The video explores marine systems, focusing on the difference between freshwater and saltwater, the origin of ocean salts, and the role of the water cycle in maintaining ocean salinity. It explains how salts are eroded from rocks and transported to oceans, discusses estuaries and brackish water, and describes various marine ecosystems like coral reefs and continental shelves. The lesson concludes with a summary of how these systems support life and maintain ecological balance.

What is the primary difference between freshwater and marine systems?

• Freshwater systems have a high salt concentration.

• Marine systems have a high salt concentration.

• Freshwater systems are found only in oceans.

• Marine systems are found only in rivers.

What is the chemical formula for the most common type of salt found in the ocean?

• MgSO4

• NaCl

• CaCO3

• KCl

How do sodium and chloride ions primarily reach the ocean?

• Via the water cycle

• By human activities

• Through atmospheric deposition

• Through volcanic eruptions

Why don't rivers and lakes accumulate salt like oceans do?

• Salt evaporates with water.

• They are constantly replenished with fresh water.

• Salt is absorbed by aquatic plants.

• They have a different type of salt.

What happens to salt when ocean water evaporates?

• It remains in the ocean.

• It forms clouds.

• It evaporates with the water.

• It turns into freshwater.

What is the term for the water found in estuaries?

• Brackish water

• Distilled water

• Saltwater

• Freshwater

Why are estuaries important for ecosystems?

• They have no ecological significance.

• They are the main source of ocean salt.

• They trap pollutants and recycle nutrients.

• They are the largest bodies of water.

What type of marine system is likely to form in tropical waters?

• Deep-sea trenches

• Coral reefs

• Polar ice caps

• Rocky intertidal zones

How do coral reefs benefit coastal communities?

• They reduce the amount of sunlight reaching the ocean floor.

• They are the primary source of freshwater.

• They increase ocean salinity.

• They serve as natural barriers against erosion.

What is a characteristic of the continental shelf in temperate climates?

• It is always covered in ice.

• It has high biodiversity like coral reefs.

• It is devoid of life.

• It supports marine food webs.