Describe biome A biome is a large region of Earth that has a certain climate and certain types of living things. Major biomes include tundra, forests, grasslands, and deserts. The plants and animals of each biome have traits that help them to survive in their particular biome. ... Each biome has many ecosystems. Temperature and precipitation, and variations in both, are key abiotic factors that shape the composition of animal and plant communities in terrestrial biomes. Some biomes, such as temperate grasslands and temperate forests, have distinct seasons, with cold weather and hot weather alternating throughout the year. Topography of Sea The term “topography” implies the study of numerous landforms that exist on or below the earth. Ocean floor topography refers to the different forms in which the ocean floor bottom can exist. You may perceive the ocean floor to be flat and sandy like the beach, but the truth is there are many different surfaces. As scientific knowledge has advanced, the capability to envisage these remote sites has increased significantly. Science has established that the topography of the ocean floor is similar to the ground topography with features such as valleys, mountains, and plateaus. Three quarters of the Earth consists of ocean water. All these details are incorporated on underwater topography maps. Features of the ocean include the continental shelf, slope, and rise. The ocean floor is called the abyssal plain. Below the ocean floor, there are a few small deeper areas called ocean trenches. Features rising up from the ocean floor include seamounts, volcanic islands and the mid-oceanic ridges and rises. MARINE AND FRESH WATER The main difference between freshwater and marine life is the habitat they come from in the wild. Freshwater fish live in streams, rivers and lakes that have salinity of less than 0.05 percent. Depending on the species, fish can survive in temperatures ranging from 5 and 24 degrees Celsius. They can adapt to a change in habitat, like the rise and fall in water levels, temperature and oxygenation levels. Marine life refers to fish living in oceans and seas. These are also known as saltwater fish because they can only stay alive in waters with high salinity levels. A marine animal's habitats include coral reef and seagrass bed. FOOD WEB AND FOOD CHAIN IN MARINE A food web consists of many food chains. A food chain only follows just one path as animals find food. eg: A hawk eats a snake, which has eaten a frog, which has eaten a grasshopper, which has eaten grass. A food web shows the many different paths plants and animals are connected. A food chain is a single pathway connecting a producer with several levels of consumers. In a typical marine food chain, dinoflagellates convert energy from sunlight into food through photosynthesis and store it in their tissues. Marine food webs describe the linkages between all living organisms found in the marine environment. At a basic level, every plant and animal species depends on another plant or animal species for its survival. This interdependency can be explored in predator–prey relationships or food chains. EUTHROPICATION Eutrophication is the enrichment of an ecosystem with chemical nutrients, typically compounds containing nitrogen, phosphorus, or both. Eutrophication can be a natural process in lakes, occurring as they age through geological time. Eutrophication was recognized as a pollution problem in European and North American lakes and reservoirs in the mid-20th century. Human activities can accelerate the rate at which nutrients enter ecosystems. Runoff from agriculture and development, pollution from septic systems and sewers, and other humanrelated activities increase the flux of both inorganic nutrients and organic substances into terrestrial, aquatic, and coastal marine ecosystems (including coral reefs). ZONES AND DEPTH OF SEA The Oceanic zone is typically defined as the area of the ocean lying beyond the continental shelf, but operationally is often referred to as beginning where the water depths drop to below 200 meters (660 feet), seaward from the coast to the open ocean. There are four ocean zones: the Sunlight zone, the Twilight zone, the Midnight zone, and the Abyssal zone. The average depth of the ocean is about 12,100 feet . The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam. SEA CREATURES The term deep sea creature refers to organisms that live below the photic zone of the ocean. These creatures must survive in extremely harsh conditions, such as hundreds of bars of pressure, small amounts of oxygen, very little food, no sunlight, and constant, extreme cold. Most creatures have to depend on food floating down from above.