Coastal Environments

Summary

This lecture focuses on coastal environments, highlighting their youth in geologic time and the complex factors shaping them, such as solar energy, atmospheric winds, human activity, and climate change. It explores the littoral zone, sea level dynamics, and the impact of tides, including spring tides caused by the moon and sun. The intertidal zone is also discussed, emphasizing how organisms adapt to fluctuating water levels. Waves and their formation, including the influence of friction and storms, are covered, with a special mention of Typhoon Noru's effects on the east coast of Japan.

Takeaways

• 😀 Coastlines are relatively young in geological terms, although they are ancient compared to human lifespans.
• 🌞 Solar energy plays a key role in atmospheric circulation, influencing climate, weather conditions, and coastal environments.
• 🌊 Waves and currents, generated by atmospheric winds, erode and shape coastlines over time.
• 🏙️ Human activities, such as settlement and pollution, significantly impact coastal environments.
• 🏖️ The littoral zone refers to the coastal area and shallow offshore areas, important for coastal ecosystems.
• 📏 The shoreline marks the contact between land and sea, constantly shifting due to tides, storms, and sea level changes.
• 🌍 Mean sea level serves as a reference for elevation on maps and varies due to ocean currents, waves, tides, winds, tectonics, and climate change.
• 📈 In the past 100 years, the average sea level has risen 8 inches, which is ten times faster than in the last 3,000 years.
• 🌊 The gravitational pull of the moon creates high and low tides, with the moon's effect being stronger than the sun's due to its proximity to Earth.
• ⚡ Spring tides occur when the moon and sun align, leading to larger tides due to their combined gravitational pull.
• 🐚 The intertidal zone is a unique habitat where organisms must adapt to fluctuating tides and harsh wave conditions.

Q & A

What does the term 'coastal environments' refer to?

Coastal environments refer to the areas where land meets the ocean, including the littoral zone and shallow offshore areas. These environments are dynamic, constantly shaped by natural forces like tides, waves, and winds, as well as human activities.

Why are coastlines considered relatively young in geological terms?

Coastlines are considered young because, in geological time, they have formed relatively recently compared to other geological features. While they are old in the context of human history, they are much younger than features like mountain ranges or rock formations that can be millions or even billions of years old.

How does solar energy impact coastal environments?

Solar energy drives atmospheric circulation, which creates climate and weather conditions. These conditions, along with winds and ocean currents, play a significant role in shaping and eroding coastlines over time.

What is the littoral zone?

The littoral zone is the area between the high tide line and the shallow offshore regions, where the water is too deep for storm waves to move sediments on the seafloor. It is an important zone for coastal ecosystems and often serves as a transition zone between land and sea.

What is the importance of mean sea level in coastal studies?

Mean sea level is important as a reference point for all other elevations on a map. It is based on the average tidal levels recorded over long periods and serves as a benchmark for understanding the rise or fall of sea levels due to tides, storms, and long-term geological and climatic changes.

How has sea level changed in the last 100 years?

In the last 100 years, average sea level has risen by 8 inches, a rate that is ten times faster than the average rate over the past 3,000 years. This rise is largely attributed to the effects of climate change and melting polar ice.

What factors contribute to the rise in sea level?

Sea level rise is influenced by a combination of factors, including the melting of ice in places like Antarctica and Greenland, the thermal expansion of water as it warms, and changes in ocean volume caused by climate change and tectonic activity.

What causes tides to occur?

Tides are caused by the gravitational pull of the moon and, to a lesser extent, the sun. The moon's proximity to Earth gives it a stronger gravitational effect, leading to the alternating rise and fall of sea levels, or tides, as Earth rotates.

What are spring tides, and how do they form?

Spring tides occur when the Earth, moon, and sun align. In this alignment, both the moon and the sun exert gravitational pull in the same direction, creating especially large tides. These tides are more extreme than regular high and low tides.

How do intertidal zones affect marine life?

Intertidal zones, which are areas that are covered and uncovered by the ocean as the tides rise and fall, provide unique environments for marine organisms. Species in this zone must adapt to extreme conditions, including fluctuations in temperature, water exposure, and wave impact.