Impact of river discharge on the coastal water pH and pCO2 levels during the Indian Ocean Dipole (IOD) years in the western Bay of Bengal

Impact of river discharge on the coastal water pH and pCO2 levels during the Indian Ocean Dipole (IOD) years in the western Bay of Bengal

Monthly variations in inorganic carbon components during January 2010–December 2011 in the coastal Bay of Bengal (BoB) were studied in relation to the variations in Godavari River (GR) discharge using ship board measurements, buoy data and satellite remote sensing data. Higher GR discharge was obser...

Full description

Saved in:
Bibliographic Details
Published in:Continental shelf research Vol. 107; pp. 132 - 140
Main Authors: Sarma, V.V.S.S., Paul, Y.S., Vani, D.G., Murty, V.S.N.
Format: Journal Article
Language:English
Published: Elsevier Ltd 01-09-2015
Subjects:
Coastal
Coastal water
Discharge
Indian Ocean
Monsoons
Rivers
Stratification
Surface wind
ISW, Indian Ocean
India, Andhra Pradesh, Godavari R
ISW, Bangladesh, Bengal Bay
ISW, North Indian Ocean
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Monthly variations in inorganic carbon components during January 2010–December 2011 in the coastal Bay of Bengal (BoB) were studied in relation to the variations in Godavari River (GR) discharge using ship board measurements, buoy data and satellite remote sensing data. Higher GR discharge was observed during the 2010 monsoon (1133m3s−1) resulting in low salinity and strong stratification in the coastal region. During 2011 monsoon season, low GR discharge (403 m3s−1) resulted in weaker stratification in the coastal waters. Contrasting atmospheric and oceanic conditions prevailed in the north Indian Ocean during 2010–2011 in association with the negative Indian Ocean Dipole (nIOD) event in 2010 and positive IOD (pIOD) event in 2011. Consequently, anomalous onshore easterly surface winds and warmer Sea Surface Temperature (SST) anomalies occurred in the BoB during nIOD event and an anomalous strong alongshore northeastward surface winds and colder SST anomalies occurred during pIOD event in the coastal western BoB. The observed weaker stratification due to low GR discharge and the anomalous alongshore surface winds favoured coastal upwelling during pIOD event in the 2011 monsoon, and consequently lowered the SST and the pH (pCO2) levels by 0.01 units (higher by 60μatm) than those observed during the nIOD event. This study thus reveals that reduced GR discharge together with pIOD event contributed to enhanced acidification and pCO2 levels in the coastal western BoB. It could be envisioned that the enhanced acidity in the coastal waters due to variations in river discharge and phases of IOD may significantly modify the coastal ecosystem that requires careful evaluation. •The phases of the Indian Ocean Dipole affect the rainfall over Indian subcontinent.•The IOD associated anomalous surface winds intensified the coastal upwelling.•Decrease in river discharge acidifies coastal waters through upwelling.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0278-4343
1873-6955
DOI:10.1016/j.csr.2015.07.015