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Multicellular Primary Producers: Seaweeds and Plants

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1 Multicellular Primary Producers: Seaweeds and Plants
Chapter 6 Multicellular Primary Producers: Seaweeds and Plants

2 BBC films

3 Seaweeds NOT PLANTS! (or weeds) More accurately, Eukaryotic
Multicellular algae Primary producers No roots, stems, leaves Difference reproductive mechanisms than plants More accurately, MACROPHYTES or MACROALGAE

4 Seaweed Structure 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

5 Types of Seaweeds

6 Types of Seaweeds Classified based upon their pigments
Revealed upon chemical analysis Green (phylum Chlorophyta) Brown (phylum Heterokontophyta; Class Phaeophyta) Red (phylum Rhodophyta)

7 Green Algae - Chlorophyta
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

8 Enteromorpha 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

9 Ulva Sea lettuce Not a distinct genera from Enteromorpha
Forms sheets but only in the presence of bacteria or other algal species Widespread, first-colonizers on new substrate © 2006 Jan Holmes

10 Caulerpa Composed of multiple think tubes (siphons) Multinucleated
Proliferative, especially in marine aquariums Tropical/subtropical Caulerpa sp. Caulerpa racemosa

11 Codium “Multinucleated filaments woven into a spongy, branching thallus” Eaten by sea slugs Chloroplasts of the algae can remain alive inside these animals

12 Halimeda Calcareous green alga
Play an important role in the build up of tropical reefs.

13 Brown Algae - Phaeophyta
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

14 Ectocarpus branching, filamentous
May exist attached to substrate or free-floating widespread

15 Dictyota Fan-shaped Lightly calcified
Now widespread, but originally from Northeast North America and Mediterranean.

16 Fucus 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

17 Sargassum 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

18 Laminaria 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

19 Nereocystis Bull kelps Whip-like stipe that is up to 30m long
Large spherical pneumatocyst at one end

20 Macrocystis 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

21 Red Algae - Rhodophyta 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

22 Ceramium Small, filamentous algae Epiphytic
Produce chemicals that make them distasteful

23 Chondrus Irish moss Ranges across the North Atlantic
Shape varies with changes in temperature, salinity, and light availability

24 Nemalion Grows as a branched ‘worm’ on rocks in the intertidal zone.
Softly cartilaginous

25 Porphyra Common on rocky shores Polar to tropical distribution

26 Corallina Coralline algae
Deposit calcium carbonate within their cell walls Can be an important reef building species in tropical waters Can grow branching or encrusting

27 Life History 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?

28 Algal Generations 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

29 Life histories of various seaweeds

30 Halimeda Life History

31 Economic Importance of Seaweeds
Harvested for food (mariculture) Produce phycocolloids used in food processing & manufacturing as thickeners or gels

32 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.

33 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 Link Ingredients: skim milk, partially hydrogenated soybean oil, disodium phosphate, carrageenan, Vitamin A Palmitate, and Vitamin D3

34 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.

35 Flowering Plants 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

36 Salt Marshes, Mangroves and Seagrasses….Oh My!

37 Marsh Metaphors

38 Salt-Marsh Grasses 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



41 Mangroves 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


43 SeaGrasses Truly marine and spend their lives entirely submerged by water Not grass; more closely related to the lily family Horizontal stems call rhizomes that grow under sediment; roots and shoots grow from stem Small flowers (no need to attract pollinators) Examples: Eelgrass – widely distributed in temperate and tropical water; inhabits shallow, well protected coastal waters Surf grass – inhabit rocky coasts exposed to heavy wave action

44 Do we have Seagrass Beds in the Chesapeake Bay?


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