A floating island is a mass of floating aquatic plants, mud, and peat ranging in thickness from several centimeters to a few meters. Sometimes referred to as tussocks, floatons, or suds, floating islands are found in many parts of the world. They exist less commonly as an artificial island. Floating islands are generally found on marshlands, lakes, and similar wetland locations, and can be many hectares in size.
Natural floating islands are composed of vegetation growing on a buoyant mat of plant roots or other organic detritus. In aquatic regions of Northwestern Europe, several hundred hectares or a couple thousand acres of floating meadows (German Schwingrasen, Dutch trilveen) have been preserved, which are partly used as agricultural land, partly as nature reserves.
They typically occur when growths of cattails, bulrush, sedge, and reeds extend outward from the shoreline of a wetland area. As the water gets deeper the roots no longer reach the bottom, so they use the oxygen in their root mass for buoyancy, and the surrounding vegetation for support to retain their top-side-up orientation. The area beneath these floating mats is exceptionally rich in aquatic lifeforms. Eventually, storm events tear whole sections free from the shore, and the islands thus formed migrate around a lake with changing winds, eventually either reattaching to a new area of the shore or breaking up in heavy weather.
Some cenotes in northern Mexico have natural floating islands. [1]
In the Brazilian Amazon, floating islands form in lakes on the floodplains of white-water rivers and are known as Matupá and range in size from a few square meters to a few hectares. [2]
In Crow Wing County, Minnesota a floating bog over four acres (1.6 ha) in size moved about the area resulting in docks and boat lifts being destroyed. As decaying mass decomposes it releases gases which keep the bog floating. [3]
Another type of natural floating island is the pumice raft, which is created by an explosive volcanic eruption, and can float on the ocean for months or even years before becoming fully saturated and sinking. [4] They may assist in the migration of plants and animals. [4]
Floating artificial islands are generally made of bundled reeds, and the best known examples are those of the Uros people of Lake Titicaca, Peru, who build their villages upon what are in effect huge rafts of bundled totora reeds. The Uros originally created their islands to prevent attacks by their more aggressive neighbours, the Incas and Collas.
The Aztec capital, Tenochtitlan, was surrounded with chinampas , small artificial islands used for agriculture known as "floating gardens" (though not really floating). Floating gardens on a large scale have been demonstrated with aquaponics [5] systems in China growing rice, wheat and canna lily on islands. [6]
Spiral Island was a more modern one-person effort to build an artificial floating island, on the Caribbean coast of Mexico. Modern artificial islands mimicking the floating reedbeds of the Uros are increasingly used by local governments and catchment managers to improve water quality at source, reducing pollutants in surface water bodies and providing biodiversity habitat. Examples include Gold Coast City Council [7] in Australia. Artificial floating reedbeds are commonly anchored to the shoreline or bottom of water body, to ensure the system does not float away in a storm event or create a hazard.
During World War II, the British Project Habakkuk proposed the construction of aircraft carriers made of ice-like Pykrete. Its size and speed made it more of an artificial iceberg or island than a ship.
Commercial development of floating islands has begun taking place. Floating habitat islands were installed with salicornia salt marsh plants at Sydney Olympic Park Authority in 2011 [8] providing nesting sites for local and migratory birds including black swans, black-winged stilts, red-necked avocets, Pacific black ducks and chestnut teals, using the Aqua Biofilter product. [9] The world's largest vegetated floating islands 1.6 hectares (4 acres) in size were installed in 2004 using Aqua Biofilter product with canna at Lake Tai, China using materials including a combination of polyurethane open cell filter foam, closed cell polyethylene flotation foam, bamboo and coconut fibre filter foam mix with wicking ability to supply water to plant roots. [10]
A commercially produced floating island was installed in the river otter enclosure at Zoo Montana in 2007. [11] In 2009 and the beginning of 2010, a few larger islands were launched to provide nesting habitat for Caspian tern colonies. The largest of the islands, at a record-setting 44,000 sq ft (4,100 m2), was launched into the water at Sheepy Lake. These islands are a collaboration between the United States Army Corps of Engineers, Oregon State University, and Floating Islands West, a Floating Island International license holder. [12]
A US Army Corps of Engineers project was built in 2012 in The Hideout, Pennsylvania, as part of a watershed management project. The floating island was created to mimic nature; help improve water quality, including reducing phosphorus levels; and buffer habitats against surges in nutrients and pollution. [13]
Buoyancy in artificial floating reedbeds is commonly provided by polyethylene or polyurethane foam, or polyethylene plastic containing air voids. Growth media include coconut fibre; mats made of polyester or recycled PET bottles; synthetic geotechnical mat; jute; soil; and sand.[ citation needed ]
Artificial floating islands are sometimes made by planting cattails and other plants on floating plastic rafts in order to reduce phosphorus levels in the water. [14] In Cleveland's Cuyahoga River floating rafts were made to restore fish populations. [15]
Artificial floating islands have been sought out as structures for different habitational and industrial purposes, [16] e.g. floating oil rigs.
Listed alphabetically by state
Lake Titicaca is a large freshwater lake in the Andes mountains on the border of Bolivia and Peru. It is often called the highest navigable lake in the world. Titicaca is the largest lake in South America both in terms of the volume of water and surface area. It has a surface elevation of 3,812 m (12,507 ft).
In ecology, a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants. More in general, the word can be used for any low-lying and seasonally waterlogged terrain. In Europe and in agricultural literature low-lying meadows that require draining and embanked polderlands are also referred to as marshes or marshland.
Pumice, called pumicite in its powdered or dust form, is a volcanic rock that consists of extremely vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular volcanic rock that differs from pumice in having larger vesicles, thicker vesicle walls, and being dark colored and denser.
Aquaponics is a food production system that couples aquaculture with hydroponics whereby the nutrient-rich aquaculture water is fed to hydroponically grown plants.
Phragmites is a genus of four species of large perennial reed grasses found in wetlands throughout temperate and tropical regions of the world.
Puno is a department and region in southeastern Peru. It is the fifth largest department in Peru, after Cuzco, Madre de Dios, Ucayali, and Loreto. It is bordered by Bolivia on the east, the departments of Madre de Dios on the north, Cusco and Arequipa on the west, Moquegua on the southwest, and Tacna on the south. Its capital is the city of Puno, which is located on Lake Titicaca in the geographical region known as the Altiplano or high sierra.
A constructed wetland is an artificial wetland to treat sewage, greywater, stormwater runoff or industrial wastewater. It may also be designed for land reclamation after mining, or as a mitigation step for natural areas lost to land development. Constructed wetlands are engineered systems that use the natural functions of vegetation, soil, and organisms to provide secondary treatment to wastewater. The design of the constructed wetland has to be adjusted according to the type of wastewater to be treated. Constructed wetlands have been used in both centralized and decentralized wastewater systems. Primary treatment is recommended when there is a large amount of suspended solids or soluble organic matter.
Ethylene-vinyl acetate (EVA), also known as poly(ethylene-vinyl acetate) (PEVA), is a copolymer of ethylene and vinyl acetate. The weight percent of vinyl acetate usually varies from 10 to 50%, with the remainder being ethylene. There are three different types of EVA copolymer, which differ in the vinyl acetate (VA) content and the way the materials are used.
The Uru or Uros are an indigenous people of Bolivia and Peru. They live on a still-growing group of about 120 self-fashioned floating islands in Lake Titicaca near Puno. They form three main groups: the Uru-Chipaya, Uru-Murato, and Uru-Iruito. The Uru-Iruito still inhabit the Bolivian side of Lake Titicaca and the Desaguadero River.
A reedbed or reed bed is a natural habitat found in floodplains, waterlogged depressions and estuaries. Reedbeds are part of a succession from young reeds colonising open water or wet ground through a gradation of increasingly dry ground. As reedbeds age, they build up a considerable litter layer that eventually rises above the water level and that ultimately provides opportunities in the form of new areas for larger terrestrial plants such as shrubs and trees to colonise.
A hydrosere is a plant succession which occurs in an area of fresh water such as in oxbow lakes and kettle lakes. In time, an area of open freshwater will naturally dry out, ultimately becoming woodland. During this change, a range of different landtypes such as swamp and marsh will succeed each other.
Totora is a subspecies of the giant bulrush sedge. It is found in South America, notably on Lake Titicaca, the middle coast of Peru and on Easter Island in the Pacific Ocean. The genus Schoenoplectus is closely related to Scirpus and sometimes included therein. This plant can reach a height of 6 m (20 ft) and commonly reaches 4 m (13 ft). The word totora comes from the Quechua language.
Schoeneoplectus californicus is a species of sedge known by the common names California bulrush, southern bulrush and giant bulrush. It is also sometimes called "tule", but the closely related Schoenoplectus acutus is the species most often referred to by that name.
Lake Orestiada or Lake of Kastoria is a lake in the Kastoria regional unit of Macedonia, northwestern Greece. It spreads out in a natural basin, surrounded by mountains and is the remnant of a huge ancient Miocene lake that reached an area of 164 square kilometres and at a depth of 50 meters. Sitting at an altitude of 630 metres, the lake covers an area of 28 square kilometres with a coastline that reaches 34 km. The maximum depth of the lake reaches about 9 meters and the average depth 4.5 meters.
Cardiff Bay Wetlands Reserve is located in Cardiff Bay in the city of Cardiff. It covers an area of approximately 8 hectares. The area was officially opened as a wildlife reserve on 25 July 2002 in what was previously an area of Site of Special Scientific Interest (SSSI) up until the opening of the Cardiff Bay Barrage in April 2001. The area had previously been salt marsh, but the Barrage created 200 hectares of freshwater lake, and from this the reserve was developed.
Reed boats and rafts, along with dugout canoes and other rafts, are among the oldest known types of boats. Often used as traditional fishing boats, they are still used in a few places around the world, though they have generally been replaced with planked boats. Reed boats can be distinguished from reed rafts, since reed boats are usually waterproofed with some form of tar. As well as boats and rafts, small floating islands have also been constructed from reeds.
Floating reedbeds are artificial or natural systems consisting of buoyancy and reeds. Plants including rice and wheat can be cultivated on floating reedbeds. The primary purpose of artificial floating reedbeds is to improve water quality through biofiltration, preventing algal blooms through denitrification and plant nutrient uptake, with a secondary benefit of habitat provision.
Recirculating aquaculture systems (RAS) are used in home aquaria and for fish production where water exchange is limited and the use of biofiltration is required to reduce ammonia toxicity. Other types of filtration and environmental control are often also necessary to maintain clean water and provide a suitable habitat for fish. The main benefit of RAS is the ability to reduce the need for fresh, clean water while still maintaining a healthy environment for fish. To be operated economically commercial RAS must have high fish stocking densities, and many researchers are currently conducting studies to determine if RAS is a viable form of intensive aquaculture.
A floating mat is a layer of mosses and other, especially stoloniferous, plants that grows out from the shore across the surface of a lake or pond. This type of habitat is protected and is designated in the European Habitats Directive as "LRT No. 7140 Transition and Floating Mat Bogs".
The Integrated Aqua-Vegeculture System (iAVs),also informally known as Sandponics, is a food production method that combines aquaculture and horticulture (olericulture). It was developed in the 1980s by Dr. Mark McMurtry and colleagues at North Carolina State University including Professor Doug Sanders, Paul V. Nelson and Dr. Merle Jensen. This system is one of the earliest instances of a closed-loop aquaponic system.
