Function

• Algae play a large and vital role in various human-made and natural processes. Algae are used for fertilizer on farms and soil conditioner in home gardens. Algae is also used in various alternative energy systems for the production of diesel and hydrogen. Similarly, algae is grown as a fuel in factories and to create electricity.
  
  Algae is also used to clean natural and human-made water systems due to their ability to capture waterborne toxins and excess nutrients. On a different level, algae are also used as a food ingredient for humans and animals, a base for scientific ingredients and cosmetics, and to feed cultured seafood such as fish and shellfish.
  
  

Significance

• The thousands of different types of algae compose a significant portion of various environmental processes. Algae are the base of the planet's oceanic food chains, acting as feed for plankton which go on to feed the rest of the ocean's life forms. Because it is the basic building block for the ocean's food system, the earth's entire ecosystem would collapse without algae to support it.
  Algae also process carbon dioxide, playing a large role in the management of earth's greenhouse gasses. Algae acts as a significant for commercial human operations, acting as a significant ingredient in various nutritional supplements and foods, commercial farm fertilizers, and scientific experiments (in the form of agar).
  
  

Types

• According to the Smithsonian National Museum of Natural History, there are more than 300,000 types of algae. Two types of algae most commonly encountered by humans are seaweed and the fine, green scum that appears in ponds, lakes, rivers and aquariums. Some types of algae are basic, single-cell organisms that free-float in aquatic environments and never achieve a larger state.
  
  Others, such as seaweed, grow to more complex, plant-like levels just like their land-based plant relatives. Such seaweeds can be divided into three basic types: Brown, red and green algae. Green algae are the most developed and come closest to land-based plant forms in terms of its level of complexity.
  
  

Geography

• Various scientists and reports have indicated differing numbers and statistics regarding the geographic and ecological distribution of algae. Of the more than 300,000 types of algae, 20,000 of them are found in Europe alone. Some are more site-specific. For example, South Africa alone is home to over 350 types of algae.
  
  Ecologically, algae are distributed in mostly ocean-based environments, though some can be found in humid, moist land environments. In general, algae have been collected and cataloged in warm to cold ecologies, centered in the more central locations of the Atlantic and Pacific oceans. Antarctica and similarly cold environments host far less of a number of algae species than more temperate geographic zones.
  
  

Prevention/Solution

• Algae sometimes become a problem when they grow at an uncontrollable pace in undesirable locations such as backyard ponds, lakes and aquariums. Such a sudden growth of algae is referred to as an "algae bloom." Such spurts of algae growth can lead to clogged waterways and unsightly green, brown or red water (depending on the species of algae involved). Uncontrolled algae growth can also block sunlight from reaching lower levels of the water, effectively killing other aquatic plants.
  
  Algae blooms usually result when more nutrients are present in the water than are being used. Thus, the first method of preventing algae growth is keeping high-nutrient runoff (such as fertilizer runoff from farms) from entering the waterway. Planting other aquatic plants can also help keep nutrient levels down and prevent an algae bloom.
  
  Mechanical forms of algae removal include water skimmers and commercial UV sterilizers that pass water through a UV filter that kills the algae.