Marine Ecosystems and Seawater Chemistry

This video explores the factors affecting the chemical composition of seawater, focusing on salinity and the role of salts and ions. It discusses how evaporation and precipitation influence salinity, with examples like the Dead Sea. The video also examines the impact of volcanic activity, runoff, and atmospheric dissolution on seawater composition, highlighting the processes of biomagnification and the importance of gases like nitrogen, oxygen, and carbon dioxide in marine ecosystems.

What percentage of seawater is composed of water?

• 70%

• 100%

• 96.5%

• 3.5%

What is the typical salinity of seawater in parts per thousand?

• 50

• 35

• 10

• 25

How does evaporation affect the salinity of seawater?

• Decreases salinity

• Neutralizes salinity

• Has no effect

• Increases salinity

Which gas is released by volcanic activity and contributes to chloride ions in seawater?

• Oxygen

• Chlorine

• Nitrogen

• Carbon Dioxide

What is biomagnification?

• The formation of salts from ions

• The decrease of salinity due to precipitation

• The process of gases dissolving in water

• The increase of pollutant concentration through the food chain

What was the main pollutant in the Minamata Bay disaster?

• Cadmium

• Arsenic

• Mercury

• Lead

Which gas is essential for photosynthesis in marine organisms?

• Carbon Dioxide

• Oxygen

• Helium

• Nitrogen

How does temperature affect the solubility of gases in seawater?

• Colder water holds more gases

• Warmer water holds more gases

• Both temperatures hold equal gases

• Temperature has no effect

What is the role of nitrogen in marine ecosystems?

• Essential for DNA and proteins

• Used for respiration

• Decreases pollution

• Increases salinity

Which factor does NOT affect the chemical composition of seawater?

• Atmospheric dissolution

• Runoff

• Volcanic activity

• Lunar phases