Algae

There are three phylums of algae:

• Chlorophyta: Green algae. Chlorophyta are photosynthetic/ autotrophic organisms.
• Rhodophyta: Red algae. They thrive in warmer temperatures, and can live at great depths.
• Phaeophyta: Brown algae. Phaeophyta has the most complex structures of all algae.

Chlorophyta:

An example of Chlorophyta found in coral reefs is known as Ulva lactuca, (sea lettuce)

• Lives: In coral reefs distributed among the oceans worldwide
• Found on rocky reef surfaces and sand substrates
• Role: Eaten by both marine animals and humans
• Used to make medicine, and food products
• Is a home for small invertebrates such as amphipods
• Anatomical structure:
• Leaves are thin, and flat
• Grows from a holdfast
• Can reach up to 18 centimeters in length

A second example of Chlorophyta found in coral reefs is known as Halimeda (macroalgae)

• Lives: In the western or outer shield reefs, because this is where the flow of nutrient-rich water occurs most prominently
• Found in places such as the Great Barrier Reef or on the northeast coast of Queensland, Australia
• Role: Has the ability to incorporate calcium carbonate into their tissues, which adds to the sediment formation in the reef ecosystem
• Anatomical structure:
• The thallus is composed of calcified green segments
• Made up of single multi-nucleate cells, consists of interwoven filaments

Alevizon, Dr. William. "Coral Reef Plants." Coral Reef Plants | Common Plant Life of Coral Reef Ecosystems. 2010-2013, http://www.coral-reef-info.com/coral-reef-plants.html.

Themes, Elegant. "Halimeda." Freakin Fucus. 2015. http://freakinfucus.co.uk/halimeda/.

Phaeophyta:

An example of Phaeophyta found in coral reefs is Sargassum

• Lives: South coast of England and several coasts in the south of Ireland
• Commonly found washed up on shore
• Attaches to rocks, corals, and shells in moderately exposed areas
• Can be seen as floating masses in the North Atlantic Sea
• Role: Provides food, refuge, and breeding sites for marine life such as fishes, sea turtles, marine birds, crabs, and shrip
• Can serve as a primary nursery area for fishes like mahi mahi, jacks, and amberjacks
• When Sargassum sinks, it provides carbon to fishes in the deep sea and a source of food
• Anatomical Structure:
• Consists of the basic anatomy of algae; a holdfast, stipe, and frond
• Has pneumatocysts ( berry-like bubbles filled with gas) which help keep it buoyant

US Department of Commerce, National Oceanic and Atmospheric Administration. "What is Sargassum?" NOAA Ocean Explorer Podcast RSS. July 16, 2014. http://oceanexplorer.noaa.gov/facts/sargassum.html.

Another example of Phaeophyta found in coral reefs is Fucus Serratus

• Lives: On the shores of the British Isles, the northeastern coast of North America, and California.
• Found on sheltered shores, from deep waters to the shallows
• Role: Because of it's high content of sodium carbonate, has many economical uses
• Such as: soapmaking, glassmaking, and even as a crop fertilizer
• Anatomical structure:
• Flattened thallus with a small stipe and holdfast
• Blades are thick and symmetrically placed (called midribs)
• Warty conceptacles

Harris, Ben. "Fucus vesiculosus." The Brown Alga Fucus vesiculosus (Bladderwrack) - Reproduction and Life Cycle. 2007. http://bioweb.uwlax.edu/bio203/2011/harris_benj/reproductionlifecycle.htm.