Lesson 1
What percentage of Earth's surface is covered by the ocean?
71%
What causes most ocean waves?
Wind blowing across the water's surface
What is plankton?
Organisms that are weak swimmers or cannot swim and drift in water
What are the two main types of Earth's crust beneath the ocean and continents?
Continental crust (under continents) and oceanic crust (under the ocean)
What tool do scientists use to map the ocean floor?
Sound waves (echolocation)
What are the two main types of ocean currents?
Surface currents (driven by wind) and density currents (caused by differences in water temperature and salinity)
Name one factor that causes salinity variation in the ocean.
Freshwater inflows or temperature
What part of the wave is the highest point?
The crest
Describe the characteristics of the abyssal plain.
It is a flat, deep part of the ocean floor covered with thick layers of mud and tiny sea
Explain the difference between spring tides and neap tides.
Spring tides occur when the Sun and Moon’s gravitational forces align, creating higher-than-normal tides, while neap tides occur when these forces counteract each other, leading to lower-than-normal tides
How do coral polyps contribute to coral reefs?
Coral polyps build limestone structures, providing shelter for various species while maintaining a symbiotic relationship with algae
How do coastal wetlands benefit marine ecosystems?
They act as natural filters, absorbing excess nutrients and pollutants, and help protect against coastal erosion
What are mid-ocean ridges, and how are they formed?
Mid-ocean ridges are underwater mountain ranges formed where tectonic plates pull apart
What are tsunamis, and how are they formed?
Tsunamis are giant waves triggered by underwater earthquakes, landslides, or volcanic eruptions
What is the role of estuaries in marine ecosystems?
Estuaries provide habitats with a mix of fresh and saltwater, supporting diverse species and acting as spawning and feeding grounds
What is the difference between an underwater mountain and a volcanic island?
An underwater mountain (seamount) does not reach the surface, while a volcanic island forms when a volcano rises above the ocean's surface
How do animals in the Midnight Zone adapt to survive?
They make their own light (bioluminescence) and withstand extreme pressure and cold
How does salinity influence ocean currents?
Higher salinity increases water density, contributing to the formation of density currents
How do hydrothermal vents support life in the deep ocean?
They provide chemical energy from gases and minerals, which deep-sea organisms rely on instead of sunlight
What adaptations allow organisms in deep-ocean ecosystems to survive extreme pressure and darkness?
They rely on chemical energy from hydrothermal vents and have evolved features like bioluminescence and slower metabolisms