Environment : Algae

Green Algae: Phylum: Chlorophyta

Brown Algae: Phylum: Phaeophta

Red Algae: Phylum: Rhodophyta

Algae are simple structured autotrophic organisms, some are unicellular while others multicellular and most photosynthesis like plants. Algae date back over billion years and some of the first plants on earth evolved from algae. Green algae are by far the most complex group and have led to the evolution of land plants. Their simple structure means they are lacking many anatomical structures that true plants have, specifically organs. Algae do not have true roots but attach to the substrate by rhizoids and rhizomes.

Some species, particularly brown algae, contain gas bladders to keep them afloat. Some algae have a symbiotic relationship with its host so that the photosynthetic products are used by the host for energy, while e the host protects the alga. In a coral reef structure these are primarily algae of the Dinoflagalatte phylum and the alga living endosymbiotically with the stony corals are called zooxanthellae. The loss of this algae is what is known as ‘coral bleaching’

“Reef Coral Identification” by Paul Humann, Ned DeLoach

en.wikipedia.org/wiki/Algae

Small Leaf Hanging Vine Green Algae: Halimeda sp. on "Vicissitudes"

Small Leaf Hanging Vine Green Algae: Halimeda sp. on "Vicissitudes"

Small Leaf Hanging Vine Green Algae: Halimeda sp. on “Vicissitudes

Small Leaf Hanging Vine Green Algae

GREEN ALGAE

The most abundant and commonly recognised algae on tropical reefs is the green algae. There are many species and most are calcareous, contributing a large amount of calcium carbonate to the reef building process. These plants form the base of the ocean food chain by carrying out photosynthesis. Chlorophyll is the pigment that forms their various shades of green colour from bright Kelly green to yellow and brown-green to Dark green.

The picture of “Vicissitudes” is suspected to show a variety of Hanging Vine Green Algae growing on it.

Genus: Halimeda sp.

Typically they appear as a flexible string of flattened leaf-like structures often referred to as segments. Each segment is a deposit of calcium carbonate covered by the algal protoplasm and connected to its neighbours by a thin strand, giving the plant its flexibility.

They are fast growing and decorative and the calcified leaves are an integral component as the major contributor of calcium carbonate to the reef sand.

“Reef Coral Identification” by Paul Humann, Ned DeLoach

en.wikipedia.org/wiki/Algae

Y Branched Brown Alga: Dictoyota sp. on "The Silent Evolution"

Y Branched Brown Alga: Dictoyota sp. on "The Silent Evolution"

Y Branched Brown Alga: Dictoyota sp. on “The Silent Evolution

Encrusting Fan Leaf Alga: Lobophora variegata on "The Silent Evolution"

Encrusting Fan Leaf Alga: Lobophora variegata on "The Silent Evolution"

Encrusting Fan Leaf Alga: Lobophora variegata on “The Silent Evolution

Serrated Strap Alga: Dictyota ciliolata on "The Silent Evolution"

Serrated Strap Alga: Dictyota ciliolata on "The Silent Evolution"

Serrated Strap Alga: Dictyota ciliolata on “The Silent Evolution

BROWN ALGAE

Leafy flat blade Brown Alga: Lobophora sp.

Serrated Strap Brown Alga: Dictoyota sp.

Y Branched Brown Alga: Dictoyota sp.

Brown algae grows into abundant coverage, often in shallow waters. They are multicellular organisms and generally bushy plants formed by blunted blades, often irregularly branched. Some kelps can grow up to 60metres long and the most abundant species of algae is seaweed. The different species come in various shades of yellow-green-brown and often tints of iridescent. The pigment Fucoxanthin gives brown algae various shades or brown-yellow, creamy brown, green-brown to dark brown.

The Silent Evolution” shows a variety of brown algal species growing as the colonisation of the reef begins.

“Reef Coral Identification” by Paul Humann, Ned DeLoach

en.wikipedia.org/wiki/Brown_Algae

Crustose Coralline Alga: Rhodaophyta sp. on "Man on Fire"

Crustose Coralline Alga: Rhodaophyta sp. on "Man on Fire"

Crustose Coralline Alga: Rhodaophyta sp. on “Man on Fire

Crustose Coralline Alga: Rhodaophyta sp. on "Vicissitudes"

Crustose Coralline Alga: Rhodaophyta sp. on "Vicissitudes"

Crustose Coralline Alga: Rhodaophyta sp. on “Vicissitudes

Early colonisation of Crustose Coralline Alga on "The Dream Collector"

Early colonisation of Crustose Coralline Alga on "The Dream Collector"

Early colonisation of Crustose Coralline Alga on “The Dream Collector

RED CRUSTOSE CORALLINE ALGAE

Phylum: Rhodophyta

Red algae is often abundant but difficult to recognise due to dull colouration and simple encrusting growth patterns yet they are the most diversified with over 5,000 tropical species. Many are calcareous (secrete calcium carbonate) species and play an important role in coral reef construction. They range from dull red to purple to dark brown-red colouration, the red pigment phycoerythrin is responsible. Most red algae are multicellular and undergo sexual reproduction unlike some of the other groups. Coralline algae prefer shade and encrust solid substrates. Colonies can be brittle and hard to distinguish from one another.

Examples are that found on the nose of “Man on Fire” and “Vicissitudes girl“.

“Reef Coral Identification” by Paul Humann, Ned DeLoach

en.wikipedia.org/wiki/Red_Algae