Question

Ls4208_endsem_2016

The question is from marine biology.

2. Fifteen of the sixty known species of seagrass worldwide occur in Great Barrier reef - Elucidate this statement from the context of seagrass biology (10 marks)

Answer 1

The Great Barrier Reef is home to the fifteen of the sixty known species of seagrass that occur worldwide. Seagrasss survive in areas where suitable light is available, presence of sediments, proper level of nutrients, minimum human disturbances. The Great Barrier Reef provides all these conditions which are necessary for their survival.

The seagrasses which have long blades, large root systems withstand a greater depostion of sediments than the shallow rooted ones. However, smaller rooted ones can once again regrow if proper conditions are available. The seagrasses are highly specialised flowering plants with leaves, rhizomes etc. They range from short lived species such as Halophila to long lived species such as Enhalus acoroides. The high growth rates of seagrasses in the Great Barrier Reef is due to the seasons. They grow in high amounts in months from June to November, peaking n spring and in early summer. Later in summer, when the condition becomes unfavourable, their growth ceases. The protected sediment covered areas also contributes further to the growth of seagrasses. The nutrient rich soft mud along with carbonate sands around cays on the great Barrier reef makes it ideal for the seagrasses. Seagrasses are known to cover up roughly 5668 square kilometers of the intertidal and shaallow subtidal habitat of the great barrier reef.

Seagrass communities are dominated by Halophila uninervis along the Cape York peninsular region. The wet tropics region holds as many as 8 different types of seagrasses. Zostera communities dominate along the Shoalwater bay.