Biodiversity and Coastal Currents in Southern Africa

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Questions and Answers

What purpose do differing patterns serve in female and juvenile fish?

To attract more males

To allow safe feeding in a male's territory (correct)

To signal danger to predators

To differentiate between species

Which of the following best describes the relationship between cleaner wrasses and larger fish?

Cleaner wrasses compete with larger fish for food

Cleaner wrasses perform useful cleaning services for larger fish (correct)

Cleaner wrasses provide harmful parasites to larger fish

Larger fish threaten the survival of cleaner wrasses

Which statement reflects a characteristic of venomous and poisonous animals?

They are equally distributed in warm and cold waters

They are more prevalent in warmer waters (correct)

They are only found in coral reefs

They are more commonly found in colder regions

What defines biodiversity in an area?

The variety of living animals and plants, including species and genetic diversity Signup and view all the answers

How do zooxanthellae contribute to the survival of corals?

By manufacturing food through photosynthesis Signup and view all the answers

Which country has the highest level of biodiversity?

Brazil Signup and view all the answers

What is the main component of the structure of coral reefs?

Calcareous exoskeletons of coral animals Signup and view all the answers

What is a 'biodiversity hotspot'?

A region that contains a significant amount of unique biodiversity Signup and view all the answers

What temperature must surface waters maintain for coral reefs to develop?

Between 16° C and 30° C Signup and view all the answers

What role do clownfish play within anemones?

They protect the anemone and remove damaged tissue Signup and view all the answers

Which region has more plant species than the entire British Isles or New Zealand?

The Cape Floristic Region Signup and view all the answers

What is the growth rate of coral reefs based on past generations' skeletons?

1 to 100 cm per year Signup and view all the answers

What is the distinction between the two oceans off South Africa’s coast?

One is warmer and has more marine life than the other Signup and view all the answers

What does the term 'upwelling' refer to?

The movement of nutrient-rich water to the surface Signup and view all the answers

What phenomenon greatly affects the distribution of animals and plants along the shore?

Tides Signup and view all the answers

Which of the following is NOT a cause of tides?

The temperature of ocean water Signup and view all the answers

What gas is produced by anaerobic bacteria during the decay of red tide organisms?

Hydrogen sulfide Signup and view all the answers

Why are rock lobsters particularly susceptible to oxygen depletion?

They are heavily dependent on the surf zone for oxygen. Signup and view all the answers

What occurs during a 'black tide' event?

Severe depletion of oxygen leading to organism poisoning. Signup and view all the answers

What is a consequence of calm weather following a plankton bloom?

Trapping of nutrients leading to death of plankton. Signup and view all the answers

Mussels can remain contaminated during red tide events for approximately how long?

Four months Signup and view all the answers

What must be done before consuming shellfish during a red tide event?

Contact the Red Tide Hotline. Signup and view all the answers

Which of the following is necessary for the development of red tide?

Specific temperature, salinity, and light conditions Signup and view all the answers

What detrimental effect does the decay of red tide organisms have on marine life?

It leads to oxygen depletion in water. Signup and view all the answers

What is the primary direction of flow for the Benguela Current?

Northwards Signup and view all the answers

What effect does upwelling have on the temperature of the West Coast water during summer?

Makes it colder than in winter Signup and view all the answers

What is a consequence of the nutrient-rich water from upwelling along the West Coast?

Enhanced growth of phytoplankton Signup and view all the answers

Which current flows southwards from the Madagascar region and carries warm water?

Agulhas Current Signup and view all the answers

What role does the South Easterly wind play in the process of upwelling?

It pushes surface water away from the coast Signup and view all the answers

What is the characteristic of the Agulhas Current concerning nutrient concentration?

It carries relatively low concentrations of nutrients Signup and view all the answers

Which of the following statements is true about the West Coast of Southern Africa?

It has a vast number of organisms with fewer species Signup and view all the answers

What phenomenon occurs when cold, nutrient-rich water rises to the surface?

Upwelling Signup and view all the answers

Which organisms dominate the upper balanoid zone?

Barnacles, winkles, limpets, and some seaweeds Signup and view all the answers

What is the primary characteristic of the lower balanoid zone on the west coast?

Thick beds of fleshy seaweed Signup and view all the answers

In which zone are red bait (sea squirts), anemones, sea urchins, and starfish predominantly found?

Infratidal or subtidal zone Signup and view all the answers

Which coastal zone is dominated by oysters?

Oyster belt zone Signup and view all the answers

What characterizes the cochlear zone?

Dense bands of pear limpets at the low-tide mark Signup and view all the answers

Which zone features Argenville's limpet?

Cochlear/Argenville zone Signup and view all the answers

How are different areas of the rocky shore identified?

By transverse and longitudinal lines indicating tides or indicator species Signup and view all the answers

What characterizes the east coast in terms of organism diversity?

Slippery, green zoanthids and brightly colored sponges Signup and view all the answers

Study Notes

Biodiversity

The diversity of living organisms in an area.
This includes the number of species, genetic variation within species, relationships between species, and their habitats.
South Africa has the third highest level of biodiversity in the world.
The Western Cape is a biodiversity hotspot.

Southern African Coastline Currents

The Benguela Current flows northward along the West Coast carrying colder water.
The Agulhas Current flows southward along the East Coast carrying warmer water from the tropics.
These currents influence the climate and marine life.

Upwelling

Occurs when offshore winds push surface water away from the coast.
This allows cold, nutrient-rich water from the ocean floor to rise to the surface.
This water fuels the growth of plankton and kelp forests.
The West Coast is the most productive due to upwelling.

Differences Between Coastal Regions

West Coast:
- Nutrient-rich due to upwelling.
- Cold, but colder in summer due to upwelling.
- Supports a vast number of organisms, but fewer species.
- Animals are territorial and some boast colorful patterns for protection or warning.
- High concentration of venomous animals.
- High diversity of algae and kelp forests.
- Seasonal changes in temperature influence plant and animal life.
East Coast:
- Warmer due to Agulhas Current.
- Less nutrient-rich.
- Supports a lower number of species than the West Coast.
- More colorful animals and less diversity of algae.

Red Tide

Occurs when there is an overgrowth of phytoplankton (algae).
Red tide organisms produce toxins that can harm marine life and humans.
Red tide blooms are triggered by nutrient-rich upwelling, calm weather, and ideal conditions for phytoplankton growth.
Dangerous if consumed by humans, particularly shellfish.
Black tide events occur when red tide organisms die and decompose, consuming oxygen and producing toxic hydrogen sulfide gas.

Tides

Caused by the gravitational pull of the moon and sun.
Spring tide: Occurs when the sun and moon are aligned, resulting in the highest high tides and lowest low tides.
Neap tide: Occurs when the sun and moon are at right angles, resulting in lower high tides and higher low tides.
Tides influence the distribution of animals and plants on rocky shores.

Rocky Shores

Divided into zones based on tidal exposure.
Upper Balanoid Zone: Characterized by barnacles, limpets, and some seaweed.
Lower Balanoid Zone: Rich in fleshy seaweed (West Coast), and zoanthids, sponges, and mussels (East Coast).
Infratidal Zone: Lowest zone, rich in sea squirts, anemones, sea urchins, starfish, and colourful seaweed.
Other zones include the Oyster Belt (East Coast) and the Cochlear Zone (South and West Coasts).
The distribution of organisms in each zone is determined by their tolerance to tidal exposure, competition, and the presence of predators.

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Description

Explore the extraordinary biodiversity of South Africa, highlighting its unique species and genetic diversity. Learn about the impact of ocean currents like the Benguela and Agulhas on marine life and climate, and discover how upwelling influences productivity along the coastline.