Figure 6-2 - uploaded by Vincent Lyne
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Marine depth zones after the schema of Lincoln et al. 1998 (as drawn in Last et al. 2010). Neritic: Water column overlying the continental shelf down to ca 200 m depth. Epipelagic: The photic zone, from the ocean surface down to the depth influenced by light. This depth to which light penetrates depends on water clarity; in clear open ocean waters this is ca 200 m in depth. Typically this is the depth within which plankton are found. Mesopelagic: The upper aphotic zone down to a depth of ca 1000 m, typically contains vertically migrating species. Bathypelagic: Extends from ca 1000 to 2500 m. Species here rely upon the rain of material from shallower depths, or deep currents. Abyssopelagic: Depth layer above the major ocean basins with a lower boundary of ca 6000 m. Species highly adapted to living in the deep dark oceans, entirely reliant on depositions from above and/or hydrothermal vent communities. Hadopelagic: Extension of layer above to deep oceanic trenches, from ca 6000 m and below.
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Executive summary
This report contains the results of a comprehensive ecological characterisation of the Bay of Bengal Large Marine Ecosystem (BOBLME), produced for the United Nations Food and Agriculture Organisation (FAO) BOBLME Project. A whole-of-system ecological characterisation that provides functional ecosystem understanding of physical dr...
Citations
Substantially resourceful and densely populated coastal zones of Bangladesh experience numerous extreme events linked to hydro-meteorological processes viz. cyclones, tidal surges, floods, salinity intrusion and erosion etc. These hazards give rise to extensive damage to property and loss of lives every year. Further, anthropogenic activities in the coastal zones are accentuating environmental degradation causing widespread suffering. Cyclones and tornadoes in particular damage infrastructures and crops every year affecting the economy of the country negatively. Some naturally adapted plants as well as landscapes usually reduce the speed of cyclones and tornadoes and thus, protect the coastal zones. However, human activities have destroyed many of the forests and landscapes. Sundarbans and Chokoria Sundarbans mangrove forests of Bangladesh are under a great threat of extinction due to illicit logging and agricultural expansion. At least 34 plant species of tropical forest are on the verge of extinction. Many animals e.g., cats, bear, porcupine, wild boars, pythons and anteater are in the process of being wiped out from the coastal areas. Among the marine and coastal species, Red crabs, jelly-fish, sharks and dolphins are also rare but these were the major species prior to 1980 s. This study revealed that during the recent decades there has been massive plantations and construction of embankment and polderization but these and other measures have been found to be impractical and ineffective in reducing disasters in coastal areas. There is a need for integration of traditional coping practices and wisdoms with modern approaches. Available knowledge on some of these traditional practices has been documented for establishing a sustainable policy for management of coastal zones of Bangladesh. Combining traditional and scientific management of coastal ecosystem with mangroves and other plants following triple-tier mechanism and habitat, it is possible to reduce the effects of natural and climate change-induced disasters. Under such a management system, the entire coastal zone can be made more productive and sustainable.
