Describe the characteristics of a marine biome.

A marine biome is a large aquatic ecosystem that covers approximately 71% of the Earth's surface. It is characterized by its saltwater environment, which is found in oceans, seas, and other bodies of saltwater. Some key characteristics of a marine biome include:

1. Salinity: Marine biomes have high salinity levels due to the presence of dissolved salts in the water. The average salinity of seawater is about 3.5%.

2. Biodiversity: Marine biomes are incredibly diverse, supporting a wide range of plant and animal species. They are home to various marine organisms such as fish, mammals, reptiles, invertebrates, and a vast array of marine plants like seaweeds and algae.

3. Depth and Zones: Marine biomes can be divided into different zones based on depth, including the intertidal zone, neritic zone, oceanic zone, and abyssal zone. Each zone has distinct characteristics and supports different types of organisms.

4. Temperature: The temperature in marine biomes can vary depending on the location and depth. Surface waters are influenced by solar radiation and tend to be warmer, while deeper waters are colder and more stable.

5. Light Availability: Light penetration decreases with depth in marine biomes. This affects the distribution of photosynthetic organisms, with most primary production occurring in the upper layers where sunlight is abundant.

6. Adaptations: Marine organisms have evolved various adaptations to survive in their environment. Some examples include streamlined bodies for efficient swimming, gills for extracting oxygen from water, and the ability to withstand high pressure in deep-sea environments.

7. Human Impact: Marine biomes are facing numerous threats due to human activities, including pollution, overfishing, habitat destruction, and climate change. These impacts can disrupt the delicate balance of marine ecosystems and harm marine life.

Overall, marine biomes are vital for the health of our planet, providing essential resources, regulating climate, and supporting a diverse range of life forms.