Algae in the Ocean

Ocean algae are among the most important organisms on Earth for human existence, providing up to 80 percent of the world's oxygen. Ocean algae are also at the beginning of the food chain for many sea and land animals, making it one of the most life-sustaining organisms. Like plants, algae use photosynthesis to turn energy from the sun into nourishment for growth. Algal blooms are dramatically important events for many organisms inhabiting the Earth.

Life Cycle

• Algae live approximately 300 feet under the ocean's surface. At this depth, ocean algae have access to the things essential for life and growth: warmth, sunlight and nutrients. Algae receive sunlight and oxygen throughout life, then fall to the bottom of the ocean and decay after death. As algae decay on the bottom of the ocean, the compounds from which the algae is made are released. When the ocean experiences an upwelling, the nutrients at the bottom are brought back to the top. This can trigger an algal bloom.

Photosynthesis

• Like plants, ocean algae capture and use energy from sunlight. Algae have organelles called chloroplasts that are inside eukaryotic cells. Pigments called chlorophylls and carotenoids capture the sunlight, then store the energy in thylakoids. The two stages of algal photosynthesis are the light reaction and the dark reaction. During the light reaction, the energy captured from the sun splits water molecules. Electrons are released from this reaction and stored. Oxygen is also produced as a product of the light reaction. During a dark reaction, algae turn carbon dioxide into sugar. In short, algae have the ability to turn carbon dioxide into oxygen. Humans benefit directly from this process although algae live up to 300 feet deep in ocean water.

Types

• Algae are often thought of as green sea plants, but there are three types: green, red and brown. Brown algae is the most abundant with more than 5,000 species. Red algae has more than 2,000 species and green algae has only about 800 ocean species. The hundreds of species of algae differ in shape, life cycle and ability. For example, Dinoflagellate algae have two flagella of unequal lengths that help them move through the water. Coccolithophores produce dimethyl sulfide, a gas that moves between the ocean and land through algae, clouds and precipitation.

Benefits

• Everything in nature lives within a delicately balanced system of life and death. Algae are primary producers, meaning that many other organisms and animals depend on algae to receive nutrients that those organisms cannot synthesize for use themselves. The more ocean algae in a certain area, the more carbon dioxide is turned into breathable oxygen. Organisms that consume algae for organic energy can eat both living and dead algae to receive the same benefits. Fish, krill, penguins, seals and even whales would be negatively affected if the algae population diminished.