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Primary Producers. Plankton and Plants. Autotrophs: The Producers . Primary producers are organisms that make their own food by photosynthesis or chemosynthesis. Phytoplankton are small, drifting, plantlike organisms which are responsible for most of the ocean’s primary productivity.
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Primary Producers Plankton and Plants
Autotrophs: The Producers • Primary producers are organisms that make their own food by photosynthesis or chemosynthesis. • Phytoplankton are small, drifting, plantlike organisms which are responsible for most of the ocean’s primary productivity. • The most important physical and biological factors that influence primary productivity are light and inorganic nutrients.
Autotrophs: The Producers • Most of marine autotrophs are large or small algae. • Algae is a collective term for autotrophs possessing chlorophyll and capable of photosynthesis, but lacking vessels to conduct sap.
Types of Phytoplankton:Single-celled Algae (Kingdom Protista) • Dinoflagellates • Most are single-celled autotrophs with two whiplike projections called flagella. One flagellum drives the organism forward, while the other causes it to rotate in the water. Their flagella allow them to adjust their orientation and vertical position to make the best photosynthetic use of available light. • Some dinoflagellates are bioluminescent. • These are an old and successful group of organisms that have lived in the oceans for more than a billion years.
Dinoflagellates, continued • They are also responsible for red tides. Red tides occur when water runoff from land, coastal upwelling, or warm weather stimulates the growth and reproduction of dinoflagellates.
Types of Phytoplankton:Single-celled Algae (Kingdom Protista) • Diatoms • The Earth’s most abundant, successful, and efficient single-celled phytoplankton. • Diatoms possess two interlocking valves made primarily of silica. The valves contribute to biogenous sediment.
Types of Phytoplankton:Single-celled Algae (Kingdom Protista) • Coccolithophores • Very small planktonic alga carrying disks of calcium carbonate, which contribute to biogenous sediment. • The famous White Cliffs of Dover in England are large deposits of fossilized coccolithophores uplifted by geologic forces
Larger Marine Plants:Multicellular Algae (Kingdom Protista) • The Seaweeds • Algae are protists. There are three main types.
The Seaweeds The Chlorophytes- Green Algae These live near the surface of the water. It is thought that land plants have evolved from chlorophyte ancestors.
The Seaweeds The Phaeophytes- Brown Algae These are the largest of all algae and include the kelps.
The Seaweeds The Rhodophytes- Red Algae Most of the world’s seaweeds are red algae.
Brown Algae: Kelp Air Bladder
Parts of the Kelp • Blade- The structures in kelp that resemble leaves. • Stipe- The stem like structures of kelp. • Holdfast- The root shaped jumble at the kelp’s base that holds it to a substrate. • Air Bladder- The gas filled structures that keep the kelp buoyant, so that the blades can photosynthesize. • Thallus- The blades, stipes, and holdfast that comprise the body of the kelp.