Chemistry of Seawater

What types of bonds form within a water molecule?

Polar covalent bonds.

What types of bonds form between multiple water molecules?

Hydrogen bonds.

What are the three major sub-atomic particles?

Protons, Neutrons, and Electrons.

How do protons differ from neutrons?

Protons have 1 atomic mass unit and a positive charge; Neutrons have 1 atomic mass unit and are neutral.

Why is water considered a polar molecule?

Water is polar due to uneven charge distribution, with oxygen having a partial negative charge and hydrogen a partial positive charge.

What are ionic bonds?

Ionic bonds form when one atom donates an electron to another, creating oppositely charged ions that attract each other.

What characterizes non-polar covalent bonds?

Non-polar covalent bonds occur when two atoms have similar electronegativity and share electrons equally.

What defines polar covalent bonds?

Polar covalent bonds occur when atoms share electrons unequally, resulting in partial charges on atoms.

What are hydrogen bonds?

Hydrogen bonds are weak attractions between slightly positive hydrogen atoms in one polar molecule and slightly negative atoms in another molecule.

What is an isotope?

An isotope is a variant of an element with the same number of protons but a different number of neutrons.

How is atomic mass calculated for isotopes?

By taking a weighted average based on the relative abundances of isotopes of the element.

What is one important chemical property of water due to its polarity?

Frozen water is less dense than liquid water.

How does high heat capacity benefit marine habitats?

It stabilizes ocean temperatures by absorbing large kinetic energy without a rapid rise in temperature.

What does cohesion in water result in?

Surface tension, which creates a barrier that can slow gas exchange between water and the atmosphere.

Why is water considered the universal solvent?

Water can dissolve many substances, facilitating biochemical reactions and nutrient distribution.

What is the average speed of sound in seawater?

1500 m/s.

How is heat transferred in the ocean?

Heat is transferred by conduction and convection among water molecules.

What is the SOFAR channel?

A layer of water where sound waves travel long distances with minimal energy loss.

What is transmission of energy?

Energy traveling through a medium without significant change.

Define scattering of energy.

Redirection of energy in multiple directions due to interactions with particles.

Use the Beers Law equation Iz = I0e-kz to determine the attenuation coefficient (k) given the data in the table below.

Depth	IO	IZ
3	1000	732

First, rearrange the equation to solve for K.

k = -ln(𝐼𝑧/𝐼0)/𝑧

Then plug in the data to solve for Iz/Io = 732/1000 = 0.73Take the natural log of Iz/Io = -0.31

Divide that value by the depth (3m) = -0.10

Multiply the value by -1 because of the negative sign in the equation. K = 0.10

What causes light to attenuate in the ocean?

Attenuation is determined by the turbidity of the water, according to Beer’s Law.

What are the two most abundant constituents in seawater?

Sodium (Na+) and Chloride (Cl-).

What is the average ocean salinity?

35 parts per thousand (‰).

What processes alter surface water salinity?

Precipitation decreases salinity; evaporation increases salinity.

What happens to ocean salinity over time?

Salt ions can be removed or balanced by various chemical and biological processes.

What is the difference between conservative and non-conservative chemical constituents of seawater?

Conservative constituents change due to physical processes; non-conservative constituents can change due to biological and chemical processes.

What is the Redfield Ratio?

The relative concentrations of Carbon: Silica: Nitrogen: Phosphorous are 106:40:16:1.

What is HNLC?

High Nutrient Low Chlorophyll, areas with high nutrients but low phytoplankton abundance.

Describe the biological pump.

It transports carbon from the surface to the deep ocean, regulates atmospheric CO2 levels.

What happens to the carbonate system when atmospheric CO2 increases?

More bicarbonate forms, and precipitation of CaCO3 becomes less favorable.