The video explores aquatic biomes, which are the largest part of the biosphere, covering 75% of Earth's surface. It distinguishes between freshwater and marine biomes based on salinity and other factors. Freshwater biomes include lakes, rivers, and wetlands, each with unique characteristics and vulnerabilities. Marine biomes, such as estuaries and intertidal zones, are rich in biodiversity but face threats from human activities. The open ocean, the largest biome, plays a crucial role in global photosynthesis but is impacted by pollution and overfishing.

What percentage of the Earth's surface is covered by the ocean, a major aquatic biome?

• 85%

• 75%

• 60%

• 50%

Which of the following is a characteristic of freshwater biomes?

• Low salt concentration

• High temperature

• High salt concentration

• Presence of coral reefs

What is eutrophication in lakes primarily caused by?

• Increased oxygen levels

• Urban and agricultural runoff

• Decreased nutrient levels

• High salinity

Which type of biome is known for its ability to filter pollution and improve water quality?

• Lakes

• Oceans

• Wetlands

• Rivers

What is a defining feature of estuaries?

• Presence of coral reefs

• High salinity

• Mixing of fresh and salt water

• Low productivity

Which organisms are commonly found in estuaries due to their ability to tolerate varying salinities?

• Coral and sea anemones

• Sea turtles and dolphins

• Mangrove trees and blue crabs

• Plankton and algae

What environmental condition is characteristic of intertidal zones?

• High salinity

• Constant submersion

• Low nutrient levels

• Cyclic exposure to air and water

Which organisms are primary producers in intertidal zones?

• Coral

• Algae and seagrass

• Sea turtles

• Fish

What is a significant contribution of the open ocean to the Earth's ecosystem?

• Providing habitat for land animals

• Supporting only small fish species

• Being a source of freshwater

• Completing half of global photosynthesis

What major issue is affecting fish populations in the open ocean?

• Increased oxygen levels

• Lack of sunlight

• Overfishing and pollution

• Decreased salinity