Chapter 6 Seawater Chemistry

What instrument is used to measure salinity, temperature, and depth in seawater?

Conductivity Temperature Depth (CTD) instrument

What are the six major ions that make up over 99% of seawater’s composition?

Sodium (Na+), Chloride (Cl-), Sulfate (SO4²-), Magnesium (Mg²+), Calcium (Ca²+), Potassium (K+)

How does the modern method of measuring salinity work?

It uses electrical conductivity, which increases as salt content increases.

What is the primary source of cations in seawater?

Rock weathering on land

What gas is produced by photosynthesis and consumed by respiration in seawater?

Oxygen (O₂)

What process helps maintain a steady-state salt composition in the ocean?

The balance between salt input (rivers, volcanic activity) and removal (sediments, hydrothermal vents, evaporites).