Tides

By: Liam Mell-Cobb, Tess Babington, Paloma Brioschi Serrano,Tony Han

How Tides Work

• Caused by the gravitational pull of the moon and the sun.

• Small tides can occur in large lakes, the atmosphere and within the Earth’s crust.

• The moon’s gravity causes the water to bulge on the side of the earth closest to the moon causing direct high tide. On the opposite side of the Earth the moon is pulling the Earth away from the water causing another outward bulge which is known as indirect high tide.

• When the Earth, moon and sun are aligned they create “spring tides”, which are tides that create the largest daily variation between high and low tides.

• When the sun and moon are at right angles to each other they create Neap Tides which have the lowest daily tidal range.

The Importance of Intertidal Zones●Intertidal Zones are those areas between land and sea that are exposed at low tide and submerged at high tide.●These areas support many different habitats with a diversity of species including organisms that have been able to adapt to environmental extremes such as exposure to rough waves, being in and out of water, and changing temperatures.●Half of the world’s population lives within 100 kilometers of coasts, people depend greatly on intertidal habitats for food and raw materials.

•With the intertidal zone's high exposure to the sun, the temperature range can be anything from very hot, to near freezing in colder climates when not exposed to the sun.●•Legal and political disputes can arise over the ownership and use of the foreshore

The Cause/Impact of Rising Sea Levels●Rising sea levels are mainly due to global warming. The Earth's temperature is rising due to chemicals such as chlorofluorocarbons (CFCs) and carbon dioxide, which is causing glaciers around the world to melt and much of the melted water is ending up in the ocean.

●There is substantial evidence that this has been happening at an increasing rate as the years pass and global warming increases.

●At the current rate of retreat, all of the glaciers in Glacier National Park will be gone by 2070.

●Global sea level has already risen by 4 to 8 inches in the past 100 years.

●The pace of sea level rise appears to be accelerating. The Intergovernmental Panel on Climate Change predicts that sea levels could rise 10 to 23 inches by 2100

Unique Tidal Zones Around The World

Unique Tidal Zones Around The WorldSplash Zone

• Highest tide level where the waves come crashing down onto the rocks.

• Marine animals found here have to be hardy to survive long periods out of water, exposure to sun, and fresh water from rainstorms.

High Zone

• Often remains wet so the dry time is not as long as in the splash zone.

• The creatures need to be strong enough to grip onto the rocks and withstand the pounding waves on their bodies.

Unique Tidal Zones Around The WorldMid Zone

• Usually covered and uncovered twice a day by the ocean’s tidal movements.

• Animals here have evolved to survive underwater and out of water.

Low Zone

• Always underwater

• A variety of sea creatures.

• Animals that live in it love to sneak around under seaweed and hide in crevices.

Questions

1. Which of the following species does NOT live tidal zones?

a) Crabs

b) Mussels

c) Shrimp

d) Eel 2. The Foreshore and Seabed Act declared that the Crown is the owner of the foreshore and seabed (except for the privately owned parts)? True or False3. What has largest effect on the tides?

a) Sun

b) Moon

c) Wind

d) None of the above 4. When do Neap Tides occur?

a) When the sun & moon are furthest away from each other.

b) When the sun & moon are perfectly aligned with the earth.

c) When the sun & moon are at right angles to each other.

d) None of the above.

5. Around about what percentage of the world population lives within 100km of coasts?

A. 30% C. 70%

B. 15% D. 50%6. Which three factors most account for difference in plant and animal life among the three levels of intertidal zones?

A. Change in temperature, type of water, sea-level change

B. Sea-level change, invasive species, weather

C. Change in temperature, sea-level change, increased storminess

D. Weather, invasive species, type of water7. By how much have sea levels risen in the past 100 years?

A)4-8 Inches B) 10-12 Inches C) 7-9 Inches D) 1-17 Inches E) 4-8 Parsecs

8. Which of the following contributes to melting ice caps?

A)LEDs B) CFLs C) SHMs D) THQs E) Impure Thoughts

Critical Questions

1. How would the world be affected if there were no tides?

2. How would the tides be affected if the moon were to shrink or disappear?

3. What is an intertidal zone and what are the three distinct intertidal zones?

4. How can we prevent rising tides on a local, national, and international level?

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