Aquatic environments are shaped by physical and chemical conditions that differ from those on land. This lesson introduces the major abiotic factors that influence aquatic life and the zones used to describe ocean habitats.
Abiotic factors are nonliving parts of an environment, such as light, temperature, oxygen, and water movement. Water absorbs light even when it is clear, so sunlight decreases with depth. Below a certain depth, too little light remains for photosynthesis.
All flashcards
What is an abiotic factor?
A nonliving component of an environment, such as light, temperature, oxygen, or water movement, that can affect organisms.
What is aquatic stratification?
The layering of water with different densities, often because surface and deep waters have different temperatures.
What is the pelagic realm?
The open-water region of the ocean.
What is the benthic realm?
The region along the ocean bottom, from the shoreline to the deepest parts of the seafloor.
How do the photic and aphotic zones differ?
The photic zone receives enough light for photosynthesis; the aphotic zone is too deep for sunlight to support photosynthesis.
Quiz questions
Why does sunlight become unavailable for photosynthesis at sufficient depth?Answer: Water absorbs light, so light intensity decreases as depth increases.
What is stratification in a lake?Answer: The formation of water layers with different densities, often associated with different temperatures.
Which term describes all of the ocean’s open water?Answer: The pelagic realm.
A habitat on the ocean floor several kilometers deep belongs to which realm?Answer: The benthic realm.
How can organisms support food webs at hydrothermal vents without sunlight?Answer: They use chemical energy from vent compounds to produce biomass.
Based on Biology 2e by Mary Ann Clark, Matthew Douglas, Jung Choi (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.