Aquatic plant

Aquatic plants are plants that have adapted to living in aquatic environments (saltwater or freshwater). They are also referred to as hydrophytes or macrophytes. A macrophyte is an aquatic plant that grows in or near water and is either emergent, submergent, or floating, and includes helophytes (a plant that grows in marsh, partly submerged in water, so that it regrows from buds below the water surface).[1] In lakes and rivers macrophytes provide cover for fish and substrate for aquatic invertebrates, produce oxygen, and act as food for some fish and wildlife.[2]

Aquatic plants require special adaptations for living submerged in water, or at the water's surface. The most common adaptation is aerenchyma, but floating leaves and finely dissected leaves are also common.[3][4][5] Aquatic plants can only grow in water or in soil that is permanently saturated with water. They are therefore a common component of wetlands.[6]

Fringing stands of tall vegetation by water basins and rivers may include helophytes. Examples include stands of Equisetum fluviatile, Glyceria maxima, Hippuris vulgaris, Sagittaria, Carex, Schoenoplectus, Sparganium, Acorus, yellow flag (Iris pseudacorus), Typha and Phragmites australis.

Nymphaea alba
The flower of Nymphaea alba, a species of water lily
Nelumbo nucifera LOTUS bud
Bud of Nelumbo nucifera, an aquatic plant.

Distribution

The principal factor controlling the distribution of aquatic plants is the depth and duration of flooding. However, other factors may also control their distribution, abundance, and growth form, including nutrients, disturbance from waves, grazing, and salinity.[6]

Evolution

Aquatic vascular plants have originated on multiple occasions in different plant families;[3][7] they can be ferns or angiosperms (including both monocots and dicots). Seaweeds are not vascular plants; rather they are multicellular marine algae, and therefore are not typically included among aquatic plants. A few aquatic plants are able to survive in brackish, saline, and salt water.[3] The only angiosperms capable of growing completely submerged in seawater are the seagrasses.[8] Examples are found in genera such as Thalassia and Zostera. Although most aquatic plants can reproduce by flowering and setting seed, many also have extensive asexual reproduction by means of rhizomes, turions, and fragments in general.[4]

One of the largest aquatic plants in the world is the Amazon water lily; one of the smallest is the minute duckweed. Many small aquatic animals use plants like duckweed for a home, or for protection from predators, but areas with more vegetation are likely to have more predators. Some other familiar examples of aquatic plants might include floating heart, water lily, lotus, and water hyacinth.

Classification of macrophytes

Based on growth form, macrophytes can be classified as:

  • Emergent macrophytes
  • Floating-leaved macrophytes
  • Submerged macrophytes
  • Free floating macrophytes

Emergent

An emergent plant is one which grows in water but which pierces the surface so that it is partially in air. Collectively, such plants are emergent vegetation.

This habit may have developed because the leaves can photosynthesize more efficiently above the shade of cloudy water and competition from submerged plants but often, the main aerial feature is the flower and the related reproductive process. The emergent habit permits pollination by wind or by flying insects.

There are many species of emergent plants, among them, the reed (Phragmites), Cyperus papyrus, Typha species, flowering rush and wild rice species. These may be found growing in fens but usually less well owing to competition from other plants. Some species, such as purple loosestrife, may grow in water as emergent plants but they are capable of flourishing in fens or simply in damp ground.[9]

Floating-leaved

Floating-leaved macrophytes have root systems attached to the substrate or bottom of the body of water and with leaves that float on the water surface. Common floating leaves macrophytes are water lilies (family Nymphaeaceae), pondweeds (family Potamogetonaceae).

Submerged

Submerged macrophytes completely grow under water with root attached to the substrate (e.g. Myriophyllum spicatum) or without any root system (e.g. Ceratophyllum demersum).

Free-floating

Free-floating macrophytes are aquatic plants that are found suspended on water surface with their root not attached to substrate or sediment or bottom of water body. They are easily blown by air and provide breeding ground for mosquito. Example include Pistia spp commonly called water lettuce, water cabbage or Nile cabbage

Morphological classification

FloatingRedBlueLilies
Water lilies grow rooted in the bottom with leaves that float on the water surface.

The many possible classifications of aquatic plants are based upon morphology.[3] One example has six groups as follows:[10]

  • Amphiphytes: plants that are adapted to live either submerged or on land
  • Elodeids: stem plants that complete their entire lifecycle submerged, or with only their flowers above the waterline
  • Isoetids: rosette plants that complete their entire lifecycle submerged
  • Helophytes: plants rooted in the bottom, but with leaves above the waterline
  • Nymphaeids: plants rooted in the bottom, but with leaves floating on the water surface
  • Pleuston: vascular plants that float freely in the water
Marchantiales cf Conocephalum 20071111
Many liverworts grow either submerged or on land.
CeratophyllumSubmersum
Ceratophyllum submersum, a free-floating plant that grows completely submerged
Waterlettuce
Pistia stratiotes, an example of a pleuston, a plant that floats freely on the water surface
Lysichton americanus in Lochnabo Burn, Scotland
Lysichiton americanus grows rooted in the bottom with leaves and flowers above the waterline.

Functions of macrophytes in aquatic system

Macrophytes perform many ecosystem functions in aquatic ecosystems and provide services to human society. One of the important functions performed by macrophyte is uptake of dissolve nutrients (N and P) from water.[11] Macrophytes are widely used in constructed wetlands around the world to remove excess N and P from polluted water.[12] Beside direct nutrient uptake, macrophytes indirectly influence nutrient cycling, especially N cycling through influencing the denitrifying bacterial functional groups that are inhabiting on roots and shoots of macrophytes.[13] Macrophytes promote the sedimentation of suspended solids by reducing the current velocities,[14] impede erosion by stabilising soil surfaces.[15] Macrophytes also provide spatial heterogeneity in otherwise unstructured water column. Habitat complexity provided by macrophytes like to increase the richness of taxonomy and density of both fish and invertebrates.[16]

Uses and importance

Food crops

World aquaculture production of food fish and aquatic plants, 1990-2016
World aquaculture production of food fish and aquatic plants, 1990–2016

Some aquatic plants are used by humans as a food source. Examples include wild rice (Zizania), water caltrop (Trapa natans), Chinese water chestnut (Eleocharis dulcis), Indian lotus (Nelumbo nucifera), water spinach (Ipomoea aquatica), and watercress (Rorippa nasturtium-aquaticum).

Watershed health indicators

A decline in a macrophyte community may indicate water quality problems and changes in the ecological status of the water body. Such problems may be the result of excessive turbidity, herbicides, or salinization. Conversely, overly high nutrient levels may create an overabundance of macrophytes, which may in turn interfere with lake processing.[2]

Macrophyte levels are easy to sample, do not require laboratory analysis, and are easily used for calculating simple abundance metrics.[2]

Potential sources of therapeutic agents

Phytochemical and pharmacological researches suggest that freshwater macrophytes, such as Centella asiatica, Nelumbo nucifera, Nasturtium officinale, Ipomoea aquatica and Ludwigia adscendens, are promising sources of anticancer and antioxidative natural products.[17]

Hot water extracts of the stem and root of Ludwigia adscendens, as well as those of the fruit, leaf and stem of Monochoria hastata were found to have lipoxygenase inhibitory activity. Hot water extract prepared from the leaf of Ludwigia adscendens exhibits alpha-glucosidase inhibitory activity more potent than that of acarbose.[18]

See also

References

  1. ^ Hickey, M.; King, C. (2001). The Cambridge Illustrated Glossary of Botanical Terms. Cambridge University Press.
  2. ^ a b c "Macrophytes as Indicators of freshwater marshes in Florida" (PDF). Retrieved 2014-04-05.
  3. ^ a b c d Sculthorpe, C. D. 1967. The Biology of Aquatic Vascular Plants. Reprinted 1985 Edward Arnold, by London.
  4. ^ a b Hutchinson, G. E. 1975. A Treatise on Limnology, Vol. 3, Limnological Botany. New York: John Wiley.
  5. ^ Cook, C.D.K. (ed). 1974. Water Plants of the World. Dr W Junk Publishers, The Hague. ISBN 90-6193-024-3.
  6. ^ a b Keddy, P.A. 2010. Wetland Ecology: Principles and Conservation (2nd edition). Cambridge University Press, Cambridge, UK. 497 p.
  7. ^ Tomlinson, P. B. 1986. The Botany of Mangroves. Cambridge, UK: Cambridge University Press.
  8. ^ "Alismatales". Angiosperm Phylogeny Website. Missouri Botanical Garden.
  9. ^ Swearingen, Jil M. (7 July 2009). "PCA Alien Plant Working Group - Purple Loosestrife (Lythrum salicaria)". National Park Service. Retrieved 24 September 2011.
  10. ^ Westlake, D.F., Kvĕt, J. and Szczepański, A. 1998. The Production Ecology of Wetlands. Cambridge University Press, Cambridge. 568 p.
  11. ^ Brix, H. (1997) Do macrophytes play a role in constructed treatment wetlands?. Water Science and Technology, 35, 11-17
  12. ^ Vymazal, J. (2013) Emergent plants used in free water surface constructed wetlands: A review. Ecological Engineering, 61, 582-592.
  13. ^ Hallin, S., Hellman, M., Choudhury, M.I. & Ecke, F. (2015) Relative importance of plant uptake and plant associated denitrification for removal of nitrogen from mine drainage in sub-arctic wetlands. Water Research, 85, 377-383.
  14. ^ Zhu, M.Y., Zhu, G.W., Nurminen, L., Wu, T.F., Deng, J.M., Zhang, Y.L., Qin, B.Q. & Ventela, A.M. (2015) The Influence of Macrophytes on Sediment Resuspension and the Effect of Associated Nutrients in a Shallow and Large Lake (Lake Taihu, China). PLoS ONE, 10.
  15. ^ Horppila, J., Kaitaranta, J., Joensuu, L. & Nurminen, L. (2013) Influence of emergent macrophyte (Phragmites australis) density on water turbulence and erosion of organic-rich sediment. Journal of Hydrodynamics, 25, 288-293.
  16. ^ Thomaz, Sidinei M.; Dibble, Eric D.; Evangelista, Luiz R.; Higuti, Janet; Bini, Luis M. (2007). "Influence of aquatic macrophyte habitat complexity on invertebrate abundance and richness in tropical lagoons". Freshwater Biology: 071116231725007––. doi:10.1111/j.1365-2427.2007.01898.x.
  17. ^ Chai TT, Ooh KF, Quah Y, Wong FC (2015) Edible freshwater macrophytes: a source of anticancer and antioxidative natural products—a mini-review. Phytochemistry Reviews 14(3): 443–457
  18. ^ Ooh KF, Ong HC, Wong FC, Sit NW, Chai TT (2014) High performance liquid chromatography profiling of health-promoting phytochemicals and evaluation of antioxidant, anti-lipoxygenase, iron chelating and anti-glucosidase activities of wetland macrophytes. Pharmacognosy Magazine 10(39): 443-455.

External links

Aquatic weed harvester

An aquatic weed harvester, also known as a water mower, mowing boat and weed cutting boat, is an aquatic machine specifically designed for inland watercourse management to cut and harvest underwater weeds, reeds and other aquatic plant life. The action of removing aquatic plant life in such a manner has been referred to as "aquatic harvesting".

Armatimonadetes

Armatimonadetes is a phylum of gram-negative bacteria.

Biddle Street, Yatton

Biddle Street, Yatton (grid reference ST423648) is a 44.8 hectare biological Site of Special Scientific Interest (SSSI) near the village of Yatton in North Somerset, notified in 1994.

Management practices and the variation in the soils has resulted in the watercourses supporting a wide range of aquatic plant

communities. Where open water occurs plants such as Common Water-starwort (Callitriche stagnalis), European Frogbit (Hydrocharis morsusranae), Fan-leaved Water-crowfoot (Ranunculus circinatus). The calcareous influence of the

underlying Compton soils also encourages Whorled Water-milfoil (Myriophyllum verticillatum) and Stonewort (Chara sp). Also present are the nationally scarce Rootless Duckweed (Wolffia arrhiza) and Hairlike Pondweed (Potamogeton trichoides).A rich invertebrate fauna is also associated with the rhynes and ditches including aquatic beetles including populations of two

nationally rare species, Hydacticus transversalis and Britain's largest water beetle, the Great Silver Water Beetle (Hydrophilus piceus). A number of dragonflies and damselflies are also found in the watercourses including the nationally scarce Variable Damselfly (Coenagrion pulchellum). Strong populations of the Common Freshwater Mussel occur as does the nationally rare Pea Mussel (Pisidium pseudosphaerium).

Eichhornia crassipes

Eichhornia crassipes, commonly known as common water hyacinth, is an aquatic plant native to the Amazon basin, and is often a highly problematic invasive species outside its native range.

Herstmonceux Park

Herstmonceux Park is a 4.3-hectare (11-acre) biological Site of Special Scientific Interest south of Herstmonceux in East Sussex.This narrow stream valley has seven examples of wetland habitats on Tunbridge Wells sandstone and it is notable for its fen vegetation. The site is the location of two plants which are rare in south-east England, milk-parsley and Cornish moneywort. There are several artificial ponds which have a variety of aquatic plant species.A public footpath runs through the site

Hippuris vulgaris

Hippuris vulgaris (from Greek: ἵππος — horse and οὐρά — tail), known as mare's-tail or common mare's-tail, is a common aquatic plant of Eurasia and North America ranging from Greenland to the Tibetan Plateau to Arizona. It prefers non-acidic waters.

Holland Haven Marshes

Holland Haven Marshes is a 208.8 hectare biological Site of Special Scientific Interest north-east of Clacton-on-Sea in Essex. It is an L shaped site which stretches along the coast from Frinton-on-Sea to Holland-on-Sea, and then north along the Holland Brook. It includes Holland Haven Country Park, a 22.1 hectare Local Nature Reserve owned and managed by Tendring District Council.A network of ditches radiates from Holland Brook, and these have several nationally scarce aquatic plant species, such as brackish water crowfoot and divided sedge. The site also has grasslands which are botanically important. There are also rare invertebrates, including the Red Book soldier fly Stratiomys singularior. There are many breeding and wintering birds. The country park has a bird hide, parking and toilets.There is access to the country park from a coastal footpath, but much of the site is on private land with no public access.

Hottonia palustris

Hottonia palustris, also water violet or featherfoil, is an aquatic plant in the family Primulaceae.

Hydrocharitaceae

Hydrocharitaceae is a flowering plant family including 16 known genera with a total of ca 135 known species (Christenhusz & Byng 2016 ), that including a number of species of aquatic plant, for instance the tape-grasses, the well known Canadian waterweed and frogbit Hydrocharis morsus-ranae.

The family includes both fresh water and marine aquatics. They are found throughout the world in a wide variety of habitats, but are primarily tropical.

Myriophyllum spicatum

Myriophyllum spicatum (Eurasian watermilfoil or spiked water-milfoil) is native to Europe, Asia, and north Africa, but has a wide geographic and climatic distribution among some 57 countries, extending from northern Canada to South Africa. It is a submerged aquatic plant, grows in still or slow-moving water, and is considered to be a highly invasive species.

North Moor

North Moor (grid reference ST325305) is a 676.3 hectare biological Site of Special Scientific Interest near Lyng in Somerset, notified in 1986.

North Moor is a nationally important grazing marsh and ditch system on the Somerset Levels and Moors. A range of neutral grassland types supporting common and scarce plants has developed mainly due to variations in soils and management practices. Aquatic plant communities are exceptionally diverse with good populations of nationally scarce species. The site has special interest in its bird life.North Moor was flooded during the Winter flooding of 2013–14 on the Somerset Levels.

Nuphar lutea

Nuphar lutea, the yellow water-lily, or brandy-bottle, is an aquatic plant of the family Nymphaeaceae, native to temperate regions of Europe, northwest Africa, and western Asia.

Padma (attribute)

Padma (Nelumbo nucifera, the sacred lotus) is an aquatic plant that plays a central role in Indian religions such as Hinduism, Buddhism, Sikhism, and Jainism. The lotus flower has many different names such as the "Indian Lotus", the "Sacred Lotus", and the "Bean of India".

Pistia

Pistia is a genus of aquatic plant in the arum family, Araceae. The single species it comprises, Pistia stratiotes, is often called water cabbage, water lettuce, Nile cabbage, or shellflower. Its native distribution is uncertain, but probably pantropical; it was first discovered from the Nile near Lake Victoria in Africa. It is now present, either naturally or through human introduction, in nearly all tropical and subtropical fresh waterways and considered an invasive species as well as a mosquito breeding habitat. The genus name is derived from the Greek word πιστός (pistos), meaning "water," and refers to the aquatic nature of the plants.

Ranunculetum fluitantis

Ranunculetum fluitantis is one of the 24 Aquatic plant communities (A18) included in the British National Vegetation Classification (NVC).

The vegetation type or community comprises stands of submerged vegetation dominated by clumps of River water crowfoot. Few other plants are found with any frequency among the denser stands but there can be Myriophyllum; Potamogeton perfoliatus and patches of moss on submerged stones.

Rheophyte

A rheophyte is an aquatic plant that lives in fast moving water currents in an environment where few other organisms can survive. Rheophytes tend to be found in currents that move at rates of 1 to 2 meters per second and that are up to 3 to 6 feet deep. The amount of force produced by these currents, and the damaging debris they can carry, makes this environment inhospitable to most plants. Rheophytes are able to live in such environments because their leaves are streamlined so as put up little resistance to the flow of water. The leaves tend to be quite narrow and flexible as well. In order to prevent the plants from being uprooted, Rheophytes have an extremely strong wide spreading root systems.

Many Rheophytes live in areas that sustain flash floods and they are dependent on the oxygenated water and buoyancy brought along with it. Simply being an aquatic plant with narrow leaves is not a sufficient condition for being a Rheophyte. Also, plants that grow in slow moving water that occasionally receive fast currents aren't Rheophytes either if they don't need these fast currents to survive. Plants that fall into this category are known as facultative rheophytes. When low water levels occur Rheophytes often quickly begin to flower to take advantage of these occurrences.

Stanford End Mill and River Loddon

Stanford End Mill and River Loddon is an area of natural grassland, between Beech Hill and Swallowfield in Berkshire, incorporating a stretch of the River Loddon and a mill built in early Victorian times on the Stratfield Saye estate. It was designated a Site of Special Scientific Interest (SSSI) in 1952, and expanded in 1986. The site is of interest mainly because of two rare plants: the fritillary (Fritillary meleagris), a native bulb, and the Loddon pondweed (Potamogeton nodosus), a rare aquatic plant. The area supports a wide range of native meadow plants, and the river supports a variety of coarse fish species, water voles and nesting birds, including little grebe, moorhen, coot, mute swan and kingfisher.

Tobico Marsh

Tobico Marsh, located just north of Bay City, Michigan, is part of the Bay City Recreation Area. Tobico Marsh was designated as a registered National Natural Landmark in 1976 because of its large size, relatively undisturbed condition and variety of aquatic plant life. With nearly 2,000 acres (8.1 km2) of wetland woods, wet meadows, cattail marshlands and oak savannah prairies, Tobico Marsh is one of the largest remaining freshwater, coastal wetlands on the Great Lakes.

West Moor SSSI

West Moor (grid reference ST420220) is a 213.0 hectare (526.3 acre) biological Site of Special Scientific Interest on the River Parrett in Somerset, notified in 1985.

West Moor lies south of Curry Rivel, Langport, and Drayton, and northwest of Kingsbury Episcopi and is part of the extensive grazing marsh grasslands and ditch systems of the Somerset Levels and moors. The site contains some of the most diverse aquatic plant communities in the country. Rhynes often have a rich aquatic flora Frogbit (Hydrocharis morsus-ranae). A rich invertebrate fauna, with many nationally and locally rare species is associated with the botanical diversity of the ditches.

Aquatic ecosystems
Generally
Classification systems
Organizations

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