Mangrove hydrodynamics

Abstract

Studies of the physical processes in mangrove swamps and mangrove-fringed estuaries are few and far between compared to those of temperate estuaries. The main reason is that these swamps are mostly located in tropical areas in less-developed countries, where research funding is inadequate and field conditions are harsh. Mangrove research has been better funded in some of these countries under the umbrella of international agencies; however as a rule these are 'applied' agencies and the studies are site-specific, short-term, and addressed to answer specific resource assessment and social, environmental and pollution problems. The estuarine physicists are usually seen only as a necessary evil, a peripheral discipline, that life scientists need to deal with in order to obtain information for management on the pathways for water, nutrients and sediment. This information is usually inadequate or poorly understood. In most of the less-developed countries, management of the mangrove resources is hampered by a large human population or prawn farms encroaching on mangroves, which are seen as wasteland. Management, where it exists, is usually carried out with inadequate scientific understanding and basically represents mismanagement that may cost mankind dearly in the future. A sound understanding of the physical processes in mangrove swamps is needed for proper management. Physical processes control several key biological and chemical processes in the mangroves. (1974) have classified mangrove forests into 5 types: a. RIVERINE FOREST: Floodplains along river drainages, which are inundated by most high tides and flooded during the wet season, b. BASIN FOREST: Partially impounded depressions, which are inundated by few high tides during dry season, and most high tides during wet season, c. FRINGE FOREST: Shorelines with steep elevation gradient, which are inundated and flushed by all high tides, 43 Coastal and Estuarine Studies Tropical Mangrove Ecosystems Vol. 41 Lugo and Snedaker

Can Mangroves Help Combat Sea Level Rise Through Sediment Accretion and Accumulation?

“…Acceleration of land building process through elevated sedimentation in mangroves was reported by Mahmood et al [32] in a protected mangrove forest of Kuala Selangor, Malaysia. Due to successive sedimentation in a mangrove ecosystem, land surface increases through sediment retention and the complex structure and root system of mangroves accelerate this process by enhancing the friction along with the reduction of tidal current speed [4,41].…”

“…Out of numerous functions, the most remarkable function of this ecosytem to coastal environment is to provide a suitable technique for trapping sediments, and due to afforementioned reason it is a recognized ecosytem that retains and accumulate suspended sediments [3][4][5][6]. Sediment accretion means the accumulation of suspended sediments rich in organic and inorganic materials borne by tidal water during high tide [2,7].…”

Spring Tide Hypoxia with Relation to Chemical Properties of the Sediments in the Matang Mangrove Estuary, Malaysia

“…It is the largest tract of mangrove forest in Peninsular Malaysia and has been under sustainable management since 1904 7 . MMFR is a Riverine Forest Type mangrove 22 , which is inundated during most spring high tides. In contrast, water is mainly confined to the channels during neap tides.…”

“…Because of microbial decomposition of mangrove litter and consumption of oxygen, low dissolved oxygen (DO) concentrations (< 1 mg/L) are commonly found near the bottom in tidal creeks where gradients in salinity occur 11,22 . In large-scale mangrove areas, waterways mainly consist of many creeks and branches, in which such hypoxic water prevails.…”

Recent Sedimentation Rate and Sediment Ages Determination of Kemaman-Chukai Mangrove Forest, Terengganu, Malaysia

“…In terms of their biological and chemical aspects, mangrove forests are highly productive source of organic matter, from which there is a net outwelling of energy that supports the complex estuarine and nearshore food web. Geologists, on the other hand, view mangroves as sediment sinks, characterized by long-term import of sediments as indicated by the substantial accretion of recent sediments, which underlie mangrove forests and adjacent coastal plains [1] . Physically, by virture of being in the intertidal areas, they can act as a recorder of environmental changes via sedimentological characteristics and in the preservation of spores and pollens.…”