Lesson #6: Marine Algae, the Primary Producers of the Oceans
Most animal life in the ocean is dependent on marine algae. These "primary producers" are the first link in almost all oceanic food webs. Like land plants, algae also contain the green pigment chlorophyll which enables them to use the sun's energy to manufacture starches and sugars. Algae also produce oxygen and provide habitats for other plants and animals.
Seaweed has a simpler structure than land plants. They have no true roots, stems, leaves or flowers. The whole body of the seaweed is called the thallus. The erect, stem-like portion of the thallus is called the stipe and the leafy parts are called the blades. The part of the seaweed that looks like roots and attaches it to a surface is called the holdfast. The holdfast differs from roots in that it is not specifically adapted to absorb nutrients. Rather, seaweed takes nourishment directly from the sea water through all exposed surfaces.
- Diversity of Species
- Types of Marine Algae
diversity of species
Marine algae come in many different sizes, shapes and colors. A thousand of the smallest algae can fit on the dot of an i, while the largest is longer than the tallest redwood.
California's offshore water has one of the richest and most diverse selections of marine algae in the world, with more than 280 genera and 660 species identified to date. This richness of marine flora results from a combination of oceanographic and climatic conditions. During March to September the upwelling of cold, nutrient-rich water nourishes the algae. In the summer, the daytime fog protects the algae from drying out during low tides. Together, these phenomena greatly increase productivity.
types of marine algae
Phytoplankton are microscopic algae that float freely in the ocean. 
There are at least 6,000 known species of phytoplankton and they account for most of the ocean's vegetation. Two of the more common phytoplankton are diatoms and dinoflagelates.
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