HCO3- and H4SiO4
Sources of ions of seawater(6)
- River inflow
- Particles transported by wind
- Evaporites
- Authigenic mineral formation: happens in the sediment
- Hydrothermal circulation
- Planktonic tests: shell that the plankton create by taking dissolved ion and make a mineral
Where do salts come from?
- Chemical weathering: happens on land (bicarbonate, fluoride, sodium, magnesium, calcium, potassium, strontium)
- Volcanism (chloride, sulphate, bromide, borate)
Where do salts go?
- Biogenic minerals
- Authigenic minerals
- Evaporites
- Interactions with silicates and ion-exchange processes
Reverse weathering
Based on evidence K+ and Mg+ have a process of reverse weathering as they reduce when increasing depth.
Scavenged/absorbed elements
Elements stick to particles and are removed to sediments
- Low concentrations
- Deep Atlantic is higher than Deep Pacific
- Short residence time
Nutrients
Low at the surface (primary production) and high in depth due to decomposition. Deep Pacific is higher than deep Atlantic.
Intermediate residence times.
Solubility of gases
Henry’s law: C = k,h,c * fc
Follow ideal gas law: C = k,h * patm
Temperature increase lowers gas solubility
Organic carbon budget
50 primary production: coastal 6 and open ocean 47
10 exported
2 deposited
0.2 buried
Production
Proportional to biomass of phytoplankton under optimal conditions but may be limited by conditions and resources.
Limiting factors:
- light (turbidity)
- temperature (diversity and more range or one species and high productivity)
- nutrients (tangent)
- irradiance (light scattered by water particles, less in open ocean)
Vertical distribution plankton –> most in euphotic zone along the coast.
Coast vs open ocean primary production
Coast has more nutrients due to upwelling and weathering. Have less light and more irradiance.
Redfield ratio
organic matter is 100% reflective of what is in the phytoplankton.C:N:P 106:16:1.
(CH2O)106 + (NH3)16 + (H3PO4) + 138(O2) <– –> 106(CO2) + 16(HNO3) + (H3PO4) + 122(H20)
O2: C ratio is about 1.3
Oxygen budget(4)
- Air-sea exchange
- Sediment uptake (only in the coastal zones)
- Physical transports
- Balance between water-column primary production and respiration
Hypoxia
< 2mg per L O2
Eutrophication: excess nutrients –> phytoplankton blooms –> die and get consumed –> remineralization or organic matter
Higher T decreases solubility of O2
Acid vs Base
Acid donates proton. Strong acid –> decrease in alkalinity.
Base accepts proton. Strong base –> increase in alkalinity.
Carbonate system
The formulas of CO2 in the water with dissolution and precipitation.
