Sea Water vs. Water

Attribute	Sea Water	Water
Taste	Salty	Neutral
Source	Ocean	Various sources (e.g. rivers, lakes)
Salinity	3.5%	Varies
Color	Blue	Clear
Minerals	High concentration	Varies

Introduction

Water is an essential element for all living organisms on Earth. It covers about 71% of the Earth's surface and is found in various forms such as rivers, lakes, oceans, and glaciers. One of the key distinctions in the types of water is between sea water and fresh water. Sea water is found in oceans and seas, while fresh water is found in rivers, lakes, and underground aquifers. In this article, we will compare the attributes of sea water and fresh water.

Composition

Sea water is composed of about 96.5% water and 3.5% dissolved salts, with the most abundant being sodium and chloride ions. On the other hand, fresh water contains very low levels of dissolved salts, usually less than 0.05%. This difference in composition is due to the continuous evaporation and precipitation cycle that occurs in the water bodies. Sea water also contains various other elements and compounds such as magnesium, calcium, and sulfate ions, which give it its characteristic salty taste.

Salinity

The salinity of sea water is around 35 parts per thousand, which means that there are 35 grams of dissolved salts in every kilogram of sea water. This high salinity makes sea water unsuitable for drinking or irrigation without desalination. In contrast, fresh water has a much lower salinity level, making it safe for consumption by humans and other animals. The low salinity of fresh water also makes it ideal for agricultural purposes, as it does not harm plants or soil.

Freezing Point

Sea water has a lower freezing point than fresh water due to its higher salt content. The freezing point of sea water is around -2°C, while the freezing point of fresh water is 0°C. This is why oceans and seas do not freeze over completely, even in extremely cold temperatures. Fresh water, on the other hand, freezes at 0°C, which is why lakes and rivers can freeze over in winter. The lower freezing point of sea water also has implications for marine life, as it allows organisms to survive in cold ocean waters.

Density

Sea water is denser than fresh water due to its higher salt content. The density of sea water is around 1025 kg/m³, while the density of fresh water is around 1000 kg/m³. This difference in density has various effects on the behavior of water bodies. For example, sea water tends to sink below fresh water, leading to the formation of layers in oceans and seas. The density difference also affects the buoyancy of objects in water, with objects floating higher in sea water compared to fresh water.

Corrosiveness

Sea water is more corrosive than fresh water due to its higher salt content. The salts in sea water can accelerate the corrosion of metals and other materials, making it important to use corrosion-resistant materials in marine environments. Fresh water, on the other hand, is less corrosive and is often used for cooling systems and other industrial applications where corrosion is a concern. The corrosiveness of sea water is also a factor in the degradation of marine structures such as ships and offshore platforms.

Ecosystems

Sea water supports a wide range of marine ecosystems, including coral reefs, kelp forests, and deep-sea habitats. These ecosystems are home to a diverse array of plant and animal species, many of which are adapted to the high salinity and other unique characteristics of sea water. Fresh water ecosystems, on the other hand, include rivers, lakes, and wetlands, which support their own unique plant and animal communities. These ecosystems are often more vulnerable to pollution and habitat destruction due to their limited size and connectivity.

Conclusion

In conclusion, sea water and fresh water have distinct attributes that make them suitable for different purposes. Sea water is characterized by its high salinity, density, and corrosiveness, while fresh water is known for its low salinity, freezing point, and suitability for drinking and irrigation. Both types of water play crucial roles in supporting life on Earth and must be managed sustainably to ensure the health of ecosystems and human populations.