Presentation on theme: "C HAPTER 6 Multicellular Primary Producers: Seaweeds and Plants."— Presentation transcript:
C HAPTER 6 Multicellular Primary Producers: Seaweeds and Plants
S EAWEEDS NOT PLANTS! (or weeds) Eukaryotic Multicellular algae Primary producers No roots, stems, leaves Difference reproductive mechanisms than plants More accurately, MACROPHYTES or MACROALGAE
S EAWEED S TRUCTURE Thallus – the entire body Blades – flattened, leaf-like portion; large area for photosynthesis (NOT leaves) Pneumatocysts (floats) – gas- filled bladders (usually carbon monoxide) that keep blades close to surface Stipe – stem-like structure used for support; not used for transport of water or nutrients Holdfast – attaches the thallus to the bottom (not used in transport) Thallus – entire body
T YPES OF S EAWEEDS
Classified based upon their pigments Revealed upon chemical analysis Green (phylum Chlorophyta) Brown (phylum Heterokontophyta; Class Phaeophyta) Red (phylum Rhodophyta)
G REEN A LGAE - C HLOROPHYTA Only 10% of species (around 700) are marine Most marine species are unicelluar More dominant in estuarine and tide pool areas Tolerate salinity variation Land plants believed to have evolved from them Examples: Enteromorpha Ulva Caulerpa Codium Halimeda
E NTEROMORPHA Filamentous Thallus is tube shaped. Common in bays, estuaries, exposed coastlines. Re-colonizers that can tolerate polluted areas Photo: Enteromorpha prolifera – Elkhorm Slough, CA by Judith Connor Photo: Enteromorpha intertinalis -- Stillwater Cove, Pebble Beach CA
C AULERPA Composed of multiple think tubes (siphons) Multinucleated Proliferative, especially in marine aquariums Tropical/subtropical Caulerpa sp.Caulerpa racemosa
C ODIUM “Multinucleated filaments woven into a spongy, branching thallus” Eaten by sea slugs Chloroplasts of the algae can remain alive inside these animals
H ALIMEDA Calcareous green alga Play an important role in the build up of tropical reefs.
B ROWN A LGAE - P HAEOPHYTA Almost all 1,500 species are marine Can dominate temperate and polar rocky coasts Vary in complexity (few celled to kelps) Color varies: olive green to dark brown Due to presence of yellow-brown pigment, fucoxanthin Examples: Ectocarpus Dictyota Fucus Sargassum Laminaria Nereocystis Macrocystis
E CTOCARPUS branching, filamentous May exist attached to substrate or free-floating widespread
D ICTYOTA Fan-shaped Lightly calcified Now widespread, but originally from Northeast North America and Mediterranean.
F UCUS Known as a ‘rockweed’ or ‘wracks’ along coastlines Have gas-filled floats (pneumatocysts) Leathery thalli often covered with mucus to withstand prolonged air exposure Strong disk-shaped holdfasts to endure intertidal zone
S ARGASSUM Have many gas-filled bladders Can grow on rocks or in huge floating masses Common in the Gulf of Mexico & Sargasso Sea Important for nursery and transport communities
L AMINARIA Sea palms, feather boa kelps, etc. Up to 3m in length Single or small group of large blades attached to a single stipe. Important food source
N EREOCYSTIS Bull kelps Whip-like stipe that is up to 30m long Large spherical pneumatocyst at one end
M ACROCYSTIS Giant kelps Enormous holdfasts that anchor multiple stipes Elongate blades branch from stipes, each with a gas-filled (CO) pneumatocyst Grow up to 100m (up to 20 cm/day) Form dense forests or ‘kelp beds’ Among most productive marine ecosystems Are harvested for several natural products
R ED A LGAE - R HODOPHYTA Most numerous (~4,000 species) in marine environment Contain a red pigment ( phycobilins ) Harvested for food and other natural products Most are filamentous Some are heterotrophic and parasitic on other algae Examples: Ceramium Chondrus Nemalion Porphyra Corallina
C ERAMIUM Small, filamentous algae Epiphytic Produce chemicals that make them distasteful
C HONDRUS Irish moss Ranges across the North Atlantic Shape varies with changes in temperature, salinity, and light availability
N EMALION Grows as a branched ‘worm’ on rocks in the intertidal zone. Softly cartilaginous
P ORPHYRA Common on rocky shores Polar to tropical distribution
C ORALLINA Coralline algae Deposit calcium carbonate within their cell walls Can be an important reef building species in tropical waters Can grow branching or encrusting
L IFE H ISTORY Refers to the series of growth, metamorphoses, and reproductive stages in an organism’s generation. A little review: Sexual vs. asexual reproduction Diploid vs. haploid Gametes Mitosis vs. Meiosis What’s a spore?
A LGAL G ENERATIONS Sporophyte – diploid ( 2n ), spore producing generation Gametophyte – haploid ( n ), gamete producing generation Alternation of generations – life histories in which two generations, a sporophyte and a gametophyte, exist Can take four basic patterns
L IFE HISTORIES OF VARIOUS SEAWEEDS
H ALIMEDA L IFE H ISTORY
Economic Importance of Seaweeds Harvested for food (mariculture) Produce phycocolloids used in food processing & manufacturing as thickeners or gels
Algin produced from giant kelp ( Macrocystis ) and bull kelp ( Laminaria ) Stabilizer and emulsifier in dairy products Prevents drying of frostings and toppings Pharmaceuticals Shampoo Plastics Pesticides Used in textiles as a thickener for printing paste SPHERICAL MANGO RAVIOLI Blend the Citras with 250g of water, add the Algin and blend once more. Bring to a boil, allow to cool and mix with the mango puree. Blend 1000g of water with Calcic. Pour the contents of a dosing spoon full of the mango and Algin mixture into this Calcic bath, leave for 2 minutes and wash in cold water. Repeat until all of the ravioli are made.
Carageenan Produced from red algae such as Chondrus Used as an emulsifier especially in dairy products, soy milk, processed foods, and puddings Toothpastes and other beauty products Used in vaccines against HPV and other sexually transmitted LinkLink Ingredients: skim milk, partially hydrogenated soybean oil, disodium phosphate, carrageenan, Vitamin A Palmitate, and Vitamin D3
Agar Extracted from several red algae including ( Gelidium, Gelidiella, and Pterocladiella ) Uses: protect meats during canning low-calorie (diet) foods thickener laxatives, cosmetics, and pharmaceuticals as a medium for bacteria and mold growth Sugar Coated Pills: Each sugar coated pill contains: sennosides USP 15 mg. Nonmedicinal ingredients: acacia, alginic acid, calcium phosphate, carnauba wax, cellulose, iron oxide, magnesium stearate, sodium benzoate, sodium lauryl sulfate, starch, stearic acid, sucrose, talc and titanium dioxide. Blister packs, boxes of 10, 30 and 60.
F LOWERING P LANTS Have true leaves, stems, and roots Structures to transport water, nutrients, and food Reproduce sexually with the production of spores in flowers Three types of marine plants; Seagrasses – completely submerged in seawater Salt-marsh plants – roots only covered at high tide Mangroves – trees and shrubs that live along shores, roots adapted to salt
S ALT M ARSHES, M ANGROVES AND S EAGRASSES ….O H M Y !
M ARSH M ETAPHORS
S ALT -M ARSH G RASSES Cordgrasses are true members of the grass family Not marine species; land plants tolerant of salt – cannot tolerate complete submergence in seawater Inhabit soft-bottom, coastal areas partially submerged by sea water at high tide – leaves are always partially exposed to air Salt glands in their leaves excrete excess salt
M ANGROVES Trees and shrubs adapted to live along tropical shores Salty environment means water loss from leaves is high and soil sediment is poor in oxygen Leaves are thick to reduce water loss Seeds germinate while on parent tree and begin to grow before falling to soft sediment
S EA G RASSES o Truly marine and spend their lives entirely submerged by water o Not grass; more closely related to the lily family o Horizontal stems call rhizomes that grow under sediment; roots and shoots grow from stem o Small flowers (no need to attract pollinators) o Examples: o Eelgrass – widely distributed in temperate and tropical water; inhabits shallow, well protected coastal waters o Surf grass – inhabit rocky coasts exposed to heavy wave action
D O WE HAVE S EAGRASS B EDS IN THE C HESAPEAKE B AY ?