A Guide to Different Water Biomes

Water biomes make up about 75% of the earth's surface and are divided into two categories: Freshwater and Marine. Fresh water biomes consist of areas with either no salt or very little salt. These areas include ponds, lakes, rivers and streams. Marine biomes generally have a salt concentration of above 3% and generally include coral reefs, oceans, seas, and estuaries. Brackish water b water that is saltier then normal freshwater, but not as salty as marine water is fairly limited in its ability to provide a home for a diverse number of flora and fauna, so it is not really considered its own biome. Within these two recognized biomes, there are three zones that scientists differentiate between based on how much light each one gets. The first area is called the Photic Zone. This is an area which light comes through well enough to allow for photosynthesis. This area is usually warmer and able to handle a wide range of aquatic plant life. The Aphotic or Profundal Zone does not get enough light to support photosynthesis. This area is usually much darker and colder than the Photic Zone, and doesn't support a wide array of aquatic plant life. The last layer is called the Benthic Zone. This is the bottom of any water biome and is usually comprised of sediment and detritus. Detritus is dead organic matter that falls from the Photic and Aphotic zones. Small community based organisms known as benthos generally call this zone home and feed off the detritus contained within.

Freshwater Biome

Freshwater biomes are basically mirror water ecosystems of the other biomes they are surrounded by. This includes their patterns, speed of flow, and the overall climate of the area. There are two different types of freshwater biome. Standing water, which includes wetlands, lakes, and ponds; and moving water which includes rivers and streams. Wetlands are areas of standing water that are found along streams, ponds and lakes. They can even be holes that have filled with rainwater. Wetlands are not always aquatic biomes. Many wetlands can evaporate during a time known as the "dry season". Lakes and ponds are studied by scientists known as Limnologists. These areas go through cycles known as the "Winterkill" and "Summerkill" that change the water ecosystems. The "Winterkill" refers to a period of time in which a layer of ice covers the surface of the water and blocks out sunlight. This also causes oxygen levels to drop. Some plants and animals can't handle these changes, and thus die off during the winter months. The "summerkill" is the opposite of this. During the summer, the ice melts and oxygen levels begin to rise again. This is a prime condition for algae to grow, which can "suffocate" certain plant and animal life. Rivers and streams do not follow the same cycles as standing water biomes do. Comprised of about 3% of the total freshwater biomes on the planet, they are made up mostly of excess sleet, rain, snow and hail. Sometimes, these rivers and streams carry sediment with them. This sediment can build up and create an artificial land mass called a delta. Except for in desert climates and arctic climates, these moving water biomes rarely dry up or ice over.

Marine Biome

Marine aquatic biomes take up around 75% of the surface of the earth, which is enough to impact the entire climate. For example, rainfall is determined by the amount of evaporated seawater is in the atmosphere, and the temperature of the oceans dictate weather patterns and currents. Plant life in these areas provide large chunk of oxygen to the atmosphere as well as takes a large amount of carbon dioxide. There are five zones within a marine biome in which animals and plants grow. The first zone is known as the Intertidal Zone. This is the area in which the water meets land, usually between low and high tide. This is considered a very harsh area, with only the hardiest of plants and animals being able to survive time both in and out of water. The second zone is the Neritic Zone. This area receives a great deal of sunlight and is generally warmer than the other zones. This is considered the most productive area of the sea, and is where most coral reefs are found. The third zone is known as the Oceanic Pelagic Zone. This is where most of the water in the ocean is found and has the largest variety of sea life. The fourth zone is the Benthic Zone. Like the Benthic Zone of freshwater, this contains detritus and sediment on the ocean floor and is home to many different fungi, seaweed, bacteria and invertebrates. The final zone is the Abyssal Zone. This area has no light or heat, little to no nutrients, and has not been explored as much as the other zones due to its extreme depth and water pressure.

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Written By: Lynn Taylor

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