Education

Sponge gardens
Mangroves
Seagrasses
Sandy beaches
Salt marshes
Rocky shores
Rocky reefs and kelp beds

Sponge gardens

Like gardens on land, sponge gardens are a beautiful tangle of soft branching corals, sponges, and long thin sea whips. Some look like flowers, plants and fruits - there are sea lilies, sea cucumbers, even sea tulips! Sponge gardens can be found off North Head at the entrance of Sydney Harbour.

Swim about twenty metres straight down and you can find them. They are most commonly found in environments with limited light and gentle currents, usually on reefs.

Mangroves

Mangroves are true plants with roots, stems and leaves that are specially adapted for life in salty seawater. Mangroves are among a very small group of land plants that can live in inter-tidal areas and can tolerate a constantly changing mixture of salt and fresh water.

Mangroves occur along sheltered intertidal shores within estuaries and inlets.

In Sydney Harbour there are two species of mangrove, the grey mangrove and the river mangrove. Major concentrations of mangroves can be found along the Lane Cove River, Parramatta River, Homebush Bay, Duck River, Tarban Creek and the upper reaches of Middle Harbour.

Seagrasses

Seagrasses are the only flowering marine plant. They grow underwater in coastal marine and estuarine environments, in the sheltered shallow waters of estuaries, generally in soft sediments like sand or mud.

Like any plant, seagrasses need light to grow and are usually restricted to the upper two metres of water where there is sufficient light. Seagrasses have either straplike or paired oval leaves. They often form dense meadows that look like the lush, green grasslands that grow on land.

Australian waters have the world's highest diversity of seagrass species:
· 22 species found in temperate (cold) waters
· 15 species found in tropical waters.
Australia has about 51 000 sq km of seagrass meadows.

Sandy beaches

The coves, bays, points and headlands of the harbour, and their parks, bushland and swimmable beaches offer many hours of rewarding exploration. However, harbour beaches are not as clean as ocean ones, and after storms are often closed to swimmers.

There are several small coves and beaches along the coast, including Camp Cove, Nielsen Park and Lady Bay.

Along the North Shore are some larger beaches including Balmoral, Chinaman's Beach, Manly Cove and Reef Beach.

There are also a number of small islands inside of the Sydney Harbour including Clarke Island, Goat Island, Port Denison, Rodd Island, and Shark Island.

Salt marsh and artificial wetland

Salt marshes are transitional areas between land and water. They are coastal wetland ecosystems, which are inundated for some period of time by seawater. Plants found in salt marshes have special adaptation capacities in order to survive the high salinity of their immediate environment. Salinity ranges from near ocean strength to near fresh in upriver marshes.

Rocky shores

Sydney Harbour is characterised by large expanses of intertidal (exposed at low tide) rocky shorelines which often extend under the water to form large subtidal (always submerged) rock platfoms.

As the tide goes out on a rocky shore, pools of water are left behind. These rock pools can be very small or very large and are home to a number of fish species. Common fish which can be seen in Sydney rockpools are juvenile Eastern Wirra , White Ear, Common Toadfish, Horned Blenny, Jumping Joey and Black-cheeked Threefin.

The rocky shoreline is the habitat that is encountered the most by people living on and visiting Sydney Harbour. It provides an important habitat for a range of animals and plants and some of Sydney's most recognisable geological features. It is also a focus for a range of popular recreational activities such as boating, walking, exploring rock pools and fishing

Rocky Reefs and Kelp Beds

Rocky reefs and their associated kelp beds are some of the most common habitats found under the waters of Sydney Harbour, extending from the intertidal zone to the depths of the harbour.

A reef is any solid surface under water that provides a home to encrusting organisms. The rocky reefs of Sydney provide homes for a wealth of encrusting organisms such as sponges, hydroids, anemones, worms, bryozoans, and soft and hard corals.

Kelp is one of the most abundant and the largest of the seaweeds.

Rocky reefs are also the home of some of Sydney's best known fish residents such as the Weedy Seadragon, Eastern Blue Groper, Port Jackson Shark, Green Moray, Red Indianfish, and Red Rockcod.