Aquatic Biomes and Tropical Rainforest Essay

An aquatic biome is an ecological community dominated by water. This biome can be broken down into two categories: oFreshwater, which includes rivers, streams, ponds, lakes and freshwater wetland. oMarine or saltwater, which includes oceans, seas, estuaries, coral reefs and saltwater wetland. Each of these aquatic ecosystems can be defined by variables such as temperature, the presence or absence of light, and the availability of nutrients. Aquatic biomes cover almost all the world (around 75% of the surface) and only 3% of them are freshwaters. Freshwater ecosystems This ecosystem is defined as having a low salt concentration of less than 1%. It helps to make up all the different animals’ life in this planet. Ponds and lakes range in size from few yards to thousands miles across, and they are divided into the littoral zone, limnetic zone and the profundal zone. The littoral zone is the part of the lake or pond which is shallow and located near the shoreline. In this zone there is abundant light, nutrients and plants. Those plants provide protection and food for animals, insects and crustaceans. The limnetic zone is offshore, where the water is deep and it receives enough sunlight to support life. There are tiny forms of life called as phytoplankton, which are tiny plant forms, and zooplankton, which are tiny animal forms. Those tiny forms of life lead to bigger animals’ life such as fish, which feed from those planktons. The profundal zone is beneath the limnetic zone, where it doesn’t receive light to sustain plants’ life. The organisms that die from above this zone settle down and are being eaten by decomposers. Because ponds and lakes are isolated from other bodies of water, they don’t have new species of animals or plant, or it is limited. Streams and rivers are defined by the flow of water in one direction. The source of these regions can be the snowmelt from the mountains, runoff of rains, or the outflows of a lake. They flow until they empty into another body of water and they usually lead ultimately to oceans. The flow of water of streams and rivers changes as it moves. At high elevations (mountains), the water’s flow moves swiftly and makes them clear and oxygenated. As it moves slower, it allows a more diversity of plants and animals. Because the water’s flow moves slowly, it carries more sediment and there is less oxygen in the water. Wetlands are standing water’s regions that support aquatic life. Wetlands can receive many names such as swamps, marshes and bogs. Marine or saltwater This ecosystem is defined by its high salt concentration. Oceans are the large aquatic ecosystem that dominates the Earth’s surface. It is divided into four zones: the intertidal zone, the pelagic zone, the benthic zone and the abyssal zone. The intertidal zone is the area that is covered and uncovered with the rising and falling of tides. Because of this, the communities are constantly changing and most of the living organisms live only where the high tides reach. The pelagic zone is the area away from the lands, which is the open ocean. This zone receives little sunlight and it has abundant plankton, which feed animals such as whales. In this zone, there are still some plants anchored to the bottom of the shore. The benthic zone is beneath the pelagic zone and it doesn’t receive sunlight, which makes it darker and colder. The abyssal zone is the deepest area beneath the benthic zone. This area is very cold, it has a great pressure, but it has a low nutrient level. Coral reefs are abundant in tropical water and it consists of a barrier of corals, anemones, and algae. The sunlight penetrates this area, which makes the water clearer and allows a diversity of living organisms. Estuaries are those areas in which freshwater merge with the ocean. This supports animals such as oysters, worms, and crabs; and supports plants such as algae and seaweeds. Tropical Rainforest Biome This is the most diverse terrestrial biome on Earth. It has a warm and moist environment and is dominated by broadleaf evergreen trees. The combination of constant warmth and moisture makes the tropical rainforest a great environment for many plants and animals, which made this biome as the only one that contains the greatest biodiversity in the world. Because of the great quantity of trees in this biome, the soil is infertile and acidic. This is because when an organism decomposes in the soil, the plants absorb it quickly for their quick grow and survival. This biome has several layers of vegetation. The tallest trees reach approximately 50 meters; below them there is a continuous canopy of treetop of approximately 40 meters. And the lower level is composed by small plants, mosses, and fungi. Most of the fauna in this biome is arboreal because the food near the ground is scarce.