Sundarbans Flashcards
Location and extent of the Sundarbans coastal zone
Extends over 10,000km2 of southern Bangladesh and India on the Bay of Bengal
Identify two natural features of this unique coastal landscape
The world’s largest delta
Extensive mangrove forest – the climatic climax vegetation
Name the rivers that feed into the delta (3)
Ganges
Brahmaputra
Meghna
Natural processes that create coastal landscape (4)
Deposition
Tidal processes
Marine erosion
Aeolian (wind) transport and deposition
Outline the role played by deposition in the formation of this landscape (4+)
The three rivers carry large amounts of silt and clay = deposited as they approach the Bay of Bengal
Sediment builds up over time = mounds or islands in the river channels
This has created a network of interconnected channels flowing round islands of sediment
The small channels are called KHALS
Outline the role played by tidal processes in the formation of this landscape (3+)
The delta is tidal = twice a day at high tide saline water washes northwards into the delta and then at low tide water washes southwards back towards the Bay of Bengal
This regular tidal flow = development of larger (up to 2km wide), straight channels in the delta running north-south
The larger channels are connected to each other by the smaller khals
Aeolian processes in the formation of this landscape (3+)
Coarser, less cohesive sand is carried further towards the mouths of the channels nearer the coastline
Some of the sand builds up on the banks to form chars
When it is above the waterline = dries out = picked up by the south-westerly Monsoon winds and transported inland = deposited to form sand dunes over time
Vegetation succession in the formation of this landscape (3+)
As sediment builds up over time in the delta = islands p remain above the water under normal condition
Vegetation succession begins with salt tolerant pioneer species and progress to the climatic climax vegetation = mangrove forest
The root system of the mangrove trees = stabilise the islands + help prevent erosion + trap more sediment over time
three goods provided by the mangrove forest + benefits (3+)
Wood = fuel for heat and cooking OR for furniture and construction
Natural poison = help in the catching of fish which is also an important food source
Rich ecosystem provides many food items = crab, shrimp, honey, leaves, and fruit
Outline services that the mangroves provide (4)
Protection from flooding and cyclones
Important carbon sink and sequesters around 4 billion tonnes of CO2 a year
Nursery grounds for fish = maintains the natural ecosystem
Value for ecotourism + education + scientific research
Key risks for people living in the Sundarbands (3)
Royal Bengal tigers = decreased habitat due to deforestation and increased population growth
Coastal flooding in the Bay of Bengal = eustatic sea level rise = higher levels of salinity in the soil making agriculture difficult and affecting freshwater drinking supplies
More intense cyclones in the Bay of Bengal
Why more intense cyclones (2)
Higher sea surface temperature = risk of erosion + flooding + damage to the forest
Risk to people and property
Ways in which the people of the Sundarbans are adapting to the challenges (3+)
Salt tolerant varieties of rice = introduced to cope with the increased salinity of the soil due to saltwater intrusion
NGOs are building latrines on higher ground to avoid contamination of the water supply during floods
USAID have trained 30,000 people in the use of improved agricultural techniques more suited to the conditions caused by climate change
Examples of how mangrove creates resilience (3)
The mangroves provide a wealth goods and services
Range of options in the face of change
Natural fertility of the soil and ecological diversity provide a range of nutritious foods
Mangrove forest resilience in face of storm how (2)
Density of trees = 30 per 0.01 hectares
Reduces the destructive force of a cyclone by up to 90%.
