Soft Bottom and Rocky Shore Habitats

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Questions and Answers

What percentage of Australia’s total forest area is comprised of Australia's Wet Tropics?

Less than 0.2% (correct)

0.5%

Which forest region in Australia is known for having a high conservation value and is home to 200 rare or threatened species?

Temperate Rainforests

Greater Blue Mountains

Gondwana Rainforests (correct)

Tarkine

What unique characteristic does the underground orchid possess?

It relies solely on symbiotic fungus for survival. (correct)

It is the largest flowering plant in Australia.

It grows entirely above ground.

It has extensive leaf structure for photosynthesis.

What is the main contention surrounding the Tarkine rainforest area?

Contention between conservationists and mining/logging interests. Signup and view all the answers

Which of the following describes the Tarkine rainforest?

It includes a mosaic of vegetation communities. Signup and view all the answers

What defines an estuary?

A semi-enclosed body of water that receives discharge from a river. Signup and view all the answers

Which type of estuary is primarily formed by rising sea levels flooding lower regions of river basins?

Drowned river valley estuary Signup and view all the answers

What is a key characteristic of saline coastal lagoons?

They have intermittently open entrances. Signup and view all the answers

Which of the following statements about estuarine salinity is true?

Salinity can fluctuate on a daily basis due to tides and wind. Signup and view all the answers

What happens in the phenomenon known as coastal squeeze?

Reduction of saltmarsh and mangrove habitats due to human development. Signup and view all the answers

Which of the following best describes mudflats and sandflats in estuaries?

They provide unique ecological roles for invertebrate populations. Signup and view all the answers

What type of estuary has a restricted entrance due to sand bars or barrier islands?

Barrier estuary Signup and view all the answers

Which statement correctly describes the impact of seasonal changes on estuaries?

Temperature and salinity can vary widely, affecting the estuarine ecosystem. Signup and view all the answers

What is the role of zooxanthellae in coral symbiosis?

They assist in the formation of coral reefs. Signup and view all the answers

What types of organisms are typically found living in the sediment of soft bottom habitats?

Fish, prawns, and sea urchins Signup and view all the answers

Which type of coral reef is characterized by being well-developed and attached to the mainland?

Fringing reef Signup and view all the answers

Which factor significantly affects the biodiversity of rocky shore communities?

Wave exposure gradients Signup and view all the answers

What is a significant threat to the Great Barrier Reef that is associated with human activities?

Coral bleaching due to rising temperatures Signup and view all the answers

Which of the following is NOT a method used for monitoring sediment biodiversity?

Satellite imaging Signup and view all the answers

Which organism is NOT typically mentioned as a contributor to cementing a coral reef?

Sea urchins Signup and view all the answers

What role do meiofauna play in soft sediment habitats?

They are small animals that help maintain sediment biodiversity. Signup and view all the answers

How is the Great Barrier Reef viewed from space?

It can be seen clearly as the largest geological structure built by organisms. Signup and view all the answers

Which of the following environmental factors does NOT affect rocky shore ecosystems?

Local fishing regulations Signup and view all the answers

What is a major environmental concern affecting soft bottom habitats?

Land runoff and contamination Signup and view all the answers

Why are rocky shores considered one of the most intensely studied marine habitats?

They are easily accessible and allow for simple experimental manipulation. Signup and view all the answers

What is bioturbation, and why is it important in soft bottom habitats?

It's the movement of sediment caused primarily by larger animals; it enhances biodiversity. Signup and view all the answers

Which species interactions are commonly studied on rocky shores?

Competition between algae and limpets Signup and view all the answers

What is the primary focus of manipulative experiments in rocky shore studies?

To determine physical and biological processes affecting species distribution. Signup and view all the answers

What type of species are grazers in rocky shore ecosystems?

Herbivores that consume algal films Signup and view all the answers

What factor is NOT mentioned as influencing the distribution of species in the intertidal zone?

Temperature fluctuations Signup and view all the answers

Which group of species serves as a local keystone predator on Sydney rocky shores?

Sea stars Signup and view all the answers

Which characteristic is true regarding zonation in animal distributions on rocky shores?

Higher diversity is found in areas low on the shore. Signup and view all the answers

What is one of the key consequences of heatwaves for intertidal ecosystems?

Mass mortality of intertidal animals Signup and view all the answers

Which human activity is noted as a significant environmental impact on rocky shore ecosystems?

Trampling by humans Signup and view all the answers

What is an important role of macroalgae in temperate rocky reef ecosystems?

They provide habitat and nutrients for various species. Signup and view all the answers

What is the significance of 'blue carbon' in macroalgal-based ecosystems?

It denotes the carbon storage potential of marine plant ecosystems. Signup and view all the answers

Study Notes

Soft Bottom Habitats

Muddy and sandy habitats support a diverse array of species, including fishes, prawns, crabs, sea stars, rays, worms, clams, and heart urchins.
Sediment can harbor massive populations of tiny animals called meiofauna.
Soft sediment habitats exhibit a full range of feeding regimes, including deposit feeders, filter feeders, scavengers, and predators.
Soft sediment is associated with high biodiversity and bioturbators.
Overfishing can impact soft bottom habitats, which are highly productive for fishing.

Environmental Concerns for Soft Bottom Habitats

These habitats are susceptible to land runoff and dredging for port development and maintaining shipping routes.
Sediment contamination can have detrimental effects on sediment biodiversity.
Environmental monitoring using sediment samples is expensive and time-consuming.

Rocky Shores

Rocky shores display large environmental gradients over short distances, ranging from marine to terrestrial environments.
Exposure to environmental factors is dependent on the elevation of the shore, including rock platforms, cliffs, and boulder fields.
Exposure gradients from low to high shore influence tidal patterns, aerial exposure, temperature, and oxygen levels.
These gradients, along with substratum type, strongly influence the distribution of animals on rocky shores.
Rocky shores harbor a diverse array of species, including grazing species (snails, limpets, sea urchins, chitons), predators (anemones, whelks), suspension feeders (barnacles, oysters, ascidians), and algae (Neptune's necklace, microalgae).

Environmental Gradients - Physical Factors on Rocky Shores

Tides, influenced by the moon's gravitational force, create a vertical gradient.
Wave exposure, a horizontal gradient, is a significant factor affecting rocky shores. Strong gradients exist from exposed to sheltered shores.
Wave action is an essential agent of disturbance and interacts with tides and temperature.

Other Variable Factors Influencing Rocky Shores

Abiotic factors include temperature, light, salinity, oxygen levels, pH, and substratum type.
Physical factors include desiccation stress and disturbance.
Biological processes include competition, predation, herbivory, and succession.
Natural and human-affected processes also influence the environment of rocky shores.

Rocky Shores: A Model for Marine Ecology

They are one of the most intensely studied marine habitats due to their easy accessibility and suitability for experimental manipulation.
Studies have focused on competition, predation, and supply-side ecology.
Manipulative experiments are essential for determining the distribution and abundance of marine organisms.
Research from intertidal rocky shores has been influential in both marine ecology and general ecology.

Ecologically Important Species on Rocky Shores

Important species vary between shores and exposure gradients.
Resident species differ according to the type of shore.
The relationships between grazers (limpets) and algae and the predator-prey relationship between whelks and barnacles are key areas of study on rocky shores.

Environmental Impacts on Rocky Shores

Heatwaves can cause significant mortality of intertidal animals, particularly during low tides.
Human harvesting, such as collecting urchins, limpets, abalone, and turban shells, is a major environmental concern.
Trampling by humans can also have negative impacts.

Temperate Rocky Reefs and Seaweed Beds

Characterised by rocky reefs dominated by large macroalgae (seaweeds).
These macroalgae are highly productive, providing habitat, nutrients, and a food base for a diverse array of species.
They play a crucial role in the carbon cycle and act as a "blue carbon" sink.
These ecosystems support an abundance of herbivorous species.

Coral Symbiosis

Zooxanthellae are algal endosymbionts that photosynthesize and provide organic matter to host corals.
Corals also feed on zooplankton, detritus, and dissolved organic matter through tentacles, mucus sheets, and mesenterial filaments.
This symbiotic relationship is essential for reef building.
Zooxanthellae are also found in other animals, such as anemones, nudibranchs, and clams.

Reef Building Processes
Corals and coralline algae are major depositors of calcium carbonate (CaCO3), contributing to reef formation.
They buffer against wave action and trap sediment.
Reefs are cemented by sponges, bryozoans, and coralline algae.

The Great Barrier Reef: A Global Icon

The Great Barrier Reef is the largest geological structure built by organisms, visible from space.
It is a crucial conservation area, supporting populations of species listed as vulnerable and endangered.

Coral Reef Development

Fringing reefs develop attached to mainland or continental islands.
Platform or lagoon reefs form as reefs grow towards the ocean surface and spread laterally, often developing lagoons.

Threats to the Great Barrier Reef

Land-use activities, such as agriculture, industry, and urbanization, contribute to water quality issues.
Coral bleaching due to rising temperatures is a significant concern.
Coastal developments, increased fishing effort, shipping, pollution incidents, and tourism can all threaten the reef.

Future Challenges Facing the Great Barrier Reef

Global climate change is a major threat, leading to decreased coral cover and mortality after bleaching events.
Increased cyclone activity and intensity pose additional challenges.

Oceanography and Connectivity

Tides and longshore currents influence reef ecosystems.
Connectivity between reefs is essential for maintaining genetic diversity and resilience.

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Description

Explore the diversity and ecological importance of soft bottom habitats and rocky shores. This quiz covers the species that inhabit these areas, their feeding regimes, and the environmental concerns affecting them. Test your knowledge on the impact of human activities on these vital ecosystems.