Final answer:
Bodies of water are classified as freshwater or saltwater based on their salt content. Freshwater includes lakes, rivers, ponds, streams, deltas, bays, groundwater, and glaciers; saltwater includes oceans, seas, and gulfs. Estuaries and some closed basin lakes may have varied salinity levels.
Step-by-step explanation:
When identifying bodies of water as either fresh or salt water, it's important to consider the salt content and the ecosystem in which they are found. Freshwater biomes, which typically have a salt concentration of less than 1%, include lakes, rivers, ponds, streams, deltas, bays, groundwater, and glaciers and ice caps.
Conversely, oceans, seas, and gulfs are classified as saltwater biomes due to their high salt content. Some water bodies, such as those in closed drainage basins, can concentrate salt and have higher salinity levels even though they may be lakes or ponds.
Estuaries are where water from rivers meets the ocean, creating a brackish environment with a complex and variable salt concentration between that of freshwater and marine levels.
Groundwater, which is one of the largest reservoirs of freshwater, can vary in salinity but is generally categorized as freshwater.
Lastly, the majority of freshwater on Earth, whether accessible to humans or not, is contained in glaciers and ice caps.
Understanding the characteristics of these various bodies of water is essential, not just for academic purposes but also for the conservation and sustainable use of aquatic resources. Freshwater resources are vital for drinking water, crop irrigation, sanitation, and industrial activities - all of which are ecosystem services provided by freshwater biomes.