All About Water

Tropical and Subtropical Grasslands

The grassland, known as savanna, is located climates in which rainfall mostly occurs during one time of the year, followed by a long drought period that is punctuated by fires that prevent trees from growing. Humans can also have this effect by overuse and underplanting of trees, as shown in a study conducted by the University of California.

Temperate Grassland

The great prairies of the Americas are temperate grasslands, but they are also found in Europe and South America. They have less rainfall than the forested regions that typically surround the grassland, and that, in conjunction with the fires that sweep through the grassland in times of drought, and the grazing of animals, keep them grassy. Many regions of temperate grassland throughout the world have been converted to prime farm land, and the pollution of over fertilization has had an impact on them.

Flooded Grassland

Flooded grasslands are typified, of course, by water. The most familiar example if the Florida Everglades, but the grassland can also be found in Africa and South America. Flooded grasslands are very vulnerable to water pollution, and the runoff from over fertilization of farmlands can cause algae blooms that kill native flora and fauna. In a sweeping and encouraging project, the restoration of the Everglades is being attempted.

Montane Grassland

Montane grassland is a derived habitat, the grassland that has come about at the disturbance of human activity. It is extensive in Africa, where it is caused by overgrazing. It can support little wildlife because of this, and the characteristically short grasses would soon give way to reforesting if the livestock were removed.

Tundra

The coldest places in the world are mostly covered with tundra, the grassland which is noted for the low temperatures year round, and low precipitation. The permafrost layer found only inches below the surface prevents the growth of trees. The tundra does not heal quickly because of the short growing seasons, so traces of human disturbance can be found for a very long time. The Canadian Geotechnical Journal has conducted a study showing the damage even a walking trail can leave on this biome.

Desert, or Xeric Grassland

Xeric, or desert, grasslands are kept grassy not by the frequent fires of their damper cousins, but by lack of rainfall, which prevents the development of deep root systems needed to support trees. The grasses in a xeric biome are more noted for their capacity to store water than to spread quickly, as grasses elsewhere must to dominate. Because of this, there is more diversity of plants in a xeric grassland than in a prairie. According to a study conducted by M Halassy between the two main types of grassland, the temperate grassland, and the xeric grassland, they account for about 85% of the world’s plants that reproduce not by seed, but by cloning themselves through production of runners.

For more information on water and biomes, check out Role of Water in Ecosystems and Biomes

Desert Climate

Deserts cover approximately one-fifth of the earth’s surface, mostly in low latitudes, though some occur in colder, northern climates. The University of California at Berkeley defines deserts as regions that have less than 50 cm of rain per year. Because of low humidity and lack of cover from trees, temperature swings of up to 100 degrees Fahrenheit are possible between day and night.

Plant and Animal Life

The harsh conditions of the desert support a great diversity of highly-specialized plant and animal life. Both plants and animals tend to be small, reducing the need for water. Cacti tend to have small root systems, absorbing most of their water from the atmosphere. Ground-hugging shrubs and trees have thick, leathery leaves that reflect heat and offer shade. Kangaroo rats, reptiles, toads and snakes are joined by rabbits and coyotes. According to Marietta College, most desert animals are nocturnal, burrowing underground or staying in the shade of plants for protection from scorching daytime heat.

Water Conservation

Life forms in the desert have species-specific ways of conserving precious water. Cacti store water in thick or thin fleshy stems, covered with spines that repel predators. According to the U.S. National Park Service, mesquite trees have root systems that sink and spread up to 75 feet in search of underground moisture. Toads in the desert burrow underground, covering themselves in a gelatinous secretion that holds moisture as they remain dormant between rainy periods. Perhaps the most famous desert animal, the camel, stores water in its hump, enabling it to travel great distances without dying of thirst between oases.

Soil Conditions

Soil conditions in the desert biome vary according to type.  Desert biomes can be classified as: coastal, arid, semi-arid or cold.  Coastal deserts like those in Chile have soils that are less salty and finer in texture. The semi-arid desert soils of the American west are coarse and gravely, and the arid deserts of Ethiopia are a mix of sand and rock particles, according to the University of California at Berkeley.  The cold deserts in parts of western Asia have soil that is heavy, salty, and silty.  As a general rule, the more rainfall the desert receives, the higher the salt content of the soil, making cold deserts far saltier than arid ones. All desert soils are porous and rainfall drains out of them rapidly.

Impact of Water Pollution

Because water is so scarce in the desert, any water pollution is a problem. Air pollution from elsewhere affects the desert in the form of acid rains, polluting the soil. Over time, chemicals leach into underground aquifers and water tables. Pollutants from vehicle exhaust have a similar effect over years of accumulation.  These sources of desert pollution will continue to be a concern for years to come.

For more information on water and biomes, check out Role of Water in Ecosystems and Biomes

The Freshwater Biome

The freshwater biome is one of our most precious ecosystems. It provides us our drinking water and a resource for agriculture, sanitation, industry and food. Forty percent of all known fish species make their home in freshwater. The freshwater biome includes ponds and lakes, streams and rivers, wetlands, reservoirs, and groundwater.

Because freshwater ecosystems are found throughout the world, their climates are highly variable. However, they are quite vulnerable to climate change in general. When water runoff patterns change, or the water temperature increases, the habitat is damaged.

Animal Life in the Freshwater Biome

The freshwater ecosystem is home to a diverse number of lifeforms, including vertebrates like fish, reptiles, amphibians, birds and mammals; invertebrates like worms, mollusks and protozoa; algae; plants; and fungi. The base of the biome food chain is composed of zooplankton and phytoplankton.

Many species native to the freshwater biome are in real danger. These include freshwater mussels (two-thirds of the species are endangered and a tenth are extinct), crayfish (half of all crayfish species are endangered), stoneflies (over forty percent are at risk), freshwater fish and amphibians (forty percent of these species are at risk), dragonflies and damselflies (eighteen percent of these species are at risk), and freshwater snails (fifty percent are endangered or extinct).

Plant Life in the Freshwater Biome

Thousands of different plant species live in the freshwater biome. They may live along the edge, like cattails; at the bottom of lakes and ponds; in areas that are only temporarily flooded; in hill and mountain springs; in the flowing water of rivers and streams; or rooted in waterlogged soil.  Most aquatic plants are widely distributed across the globe; this is often due to human activity, such as the transportation of seeds or fruit. However, animals also aid in the distribution. Aquatic plants adapt to the water zones mostly by changing their leaf structure. The three basic leaf patterns of aquatic plants are submersed leaves, which are thin, narrow, and highly flexible; floating leaves, which are flexible but firm and leathery to withstand currents; and aerial leaves, which are similar to those of nearby terrestrial plants.

An Ecosystem in Danger

Freshwater rivers and streams are among the most endangered ecosystems on the planet. Rates of endangered and extinct freshwater species are a cause for concern. According to a report by The Nature Conservancy, since European settlers first landed on North America, twenty-one out of the 822 fish species native to America have become extinct. The southeastern United States appears to be the location most at risk. Major threats to the freshwater biome include agricultural and urban runoff, dams and water diversion, the introduction of invasive species, exploitation, climate change, and pollution.

For more information on water and biomes, check out Role of Water in Ecosystems and Biomes

Tropical Rainforests: The Good, The Bad, and The Facts

The Destruction of the Rainforest