Unique Nature of Pure Water
What type of bond forms between water molecules, giving water its unique cohesion?
What is a hydrogen bond?
What is the average salinity of seawater?
What is about 35 parts per thousand (ppt)?
What term describes the total amount of dissolved salts in seawater?
What is salinity?
What gas is primarily responsible for ocean acidification?
What is carbon dioxide (CO₂)?
What process removes CO₂ from the atmosphere and stores it in plants or phytoplankton?
What is photosynthesis?
What property allows water to stick to other substances?
What is adhesion?
Which two ions make up most of the salt in seawater?
What are sodium (Na⁺) and chloride (Cl⁻)?
What does the principle of constant proportions state?
The ratio of major ions in seawater remains nearly constant, regardless of total salinity.
When CO₂ dissolves in seawater, what weak acid does it form?
What is carbonic acid (H₂CO₃)?
What process releases CO₂ back into the atmosphere or ocean water?
What is respiration or decomposition?
Why does ice float on liquid water?
Because solid water is less dense due to hydrogen bonds forming an open crystalline structure.
How does temperature affect the density of seawater?
Colder water is denser than warmer water.
What process adds dissolved oxygen to seawater?
Photosynthesis and mixing with the atmosphere.
How does ocean acidification affect organisms with calcium carbonate shells?
It makes it harder for them to build and maintain their shells.
What is the term for the movement of carbon through the atmosphere, ocean, land, and living things?
What is the carbon cycle?
What is the term for water’s ability to absorb large amounts of heat without changing temperature rapidly?
What is high specific heat capacity?
What happens to the freezing point of water as salinity increases?
It decreases — saltwater freezes at lower temperatures.
What process removes oxygen from seawater?
Respiration and decomposition by marine organisms.
What ion decreases in concentration as a result of ocean acidification, threatening shell-building species?
What is carbonate (CO₃²⁻)?
How does the ocean act as a “carbon sink”?
It absorbs and stores large amounts of atmospheric CO₂.
How does water’s polarity contribute to its effectiveness as a solvent?
The positive and negative ends of water molecules surround and separate ions or polar molecules, dissolving them easily.
Explain how temperature and salinity combine to create thermohaline circulation.
Differences in temperature (thermo) and salinity (haline) create density gradients that drive deep ocean currents.
Why does pH vary slightly with depth in the ocean?
Surface waters are more basic due to photosynthesis, while deeper waters are more acidic due to respiration and CO₂ accumulation.
Explain the relationship between atmospheric CO₂ levels and the pH of seawater.
As atmospheric CO₂ increases, more dissolves in the ocean, forming carbonic acid and lowering pH (making the water more acidic).
Explain how the biological pump transfers carbon to the deep ocean.
Marine organisms fix carbon during photosynthesis; when they die, their remains sink, carrying carbon to deep waters and sediments.