Salinity

Salinity refers to the concentration of dissolved salts in water. It is an important factor in various Earth science processes, including ocean circulation, climate, and the distribution of marine life. Understanding the concept of salinity is essential in studying the Earth's hydrosphere.

Factors Affecting Salinity

The salinity of water is influenced by several factors:

• Evaporation and Precipitation: When water evaporates, it leaves the salts behind, increasing the salinity. Conversely, precipitation can dilute the water, reducing its salinity.
• Runoff and Erosion: The flow of freshwater from rivers and streams into the ocean can decrease salinity, while erosion of rocks and minerals can increase it.
• Freezing and Melting: When seawater freezes, the salt is left behind, leading to increased salinity in the remaining unfrozen water.

Measurement of Salinity

Salinity is commonly measured in parts per thousand (ppt) or practical salinity units (psu). The average salinity of seawater is about 35 ppt, meaning there are 35 grams of dissolved salts for every 1,000 grams of water.

Effects of Salinity

Salinity has significant impacts on marine life and ocean circulation. Many marine organisms have adapted to specific salinity levels, and abrupt changes in salinity can be harmful to their survival. Variations in salinity also affect the density and buoyancy of water, influencing ocean currents and the global climate.

Study Guide

To understand salinity thoroughly, it is important to focus on the following key points:

1. Define salinity and explain its significance in Earth science.
2. Describe the factors that affect the salinity of water.
3. Explain the methods used to measure salinity.
4. Analyze the effects of salinity on marine life and ocean circulation.

Additionally, conducting experiments to observe the effects of salt on the density of water, and studying the distribution of salinity in different oceanic regions, can provide a practical understanding of this topic.

[Salinity] Related Worksheets and Study Guides:

• Exploring the Oceans/OceanographyScience • Seventh Grade