Why is it that the seashore is not self-supporting ecosystem?

A biome is an ecosystem containing plant and animal species that are characteristic of a specific geographic region. An ecosystem is the community of plants and animals in an area considered together with their environment. The nature of a biome is determined primarily by climate, including a region's annual average temperature and amount of rainfall. Biomes are often named for the vegetation found within them. They can be classified as terrestrial (land), aquatic (water), or anthropogenic (heavily modified by humans). Some familiar examples of biomes include tundra, desert, chaparral, and open ocean. The accompanying drawing shows the variety of biomes that can be found along just two lines of longitude on Earth 's surface