Biomimicry, (Mangroves)
For this project an examination through the means of design through biomimicry will be undertaken, for this an item has to be selected in which I will mimic. This item is to be site specific, after some research a mangrove ecosystem has been selected. This fits into the project because on the site pre European influence there was a mangrove forest as the water line of the harbour was much higher and secondly much of the surrounding context of Newcastle still has mangrove forests, both these gives this mimicry selection historical and present context.
When it comes to delving further into the biomimicry theory and using the mangrove ecosystem there are many variables that can be used, ranging from the ecosystem as a whole to individual aspects. For this project I would like to have an overall understanding of the ecosystem within the design and Architecture and focus on individual parts of the ecosystem such as the mangrove tree for architectural details such as facade systems.
Description
Mangroves are various kinds of trees up to medium height
and shrubs that grow in saline coastal sediment habitats in the tropics and subtropics – mainly
between latitudes 25° N
and 25° S. The mangrove biome, or mangal, is a distinct saline woodland or shrubland habitat
characterized by a depositional coastal environments, where fine sediments (often with high organic content)
collect in areas protected from high-energy wave action. Mangroves dominate
three quarters of tropical coastlines. The saline conditions tolerated by
various mangrove species range from brackish water, through
pure seawater (30 to 40 ppt), to water
concentrated by evaperation to over twice the salinity of ocean seawater (up to 90 ppt).
Economic Values
Mangroves
protect coastal areas from erosion, storm surge, and tsunamis. The massive root
systems of mangroves are efficient at dissipating wave energy. Mangroves retard
the tidal movement of water, allowing sediment to be deposited as the tide
comes in, and leaving all except fine particles when the tide ebbs. Mangroves
therefore build their own environment. The
commercial and recreational fishing industries are prime beneficiaries of
mangrove forests, which provide breeding and feeding grounds for fish and
prawns. About 75% of the fish and prawns caught for commercial and recreational
purposes in Queensland spend at least part of their lifecycles in mangroves. In some coastal communities,
boardwalks and bird-viewing areas in mangrove forests provide attractions for
the eco-tourism industry, for example, at Boondall Wetlands.
Threats
Threats to
mangrove ecosystems include;
▪
coastal
modifications such as reclaiming land (e.g. for building canal estates and
marinas);
▪
erosion
of shorelines in coastal lakes and estuaries;
▪
elevated
levels of nutrients and sediments from land clearing, overgrazing and cropping;
▪
increased
levels of heavy metals such as copper, lead, cadmium, zinc and mercury, and
tributyl tin (TBT) from anti-fouling paints;
▪
marine
oil pollution from sewage systems and drains, which are estimated at 16,000
tonnes a year over the whole of Australia;
▪
accidental
spills during re-fuelling of vessels in ports.
Removal of
mangrove forests can lead to erosion of the shoreline, exposure of acid sulphate soils,
shallowing of estuaries and waterways, and a reduction in water quality. These
threats can deplete the populations of fish, prawns, crabs and other sea life
that use mangroves as breeding and feeding grounds, which would then impact on
commercial and recreational fishing.
Local Environment
Local Newcastle
mangrove consists mainly of the Avicennia marina, commonly known
as grey mangrove
Description
Excreted salt on the underside
of a Avicennia marina var. resinifera leaf Grey mangroves grow as
a shrub or tree to a height of three to ten metres, or up to 14 metres in tropical
regions. The habit is a gnarled arrangement of multiple branches. It has smooth
light-grey bark made up of thin, stiff, brittle flakes. This may be whitish, a
characteristic described in the common name. The leaves are thick, five to
eight centimetres long, a bright, glossy green on the upper surface, and
silvery-white, or grey, with very small matted hairs on the surface below. As
with other Avicennia species, it has aerial roots (pneumatophores); these grow to a height of about 20 centimetres, and a
diameter of one centimetre. These allow the plant to absorb oxygen, which is
deficient in its habitat. These roots also anchor the plant during the frequent
inundation of seawater in the soft substrate of tidal systems. The flowers
range from white to a golden yellow colour, are less than a centimetre across,
and occur in clusters of three to five. The fruit contains large cotyledons that surround
the new stem of a seedling. This produces a large fleshy seed, often
germinating on the tree and falling as a seedling. The grey mangrove can
experience stunted growth in water conditions that are too saline, but thrive
to their full height in waters where both salt and fresh water are present. The
species can tolerate high salinity by excreting salts through its leaves. Avicennia
marina var. resinifera fruit Grey mangrove is a highly variable
tree, with a number of ecotypes, and forms closely resembling other species. It
has been reported to tolerate extreme weather conditions, high winds, and
various pests and diseases. It is a pioneer in muddy soil conditions with a PH
value of 6.5 to 8, but is intolerant of shade
Sources:
- Mangrove Management in the Northern Territory
- Trees in Newcastle: PLANT COMMUNITY FIELD GUIDE, Mangrove Estuarine Complex Saltmarsh
- Natural Heritage Trust
- Hunter Central Rivers, Catchment Management Authority
- Landcare
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