Sea level changes

What are the two types of sea level changes?

Eustatic and Isostatic.

What causes eustatic sea level changes?

Changes in the volume of water in the sea or changes in the shape of ocean basins.

What are the main causes of eustatic sea level rise?

1) Climate changes, increase in temp leading to ice sheet melting and thermal expansion of water. decrease in temp causes more precipitation to fall as snow, increases the volume of water stored in glaciers and so reduces the volume of the sea, which decreases sea level

2) Tectonic movements altering ocean basin shape.

How does temperature affect sea level?

• An increase in temperature causes ice sheets to melt and water to expand, raising sea level.

• A decrease in temperature leads to more snow accumulation, reducing sea level.

What is isostatic sea level change?

It is caused by vertical movements of the land relative to the sea.

What happens to sea level when land undergoes downward movement?

Sea level rises locally

What causes local sea level to fall?

Uplift of land.

What are the main causes of isostatic sea level changes?

1) Uplift or depression of the Earth's crust due to ice sheet dynamics

2) Subsidence from groundwater abstraction

3) Tectonic processes at plate margins

What factors cause daily variations in sea level?

• The tidal cycle

• onshore winds

• low atmospheric pressure systems

What is the effect of tectonic movements on eustatic sea level?

They can alter the shape and volume of ocean basins, affecting sea level.

What is the relationship between sediment accumulation and isostatic change?

Accumulation of sediment can cause depression of the land.

How does the melting of ice sheets influence isostatic uplift?

It can lead to slow uplift of land for thousands of years after the glacier retreats.

What is the impact of groundwater abstraction on land and sea level?

It can cause subsidence of land, leading to local sea level rise.

What role do tectonic processes play in isostatic sea level changes?

They can cause vertical movements of the Earth's crust, affecting local sea levels.

What is the significance of the last glacial period in relation to sea level?

During this period, water was stored in ice sheets, resulting in lower sea levels.

How does climate change affect sea level on a global scale?

It can lead to both rising sea levels through ice melt and thermal expansion, and falling sea levels through increased glacier accumulation.

What is the impact of sea floor spreading on sea level?

It increases the volume of ocean basins, which can decrease sea level.