A Broadly Applied Name

  Algae are the ocean counterparts of plants, accounting for as much as 90% of the Earth’s primary productivity and oxygen production. Algae are the foundation for all marine life.  Taxonomic Definition: those organisms that belong in one of seven specific phyla to classify algae.  Seven phyla of algae: Cholorphyta, Rhodophyta, Phaeophyta, Dinophyta, Bacillariophyta, Euglenophyta, Chrysophyta What are algae? How many phyla of algae are there?

 -Most productive phytoplankton ; very diverse group (5,000-50,000 species) -Larger than prokaryotes -Shell made of silicon that comes in an array of shapes among the species -Relatively dormant through winter months because they are photosynthesizers -When sunlight levels rise in spring, they photosynthesize, grow, and reproduce -Reproduce asexually: budding -Account for about 25% of all photosynthetic biomass on Earth -Can cause: Harmful Algal Blooms (HABs) by producing toxins Phylum: Bacillariophyta: The Diatoms

  Second most productive group of primary producers  Use flagella to swim; just a little larger than diatoms; still small enough to be classified as microplankton  Noctiluca : heterotrophic dinoflagellate; capable of bioluminescence: ability of an organism to emit light (firefly); contain chemicals in photophore that when mixed emit light ;  Use this light to attract prey, fool predators, attract mates, and sometimes as light source for vision  Noctiluca emit light when agitated  Genus Symbiodinium: autotrophic dinoflagellates; live in coral polyps; provides food for the coral polyps; example of mutualism: two species live together and benefit from the relationship; coral could not exist without these dinoflagellates  Also live in giant clams and some species of sponge Phylum Dinophyta: The Dinoflagellates

  Dinoflagellates can also cause toxic red tides (HABs)  Toxins can be even more toxic than cyanide  These toxins can accumulate over time in shellfish and fish and can cause seafood poisoning  Fish at higher trophic levels have a higher toxin risk due to the accumulation of toxins with each level and more concentration as you go up Dinoflagellates: Cont’

 Phylum Chlorophyta: Green Algae  Macro Algae : applies to several algae phyla, but refers to multicellular species  Share same green color as land plants  Share the same pigments and have many similar biochemical characteristics: chlorophyll a & b  Chlorophyll a : pigment directly involved with photosynthesis  Chlorophyll b : assists chlorophyll a in capturing light for use in photosynthesis  7,000 species of green algae  Do not have system of roots, veins, and stems that land plants have  Some species have holdfasts : appendages that look like roots, but simply anchor the algae to rocks; don’t carry nutrients  Green algae vary in complexity within the classification, ranging from single cell to multi cell varieties

  Consists of freshwater and marine algae;  4,000 species; mostly macro algae; do not produce cellulose  Have chlorophyll a but NOT chlorophyll b  Have red pigments: phycoerythrins which give color  This pigment has not been found in any other eukaryote; does exist in cyanophytes  This pigment allows red algae to live deeper than any other algae; some as deep as 200 meters (656 ft)  Also important for coral reefs ; think of red algae as cement for building coral reef wall  Red algae secrete calcium carbonate shell which bond individual coral colonies and debris together which in turn holds the coral reef structure together  Not all red algae do this  Some eat red algae of certain genera; rich in protein and minerals Phylum Rhodophyta: Red Algae

  More complex than other algae  Brown algae have holdfasts, blades (which are equivalent to leaves)  Many species live in the littoral zone, so stipes bend easily to resist breakage by waves  Pneumatocysts : natural gas-filled float structures that lift the algae off the bottom ; also resist drying out which helps them when stranded partially or wholly above surface during low tides.  1500 species with the largest and most impressive are the various species of kelp ;  Not all Brown Algae live anchored by holdfasts  For example: Sargassum genera: brown algae that thrives on the surface of the Sargasso Sea Phylum Phaeophyta: Brown Algae

  Giant kelp can grow more than 30 cm per day and reach the surface from 79 ft deep  It is important because it is the foundation for many temperate coastal ecosystems; much like coral is the foundation for many tropical marine ecosystems  Kelp forests dominate the coasts of California, Mediterranean, and New Zealand Why is kelp important?