Variability in biological responses influenced by upwelling events in the Eastern Arabian Sea

Habeebrehman, H.; Prabhakaran, M. P.; Jacob, J.; Sabu, P.; Jayalakshmi, K. J.; Achuthankutty, C.T.; Revichandran, C.

doi:10.1016/j.jmarsys.2008.04.002

Cited by 79 publications

(22 citation statements)

References 26 publications

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“…During this period, primary production ranging from 12.0 to 648.0 mg C m -2 day -1 was reported (Sarupria and Bhargava 1993;Habeebrehman et al 2008). The upwelling process, supported by the southerly current observed along the coastal waters during the southwest monsoon, results in maximum fluctuation in primary production ranging between 40.0 and 1225.0 mg C m -2 d -1 (Sarupria and Bhargava 1993;Habeebrehman et al 2008;Joshi and Rao 2012). Following the southwest monsoon, the hydrographic parameters change causing a very strong freshwater discharge from backwaters, and this results in the lowest primary production in the area, ranging from 21.0 to 263.0 mg C m -2 d -1 (Sarupria and Bhargava 1993;Srinivas and DineshKumar, 2006;Habeebrehman et al 2008).…”

Section: Study Areamentioning

confidence: 91%

“…During the transition phase between these monsoons, the study area experiences strong vertical mixing due to wind-induced upwelling along with a northward undercurrent and southward surface flow (Hareesh Kumar and Mohan Kumar 1996). During this period, primary production ranging from 12.0 to 648.0 mg C m -2 day -1 was reported (Sarupria and Bhargava 1993;Habeebrehman et al 2008). The upwelling process, supported by the southerly current observed along the coastal waters during the southwest monsoon, results in maximum fluctuation in primary production ranging between 40.0 and 1225.0 mg C m -2 d -1 (Sarupria and Bhargava 1993;Habeebrehman et al 2008;Joshi and Rao 2012).…”

Section: Study Areamentioning

confidence: 98%

“…The upwelling process, supported by the southerly current observed along the coastal waters during the southwest monsoon, results in maximum fluctuation in primary production ranging between 40.0 and 1225.0 mg C m -2 d -1 (Sarupria and Bhargava 1993;Habeebrehman et al 2008;Joshi and Rao 2012). Following the southwest monsoon, the hydrographic parameters change causing a very strong freshwater discharge from backwaters, and this results in the lowest primary production in the area, ranging from 21.0 to 263.0 mg C m -2 d -1 (Sarupria and Bhargava 1993;Srinivas and DineshKumar, 2006;Habeebrehman et al 2008). The study area draws special attention because of the occurrences of seasonal mudbanks at certain locations during the southwest monsoon period (Balachandran 2004) and also phytoplankton blooms (Srinivas and Dineshkumar 2006).…”

Section: Study Areamentioning

confidence: 99%

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Effect of optically active substances and atmospheric correction schemes on remote-sensing reflectance at a coastal site off Kochi

Minu

Lotliker

Shaju

et al. 2014

International Journal of Remote Sensing

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The present study focused on understanding the variability of optically active substances (OASs) and their effect on spectral remote-sensing reflectance (R rs ). Furthermore, the effect of atmospheric correction schemes on the retrieval of chlorophyll-a (chl-a) from satellite data was also analysed. The OASs considered here are chl-a, coloured dissolved organic matter (CDOM), and total suspended matter (TSM). Satellite data from the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Aqua satellite was used for this study. The two atmospheric correction schemes considered were: multiscattering with two-band model selection NIR correction (hereon referred as 'A1') and Management Unit of the North Sea Mathematical Models (MUMM) correction and MUMM NIR calculation (hereafter referred as 'A2'). The default MODIS bio-optical algorithm (OC3M) was used for the retrieval of chl-a. Analysis of OASs showed that chl-a was the major light-absorbing component, with highly variable distribution (0.006-25.85 mg m -3 ). Absorption due to CDOM at 440 nm (a CDOM 440) varied from 0.002 to 0.31 m -1 whereas TSM varied from 0.005 to 33.44 mg l -1 . The highest concentration of chl-a was observed from August to November (i.e. end of the southwest monsoon and beginning of the northeast monsoon), which was attributed to coastal upwelling. The average value of a CDOM 440 was found to be lower than the global mean. A significant negative relationship between a CDOM 440 and salinity during the southwest monsoon indicated that much of the CDOM during this season was derived from river discharge. Spectral R rs was found to be strongly linked to the variability in chl-a concentration, indicating that chl-a was the major light-absorbing component. Satellite-derived spectral R rs was in good agreement with that in situ when chl-a concentration was lower than 5 mg m -3 . The validation of chl-a, derived from in situ R rs , showed moderate performance (correlation coefficient, R 2 = 0.64; log 10 (RMSE) = 0.434; absolute percentage difference (APD) = 43.6% and relative percentage difference (RPD) = 42.33%). However the accuracy of the algorithm was still within acceptable limits. The statistical analysis for atmospheric correction schemes showed improved mean ratio of measured to estimated chl-a ('r' = 1.6), log 10 (RMSE) (0.49), APD (25.46%), and RPD (17.57%) in the case of A1 as compared with A2, whereas in the case of A2, R 2 (0.56), slope (0.26), and intercept (0.27) were better as compared with A1. The two atmospheric correction schemes did not show any significant statistical difference. However the default atmospheric correction scheme (A1) was found to be performing comparatively better probably due to the fact that the concentration of TSM and CDOM was much lower to overcome the impact of chl-a.

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Section: Study Areamentioning

confidence: 91%

Section: Study Areamentioning

confidence: 98%

Section: Study Areamentioning

confidence: 99%

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Effect of optically active substances and atmospheric correction schemes on remote-sensing reflectance at a coastal site off Kochi

Minu

Lotliker

Shaju

et al. 2014

International Journal of Remote Sensing

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“…In contrast, the phytoplankton community was dominated by blue-green algae (>85%, 19400 cells L −1 ) at station 6 followed by diatoms (13 (Table 2). (See Habeebrehman et al [22] for distribution of chlorophyll a and abundance and composition of phytoplankton community during these periods. )…”

Section: Chlorophyll a And Phytoplanktonmentioning

confidence: 99%

Aggregation ofEuphausia sibogaeduring Summer Monsoon along the Southwest Coast of India

Jayalakshmi¹,

Purushothaman²,

Muraleedharan³

et al. 2011

Journal of Marine Biology

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The influence of environmental parameters on the spawning aggregation of Euphausia sibogae was investigated along the southwest coast of India during the peak phase of summer monsoon 2005. The prevailing ecological conditions between the aggregation period (peak phase) and non-aggregation period (early phase) were also compared. The aggregation was observed at station 1 (8 • N; 76.5• E, 480 ind·m −3 ) and 6 (10 • N; 75.5 • E, 839 ind.m −3 ) during the peak phase of the summer monsoon. Eggs (14769 eggs m −3 ) and different developmental stages were observed in higher abundance at station 6. The physicochemical conditions indicated that the aggregation coincided with the upwelling. The nutrient enrichment due to the upwelling triggered phytoplankton blooms, and this appeared to provide a conducive environment for spawning and development of E. sibogae.

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“…This phenomenon brings nutrient-rich, cold subsurface water into the euphotic zone, which results in high biological productivity in Arabian Sea which is one of the most productive areas in the world (Habeebrehman et al, 2008;Prasanna Kumar et al, 2001;Sankaranarayanan et al, 1978;Wiggert et al, 2005). Coastal upwelling in the Arabian Sea is an annual phenomenon occurring during summer monsoon.…”

Section: Introductionmentioning

confidence: 99%

Alkaline phosphatase activity at the southwest coast of India: A comparison of locations differently affected by upwelling

Mamatha

Malik

Varik

et al. 2015

Journal of Sea Research

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Variability in biological responses influenced by upwelling events in the Eastern Arabian Sea

Cited by 79 publications

References 26 publications

Effect of optically active substances and atmospheric correction schemes on remote-sensing reflectance at a coastal site off Kochi

Effect of optically active substances and atmospheric correction schemes on remote-sensing reflectance at a coastal site off Kochi

Aggregation ofEuphausia sibogaeduring Summer Monsoon along the Southwest Coast of India

Alkaline phosphatase activity at the southwest coast of India: A comparison of locations differently affected by upwelling

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