Unique Nature of Pure Water
Covalent bond
What type of bond holds hydrogen and oxygen together in a water molecule?
About 35 parts per thousand
What is the average salinity of seawater?
Sodium and Chloride
What ions make up most of the salt in seawater?
Carbon dioxide
What gas dissolves into seawater and causes acidification?
Carbon dioxide
What is the main gas exchanged between the atmosphere and the ocean in the carbon cycle?
Uneven sharing of electrons causes one side to be slightly negative (oxygen) and the other slightly positive (hydrogen)
What makes water a polar molecule?
Colder water is denser than warmer water.
How does temperature affect the density of seawater?
Around 7.8 to 8.3 (slightly basic)
What is the pH range of normal seawater?
Carbon dioxide reacting with water
What is carbonic acid formed from?
Dissolved carbon dioxide
What form of carbon is taken in by marine plants during photosynthesis?
a universal solvent due to its polarity.
What property allows water to dissolve many substances?
Higher salinity lowers the freezing point
How does salinity affect the freezing point of seawater?
The balance between evaporation, precipitation, river input, and mineral deposition.
What process helps maintain constant ocean salinity over time?
Hydrogen ion
What ion is released when carbonic acid breaks down, making the ocean more acidic?
Through respiration, which releases CO2
How does carbon move from animals to the atmosphere?
Hydrogen bonding creates strong attraction between water molecules at the surface.
Why does water have a high surface tension?
Because it is denser due to lower temperature and higher salinity.
Why does cold seawater sink below warm seawater?
Differences in evaporation, rainfall, river inflow, and melting/freezing of ice.
What causes salinity to vary between different parts of the ocean?
It reduces carbonate ions needed for shells, making them weaker or harder to form.
How does ocean acidification affect shell-forming marine organisms?
As dissolved carbon compounds, sediments, or the shells of dead organisms.
How is carbon stored long-term in the deep ocean?
They absorb and release heat slowly, allowing water to resist rapid temperature changes.
How do hydrogen bonds contribute to water’s high heat capacity?
It increases salinity by removing freshwater and leaving salts behind.
How does evaporation affect the salinity of surface water in hot regions?
They absorb or release hydrogen ions to keep the pH stable.
How do chemical buffers help maintain ocean pH levels?
CO2‚ dissolves forms carbonic acid breaks into hydrogen and bicarbonate ions increases acidity decreases carbonate availability.
Explain the chain reaction that starts when CO2 dissolves into seawater.
CO2‚‚ enters ocean used by phytoplankton passes through food chain sinks as waste or shells stored in deep ocean eventually released back to atmosphere.
Explain the full pathway of carbon through the ocean from atmosphere to deep sea and back again.