3 Seaweeds NOT PLANTS! (or weeds) More accurately, Eukaryotic Multicellular algaePrimary producersNo roots, stems, leavesDifference reproductive mechanisms than plantsMore accurately,MACROPHYTES orMACROALGAE
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 surfaceStipe – stem-like structure used for support; not used for transport of water or nutrientsHoldfast – attaches the thallus to the bottom (not used in transport)Thallus – entire body
6 Types of Seaweeds Classified based upon their pigments Revealed upon chemical analysisGreen (phylum Chlorophyta)Brown (phylum Heterokontophyta; Class Phaeophyta)Red (phylum Rhodophyta)
7 Green Algae - Chlorophyta Only 10% of species (around 700) are marineMost marine species are unicelluarMore dominant in estuarine and tide pool areasTolerate salinity variationLand plants believed to have evolved from themExamples:EnteromorphaUlvaCaulerpaCodiumHalimeda
8 Enteromorpha Filamentous Thallus is tube shaped. Common in bays, estuaries, exposed coastlines.Re-colonizers that can tolerate polluted areasPhoto: Enteromorpha prolifera – Elkhorm Slough, CA by Judith ConnorPhoto: Enteromorpha intertinalis -- Stillwater Cove, Pebble Beach CA
10 Caulerpa Composed of multiple think tubes (siphons) Multinucleated Proliferative, especially in marine aquariumsTropical/subtropicalCaulerpa sp.Caulerpa racemosa
11 Codium“Multinucleated filaments woven into a spongy, branching thallus”Eaten by sea slugsChloroplasts 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 marineCan dominate temperate and polar rocky coastsVary in complexity (few celled to kelps)Color varies: olive green to dark brownDue to presence of yellow-brown pigment, fucoxanthinExamples:EctocarpusDictyotaFucusSargassumLaminariaNereocystisMacrocystis
14 Ectocarpus branching, filamentous May exist attached to substrate or free-floatingwidespread
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 exposureStrong disk-shaped holdfasts to endure intertidal zone
17 Sargassum Have many gas-filled bladders Can grow on rocks or in huge floating massesCommon in the Gulf of Mexico & Sargasso SeaImportant 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) pneumatocystGrow up to 100m (up to 20 cm/day)Form dense forests or ‘kelp beds’Among most productive marine ecosystemsAre harvested for several natural products
21 Red Algae - RhodophytaMost numerous (~4,000 species) in marine environmentContain a red pigment (phycobilins)Harvested for food and other natural productsMost are filamentousSome are heterotrophic and parasitic on other algaeExamples:CeramiumChondrusNemalionPorphyraCorallina
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 PorphyraCommon on rocky shoresPolar to tropical distribution
26 Corallina Coralline algae Deposit calcium carbonate within their cell wallsCan be an important reef building species in tropical watersCan grow branching or encrusting
27 Life HistoryRefers to the series of growth, metamorphoses, and reproductive stages in an organism’s generation.A little review:Sexual vs. asexual reproductionDiploid vs. haploidGametesMitosis vs. MeiosisWhat’s a spore?
28 Algal GenerationsSporophyte – diploid (2n) , spore producing generationGametophyte – haploid (n), gamete producing generationAlternation of generations – life histories in which two generations, a sporophyte and a gametophyte, existCan take four basic patterns
31 Economic Importance of Seaweeds Harvested for food (mariculture)Produce phycocolloidsused in food processing & manufacturing as thickeners or gels
32 Algin produced from giant kelp (Macrocystis) and bull kelp (Laminaria) Stabilizer and emulsifier in dairy productsPrevents drying of frostings and toppingsPharmaceuticalsShampooPlasticsPesticidesUsed in textiles as a thickener for printing pasteSPHERICAL 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 thisCalcic 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 puddingsToothpastes and other beauty productsUsed in vaccines against HPV and other sexually transmitted LinkIngredients: skim milk, partially hydrogenated soybean oil, disodium phosphate, carrageenan, Vitamin A Palmitate, and Vitamin D3
34 AgarExtracted from several red algae including (Gelidium, Gelidiella, and Pterocladiella)Uses:protect meats during canninglow-calorie (diet) foodsthickenerlaxatives, cosmetics, and pharmaceuticalsas a medium for bacteria and mold growthSugar 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 foodReproduce sexually with the production of spores in flowersThree types of marine plants;Seagrasses – completely submerged in seawaterSalt-marsh plants – roots only covered at high tideMangroves – trees and shrubs that live along shores, roots adapted to salt
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 seawaterInhabit soft-bottom, coastal areas partially submerged by sea water at high tide – leaves are always partially exposed to airSalt 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 oxygenLeaves are thick to reduce water lossSeeds germinate while on parent tree and begin to grow before falling to soft sediment
43 SeaGrassesTruly marine and spend their lives entirely submerged by waterNot grass; more closely related to the lily familyHorizontal stems call rhizomes that grow under sediment; roots and shoots grow from stemSmall flowers (no need to attract pollinators)Examples:Eelgrass – widely distributed in temperate and tropical water; inhabits shallow, well protected coastal watersSurf grass – inhabit rocky coasts exposed to heavy wave action
44 Do we have Seagrass Beds in the Chesapeake Bay?
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