Aquatic biomes are unique ecosystems primarily defined by their physical and chemical environments rather than climate and vegetation, as seen in terrestrial biomes. These biomes are categorized into two main types: freshwater and marine biomes. Freshwater biomes, which include lakes, rivers, and streams, have low salt concentrations, typically less than 0.1%. In contrast, marine biomes, encompassing the world's oceans, have higher salt concentrations, around 3%.
Interestingly, freshwater biomes make up only about 3% of Earth's total water, while marine biomes dominate, accounting for approximately 97%. This significant difference highlights the vastness of marine environments compared to their freshwater counterparts. As we delve deeper into the study of aquatic biomes, we will first explore freshwater ecosystems before transitioning to marine biomes, providing a comprehensive understanding of these vital habitats.