Eco Friendly World - The World's Biomes
Biomes, large regions around the world with similar ecosystems, consist of animals, vegetation, and other living things that have adapted to the specific climates and conditions of any given environment. Biomes can change, and it is believed that these changes may be due to human activities. This has prompted the scientific community to observe, alert, and assist in the conservation and preservation of the world's major biomes. The most commonly known biomes include six major natural settings, such as freshwater, marine, desert, forest, grassland, and tundra habitats. Due to human exploitation, some of these biomes face extinction. In fact, each biome has its own unique threat that may affect its diverse biotic communities with more severe implications.
Freshwater biomes, low-salt concentrated regions with plants and animals having adjusted to their particular habitat, consists of three major environments including ponds and lakes, streams and rivers, and various wetlands. Only freshwater species can survive in a low-salt concentrated environment of 1% lower.
Ponds and lakes usually measure between a few square meters to thousands of square kilometers. Ponds are believed to largely be remnants from the Pleistocene glaciers. Many suspect that the seasonal formation existing in lakes and ponds has limited the species' diversity. Lakes and ponds have three major zones, including the littoral, limnetic, and profundal zones. Each zone is determined by the depth and distance from the shoreline.
- Littoral zone: the uppermost region near the shore of a lake or pond. Due to its shallowness, the littoral zone absorbs the Sun's heat, which enables it to sustain a diverse community of algae, clams, insects, crustaceans, amphibians and fishes.
- Limnetic zone: a well-lighted region near the littoral zone, primarily consists of plankton, phytoplankton, and zoo-plankton. A small variety of fish also occupy this zone.
- Profundal zone: the deepest region of the lake or pond where decaying fish and plankton reside. The profundal zone is much colder and dense than the other two.
Streams and rivers, flowing bodies of water moving in one direction, can be discovered anywhere in nature. Streams and rivers usually start at the headwaters of springs, melting snow, and even the mouths of a water channel or ocean. An abundance of seaweeds, algae, trout and heterotrophs can be found in one of these environments.
Wetlands are bodies of stationary water that do not flow in a particular direction. These natural habitats include all living beings within the marshes. Wetlands are not exclusive freshwater ecosystems. In fact, some wetlands have high salt concentrations, which support various species of animals, including shrimp, shellfish, and sea vegetation.
Marine biomes stretch across 3/4ths of the Earth's surface, including oceans, coral reefs, and estuaries. In fact, marine algae provides much of the Earth's oxygen supply and cycles the vast amount of carbon dioxide emitted into the atmosphere.
Oceans are the biggest of all ecosystems, whereby extensive bodies of water cover the Earth's surface. Some say that though the ocean is not home to as many species of plant and animal life as land, it has a far greater diversity of life. Oceans have four separate zones that mirror ponds and lakes, including the intertidal, pelagic, abyssal, and benthic zones.
- The intertidal zone is the point where the ocean tide meets dry land. The intertidal zone may be submerged or partially exposed, depending on the waves and tides affecting the sea elevation. This fluctuation causes communities to constantly change, especially along rocky shores.
- The pelagic zone is the region commonly referred to as the open ocean. It has fluctuating temperatures, however the waters are typically colder due to the combining of warm and cold ocean water. The flora in the pelagic zone may include sea algae. The fauna includes many different species of fish and mammals.
- The benthic zone (PDF) is located below the pelagic zone, but does not reach into the deepest regions of the ocean. The benthic zone harbors mostly sand, clay, and decaying plant and animal matter. Light is restricted from penetrating through the deeper water, which makes the temperature drop as it nears the abyssal zone.
- The abyssal zone (PDF) is the deepest part of the ocean, where the overall temperature reaches around 3° Celsius. The abyssal zone consists of invertebrates and other fish. It also has underwater ocean ridges, hydrothermal vents, and chemosynthesis.
Other regions of marine biomes include: coral reefs and estuaries. The former consists of captivating barriers along continents, islands, and atolls. Corals can be found in warm shallow waters and have a composition consisting of algae and animal polyp. Corals obtain their nutrition through photosynthesis and plankton floating in nearby waters. Fauna around the coral reef generally includes: tropical fish, urchins, octopuses, sea stars, and invertebrates.
Estuaries (PDF) are regions where freshwater streams merge with the ocean currents. This brackish ecosystem creates different salt concentrations, which provides an environment for varying micro and macro flora, such as seaweeds, marshes, and mangrove trees. Estuaries support a variety of fauna, including worms, oysters, and crabs.
Deserts comprise about 1/5th of the Earth's surface, and are a biome in which less than 50 centimeters of rainfall occurs annually. They are found on various continents throughout the world, including the Sahara in North Africa and various deserts located in the United States, Mexico, and Australia. A cold desert can be found in the lower basins of Utah, Nevada, and western Asia. Deserts have varying plant and animal life, typically only found within the extreme conditions offered in many global regions. Many native plants, vertebrate, and invertebrates produce the necessary nutrients needed to sustain life under harsh conditions. The soils provide an abundance of nutrients, however the plants only need water to bring them to life. Mammals are not generally found in deserts, especially since shelter and food are often limited. There are four major types of deserts, including hot and dry, semiarid, coastal, and cold.
- Hot and dry deserts typically have fluctuating temperatures that exhibit extremes because of the atmosphere's inability to block the Sun's rays. The lack of humidity in the air results in extreme temperature fluctuations. Rainfall hardly ever occurs in hot and dry desert climates. Desert animals are usually nocturnal carnivores that are active at night.
- A semiarid desert generally has long and dry summers; however, these desert regions will receive very low rainfall concentrations. Some estimate that the cold nights help to restore moisture loss from sweating and breathing. The average rainfall average is between 2 and 4 centimeters annually.
- A coastal desert produces cool to moderately warm temperatures during the cold winters. The summer months follow closely behind to create a warmer climate. The average rainfall consists of 8 to 13 centimeters annually. Salt bush, Buckwheat bush, Black bush, rice grass, and more all contribute to their natural desert surrounding.
- A cold desert actually receives snow and high percentages of rainfall during the winter months. Cold deserts are located in the Great Basin of the Colorado Plateau of Arizona, Utah, and Nevada and in western Asia. The soil is heavy and salty with plants wildly scattered throughout the desert. Most of the plants are deciduous. Some of the animals native to these deserts are rodents and jack rabbits.
Ancient plant life began over 420 million years ago during the Silurian Period with arthropods and other land colonizers. In fact, the first forests consisted of giant horsetails, ferns, and club mosses. Gymnosperms later evolved during the Paleozoic Period before dominating the Earth's forests during the Triassic Period. The surface of the planet radically changed during the Pleistocene Ice Ages, which allowed for the formation of the tropical forests in the Northern Hemisphere. Forests currently occupy about 1/3rd of the Earth's landmass and harbor about 2/3rd of land plants. As human populations increase, however, so does the expanse of these magnificent forests. This is mainly due to the destructive behaviors of deforestation, pollution, and industrial expansion. There are three major types of modern forests according to latitude, including tropical, temperate, and boreal.
- Tropical forests have the largest variety of species. Tropical forests are located along the equator, which makes for rainy and dry seasons. The average day lasts for about twelve hours in the tropical forest. The average temperature ranges between 20 and 25 degrees Celsius and rarely varies outside of the aforementioned spectrum. Tropical forests receive over 2,000 milometers of rainfall per year. The soil is acidic and has few nutrients due to rapid decomposition and heavy leaching. Tropical forests have a multi-layered canopy that provides various degrees of light penetration for the native plants and animals.
- Temperate forests are located in eastern North America, northeastern Asia, and Europe. Temperate forests have well-defined seasons, including moderate climate between 140 to 200 days. This allows vegetation and other wild life to grow in the forest during a four to six frost-free month period. The soil is fertile with decaying litter. The temperature varies between negative and positive 30 degrees Celsius. There's an even distribution of rainfall throughout the year.
- Boreal forests represent the most expansive biome. Boreal forests are found in Eurasia and North America, mostly in Siberia and Scandinavia, Alaska, and Canada. The seasons usually consist of short, wet, and warm summers along with cold, dry and very long winters. The growing seasons last for about 130 days in boreal forests.
Grasslands consist of large plots of land that are heavily overtaken by grasses rather than shrubbery and trees. Grasslands originated during the Miocene and Pliocene Epoch periods, which spanned close to twenty five million years ago. Mountains formed in western North America, which created a favorable climate for these lush biomes. As ancient forests declined, grasslands spread in their place, especially following the Pleistocene Ice Ages, where hotter climates had dominated the globe. There are two types of grasslands, including tropical and temperate.
- Tropical grasslands or Savannas consist of scattered trees and shrubbery. Savannas cover close to half of Africa, Australia, South America, and India. Frequent precipitation occurs in these grasslands, with more than 20 to 50 inches of rainfall occurring per year. If the rainfall were more evenly distributed, then these grasslands could eventually become tropical forests. There are three types of savannas, including the climatic savanna, which occur from climate alone; the edaphic savanna, which occur from soil conditions other than fire; derived savannas, which occur due to deforestation. A savanna's soil is porous, allowing for rapid drainage of water. Savannas are often classified as forests, because of the lush vegetation and animal life residing within them, and have both dry and rainy seasons. Fires often occur due to poachers setting fires during a dry season to expel animals from their habitats.
- Temperate grasslands are grasslands with dominant vegetation. Temperate grasslands do not have trees and large shrubbery. Temperatures are varied for summer, rather than winter. Additionally, there is a minimal amount of rainfall in comparison with savannas. The soil is deep and dark in temperate grasslands, with the exception of seasonal droughts. Wide arrays of grasses populate these grasslands, including purple needlegrass, blue grama, and buffalo grass.
The Tundra is a treeless plain, covered with frost and bitter cold temperatures, and they are the coldest biomes on the planet. The little life that thrives in a tundra does so on dead organic material. The two major sources of nutrients are nitrogen and phosphorous. The characteristics of a tundra can be described by the extreme cold, low biotic populations, minimal vegetation, poor drainage, short growing season and reproduction, nutrients pulled from dead organic materials, instead of living organisms, and large population oscillations. There are two types of tundra, including the Arctic and Alpine tundra.
- The Arctic tundra can be located in the northern hemisphere and reaches south to the taiga forests. The Arctic is described as a cold, barren wasteland. The growing season lasts for approximately sixty days. The average temperature ranges below negative 34 degrees Celsius; however, the summer temperatures can reach to negative 12 degrees Celsius, which allows the biome to remain alive. Soil is formed slowly. During the summer, bogs and ponds may form once the snow begins to melt. There are about 1,700 different plant species in the Arctic, including low shrubbery, four hundred varieties of flowers, and lichen. Each of these plants has adapted to the harsh climate conditions.
- The Alpine tundra can be found on mountaintops at a very high altitude where trees cannot possibly grow. The growing season lasts for approximately 180 days. The temperature at night usually ranges below freezing. The soil does have great drainage, however, which allows for the growth of small plants and shrubbery. Small mammals, such as mountain goats, elk, and sheep live in the alpine tundra. Small insects, such as beetles, spring-tails, and butterflies also exist in this region.