Dept of Bio-Chemistry
University of Calcutta
The eastern part of the coastal region of
West Bengal is characterized by the spectacular mangrove forest of Sundarbans.
The forest performs several important ecological functions for its sustenance.
On one hand, the mangrove forest acts as a bio-shield against severe storms and
cyclones coming from the Bay of Bengal that have the potential of causing large
scale damage to the coastal areas. On the other hand, the mangrove forest
participates in complex physical, chemical and biological interactions that
produce a unique ambience for healthy and luxuriant growth of the forest.
People living in and around the forest draw their livelihood from the living
and renewable resources provided by the forest. The forest acts as a sink of
carbon in as much as it is suspected that they emit methane, a greenhouse gas,
to the atmosphere. It is also known that carbon dioxide is produced by
heterotrophic activity in a mangrove swamp. However, a correct assessment of
the contribution of mangrove forest towards controlling the climate
change/global warming is still not available due to absence of reliable
measured data. Conversely, the expected changes in carbon bio-geochemical cycle
in the mangrove system in relation to the anticipated climate change/global
warming are still to be understood due to the aforementioned reasons.
The life forms in the Sundarbans have a
complex inter-related existence to maintain equilibrium dynamics within the
extant of physical and chemical environment. The mangrove produces rich organic
debris (consisting of decaying spores, pollens, seeds, leaves, fruits, twigs
and branches of trees, etc.) due to its high biological productivity with
unique concentrations of nutrients in the debris. The nutrients are released both to the water
and soil of the mangrove wetland of Sundarbans. Parts of these “foods” are
consumed by a group of organisms (like fishes, birds, amphibians, mammals, etc)
either directly or through the water or the soil medium to sustain their body
metabolic functions. The other parts are assimilated in the substrate soil,
“consumed” by various forms of microbes which return some part of the
“digested” consumed food to the soil as organic fertilizers. The fertilized
soil (humification) thus supports further luxuriant growth of the mangrove
forest. There is, however, a residual flow of nutrients and organic carbon from
the mangrove system to the coastal water. The microbial diversity of a mangrove
forest is mind-boggling and the various forms interact with the environment at
various energy levels to set up a complex food web and growth of mangrove
vegetation.
Background
It has been noted that the coastal and estuarine
wetlands in the Sundarban region are in dire risk due to sea-level rise and
saltwater intrusion. The impact of natural and anthropogenic stressors on
biogeochemical cycles in coastal and inland wetlands is also taking its toll on
the fragile ecosystem of Sundarban as gradually the salinity gradient moved
into the saline/tidal marshes, then brackish marshes, freshwater marshes, and
ending with freshwater/forested wetlands.
It has been worked out that within the ICZMP, Calcutta University will act as one of the Pilot Investment Executing Agencies that will perform basic research work to explore diversity of microbes in Sundarban and their role on withstanding coastal erosion and other ecological processes, etc. The University of Calcutta is supposed to investigate the following:-
·
Understanding the functioning of the
Sundarbans mangrove system through the research on activities of the microbes
present in the substrate sediments and understanding the role of microbial
diversity in maintaining the system.
·
Understanding the natural process of
capture of carbon and emission of greenhouse gases from mangrove forests of
Sundarbans thereby assessing the contribution of mangrove forest towards
controlling global warming.
·
Predicting the changes in carbon
bio-geochemical cycle in the mangrove system of Sundarbans in relation to
climate change/global warming.
·
Understanding the natural process of flow
of the nutrients and organic carbon from the mangrove system to the coastal
sediment and water in Sundarbans to self-support the mangrove system of
Sundarbans.
·
Assessing the amount of carbon
sequestration through mangrove forest of Sundarbans towards controlling global
warming.
In order to achieve the above objectives,
one research program has been envisaged. Planned procurement of the instruments
as envisaged in the present project will essentially support two research
programs as part of capacity building of the participating departments of the
Calcutta University.
The first program will involve collection
of representative soil and water samples from areas of Sundarbans having
different vegetation assemblages and analysing the microbial diversity using
structural and functional metagenomics. For this purpose one Pyrosequencer and
Thermocycler or PCR machine have already been purchased. Pyrosequencer is the
main instrument which provides detailed DNA sequence of the DNA samples.
Pyrosequencer can also be used for performing both structural and functional
metagenomics in order to understand microbial diversity. A Gel Documentation System
has also been procured. Thermocycler has been used for the purpose of DNA
amplification.
The program includes the following
objectives:
- measurement
of CO2 sequestration and CH4 emission from the
mangrove forest and water,
- estimation
of bacterial abundance (BA) and bacterial productivity (BP),
- measurement
of inadvertent fertilization by nutrient flux (dissolved inorganic
nitrogen), dissolved inorganic phosphate silicate from rivers
- measurement/estimation
of residual flow of nutrients and organic carbon from the mangrove system
to the coastal water
The other instrumental facilities that have
been procured are:
·
Upright wide
field research microscope with bright field, dark field, phase contrast and
fluorescence with CCD camera and software
·
Total carbon analyzer
·
Liquid scintillation counter
·
Variable
temperature programmable Incubator with Shaker system (BOD incubator)
·
Nitric oxide
analyser
·
Fluorescence spectrometer with life time
measurement
The
University of Calcutta planned to execute the entire task in micro stages that
are as noted as:
¨ Reconnaissance
survey of the entire area, selection of field stations, gathering of basic
knowledge about the area, recruitment of research personnel, procurement of
instruments.
¨ Sample
collection for bacterial culture and to undertake organic, pollutant and
chemical analysis of coastal sediments.
¨ Metagenomic
analysis and cataloguing of bacterial population. Estimation of primary productivity of the
ecosystem. Measurement of nutrient flux.
¨ Collation
of data and Information, computational and bio-informatics study, model
development.
Expected Outcome
Expected outcome of the project is
cataloguing and describing the microbial diversity of Sundarban which is needed
for the conservation and sustenance of this heritage site. The capacity
building through this project will also construct an instrumental facility to
support marine research. The third outcome is to create awareness among the new
generation regarding the importance of coast and marine areas.
The project cost
has been estimated at `5.6 crores out of which capital cost will be about `3.125 crores
towards procurement of equipment and recurring cost will be about `2.475 crores.
