Red Sea CARE PROGRAM Algae Management Manuel Utilisateur page 4

2 | Red Sea | Reef Care Program
Supporting the natural processes by regular dosing of a suitable carbon source and mineral
co-factors provides an easy and reliable method of incremental control of the algae
nutrient levels to safely control both the presence of nuisance algae and the population of
the symbiotic Zooxanthellae.
Coral's Symbiotic Zooxanthellae Algae
Understanding the role played by the symbiotic Zooxanthellae algae and their relationship
with the coral is essential for successful implementation of the algae management
program.
In nature corals host Zooxanthellae inside their soft tissue. The corals derive approx 85%
of their energy from the Zooxanthellae and produce the remaining 15% in their soft tissue
by metabolizing coral nutrients (Carbohydrates, Amino and Fatty acids) that are available
in the surrounding water. This energy fuels all of the corals' metabolic processes such as
protein production and coral skeleton growth.
The Zooxanthellae use the strong sunlight on the tropical reef as their primary energy
source and pass on up to 95% of their photosynthesis products (Carbohydrates, Amino and
Fatty acids) to their coral host and utilize the balance for their own metabolic processes.
The coral host provides the Zooxanthellae with nutrients, nitrogenous compounds,
. It is this symbiotic relationship, involving the recycling of nutrients,
phosphates and CO
2
that is the key to the ecological success.
Another aspect of this symbiosis relates to photo-protection from strong radiation. In
nature, the Zooxanthellae protect the corals from intense UV radiation by absorbing the
light energy and shading the delicate inner layers of the coral soft tissues.
In nature the Zooxanthellae population is controlled by the algae nutrients (nitrates and
phosphates) excreted by the coral, however in an artificial reef aquarium the amount of
algae nutrients accumulate rapidly and if left uncontrolled will induce an over-density of
the Zooxanthellae populations.