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- Reclamation in Hong Kong

- Dredging

- Simulation of dredging

- Introduction to brine shrimp

- Effect of dredging to brine shrimp (Q1 – Q2)

- Pollutants in the sediment (Q3)

- NOS: Scientists often make hypotheses based on careful observations (Q4)

- Limitations of the set-up

- Needs for different types of data in EIA

- Extension activity: Pollution indicator

- Extension activity: Other impact of reclamation

Disneyland development: Benefit or lossDisneyland development: Benefit or loss

Activity 2

Click the links below to access the slides:

Impact of reclamation on marine life forms

When did the earliest reclamation in Hong Kong

begin?1850s

Where was it?

In Sheung Wan, HK Island

(Around Bonham Strand, Morrison Street)

(The present tram line was sea before 1850)

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Earliest reclamation in HK

Can you name some places that are reclaimed land?

Is your school and home built on reclaimed land?Is your school and home built on reclaimed land?

Check it out!Check it out!http://www.landsd.gov.hk/mapping/en/download/download/map/ar9_4e.pdf

Check it out!Check it out!http://www.landsd.gov.hk/mapping/en/download/download/map/ar9_4e.pdf

Dredging (挖泥 ) is often involved in reclamation

Dredging is the process of excavating Dredging is the process of excavating or moving sand / rock underwater.or moving sand / rock underwater.

What is dredging?What is dredging?

How does dredging affect the How does dredging affect the environment?environment?

Disneyland construction commenced without permission

Evacuation of sand harnesses coral reefs in Po Toi Island

Dredging in East Lamma Channel threatens Lamma fish culture zone

Investigation: Simulation of dredging

Simulation of dredgingTry it yourself!Try it yourself!

Seawater with 30 live brine shrimps

Tank A

no dredging

Start day

No. surviving

Day 1

No. surviving

Day 2

No. surviving

Tank B

with “dredging”

Start day

No. surviving

Day 1

No. surviving

Day 2

No. surviving

“Dredging”: Removal of 40 ml sand per day

Brine shrimp is used to represent the marine organisms

Female Male Larvae

1 cm

1 mm

Dredge sand from the sea!Dredge sand from the sea!

Is the survival of brine shrimp affected Is the survival of brine shrimp affected by dredging? How?by dredging? How?

Is the survival of brine shrimp affected Is the survival of brine shrimp affected by dredging? How?by dredging? How?

What are the differences between the What are the differences between the

water with or without dredging?water with or without dredging?

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Did you notice the blue particles (copper sulphate) after dredging?

They represent some particles that are normally separated from the environment

by sediment.

Once the sediment is removed, they are Once the sediment is removed, they are exposed to the environmentexposed to the environment … …

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What might happen when these particles

What might happen when these particles are released into the environment?are released into the environment?

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How can the observations in Q2 and Q3 help you to explain the impact of

dredging?

Scientists use their imagination in

Scientists use their imagination in making a hypothesis!making a hypothesis!

A hypothesis is based on careful A hypothesis is based on careful

observations.observations.

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What are the limitations of the set-up compared with the real situation?

Discuss!

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Prediction about the impact of dredging in the real world

The EIA involves simulation modeling by computer to determine effects caused by

dredging.

What kinds of data would

be needed in the model to

predict reliably the impact

of dredging?

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What kinds of data would be needed?

• Which factors affect the dispersal of suspended solids?

• Do wave and tidal actions affect the distance traveled by the sediment stirred up?

• How does the type of dredger used affect the amount of suspended solids?

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Collaboration is common between scientists in different

fields

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Extension activity: Pollution indicators

The abundance of an organism or evidence of changes in its physiological processes can indicate

the degree of pollution

Can you name an example?

Organisms showing great changes Organisms showing great changes may be called pollution indicatorsmay be called pollution indicators

What might be the criteria for choosing a species to indicate the degree of pollution?

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Extension Activity 1: Other impacts of reclamation

Try to identify other possible evidence of environmental impact in the drawing!

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What features should the seawall have in order to minimize the impact of reclamation and to withstand wave

action?

A seawall is built before reclamation to withstand wave

action and to minimize the effect of reclamation on the

environment.

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Compare these seawalls

Old style seawall

Seawall built recently

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How did the development of scientific knowledge contribute to the improvement

of seawall design?

Advances in science and engineering enable better design of seawalls which

might reduce loss of microhabitats

In designing the seawall, scientists in different fields collaborate.

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AcknowledgementsChao Yeuk Lan, Crystal

Chow Chi-yui, Shirley