Chapter 4 (Limiting Factors and Trophic Levels/Food Webs)

Limiting factor

Something in the ocean (like light, nutrients, or oxygen) that limits how much plants and animals can grow.

Photosynthesis

When plants, algae, and phytoplankton use sunlight, water, and carbon dioxide to make food and oxygen.

Upwelling

When deep, cold water full of nutrients rises to the surface, helping plants and animals grow.

Eutrophication

Too many nutrients (from things like fertilizer runoff) cause lots of phytoplankton to grow, which can use up oxygen, when later they are being decomposed by bacteria, and harm sea life.

Nitrogen Fixation

Special bacteria (nitrogen fixing) change nitrogen from the air into a form plants and algae can use.

Stratification

When ocean water forms layers that don’t mix well, keeping nutrients trapped below (really hot layer on top/really cold layer below)

Thermocline

A layer in the ocean where the temperature changes quickly with depth.

Trophic Level

A step or position in a food chain or food web that shows how organisms get their energy

Producers

Plants, algae, and phytoplankton that make their own food and start the food chain.

Primary consumers

Organisms (like zooplankton or small fish) that eat producers.

Secondary consumers

Organisms that eat primary consumers.

Tertiary consumers

Organisms that eat secondary consumers.

Quaternary consumers

Organisms that eat tertiary consumers.

Herbivores

Organisms that only eat plants or other photosynthetic organisms/producer.

Carnivores

Organisms that eat other consumers.

Keystone Species

A very important species that keeps the whole ecosystem balanced.