Brown Lake is a lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 on North Stradbroke Island

North Stradbroke Island

North Stradbroke Island is an Australian island in the state of Queensland, 30 km southeast of the capital Brisbane. Before 1896 the island was part of the Stradbroke Island. In that year a storm separated it from South Stradbroke Island, forming the Jumpinpin Channel. It is known...

, in Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

, Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

.

Known as a perched lake like other lakes on the sandy islands in the region of South-East Queensland it retains its water due to a layer of leaves lining the lake floor. This is particularly apparent in the Brown Lake as tannin

Tannin

A tannin is an astringent, bitter plant polyphenolic compound that binds to and precipitates proteins and various other organic compounds including amino acids and alkaloids.The term tannin refers to the use of...

 is exuded from the leaves, dropped from surrounding Paperbark Melaleuca

Melaleuca

Melaleuca is a genus of plants in the myrtle family Myrtaceae known for its natural soothing and cleansing properties. There are well over 200 recognised species, most of which are endemic to Australia...

 and Ti-trees Leptospermum

Leptospermum

Leptospermum is a genus of about 80-86 species of plants in the myrtle family Myrtaceae. Most species are endemic to Australia, with the greatest diversity in the south of the continent; but one species extends to New Zealand, another to Malaysia, and L. recurvum is endemic to Malaysia.They...

, stains the water to a rich brown colour not dissimilar to that of tea.