Marine Algae

By: Mike Dedio, Christian Bailey, Alex Zimm, Arianna Dean

Algae Basics

• Algae are Eukaryotic meaning that their cells have a nucleus-classified under the kingdom of protista

• They are autotrophs, producing their own food from photosynthesis

• Algae and marine plants produce upwards of 70% of the oxygen for terrestrial life

Algae Basics Continued…

• Many algae species form symbiotic relationships with other species supplying organic substances and receiving protection

• Used as fertilizer, engergy source, food source, for pigments, pollution control, and medicinal purposes

Seaweeds

• Seaweeds are multicellular algae that live in the sunlit waters of the ocean.

• Ulva- A common tissue thin seaweed that contains chloroplasts.

• Some marine animals eat alga for the nutrients it provides while others filter the nutrients from the water such as barnacles

Seaweeds

Reproductive Cycle of Algae

• Thallus- The leafy part of seaweed.

• Ulva use asexual reproduction.

• Specialized cells at the end of the Thallus produce spores called sporophyte thallus which is diploids.

• Spore- A repoductive cell that contains the organisms number of chromosomes.

Reproductive Cycle of Algae continued.

• Spores have flagella that move back and forth, the spores will at some point reach the ocean floor.

• They land on a suitable substrate each develop into a leafy thallus that produces gametes.

• Gametes- Are reproductive cells that contqain the haploid number of chromosomes necessary for sexual reproduction.

Reproductive Cycle of Algae Continued

• The life cycle of Ulva is composed of two separte stages or generations- the sporophyte and gametophyte gernerations

• The succession of two types of generations is called alternation of generations.

Brown Algae

• Classified in the phylum Phaeophyta

• Brown or olive green in color, the color results from mixtures of pigments in the cells of the algae

• Mostly the green pigment chlorophyll and the yellow pigment xanthophyll, the blending of these pigments result in a brown color.

Brown Algae

Brown Algae Continued..

• Provide shelter and/or nutrients for other organisms, and are used materials people find valuable.

• For example, the sea palm which grows on rocks and resembles a tiny palm tree can be eaten raw or cooked.

• Rockweed attaches to rocks in the intertidal zones along the Atlantic, Pacific, and Gulf coasts.

• The rockweed’s holdfast, anchors the algae to rocks, it is a tough, fibrous pad of tissue, and it also prevents the algae from being dislodged from his holding from strong currents and waves for example.

Brown Algae Continued..

• The largest seaweeds in the ocean are called kelp which falls under the category of brown algae.

• Laminaria, a type of kelp, thrives in the color waters of the temperate zone, mainly concentrated of the coasts of Maine and California.

• They grow rapidly from the seafloor to the surface of the water.

Brown Algae Continued…

• Giant kelps, like the Nereocystis and Macrocystis, can reach a length of more than 60 meters.

• Fish, shellfish, sea urchins, sea lions, sea otters, and sharks all live around giant kelp for food and shelter.

• A chemical in algae called algin, is used in many different industries for food preparations, medicines, paints, and paper products.

Brown Algae Continued….

• One type of brown algae that is not anchored to a substrate is the Sargassum, floats on the waters surface in places such as South Atlantic Ocean and in some seas off the coasts of Asia.

Red Algae• Most abundant of the marine algae• Classified in phylum Rhodophyta• Found in intertidal to subtidal zone

and some species at great depths of ocean

• Contains red pigment phycoerythin and the blue pigment phycocyanin

• These two pigments allow for photosynthesis to occur at much deeper waters to carry out photosynthesis

Red Algae continued• types of red algae include Coralline Algae,

Irish Moss, Porphyra, and Lithothamnion

Coralline Algae(Corallinia)

• Hard and brittle red algae with calcium carbonate in the cell walls

• Found attached to rocks in lower intertidal zone

• Many are epiphytic (growing on other algae and marine angiosperms) or epizoic (grow on animals)

• Used as soil conditioners and in medicine

Irish moss(Chrondrus Crispus)

• Short, bushy, spongy red algae• Found in lower intertidal and subtidal zones• Found carpeting rocks• Contains a chemical called carrageean which is

used as a binding agent in ice cream, puddings, and toothpaste

• Others like this contain a chemical called agar that is used to make food, medicinal products as well as a medium for growing bacteria

Porphyra

• Thin and delicate, sheetlike red algae

• Also called Nori

• Grows in intertidal zone usually attached to rocks

• Is the most commonly eaten seaweed

• There are 60-70 species of porphyra found world wide

Lithothamnion

• Known as encrusting stony red algae

• Grows on rocks and is often found on the shells of hermit crabs

• Adorns shells with a bright red color