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Standards
Saving the Kelp Forest supports the following California Science Standards:
Physical Sciences
Energy and matter have multiple forms and can be changed from one form to another. As a basis for understanding this concept, students know machines and living things convert stored energy to motion and heat.
Life Sciences
Adaptations in physical structure or behavior may improve an organism's chance for survival. As a basis for understanding this concept, students know plants and animals have structures that serve different functions in growth, survival and reproduction; living things cause changes in the environment where they live, some of these changes are detrimental to the organism or other organisms, whereas others are beneficial; when environments change, some plants and animals survive and reproduce, and others die or move to new locations.
All organisms need energy and matter to live and grow. As a basis for understanding this concept, students know plants are the primary source of matter and energy entering most food chains; producers and consumers (herbivores, carnivores, omnivores and decomposers) are related in food chains and food webs, and may compete with each other for resources in an ecosystem; decomposers recycle matter from dead plants and animals.
Living organisms depend on one another and on their environment for survival. As a basis for understanding this concept, students know ecosystems can be characterized in terms of their living and nonliving components; for any particular environment, some kinds of plants and animals survive well, some survive less well and some cannot survive at all; many plants depend on animals for pollination and seed dispersal, while animals depend on plants for food and shelter.
Investigation and Experimentation
Asking meaningful questions and conducting careful investigations makes scientific progress. As a basis for understanding this concept students should develop their own questions and perform investigations. Students will collect data in an investigation and analyze them to develop a logical conclusion.
Background Information
Kelp is a type of algae. Unlike land plants they have no roots, stems,
leaves, or flowers. Algae comes in every possible size; usually any
marine algae that is not microscopic is called seaweed.
Seaweed comes in many different colors and is grouped by its color.
The most common are greens, reds and browns, but their scientific
grouping does not always match the color that they appear to be.
The word kelp comes from eighteenth century Scotland. Potash
makers were originally making potash (for fertilizer and black
explosive powder) from woodash. When their supply ran low they
began to use seaweed ashes referred to as kelp. Today kelp refers to a
specific group of brown algae.
Kelp Plant Anatomy
Kelp plants have 3 basic parts. These are the holdouts, stipe and blade.
The holdfast anchors the kelp plant to the bottom of the ocean, which
prevents the plant from being carried away by waves and currents.
The holdfasts attach themselves to rocks or crevices they find in the
bottom. The holdfast does not absorb nutrients or water.
The stipe is like the stem of a plant. Some stipes have gas-filled floats
at the base of each blade to keep the blade at the surface of the water.
Kelp blades are the leaves. They absorb carbon dioxide, water,
nutrients and sunlight. Through photosynthesis the blades convert
these into usable materials for the plant's growth.
Stipes, floats and blades of the kelp grow to the surface of the water
and then spread as they continue to grow. This area on the surface is
known as a canopy or raft.
Kelp Environment
Kelp needs several environmental factors working in its favor to
survive and prosper. The most important, of course, is an attachment
site. Without a secure attachment, water motion will rip the kelp from
its base. Since many kelp plants are tangled together, dislodging one
often results in the displacement of many, many others.
Water temperature is very important to a kelp plant's survival. Waters
less than 68 degrees F appear to be optimal for kelp survival. When
waters warm to about 74 degrees F the reproduction cycle is disrupted,
growth rates decrease and plant tissues die. Water clarity is also an
issue since the plant needs access to sunlight through the water.
Upwelling of nutrients is also important. Upwelling occurs when
deep, cold, nutrient-rich water comes to the surface to replace surface
waters. This is most often accomplished by wind movement.
The Kelp Forest
Hundreds of organisms make their home in the layers of the kelp
forest. Some of the more common inhabitants at the bottom level
would be sea urchins, brittle stars, polychaete worms, nudibranches,
garibaldi and California sheephead. Animals commonly found in the
midwater or canopy level are kelp crabs, senorita fish, marine
mammals such as sea lions, harbor seals and sea otters. Gray whales
will often swim into the forests to feed or rest.
Human Uses of Seaweed
Millions of tons of seaweed are consumed worldwide. These
seaweeds find themselves used for food, fertilizer, medicine or in
industry. While most are eaten directly, much is processed for use in
other products. We are most familiar with algin, agar and carrageenan.
Agar is a gelling agent used for growing bacteria in research and
medicine. It is also used as a thickening agent in ice cream.
Carrageenan is a thickener used in dairy products and canned soups.
Algin is probably the most important product and is used to make
water-based foods thicker and creamier. It also improves the texture of
baked goods. Kelp harvesting is a major industry in California that
takes in about $35 million per year.
Please let me know how you and your students use this lesson.
I would be interested in your comments and suggestions.
E-mail to: Dana Weld
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