BIOMESMajor regional ecological community of plants and animals
Aquatic Biomes• Water makes up the largest part of the biosphere, covering nearly 75% of the Earth’s surface.• The aquatic biome can be broken down into two basic regions: freshwater (i.e, ponds and rivers) and marine (i.e, oceans and estuaries).
Freshwater Region• Freshwater is defined as having a low salt concentration—usually less than 1%.• There are different types of freshwater regions: ponds and lakes, streams and rivers, and wetlands.Lakes and ponds• Lakes and ponds are inland depressions containing standing water varying in depth from 1 m to over 2000 m.• Ponds are small shallow bodies of water that rooted plants can grow over the bottom; lakes are usually large.• They are divided into zones based on the penetration of light.• The major zones (from the topmost) are the littoral or shallow water zone, limnetic or open water zone and the profundal zone
Streams and rivers• These are bodies of flowing water moving in one direction.• Streams and rivers get their starts at headwaters, which may be springs, snowmelt or even lakes, and then travel all the way to their mouths, usually another water channel or the ocean.• The characteristics of a river or stream change during the journey from the source to the mouth.• The water is also clearer, has higher oxygen levels, and freshwater fish such as trout and heterotrophs can be found there.• Towards the middle part of the stream/river, the width increases, as does species diversity—numerous aquatic green plants and algae can be found.• Toward the mouth of the river/stream, the water becomes murky from all the sediments that it has picked up upstream, decreasing the amount of light that can penetrate through the water.
Wetlands• Wetlands are areas of standing water that support aquatic plants.• Marshes, swamps, and peatlands are all considered wetlands.• Marsh-dominated by herbaceous vegetation; swamps- forested wetlands; peatlands- wetlands that is accumulated with decayed organic matter• Plant species adapted to the very moist and humid conditions are called hydrophytes (e.g. pond lilies, cattails, sedges, tamarack, and black spruce).•• Wetlands have the highest species diversity of all ecosystems. Many species of amphibians, reptiles, birds (such as ducks and waders), and furbearers can be found in the wetlands.
Marine Regions• Marine regions cover about three-fourths of the Earth’s surface• include oceans, coral reefs, and estuaries.Oceans• The largest of all the ecosystems, oceans are very large bodies of water that dominate the Earth’s surface.• The ocean regions are separated into separate zones: intertidal, pelagic, abyssal, and benthic.• The intertidal zone is where the ocean meets the land—sometimes it is submerged and at other times exposed, as waves and tides come in and out.• The pelagic zone includes those waters further from the land, basically the open ocean.• The benthic zone is the area below the pelagic zone, but does not include the very deepest parts of the ocean The deep ocean is the abyssal zone.
Coral reefs• Coral reefs are an accumulation of dead skeletal material• Coral reefs are widely distributed in warm shallow nutrient-poor waters. They can be found as barriers along continents, fringing islands, and atolls.• the dominant organisms in coral reefs are corals.• Corals are modular animals, anemone-like cylindrical polyps with prey- capturing tentacles• It also include several species of microorganisms, invertebrates, fishes, sea urchins, octopuses, and sea stars.
Estuaries• Estuaries are areas where freshwater streams or rivers merge with the ocean. It is the place where freshwater joins salt water.• Estuaries are semienclosed parts of the coastal ocean where seawater is diluted• Microflora like algae, and macroflora, such as seaweeds, marsh grasses, and mangrove trees (only in the tropics), can be found here.• Estuaries also support a variety of worms, oysters, crabs, and waterfowl.
Terrestrial Biomes• The terrestrial biomes include the desert, chaparral, savanna, temperate grassland, temperate rain forest, tropical rain forest, temperate deciduous forest, taiga (coniferous, needle leaf or boreal forests), and tundra (artic and alpine) biomes. Distribution of the Earths eight major terrestrial biomes
Desert• Deserts occupy about 26% of the Earths surface area.• Deserts are characterized by low rainfall and generally receive fewer than 10 inches of rain a year..• Rain itself is infrequent and comes in the form of thunderstorms. Since the rate of evaporation is high, the rain provides only brief periods of rapid growth.• Temperatures vary greatly, creating both "cold" deserts (mean annual temperature ranges of 0 to 15°C) and "hot" deserts (mean annual temperatures ranges of 15 to 30°C).• Desert soils are generally low in organic matter and high in calcium carbonate and soluble salts. The surface is composed of a mosaic of closely packed sand, pebbles and boulders. Because of the reduced plant cover, desert soils are easily eroded by wind and rain.• Both plants and animals are adapted to scarcity of water either by drought evasion or by drought resistance
Chaparral• Chaparrals (temperate shrublands) occur predominately in the transition zones between desert and temperate forest biomes.• Chaparrals are characterized by hot, dry summers and mild rainy winters.• Dense, spiny shrubs with tough evergreen leaves dominate these areas.• The combination of dry summers and dense shrub vegetation create ideal conditions for frequent fires. Thus, chaparral can be considered a “fire maintained” ecosystem.• Chaparral soils are fragile with low to moderate fertility. They are easily eroded, particularly after a fire.• To prevent desiccation many plants have adapted by having small leathery leaves and becoming dormant during the dry season. The animal biodiversity is high in both vertebrates and invertebrates species.
Savanna• Savannas are tropical grasslands with scattered individual trees.• Most are found in transitional climate zones between tropical rainforest and desert biomes.• Savannas are characterized by warm year-round temperatures. Annual precipitation occurs during the summer wet season. Fires are frequent during the dry season.• Soils are poor, being low in nutrients and permeability. They tend to retain water near the surface during the wet season.• Vegetation consists of low-growing grasses, forbs (small broad-leaf plants), deciduous trees and shrubs that are scattered against an open park-like landscape. Trees are also adapted to being fire-resistance.• Savannahs are populated with wandering animals that move in response to seasonal variation in food and water (e.g. wildebeest, rhinos, water buffalos, warthogs, gazelles, zebras, giraffes, antelope, and elephants).
Temperate Grassland• Temperate grasslands are characterized by hot summers and cold winters• grassland soils are very fertile and rich in organic material.• The soil is held in place by a thick network of intertwining roots of drought- tolerant perennial grasses.• Temperate grasslands are dominated by herbaceous vegetation which is adapted to periodic drought and fire conditions. The grasslands are generally treeless, with trees and shrubs being limited to the edges of streams and rivers. Wildflowers are abundant and include anemones, ranuculus, iris and others.• A number of grazing mammals prevails. A large variety of small herbivores such as prairie dogs, mice, rabbits, squirrels, grouse, and meadowlarks predominate. They intern are preyed upon by fox, wolves, coyotes, ferrets, snakes and birds of prey (hawks and eagles).
Temperate Rain Forest• Temperate rain forests are dominated by dense stands of large coniferous trees.• The ocean moderates the climate so that winters are mild and summers are cool. Rain and fog from ocean currents create a very moist climate• Soil is nutrient-poor with high organic content.• In the North American temperate rain forests large evergreen trees, such as western hemlock, Sitka spruce, Douglas fir and red woods, dominate. Epiphytes are common and include several species of mosses, lichens, and ferns. Deciduous shrubs, such as vine maple are found in open areas.• a dense vegetation biomass reminiscent of tropical rain forests is present but dominated by only a few tree species.• Squirrels, mule deer, elk, and many species of birds, reptiles and amphibians are the common wildlife in this biome.
Tropical Rain Forest• Tropical rain forests are broadleaf evergreen forests, which contain the highest diversity of plant and animal species on Earth.• Because the major tropical rain forests are found near the equator, where hot moisture-laden air rises and dumps its moisture, they are characterized by year-round warmth and high rainfall.• Tropical rain forests soils are often nutrient-poor, acidic, thin, and low in organic matter. Most of the nutrients are stored in the living biomass of the rain forest vegetation.• Because of the warm moist climate and high number of decomposers (bacteria, fungi, and soil invertebrates), nutrients are quickly recycled by rapid decomposition.• There is an enormous number of species residing on this biome (insectivorous and carnivorous mammals and birds etc.)• Insects numbers in millions
Temperate Deciduous Forest• Temperate deciduous forests are found where there is sufficient moisture to support the growth of large trees.• Deciduous trees have a distinct annual rhythm in which the trees drop their leaves, become dormant in winter, and produce new leaves each spring.• Temperate deciduous forests are characterized by seasonally cold winters and warm summers.• Soils consist of fertile topsoil, rich in organic material, and a clay-rich lower layer.• Temperate deciduous forests are dominated by a few species of broadleaf deciduous trees such as oak, maple, polar, sycamore, beech, and hickory. Herbs are found at the lowest level, followed by a layer of shrubs, then by shade tolerant under story trees and finally the canopy of large mature trees.• A rich diversity of birds, mammal, insects and reptiles are found at all levels. These include deer mice, squirrels, fox, bear, white-tailed deer, opossums and raccoons. Gone, however are the larger mammals, including the woodland bison, wolves, mountain lions (puma) and bobcats. Many species of birds also occur. These include grouse, woodcock, woodpeckers, owls, hawks, warblers etc.
Taiga• Taigas are also known as coniferous or boreal forest. Covering about 11% of the earths land surface, they are the largest terrestrial biome on earth.• The taiga zone includes a variety of climate conditions, from moderate to severe. Overall winters are cold and long and summers are mild and short. Because of low temperatures, evaporative rates are low and drought is infrequent.• Taiga soils are thin, nutrient poor, and acidic.• Taigas are dominated by evergreen conifers such as spruce, fir, cedar, hemlock, tamarack, and pine. The small, needle-shaped, wax-coated leaves are adapted to withstand the intense cold and drought of winter. Willows, aspen, and birch occur sporadically, particularly in new growth areas. Because of acidic and nutrient-poor soils there are relatively few herbaceous plants under the thick forest canopy.• Some of the more common large mammals found in taigas are elk, moose, wolves, and bears. Smaller mammals include hare, rodents, lynx, wolverine, porcupines, and squirrels. Several species of resident birds are present, such as crossbills, nutcrackers, warblers, grouse, and jays. Insects, particularly flies and mosquitoes are common, but amphibians and reptiles are less prevalent and may be absent in some areas.
Tundra• Tundra means marshy plain.• The tundra biome is characterized by an absence of trees, the presence of dwarf plants, and a ground surface that is wet, spongy, and hummocky.• Soils of this biome are usually permanently frozen starting at a depth of a few centimeters to meter or more.• Within this biome, temperature, precipitation, and evaporation all tend to be at a minimum. Most tundra locations, have summer months with an average temperature below 10 degrees Celsius.• The species diversity of tundra vegetation is relatively small. Plant communities are usually composed of a few species of dwarf shrubs, a few grass species, sedges, and mosses.• The principal herbivores in this biome include caribou, musk ox, arctic hare, voles, and lemmings. Most of the bird species of the tundra have the ability to migrate and live warmer locations during the cold winter months. The herbivore species support a small number of carnivore species like the arctic fox, snow owl, polar bear, and wolves. Reptiles and amphibians are few or completely absent because of the extremely cold temperatures.