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Bay of Bengal Process Studies (BOBPS) Final Report

DRS at CSIR-National Institute of Oceanography

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Title Bay of Bengal Process Studies (BOBPS) Final Report
 
Creator PrasannaKumar, S.
Sardessai, S.
Ramaiah, N.
Bhosle, N.B.
Ramaswamy, V.
Ramesh, R.
Sharada, M.K.
Sarin, M.M.
Sarupria, J.S.
Muraleedharan, U.
 
Subject Bay of Bengal
Biogeochemistry
Upper ocean variability
Thermo-haline structure
Cold-core eddies
Nutrient distribution
Chlorophyll a
Biological productivity
Lithogenic flux
Organic Carbon
CO2 flux
Bacterial Carbon
Zoo Plankton
Amino acids
New Production
Total suspended sediment
 
Description The Bay of Bengal Process Studies (BOBPS) was conceived in early 1997 as a sequel to the JGOFS (Joint Global Ocean Flux Study) India - Arabian Sea Process Study. Soon after the completion of the JGOFS field experiments in the Arabian Sea in February 1997 a consolidated national BOBPS programme was submitted to Department of Ocean Development (DOD), New Delhi in February 1999. The overall objectives of the Bay of Bengal Process Studies were: 1. Spatial and temporal variations in physical, chemical and biological properties (i.e, temperature, salinity, density, wind, pressure, SST, air temperature, humidity, nutrients, primary productivity, abundance and annual cycle of bacteria, micro- & meso-zooplankton, POC) and the effect of various forcing such as fresh water, suspended discharge, evaporation, precipitation etc. in contributing to this. The Bay of Bengal is known for its cyclones. These transients would have significant effects on the distribution of chemical and biological properties and biogeochemical cycling of carbon. Attempts are being made to sample the water column after such events to assess their significance. 2. Seasonal and inter-annual variability in the overall CO2 air-sea exchange balance in the Bay of Bengal. 3. The role of remote forcing in the spatio-temporal variability of the water column in terms of nutrients and productivity. For achieveing the above objectives 9 sub-projects were approved and funded by DOD by the administrative approval on 19 October 2000 for a total budget of Rs. 146.93 lakhs. The institutions involved were National Institute of Oceanography (NIO), Goa, Physical Research Laboratory (PRL), Ahmedabad, Centre for Mathematical Modelling and Computer Simulation (C-MMACS), Bangalore and Goa University (GU), Goa. In all 4 cruises were conducted during 2001 and 2006. Out of this, three were on board ORV Sagar Kanya during summer 2001, fall intermonsoon 2002, spring intermonsoon 2003 and one onboard FORV Sagar Sampada during winter 2005. In all the cruises sampling were carried out at the same location so as to decipher the seasonal cycle. In each of the cruise, 24 CTD stations - 14 along the 88oE and 10 were along the western boundary - and 9 primary productivity (PP) stations - 5 were along 88oE, and 4 were along western boundary - were covered. In all 35 parameters were measured. Several new insights are emerging out of the BOBPS data analysis. We now understand why Bay of Bengal is a biologically low productive basin. This is largely due to the strong straification driven by the immense fresh water flux and in parts due to the shallow euphotic zone especially in the northern Bay due to immense suspended sediment load. The role of sub-surface cold-core eddies in supporting enhanced biological production due to up-ward eddy-pumping of nutrients across the halocline is clearly seen. This to some extent will address the issue of comparable down-ward particle (organic) flux in the Bay of Bengal and the Arabian Sea despite contrasting surface chlorophyll concentrations and production. Existence of large bacterial abundance, crucial for microheterotrophs, explains why the mesozooplankton biomass may be decoupled with chlorophyll and primary production. Contrary to the conventional belief that the Bay of Bengal may be asink for atmospheric CO2, the pCO2 and TCO2 measurements indicate that except in the northern Bay during summer and fall intermonsoon, the Bay of Bengal is a minor source of CO2 to atmosphere. In the absence of any strong upwelling region in the Bay of Bengal this appers to be driven by eddy-pumping of CO2-rich subsurface waters to the upper layers which then diffuses under the action of prevailing winds.
Department of Ocean Development (DOD), New Delhi
 
Date 2007-01-17T04:20:07Z
2007-01-17T04:20:07Z
2007
 
Type Technical Report
 
Identifier Bay of Bengal process studies, Technical Report; 142P
http://drs.nio.org/drs/handle/2264/535
 
Language en
 
Format 4286687 bytes
application/pdf
 
Publisher Department of Ocean Development, New Delhi