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(Mangroves)
(Monitoring coastal morphodynamics using high-precision multibeam technology)
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==Mangroves==
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==Monitoring coastal morphodynamics using high-precision multibeam technology==
  
[[image:mangrove thailand.jpg|right|thumb|300px|caption|Mangal in Thailand <ref>http://teqje.web-log.nl</ref>]]
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[[Image:Multibeam_2.jpg|thumb|left|'''Figure 1''' The multibeam system as implemented onboard the RV “Ludwig Prandtl”. The light underwater cone symbols the beam swath, devices inside the circles show (from left to right) gyro compass, motion senor, ship-borne GPS-RTK, sound profiler, and RTK land base.]]
  
This article describes the [[habitat]] of the Mangrove forests. It is one of the sub-categories within the section dealing with biodiversity of [[marine habitats and ecosystems]]. It gives an overview about the characteristics, distribution, biota, functioning and adaptation to general problems the organisms are facing with. A short discussion about the threats is also present.
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Monitoring coastal morphodynamics is of importance when for example coastal erosion of accretion is present or protective measure are taken and the effectiveness of these measures need to be known. Monitoring this process in time is of importance to manage the developments in the right way. A technique to do this is by high-precision multibeam technology. This technology is explained in this article and an example of application is given. This shows how high-precision multibeam technology can be used in practice.
  
Mangroves are the only trees that are capable of thriving in salt water. They form unique [[intertidal]] forests at the edge of land and sea. They are represented on all continents with tropical and subtropical coasts, i.e. North and South America, Africa and Middle-East, Asia and Oceania (incl. Australia). <ref name="vliz">http://www.vliz.be/vmdcdata/mangroves</ref>
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[[Coastal erosion]], [[bathymetry|bathymetric]] changes of the near coast seabed or the stability and dispersal of dredged and disposed material are among the key questions of [[coastal management]]: What are the effects of [[coastal protection]] measures? How effective are they? Do they generate new burdens on the coastal system? Which processes control the movement of the seabed? What are the typical scales for the rearrangement of bed material? What types of seabed structures contribute most to the transport of the bed material? To what extent are morphological changes predictable?
 
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Answers to these questions are still limited by a lack of observational evidence. Most of all, area-wide data are required to allow for comprehensive views of the relevant bed structures ranging over horizontal scales from decimetres to kilometres. The detection of seabed changes over these wide ranges of scales requires observational systems that combine high spatial resolution down to decimetres with high precision and accuracy in the horizontal and vertical positioning of the seabed structures in the range of centimetres.
Mangrove forests or '''mangals''' are a type of [[intertidal]] wetland [[ecosystems]]. The word mangrove is derived from the Portugese word mangue which means “tree” and the English word grove which is used for trees and shrubs that are found in shallow, sandy or [[mud]]dy areas. <ref>Karleskint G. 1998. Introduction to marine [[biology]]. Harcourt Brace College Publishers. p.378</ref>  They replace [[Salt marsh]]es in tropical and subtropical regions.
 
They are salt-tolerant forested [[wetlands]] at the sea-land interface which forms the link between the terrestrial landscapes and the marine environment. The dominant plants are several species of mangrove (for a species overview, check the Mangrove Species Database <ref name="vliz"/>).
 
Mangroves are woody trees and shrubs with a thick, partially exposed network of roots that grow down from the branches into the water and sediment. They occur where there is little [[waves|wave action]] and where [[sediments]] accumulate. These fine grained (muddy and sandy) sediments lack oxygen. <ref>Hogarth P.J. 1999. The biology of mangroves. Oxford University Press. p.228</ref>
 
They are frequently associated with saline [[Lagoon|lagoons]] and are regularly found on protected sides of islands, [[Island atolls|atolls]] and tropical [[estuaries]]. <ref>Karleskint G. 1998. Introduction to marine biology. Harcourt Brace College Publishers. p.378</ref>
 

Revision as of 10:32, 2 February 2009

Monitoring coastal morphodynamics using high-precision multibeam technology

Figure 1 The multibeam system as implemented onboard the RV “Ludwig Prandtl”. The light underwater cone symbols the beam swath, devices inside the circles show (from left to right) gyro compass, motion senor, ship-borne GPS-RTK, sound profiler, and RTK land base.

Monitoring coastal morphodynamics is of importance when for example coastal erosion of accretion is present or protective measure are taken and the effectiveness of these measures need to be known. Monitoring this process in time is of importance to manage the developments in the right way. A technique to do this is by high-precision multibeam technology. This technology is explained in this article and an example of application is given. This shows how high-precision multibeam technology can be used in practice.

Coastal erosion, bathymetric changes of the near coast seabed or the stability and dispersal of dredged and disposed material are among the key questions of coastal management: What are the effects of coastal protection measures? How effective are they? Do they generate new burdens on the coastal system? Which processes control the movement of the seabed? What are the typical scales for the rearrangement of bed material? What types of seabed structures contribute most to the transport of the bed material? To what extent are morphological changes predictable? Answers to these questions are still limited by a lack of observational evidence. Most of all, area-wide data are required to allow for comprehensive views of the relevant bed structures ranging over horizontal scales from decimetres to kilometres. The detection of seabed changes over these wide ranges of scales requires observational systems that combine high spatial resolution down to decimetres with high precision and accuracy in the horizontal and vertical positioning of the seabed structures in the range of centimetres.