General sketch-map of a tidal plain, showing the typical tripartition in supratidal
zones. The most apparent character of the area is the development of tidal channels, affecting mainly the intertidal zone
. In this case, the tidal flat is protected seaward by a beach barrier
, but in many cases (low-energy waves
and longshore currents
) the tidal flats may directly pass into a shallow marine environment.
Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and marine animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily.
In the past tidal flats were considered unhealthy, economically unimportant areas and were often dredged and developed into agricultural land. Several especially shallow mudflat areas, such as the Wadden Sea, are now popular among those practising the sport of mudflat hiking.
On the Baltic Sea coast of Germany in places, mudflats are exposed not by tidal action, but by wind-action driving water away from the shallows into the sea. These wind-affected mudflats are called windwatts in German.
Tidal flats, along with intertidal salt marshes and mangrove forests, are important ecosystems. They usually support a large population of wildlife, and are a key habitat that allows tens of millions of migratory shorebirds to migrate from breeding sites in the northern hemisphere to non-breeding areas in the southern hemisphere. They are often of vital importance to migratory birds, as well as certain species of crabs, mollusks and fish. In the United Kingdom mudflats have been classified as a Biodiversity Action Plan priority habitat.
The maintenance of mudflats is important in preventing coastal erosion. However, mudflats worldwide are under threat from predicted sea level rises, land claims for development, dredging due to shipping purposes, and chemical pollution. In some parts of the world, such as East and South-East Asia, mudflats have been reclaimed for aquaculture, agriculture, and industrial development. For example, around the Yellow Sea region of East Asia, more than 65% of mudflats have been destroyed over the past 50 years.
Mudflat sediment deposits are focused into the intertidal zone which is composed of a barren zone, marsh and salt pan. Within these areas are various ratios of sand and mud that make up the sedimentary layers. The associated growth of coastal sediment deposits can be attributed to rates of subsidence along with rates of deposition (example: silt transported via river) and changes in sea level.
Barren zones extend from the lowest portion of the intertidal zone to the marsh areas. Beginning in close proximity to the tidal bars, sand dominated layers are prominent and become increasingly muddy throughout the tidal channels. Common bedding types include laminated sand, ripple bedding, and bay mud. Bioturbation also has a strong presence in barren zones.
Marshes contain an abundance of herbaceous plants while the sediment layers consist of thin sand and mud layers. Mudcracks are a common as well as wavy bedding planes. Marshes are also the origins of coal/peat layers because of the abundant decaying plant life.
Salt pans can be distinguished in that they contain thinly laminated layers of clayey silt. The main source of the silt comes from rivers. Dried up mud along with wind erosion forms silt dunes. When flooding, rain or tides come in, the dried sediment is then re-distributed.
Selected example areas
- Arcachon Bay, France
- Banc d'Arguin, Mauritania
- Great Rann of Kutch, India
- Belhaven, East Lothian Scotland, United Kingdom
- Bridgwater Bay and Morecambe Bay, United Kingdom
- Cape Cod Bay, Massachusetts, United States
- Cook Inlet, Alaska, United States
- Lindisfarne Island, England, United Kingdom
- Minas Basin, Nova Scotia, Canada
- Green Beach, Incheon, South Korea
- Padilla Bay, Washington, United States
- Plymouth Bay, Massachusetts, United States
- Port of Tacoma, Washington, United States
- Skagit Bay, Washington
- Snettisham Norfolk England, United Kingdom
- Wadden Sea: Netherlands, Germany, Denmark
- West coast of Andros Island, Bahamas
- Yellow Sea, China, Korea
- Moreton Bay, Queensland, Australia
- ^ Dredging Indian River Lagoon Wetlands 1920 - 1950s
- ^ Tidal flat habitats
- ^ Mud crab (Scylla serrata) culture in tidal flats with existing mangroves
- ^ Manko - Tidal Flat, Mangrove Forest
- ^ MacKinnon, J.; Verkuil, Y.I.; Murray, N.J. (2012), IUCN situation analysis on East and Southeast Asian intertidal habitats, with particular reference to the Yellow Sea (including the Bohai Sea), Occasional Paper of the IUCN Species Survival Commission No. 47, Gland, Switzerland and Cambridge, UK: IUCN, p. 70, ISBN 9782831712550
- ^ Murray, N.J.; Clemens, R.S.; Phinn, S.R.; Possingham, H.P.; Fuller, R.A. (2014), "Tracking the rapid loss of tidal wetlands in the Yellow Sea", Frontiers in Ecology and the Environment 12 (5): 267–272, doi:10.1890/130260/
- ^ a b c d e Reineck, H.E, and I.B Singh, Deposistional Sedimentary Enviornments, 2nd Ed. New York: Springer-Verlag Berlin Heidelberg, 1980, pp. 418-428
||Wikimedia Commons has media related to Mudflat.
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http://thebuffleheadbirder.com/ - a Killdeer chick searches for worms and small insects in the muddy shore along a pond. This little bird proved itself to be...
Chris Lowther created this short film for the Raincoast Education Society's "More Than Just Mud" MiNiFLiCK Contest to celebrate the Tofino Mudflats Wildlife ...
Bottlenose Dolphin: Mudflat Hunting
In a strange hunting technique, Bottlenose Dolphins in Georgia and South Carolina waters not only drive fish ashore but throw themselves onto land to collect...
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Watch as Ice Team pro Matt Johnson demonstrates a technique to catch big walleyes that are using a big mud flat out on Mille Lacs in MN. Same technique could...
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Due to the development of the new London Gateway Port extending into mudflats, AECOM designed a new earth embankment to allow the old riverbank to be breache...
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http://www.laricciamediaproductions.com Mudflat Studio in Somerville Massachusetts, Wayne Fuerst, Teacher demonstrates pottery making at Grand Opening 9-10-1...
This is The West Country
This is The West Country
Tue, 05 Aug 2014 23:40:40 -0700
COASTGUARDS in Burnham used hovercrafts to rescue a man in difficulty on the mudflats a mile from the shore. Beach lifeguards at Berrow raised the alarm after spotting the struggling walker and volunteers from BARB search and rescue, along with ...
Fri, 29 Aug 2014 06:30:00 -0700
This year's festival got off to an inauspicious start when rainstorms delayed its opening, turning the desert venue to a mudflat. Festival-goers' cars are prohibited onsite due to safety concerns, and a temporary transit system instituted for the ...
New York Law Journal (registration)
New York Law Journal (registration)
Tue, 26 Aug 2014 15:41:15 -0700
A couple who was marooned on a Long Island river mudflat in a rented canoe cannot hold the rental company liable for the mishap, a judge has ruled. "It is determined that getting stranded at low tide, whether on a river or on a sand bar near a beach ...
Minneapolis Star Tribune
Minneapolis Star Tribune
Thu, 21 Aug 2014 15:09:19 -0700
It was July of 1974, and I had just been hired by the Minnesota Department of Natural Resources as assistant manager of the Lac qui Parle Refuge. Refuge manager Arlin Anderson and I were visiting an island on Marsh Lake to check on a colony of American ...
Fri, 08 Aug 2014 10:15:00 -0700
Mudflat Safaris are during minus tides from 12:30-2:30 p.m. Tuesday, Aug. 12 and 10 a.m. to noon Friday, Aug. 22. Nature center guides will lead a limited number of participants into the eelgrass meadow, which be exposed during the extreme low tides ...
The News Journal
Wed, 06 Aug 2014 20:05:25 -0700
92 CONNECTTWEET 3 LINKEDINCOMMENTEMAILMORE. It is low tide along the Mispillion River at a rapidly receding mudflat near the inlet to Delaware Bay. Josh Moody and a team of scientists and volunteers are working to hold the shoreline in place and ...
South China Morning Post (subscription)
Sat, 09 Aug 2014 14:53:14 -0700
Clam diggers may be damaging a Yuen Long coastal mudflat by using salt to draw the molluscs from their burrows. Conservationists warn that the technique can be detrimental to many other organisms co-existing in the mudflat, but the government's ...
Marinscope Community Newspapers
Thu, 14 Aug 2014 15:52:30 -0700
Kerry Wilcox, Sanctuary Manager at the Richardson Bay Audubon Center, said the shoreline and mudflat area is likely to be used by common Bay Area shorebirds including the Black-bellied Plovers, Black-necked Stilts, Willets, Marbled Godwits, Least ...
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