Mangroves and Salt Marshes 

About: Mangroves and Salt Marshes is an academic journal. The journal publishes majorly in the area(s): Mangrove & Salt marsh. It has an ISSN identifier of 1386-3509. Over the lifetime, 74 publications have been published receiving 3918 citations.

Traditional and medicinal uses of mangroves

Abstract: This review examines the recent investigations on the biological activities of extracts and chemicals identified from mangroves (mangroves, mangrove minors and mangal associates). It describes how people have and are using mangroves on a traditional basis. It also describes the world's mangrove resources and products, in terms of their economical importance, medicinal values and other uses and functions. The economical uses of products from mangrove ecosystems are many and varied. Traditionally, the mangroves have been exploited for firewood and charcoal. Use has also been found for mangroves in the construction of dwellings, furniture, boats and fishing gear, tannins for dyeing and leather production. The mangroves provide food and wide variety of traditional products and artefacts for the mangrove dwellers. Extracts and chemicals from mangroves are used mainly in folkloric medicine (e.g. bush medicine), as insecticides and piscicides and these practices continue to this day. However the extraction of novel natural chemical compounds from mangroves, in addition to those already known to the pharmacopoeia of the people is in its infancy. A knowledge of the biological activities and/or chemical constituents of plants is desirable, not only for the discovery of new therapeutic agents, but because such information may be of value in disclosing new sources of already known biologically active compounds. It is of further value to those interested in “deciphering” the actual value of folkloric remedies.

Mangroves as a coastal protection from waves in the Tong King delta, Vietnam

Abstract: The wave reduction (wave period; 5–8 sec.) was investigated in amangrove reforestation area (Kandelia candel) close toaquaculture ponds in the Tong King delta, Vietnam. On one site where only young mangrove trees grew, the wavereduction due to the drag force on the trees was hardlyeffective. On the other site where mangrove trees weresufficiently tall, the rate of wave reduction per 100 m was aslarge as 20%. Due to the high density of vegetation distributedthroughout the whole water depth, the effect of wave reductionwas large even when the water depth increased. These resultsdemonstrate the usefulness of mangrove reforestation for coastalprotection.

Drag force due to vegetation in mangrove swamps

Abstract: Field studies of tidal flows in largely pristine mangrove swamps suggestthat the momentum equation simplifies to a balance between the water surfaceslope and the drag force. The controlling parameter is the vegetation lengthscale LE, which is a function of the projected area ofmangrove vegetation and the volume of the vegetation. The value ofLE varies greatly with mangrove species and water depth. It isfound that the drag coefficient is related to the Reynolds number Re definedusing LE. The drag coefficient decreases with increasingvalues of Re from a maximum value of 10 at low value of Re (<104), and converges towards 0.4 for Re < 5 ×104.

Sedimentation in Mangrove Forests

Abstract: The tidal currents in mangrove forests are impeded by the friction caused by the high vegetation density The tidal currents are also complex comprising eddies, jets and stagnation zones The sediment particles carried in suspension into the forest during tidal inundation are cohesive, mainly clay and fine silt, and form large flocs These flocs remain in suspension as a result of the turbulence created by the flow around the vegetation The intensity of sedimentation is largest for trees forming a complex matrix of roots such as Rhizophora sp and smallest for single trees such as Ceriops sp The flocs settle in the forest around slack high tide At ebb tides the water currents are too small to re-entrain this sediment Hence the inundation of coastal mangrove forests at tidal frequency works as a pump preferentially transporting fine, cohesive sediment from coastal waters to the mangroves Mangroves are thus not just opportunistic trees colonising mud banks but actively contribute to the creation of mud banks

Vertical accretion and shallow subsidence in a mangrove forest of southwestern Florida, U.S.A

Abstract: Simultaneous measurements of vertical accretion from artificial soilmarker horizons and soil elevation change from sedimentation-erosion table(SET) plots were used to evaluate the processes related to soil building infringe, basin, and overwash mangrove forests located in a low-energy lagoonwhich receives minor inputs of terrigenous sediments. Vertical accretionmeasures reflect the contribution of surficial sedimentation (sedimentdeposition and surface root growth). Measures of elevation change reflectnot only the contributions of vertical accretion but also those ofsubsurface processes such as compaction, decomposition and shrink-swell. Thetwo measures were used to calculate amounts of shallow subsidence (accretionminus elevation change) in each mangrove forest. The three forest typesrepresent different accretionary environments. The basin forest was locatedbehind a natural berm. Hydroperiod here was controlled primarily by rainfallrather than tidal exchange, although the basin flooded during extreme tidalevents. Soil accretion here occurred primarily by autochthonous organicmatter inputs, and elevation was controlled by accretion and shrink-swell ofthe substrate apparently related to cycles of flooding-drying and/or rootgrowth-decomposition. This hydrologically-restricted forest did notexperience an accretion or elevation deficit relative to sea-level rise. Thetidally dominated fringe and overwash island forests accreted throughmineral sediment inputs bound in place by plant roots. Filamentous turfalgae played an important role in stabilizing loose muds in the fringeforest where erosion was prevalent. Elevation in these high-energyenvironments was controlled not only by accretion but also by erosion and/orshallow subsidence. The rate of shallow subsidence was consistently3–4 mm y–1 in the fringe and overwash island forests butwas negligible in the basin forest. Hence, the vertical development ofmangrove soils was influenced by both surface and subsurface processes andthe processes controlling soil elevation differed among forest types. The mangrove ecosystem at Rookery Bay has remained stable as sea levelhas risen during the past 70 years. Yet, lead-210 accretion data suggest asubstantial accretion deficit has occurred in the past century (accretionwas 10–20 cm < sea-level rise from 1930 to 1990) in the fringe andisland forests at Rookery Bay. In contrast, our measures of elevation changemostly equalled the estimates of sea-level rise and our short term estimatesof vertial accretion exceeded the estimates by the amount of shallowsubsidence. These data suggest that (1) vertical accretion in this system isdriven by local sea-level rise and shallow subsidence, and (2) the mangroveforests are mostly keeping pace with sea-level rise. Thus, the vulnerabilityof this mangrove ecosystem to sea-level rise is best described in terms ofan elevation deficit (elevation change minus sea-level rise) based on annualmeasures rather than an accretion deficit (accretion minus sea-level rise)based on decadal measures.