Chemical Environment

Chemical Oceanography is dictated by what three major factors?

Salts
Gases
Nutrients

Why is the ocean salty?
2 sources

River inputs (weathering of rocks)
Mid-ocean ridges (venting)

Why is the ocean salty?
1 sink

Sediment deposition

Rate of sources equals rate of sinks (for ocean salinity), so salinity is _____

constant

What 4 elements account for 97% of sea salts?

Chloride
Sodium
Sulfate (SO4)
Magnesium

Order these areas by salinity, lowest to highest:
Open ocean
Coastal waters
Hypersaline waters
Estuaries

Estuaries
Coastal waters
Open ocean

Hypersaline waters

What are the three sources of oxygen in the ocean?

Photosynthesis
Surface mixing w/ atmosphere
Deep-water circulation

What is the major sink of oxygen in the ocean?

Respiration (decomposition)

Oxygen minimum zones are low in O2 because there is no photosynthesis to add, and ______ deplete the oxygen

bacteria

The increase in oxygen with depth under the OMZs is thanks to ____ _____

thermohaline circulation

Salty, anoxic waters are high in _____ to replace O2 chemically

Sulfur

Source of inorganic carbon for photosynthesis and the basis for the pH buffering system in the ocean

CO2

pH of the ocean is dropping, but has historically remained at

8

Lowering pH will cause a decrease in ___ concentrations, which is bad for calcareous shells

CO3 (carbonate)

lowering pH will cause an increase in ___ concentrations, which takes from CO3 solubility

HCO3 (bicarbonate)

An essential element for life that has to be obtained externally

Nutrient

If any required element is not available then growth will stop no matter the abundance of the other elements

Law of the Minimum

What two nutrients are the major limiting nutrients?

N and P

Does phosphorous or nitrogen have a major gaseous reserve in its cycle?

Nitrogen

Does nitrogen or phosphorous have a larger sediment reservoir in its cycle?

Phosphorous

The source of bioavailable N and P in the ocean is

decomposition T

The sink of bioavailable N and P in the ocean is

photosynthesis

There are low levels of N and P at the surface due to

phytoplankton usage

There are high levels of N and P at depth due to

decomposition of organic material