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11.
Impact of atmospheric and physical forcings on biogeochemical cycling of dissolved oxygen and nutrients in the coastal Bay of Bengal 总被引:1,自引:0,他引:1
V. V. S. S. Sarma B. Sridevi K. Maneesha T. Sridevi S. A. Naidu V. R. Prasad V. Venkataramana T. Acharya M. D. Bharati Ch. V. Subbaiah B. S. Kiran N. P. C. Reddy V. V. Sarma Y. Sadhuram T. V. R. Murty 《Journal of Oceanography》2013,69(2):229-243
Time-series observations were conducted off Visakhapatnam, central west coast of Bay of Bengal, from October 2007 to April 2009 to examine the influence of physical and atmospheric processes on water column nutrients biogeochemistry. The thermal structure displayed inversions of 0.5 to 1.0° C during winter and were weaker in summer. The water column was vertically stratified during the entire study period and was stronger during October–November 2007 and August–December 2008 compared to other study periods. High concentrations of chlorophyll-a and nutrients were associated with the extreme atmospheric events. The strong relationship of nutrients with salinity indicates that physical processes, such as circulation, mixing and river discharge, have a significant control on phytoplankton blooms in the coastal Bay of Bengal. Phosphate seems to be a controlling nutrient during winter whereas availability of light and suspended matter limits production in summer. Formation of low oxygen conditions were observed in the bottom waters due to enhanced primary production by extreme atmospheric events; however, re-oxygenation of bottom waters through sinking of oxygen-rich surface waters by a warm core (anticyclonic) eddy led to its near recovery. This study reveals that atmospheric and physical processes have significant impacts on the water column biogeochemistry in the coastal Bay of Bengal. 相似文献
12.
Malay Mukul Sridevi Jade Anjan Kumar Bhattacharyya Kuntala Bhusan 《Journal of the Geological Society of India》2010,75(1):302-312
Deformation in active mountain belts like the Himalaya is manifested over several spatial and temporal scales and collation
of information across these scales is crucial to an integrated understanding of the overall deformation process in mountain
belts. Computation and integration of geological shortening rates from retrodeformable balanced cross-sections and present-day
convergent rates from deforming mountain belts is one way of integrating information across time-scales. The results from
GPS measurements carried out in NE India indicate that about 15–20 mm/yr of convergence is being accommodated there. Balanced-cross
sections from the NE Himalaya indicate about 350–500 km of shortening south of the South Tibet Detachment (STD). Geothermobarometry
suggest that the rocks south of the STD deformed under peak metamorphic conditions at ∼ 22 Ma. This indicates a geological
convergence rate of ∼ 16–22 mm/yr which appears to be fairly consistent with the GPS derived convergence rates. Approximately
1.5 to 3.5 mm/yr (∼ 10–20 %) of the total N-S of the present-day convergence in the NE Himalaya is accommodated in the Shillong
Plateau. In addition, ∼ 8–9 mm/yr of E-W convergence is observed in the eastern and central parts of the Shillong Plateau
relative to the Indo-Burman fold-thrust belt. Balanced cross-sections in the Indo-Burman wedge together with higher resolution
GPS measurements are required in the future to build on the first-order results presented here. 相似文献