Kelp Forests I. Factors Affecting Kelp Forests A. vanaqua.org Intensity and frequency of winter storms Presence/Absence of urchin predators (sea otters/lobsters) Abundance and behavior of herbivores Winter storms can rip kelps from their holdfasts After severe storms, portions of sea floor may be stripped of kelp 1. 2. 3. • • • • Urchins deprived of preferred foods (mature kelp or drift algae) may increase mobility and eat newly recruited kelps Grazing may prevent kelps from re-growing • Leads to establishment of more resistant coralline algae • Leads to urchin barrens
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Kelp forests Kelp forests are found on rocky bottoms and provide habitat for many organisms Gant brown bladder kelp Macrocystis has a strong holdfast and gas-filled floats Macrocystis can grow up to 0.6 meter (2 feet) per day Figure 15-15a
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Kelp Forests I. Kelp Forest Ecology B. Sea otters/Lobsters important top-down regulators of community structure • • • • Prey on important grazers like urchins (Pac/Atl) and abalones (Pac) Urchins, abalones, other herbivores graze on attached seaweeds, drift kelp Urchin populations can have a major impact on community composition Fig. 16-11
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Multicellular Protists (algae) • More photoautotrophic protistans… known as: – Algae, seaweed, kelp – Thalli may be filamentous, grow in mats or crusts, sheets, or kelp • “ Plant-like” primary producers, but not plants: – Lack true leaves, stems & roots • Organized by pigment variations – Phaeophyta (browns) – Rhodophyta (reds) – Chlorophyta (greens)
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Figure 36.5b-0 Proportional mortality Kelp perch 1.0 0.8 0.6 0.4 0.2 0 0 10 20 30 40 50 Kelp perch density (number/plot) 60 Data from T. W. Anderson, Predator Responses, Prey Refuges, and Density-Dependent Mortality of a Marine Fish, Ecology 82: 245–257 (2001). © 2015 Pearson Education, Inc.
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Kelp Forests I. Dominated by brown algae Found in shallow open coastal settings where water temperature usually <20 oC Bottom depth typically <20 m • • • • Light readily available Highly productive, diverse ecosystems • • Productivity related to fast kelp growth rates
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Ecology – ecosystem diversity near shore systems – kelp forests
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 Brown algae (kelp)  Multicellular  Store carbohydrates  Harvested for algin-food thickener found in ice cream and cake decorations. Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 12.11b
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To Maintain Good Health a Diet many Recommend is: ~ 60% Alkaline Forming Foods ~ 40% Acid Forming Foods Strongly Acidic pH 4.0 Mildly Acidic pH 4.5 to 6.5 Neutral pH 7.0 Mildly Alkaline pH 7.5 to 9.5 Strongly Alkaline pH 10.0 White Bread, Processed Cheese Alcohol, Beers Sodas, Tea, Coffee Sugar, French Fries Peanuts, Walnuts Meat and Fish, Canned Fruits De-ionized Water Many Fruits, Coconut Legumes Most Nuts Egg Yolks Raw Milk Brown Rice Basmati Rice Artificial Sweeteners Dairy, Cocoa Raw Cream, Whey Most Vegetables Asparagus, Garlic Almonds Cayenne Pepper Cucumber Avocados Raw Spinach Kale Quinoa, Kelp, Celery, Buckwheat Broccoli Falx Seed Raw Swiss Chard Olive oil Cooked Spinach Raw Honey Melon, Raisins, Vegetable Juices
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Phaeophyta • Brown/yellow pigment – Fucoxanthin, some phycobilin, some carotenoids (& chl) • Diverse morphologies – Simple, small individual to large & complex (i.e. lengths up to 100m) • kelp forest communities • Some exhibit rapid growth – 1 to 2 feet a day – Important source of algin • Thickener, stabilizer, emulsifier in many products
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Seaweeds And Land Plants Are Diverse and Effective Primary Producers (a) The thallus (body) of a typical multi-cellular alga. These organisms can grow at a rate of 50 centimeters (20 inches) per day and reach a length of 40 meters (132 feet). (b) Macrocystis. This fastgrowing, alga is one of the common kelp forest species of western North America.
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Seaweeds And Land Plants Are Diverse and Effective Primary Producers Distribution of kelp beds and mangrove communities worldwide.
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Shallow offshore ocean floor Extends from the spring low-tide shoreline to the edge of the continental shelf Mostly sediment-covered but contains rocky exposures Includes: Kelp forests Coral reefs
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Keystone Predator (or Keystone Consumer –) • Species essential to maintenance of ecosystem structure/diversity • Example (there are many): CA sea otter – kelp forest community
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39. Kelp Harvest
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I. Kelp Forests Atlantic Pacific Grazers Urchins Urchins, Abalones, Limpets Suspension Feeders Mussels Mussels Predators Maine Lobsters Sea Otters
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 DIVISIONS OF ALGAE  Green algae: May be unicellular or multicellular.  Have cellulose cell walls, contain chlorophyll a and b, and store starch like plants. Most are microscopic. Live close to water surface. Believed to be the ancestors of terrestrial plants.  Brown Algae or Kelp: Macroscopic (up to 50 m long). Most are found in coastal waters, at intermediate depths. Rapid growth. Can be harvested regularly.  Red Algae: Live at greater ocean depths than other algae. Red pigments allow them to absorb blue light that penetrates deepest into ocean. Agar is extracted from many red algae. Some produce lethal toxins.
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Global Kelp Distribution
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Kelp Life Cycle
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Kelp Communities
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