Chemical Oceanography HW 1

Water masses, nutrient profiles, residence times, why is the ocean salty

What is the average temp and salinity for AAIW?

T: 2 to 3 degrees Celsius

S: 34.2 PSU

What is the average temp and salinity for NADW?

T: 2 to 3 degrees Celsius

S: 34.9 - 35 PSU

What is the average temp and salinity for AABW?

T: -2 to 0 degrees Celsius

S: 34.6 - 34.7 PSU

What is the average temp and salinity for NPIW?

T: 2 to 4 degrees Celsius

S: 33.8 - 34 PSU

What is the residence time of Na+ in the ocean?

80 × 10^6 years

What is the residence time of Ca2+ in the ocean?

1.2 × 10^6 years

What order of magnitude is the residence time for phosphate?

10^4

What is the Redfield ratio of organic matter?

C:N:P = 106:16:1

Where do ocean salts come from?

• Weathering carbonate and silicate rocks

• Rivers are main source of ions to the ocean

What controls salinity?

• ion supply from rivers

• difference in reactivities

Highly reactive elements have ____ residence times

shorter

Less reactive elements have ____ residence times

longer

What causes low phosphate at the ocean surface?

Phytoplankton take up phosphate for photosynthesis. Phosphate is higher at slightly lower depths as sinking organic matter is decomposed by respiration and remineralization releasing phosphate back into the water.

Why is there more phosphate in the Pacific vs Atlantic Ocean?

• Pacific water is older

• Thermohaline circulation and remineralization