Zooxanthellae

Introduction

Zooxanthellae are a group of closely related dinoflagellates found in corals, anemones and some other cnidarians. It was once thought to be a single species, but now it is believed there multiple species and possibly even multiple genera of zooxanthellae. Organisms that contain zooxanthellae are called zooxanthellate and those without azooxanthellate.

Zooxanthellae live within the tissue of their hosts and provide the host with the products of photosynthesis: carbohydrates and oxygen. Carbohydrates only provide for the hosts energy needs and they still need other sources of nutrients. The host provides a "safe" place to live as well as the nutrients (nitrogen and phosphorus) that the zooxanthellae require.

Zooxanthellae are golden brown in colour and this is what gives corals and other cnidaria their basic colouration. Other coral colours (for example, blue, green, pink) come from pigments produce by the coral itself. The density of zooxanthellae in coral tissue ranges from 0.5 and 5 x l0⁶ cell.cm^-2 .

Resources

• Getting Really Up to Date on Zooxanthellae (Symbiodinium spp.) by Dana Riddle - Advanced Aquarist's Online Magazine
• The Role of Symbiotic Algae in Marine Invertebrates by J. Charles Delbeek - Freshwater and Marine Aquaria
• Lighting by Number: "Types" of Zooxanthellae and What They Tell Us by Dana Riddle - Advanced Aquarist's Online Magazine
• PAM Fluorometer Experiments - Part I: Effects of Metal Halide Lamp Spectral Qualities on Zooxanthellae Photosynthesis in Photoacclimated Fungia Corals: The Red Light Theory - Part II: Effects of Water Motion on Zooxanthellae Photosynthesis by Dana Riddle - Advanced Aquarist's Online Magazine
• Specificity of a Model Cnidarian-Dinoflagellate Symbiosis - journal article exploring the flexibility of symbiotic associations in coral reefs.
• Zooxanthallae - Microbe Wiki
• wikipedia:Zooxanthallae