Description of Botany Bay Ecosystem
An Overview of the local ecosystem.
Abiotic Factors The Abiotic factors of the Botany Bay Wetland ecosystem include sunlight (light penetration), temperature variation, availability of gases, tides and salinity levels. This environment receives a large exposure to sunlight as it is orientated on the northern side of the Kurnell Peninsula. The shallow depth of the seagrass beds allows for 100% light penetration. However, the mangrove ecosystem doesn’t allow for much direct light penetration through its thick foliage, except for some filtered light. The area is a temperature climate due to its position south of the equator. The gases (oxygen and carbon dioxide) in this area are all readily available in the air, open to the mangrove population, but somewhat limited with the seagrass, as oxygen decreases in water as depth increases. Whilst the water logged soils in which the mangroves grow have low levels of oxygen, pneumatophores allow the plant to take in oxygen, increasing the surface area of oxygen intake. This environment is affected by changing tides and currents. It receives two tides a day, each incoming tide providing food for the mangrove and seagrass communities, and each outgoing tide removing wastes from the area. The water source for this environment is the estuary water from the ocean, bay and fresh water from rainfall. The salinity of the water in the area (34g) is close to that of seawater (35g), maintaining an appropriate environment for which the organisms to live. Salt glands mostly on the underside of leaves of the mangroves excrete salt. Mangrove roots filter approx. 90% of the salt during the uptake of water. Some salt can be stored in the tissue of the plant. Seagrass contains a gene which transfers sodium into the vacuole of a cell, giving it a lower water potential than the saltwater surrounding it. |
Location
The Botany Bay wetland ecosystem studied at Bonna Point Reserve is located on the far end of the Kurnell peninsula, in the south-east corner of Botany Bay. The ecosystem stretches from the seagrass shoreline of Bonna Point Reserve to the sheltered habitats of the mangrove forests of Towra Point Aquatic Reserve. Biotic Factors
The Biotic factors of the Botany Bay Wetland ecosystem include all living things of this environment which affect an organism’s survival. Factors include food sources, predators, and decomposers or bacteria. Food sources include strapweed, algae, as well as the trees, fruits, twigs, leaves and bark of mangroves. These producers are consumed by animals like prawns and crabs, whilst these primary consumers are food sources for other organisms like seahorses and pipefish (carnivores). Predators, such as pygmy squid and blue-lined octopus are the tipping point between whether an organism will survive, as they are the main control of the organism’s population. Bacteria and fungi are decomposers, breaking down waste material into high-protein food for organisms such as fish and prawns. The waste product of fish and prawns is eaten by molluscs and small crustaceans, and dissolved substances by plankton. New mangroves growing near the shoreline.
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