Jervis Bay Marine Park
Currambene Creek is part of the Jervis Bay Marine Park which is the second marine park created in NSW, the marine park covers approximately 215 km2 and spans over 100 km of coastline and adjacent oceanic, embayment and estuarine waters. The park was established in 1998 and its zones and management rules commenced in October 2002.
Jervis Bay's clear waters are largely due to the joining of warm water from the East Australian Current and cooler water from the Bass Strait. With periodic upwelling of cold, nutrient-rich waters from the nearby Continental Shelf, these combined currents flow clockwise around the bay, completely flushing it out every 24 days or so.
About Currambene Creek
Currambene Creek is the largest waterway entering Jarvis Bay and is significant because there is very little development along its shores, and is mangroves along this part of the creek create a buffer from the from pollutant’s and soil sediments from land based run-off which reduces nutrient input and sedimentation of the creek.
The mangroves create a nursery for the invertebrate population and local fish species to feed and reproduce.
Currambene Creek Mangroves are in the Currambene Creek Mudflats Sanctuary Zone and the area can only be used for recreational Boating and is one of the larger mangroves forests in NSW
Types of Mangroves
The Mangrove forest type occurs in many of Australia’s coastal regions, but has a total area of only 0.9 million hectares, or less than 1 per cent of Australia’s forest cover. Australian Mangrove forests contain 41 species of mangrove from 19 plant families. More than half of the world’s mangrove species are found in Australia.
Mangroves are found in the intertidal zones of tropical, subtropical and protected temperate coastal rivers, estuaries and bays, where they grow in fine sediments deposited by rivers and tides.
Mangrove trees have a characteristic growth form, including aerial structural roots and exposed breathing roots. This helps them cope with regular tidal inundation and a lack of oxygen in the soil.
The most common mangrove is white mangrove (Avicennia marina), which is found in mainland coastal areas and comprises three subspecies. Subspecies A. m. marina is found in Western Australia from Bunbury in the south to the Kimberley region in the north. Subspecies A. m. eucalyptifolia is found from Wyndham in northern Western Australia to Mackay in Queensland. Subspecies A. m. australasica is found from south of Rockhampton in central Queensland to Victoria and South Australia.
Jervis Bay contains only two species of mangrove, the grey mangrove (Avicenna marina) and the river mangrove (Aegiceras corniculatum ). There are approximately 125 ha of mangrove forests in the Bay, giving Jervis Bay a rank of sixteenth amongst the 133 estuaries in the State. The small area of mangroves relative to the size of Jervis Bay is not unexpected as there are few suitable sites. Mangroves generally require protection from wind and waves and reach their greatest development on muddy sediments and in brackish environments.
In Jarvis Bay mangroves are generally restricted to the creeks with Avicenna dominating in most areas. Individual mangroves are relatively small, with the exception of large dense stands of tall trees in Currambene Creek and Carama Inlet.
Geology of Mangroves Areas
Mangroves contribute many environmental benefits to coastal and estuarine ecosystems. Mangrove tree and root structures prevent erosion by stabilising soils and sediment in intertidal zones, and provide buffer zones from severe storms and cyclones.
Mangrove areas are made up from sediments accumulating beneath a mangrove swamp may be of two types.
Allochthonous sediments are those which are derived from outside the swamp itself and are brought into the swamp either from landward or from seaward. In deltaic areas much terrigenous (land based) sediment may be imported by the river system; in estuaries both terrigenous and marine sediments may accumulate; and on the broad mud flats of shallow-water carbonate banks.
Mangroves may also grow on intertidal calcareous flats in which the sediment is almost totally marine in origin.
Autochthonous sediments are those which are deposited in situ and include mangrove-derived peats, with a high organic content, which may underlie mangroves in areas where allochthonous sediment supply is low. In addition, mangroves can grow on sandy, reefal or rocky substrates.
Mangrove swamps develop only where coastal physiography and energy conditions are favourable. They are most extensive where there is a low shore gradient, and occupy a broader belt on shorelines which have a large tidal range. Sheltered habitats are essential for mangrove development, and on coasts which are exposed, mangroves are localised in the lee of other coastal landforms
Mangroves have traditionally been used by Indigenous Australians as sources of food, including mangrove fruit, mud crabs, clams and fish such as barramundi. Mangrove timber has traditionally been used to make canoes, paddles and weapons such as shields, spears and boomerangs.
https://www.dpi.nsw.gov.au/fishing/marine-protected-areas/marine-parks/jervis-bay-marine-park
https://www.agriculture.gov.au/abares/forestsaustralia/profiles/mangrove-2019
Sedi- © 1983 Dr W. Junk Publishers, The Hague. All rights reserved. ISBN 978-90-481-8526-9
https://wetlandsaustralia.com/articles/10.31646/wa.105/galley/103/download/
Notice: This is a national park area no domestic animals allowed
As you walk along the boardwalk, Take note of the landscape;
Questions to answer
At the start of the board walk as you look to the north, describe the area on the high tide mark.
Do you think the mangroves were originally passed the high tide mark at this location?
Describe how the mangroves change the land
In your opinion what type of sediments have mainly created this mangrove forest ?
At the end off the boardwalk at the seating area, describe how the deeper water and tides here affects the speed of retention of sediment, and consider how the smaller/larger plants affect the retention of sediments.
You may log your find immediately, but if the answers are not sent to me, via my profile email or GC Messenger, within 10 days, your find log may be deleted.