Ocean Acidification

Why is the ocean’s ph decreasing?

acid rain and rising CO2 levels in the atmosphere

How does the ocean form carbonic acid?
How does the formation of carbonic acid lower the ph of ocean water?

It absorbs CO2, forming H2CO3 (H2O + CO2).

Then it partially dissociates, creating H+ and HCO3-. The H+ increases the H+ concentration, therefore higher acidity.

What are some factors that naturally affect ocean pH?

Salinity (salt content in the water), temperature (affects algae growth)

What are carbon reservoirs?

places where carbon is stored (in the ocean)

Why do marine organisms act as carbon reservoirs?

They contain carbon, so when they die, they sink to the bottom, causing the carbon to stay in the ocean.

Other than marine organisms, why is there more CO2 at the bottom of the ocean?

Since cold temperature and high pressure means higher gas solubility, the bottom of the ocean can hold much more CO2 than the surface.

Where else is carbon found in?

Calcium carbonate (limestone), which are found in seashells and skeletons

Why does calcium carbonate decompose into carbon dioxide at the bottom of the ocean?

high pressure and low temperature makes the carbonate shells dissolve completely (like how sugar dissolves in water)

How do surface ocean currents affect climate?

Heat is transferred between the ocean and atmosphere, transferring from high to low temperature areas.

What is the Coriolis Effect

The curved path an object takes (When looking on a 2d map) when it moves in a straight line across the globe.

How is the flow of currents different in the northern and southern hemispheres?

Northern: clockwise
Southern: counter-clockwise

What causes the difference in density in deep ocean currents?

Cold water is denser than warm water. This is mostly driven by polar water because water is much colder at the poles of earth.

Why is the absorption of heat by oceans not a permanent solution to global warming?

The heat will be returned to the surface and back into the atmosphere

What are the effects of rising ocean temperatures

higher temperature increases the solubility of gas, meaning less oxygen can fit in the ocean. (less oxygen available for marine life)

Acid rain is rain with a pH below __

5.6

What is acid deposition?

all forms of precipitation containing acidic components

name some examples of wet and dry acid deposition

wet: rain, snow, sleet

dry: dust / smoke that later dissolve in water to form acid

Why is rain naturally acidic (below 7)

dissolved CO2 in the atmosphere combines with water to make carbonic acid (like the ocean)

Why has increased industrialization led to acid rain?

greater production of nitrogen and sulfur oxides.

sulfur oxides come from ____ while nitrogen oxides come from ___

burning of fossil fuels (50% from coal), internal combustion engines

Why do nitrogen and sulfur oxides cause acid deposition

they dissolve in water to form HNO3, HNO2, H2SO4, H2SO3 (2 are strong acids!)

What is the effect of acid deposition on building materials?

erosion on calcium carbonate (marble / limestone), and corrosion with metals.

What is the difference between erosion and corrosion

erosion is the physical wearing away of materials, while corrosion is the chemical deterioration of metals (on molecular level).

What is the effect of acid deposition on plants?

1. The decreased ph increases the solubility of essential plant ions, so they are easily washed away (leach) with the water, making it harder for the plant to grow

2. A couple of these ions that wash away could be toxic to plants (Al3+)

3. Dry deposition (like dust / dirt) could block the pores of the plants

What is the effect of acid deposition on water

the Al3+ leached interferes with fish being able to breathe. Also it causes eutrophication (death of a lake)

How does acid deposition affect human health?

sulfates and nitrates iritate and harm the respiratory tract and eyes.
Also toxic metal cations could be released into water supply.

What is the effect of acid deposition on the ocean

1. acidity can dissolve organism’s shells

2. red tide - algae grows rapidly (bloom), so it takes up nutrients and blocks sunlight

   1. Coral bleaching (it expels algae until it turns white and looks like it has been bleached)

What are the general ways to combat acid deposition

Reduce SO2 emissions , Reduce NOx emissions, add strong bases to neutralize rain acidity

How can we reduce SO2 emissions

1. Washing sulfur out of the coal

2. Use methods of generating electricity that don’t combust with sulfur

Name some methods of generating electricity that doesn’t burn fossil fuels

Solar power, wind power, water (hydroelectric) power, nuclear power

How do we reduce NOx emissions

1. catalytic converters (react with CO and NO (which are very bad) to form CO2). but this contributes to global warming

2. Lower temperature combustion. There is less of a shift in equilibrium so less NO is produced. (Accomplished by recirculating exhaust gases back to lower temperature of the engine)