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2 Water Hyacinth
Aquatic weeds are generating a huge amount of biomass in the aquatic environment.
Some of the well-known aquatic weed species such as Eichhornia crassipes (also
known as water hyacinth), Pistia stratiotes and Salvinia auriculata are rapidly
growing plants [15]. Eichhornia crassipes (Mart.) Solms belongs to the pickerelweed family (Pontederiaceae) and is seen in the tropical and subtropical regions. It
was first seen in Zimbabwe (1937). Afterwards its presence was seen in the Incomati
River in Mozambique (1946) and the Zambezi river and some important rivers in
Ethiopia (1956). In West Africa it was first found between 1997 and 2000. In
Nigeria, almost all rivers are affected by the water hyacinth [16]. It has reached
River Nile Delta in Egypt and also found in southwards. European countries like
France, Hungary, the Netherlands, Belgium, Italy,the Czech Republic and Romania
are also badly affected by this aquatic weed. In Asia, it is found in dense mat on
freshwater wetlands of the Mekong Delta. It has also been observed in the
Sundarbans forest of Bangladesh [17] and the Kaziranga National Park, India. A
freshwater lake, Deepor Beel, formed by the Brahmaputra river, Assam (India), is
highly affected because of this invasive plant [12]. In southern China, the weed has
disturbed the economic, environmental and social life [18]. A catastrophic imbalance has been caused by water hyacinth in the Sacramento-San Joaquin River Delta
in California [19]. It has origin from Amazon basin, but it spreads in lakes and is
slowly moving to rivers as it prefers nutrient-enriched water to grow. It further proliferates by human activities throughout the world in Africa, Asia, Australia and
North America [20] and the countries lying between 40°N and 40°S which include
India, South Africa and the USA. The optimum range of pH to grow water hyacinth
is 6–8, and temperature varies in the range of 1–40 °C, whereas the optimum growth
is observed at 25–27.5 °C. The growth rate of water hyacinth depends mainly on
nitrogen present in water bodies, and it increases with an increase in nitrogen content. It has attractive purple or blue flowers along with oval glossy leaves and bulbous petioles and used as an ornamental plant in many countries. Eichhornia
crassipes is among the top ten worse aquatic weeds [21], and International Union
for Conservation of Nature (IUCN) has listed it in 100 unwieldy invasive plants [22].
Water hyacinth has the potential to grow rapidly, and excessive growth of this
weed destructs the biodiversity. Water hyacinth can cause oxygen depletion, as
dense mat blocks the oxygen transfer from air to water and dissolved oxygen content in the water decreases dominantly apart from depleting the water body of nutrients. The low content of dissolved oxygen catalyses the manumission of phosphorous
residing in the alluvium that is responsible for eutrophication, thereby further accelerating the growth of water hyacinth or algal bloom [23]. It can damage the navigation, fish production, power generation and irrigation [14]. The fisherman faces the
problems because of low fish population, difficulty during access and loss of fishing
equipment. In many rivers water hyacinth has negatively affected the navigation and
water distribution system for agriculture. Water hyacinth dense mat slows the water
flow in the irrigation channels leading to severe flooding. Many hydropower plants
P. V. Ganorkar et al.
2 Water Hyacinth
Aquatic weeds are generating a huge amount of biomass in the aquatic environment.
Some of the well-known aquatic weed species such as Eichhornia crassipes (also
known as water hyacinth), Pistia stratiotes and Salvinia auriculata are rapidly
growing plants [15]. Eichhornia crassipes (Mart.) Solms belongs to the pickerelweed family (Pontederiaceae) and is seen in the tropical and subtropical regions. It
was first seen in Zimbabwe (1937). Afterwards its presence was seen in the Incomati
River in Mozambique (1946) and the Zambezi river and some important rivers in
Ethiopia (1956). In West Africa it was first found between 1997 and 2000. In
Nigeria, almost all rivers are affected by the water hyacinth [16]. It has reached
River Nile Delta in Egypt and also found in southwards. European countries like
France, Hungary, the Netherlands, Belgium, Italy,the Czech Republic and Romania
are also badly affected by this aquatic weed. In Asia, it is found in dense mat on
freshwater wetlands of the Mekong Delta. It has also been observed in the
Sundarbans forest of Bangladesh [17] and the Kaziranga National Park, India. A
freshwater lake, Deepor Beel, formed by the Brahmaputra river, Assam (India), is
highly affected because of this invasive plant [12]. In southern China, the weed has
disturbed the economic, environmental and social life [18]. A catastrophic imbalance has been caused by water hyacinth in the Sacramento-San Joaquin River Delta
in California [19]. It has origin from Amazon basin, but it spreads in lakes and is
slowly moving to rivers as it prefers nutrient-enriched water to grow. It further proliferates by human activities throughout the world in Africa, Asia, Australia and
North America [20] and the countries lying between 40°N and 40°S which include
India, South Africa and the USA. The optimum range of pH to grow water hyacinth
is 6–8, and temperature varies in the range of 1–40 °C, whereas the optimum growth
is observed at 25–27.5 °C. The growth rate of water hyacinth depends mainly on
nitrogen present in water bodies, and it increases with an increase in nitrogen content. It has attractive purple or blue flowers along with oval glossy leaves and bulbous petioles and used as an ornamental plant in many countries. Eichhornia
crassipes is among the top ten worse aquatic weeds [21], and International Union
for Conservation of Nature (IUCN) has listed it in 100 unwieldy invasive plants [22].
Water hyacinth has the potential to grow rapidly, and excessive growth of this
weed destructs the biodiversity. Water hyacinth can cause oxygen depletion, as
dense mat blocks the oxygen transfer from air to water and dissolved oxygen content in the water decreases dominantly apart from depleting the water body of nutrients. The low content of dissolved oxygen catalyses the manumission of phosphorous
residing in the alluvium that is responsible for eutrophication, thereby further accelerating the growth of water hyacinth or algal bloom [23]. It can damage the navigation, fish production, power generation and irrigation [14]. The fisherman faces the
problems because of low fish population, difficulty during access and loss of fishing
equipment. In many rivers water hyacinth has negatively affected the navigation and
water distribution system for agriculture. Water hyacinth dense mat slows the water
flow in the irrigation channels leading to severe flooding. Many hydropower plants
P. V. Ganorkar et al.