arga anil - Academia.edu (original) (raw)

Papers by arga anil

Marine Pollution Bulletin, Feb 1, 2023

Marine Pollution Bulletin, Nov 1, 2021

Port environments are highly dynamic and hotspots for marine bioinvasion. This study investigated... more Port environments are highly dynamic and hotspots for marine bioinvasion. This study investigated the bacterial diversity at two geographically distant ports (Mangalore-marine port; and Haldia-riverine port) using next-generation sequencing during southwest monsoon and non-monsoon (Pre-monsoon) seasons. During southwest monsoon, at both marine and riverine ports, operational taxonomic units (OTUs) affiliated to bacteria reported to have hydrocarbon degrading ability were observed. Whereas during pre-monsoon, a significant increase in benthic bacterial OTUs was evident at the marine port, and the riverine port was characterized by oceanic species OTUs. Results suggest that the dynamics of prevalent environmental conditions, driven by seasons, led to emergence of ecologically relevant bacteria, many of which have been observed for the first time in Indian coastal waters. Their presence could be used as indicators of prevailing environmental conditions and nature of anthropogenic influence in port ecosystems. Unravelling functional roles of such ecologically relevant species is a way forward.

Journal of Marine Systems, Nov 1, 2019

Abstract The westward propagating Rossby waves and associated currents transport low salinity nut... more Abstract The westward propagating Rossby waves and associated currents transport low salinity nutrient-rich water mass from the Bay of Bengal into the southeastern Arabian Sea (SEAS) during winter monsoon, and ensuing changes in physicochemical properties of water column regulate phytoplankton distribution in the latter region. Herein, we elucidate the influence of Rossby wave propagation on picophytoplankton community composition in the SEAS. We compare the picophytoplankton community structure between the Rossby front (low saline, high nitrate concentration and strong current) and the surrounding non-frontal regions (high saline, low nitrate and weak current) along a cruise track in the SEAS during early winter monsoon (November 2016). The higher abundance of phycoerythrin-rich Synechococcus (‘dim’ and ‘bright’ types) and lower abundance of Prochlorococcus in the frontal region than the non-frontal regions suggest that salinity and nitrate concentration in the water column significantly influence the picophytoplankton community dynamics. We argue that the advection of low saline water mass from the Bay of Bengal associated with Rossby wave propagation introduces a ‘dim’ phycoerythrin-rich Synechococcus group in the frontal region, and the ensuing physicochemical changes in water column favor their growth, whereas low cell abundance of Prochlorococcus and Phycocyanin-rich Synechococcus suggests restricted growth of both the groups. These inferences indicate that Rossby wave associated circulation pattern and physicochemical changes in the water column regulate picophytoplankton community composition and its contribution to food web dynamics in the SEAS.

Journal of Marine Systems, Apr 1, 2018

Abstract The deepening of mixed layer and ensuing changes in optical and physicochemical properti... more Abstract The deepening of mixed layer and ensuing changes in optical and physicochemical properties of euphotic zone can influence phytoplankton community dynamics in the northeastern Arabian Sea during winter monsoon. The response of picophytoplankton community to such changes during winter convective mixing is not well understood. Herein, we have compared variations in the picophytoplankton community structure during early (November–December 2012), peak (end-January 2014) and late (mid-February 2015) winter monsoon from three separate cruises in the southern northeastern Arabian Sea. The higher Synechococcus abundance owing to entrainment of nutrients in mixed layer was observed during peak winter monsoon, while the concomitant changes in nitrate concentration, light and oxygen environment restricted Prochlorococcus growth resulting in lower abundance during the same period. This highlights the diverse responses of picophytoplankton groups to physicochemical changes of water column during winter convective mixing. The divinyl chlorophyll b/a ratio (marker for Prochlorococcus ecotypes) indicated prevalence of one low-light adapted ecotype (sensitive to light shock) in sub-surface water, one high-light adapted ecotype in surface water during early winter monsoon and both disappeared during intense mixing period in peak winter monsoon. Subsequently, a distinct low-light adapted ecotype, capable to tolerate light shock, was noticed during late winter monsoon and we argue that this ecotype is introduced to southern northeastern Arabian Sea through advection from north by sub-surface circulation. The total picophytoplankton biomass available to microbial loop is restored during late winter monsoon, when stratification begins, with a higher abundance of Synechococcus and the re-occurrence of Prochlorococcus population in the region. These inferences indicate that variability in picophytoplankton community structure and their contribution to the microbial loop are driven by convective mixing and advection, which in turn influence ecosystem functioning and trophodynamics of the southern northeastern Arabian Sea.

Marine Pollution Bulletin, Feb 1, 2017

Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, I... more Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, India, was investigated to assess the anthropogenic impact on coastal water quality. At the densely inhabited Port Blair Bay, the dominance of mixotrophs in water and Protoperidinoids in sediments was attributed to anthropogenic nutrient enrichment and prey availability. A significant decrease in dinoflagellate abundance from inner to outer bay emphasize the variation in nutrient availability. The dominance of autotrophs and Gonyaulacoid cysts at the North Bay highlight low nutrient conditions with less anthropogenic pressure. The occurrence of oceanic Ornithocercus steinii and Diplopsalis sp. could evince the oceanic water intrusion into the North Bay. Nine potentially harmful and red-tide-forming species including Alexandrium tamarense complex, A. minutum were identified in this study. Although there are no harmful algal bloom (HABs) incidences in this region so far, increasing coastal pollution could support their candidature towards the future HABs initiation and development.

Journal Of Geophysical Research: Oceans, Sep 1, 2016

The intense winter phytoplankton bloom during November-February in the northeastern Arabian Sea (... more The intense winter phytoplankton bloom during November-February in the northeastern Arabian Sea (NEAS) was thought, until recently, to be controlled only by a convective deepening of the mixed layer (ML) owing to cool and dry northeasterlies. But, a recent study has shown that the deepening of the ML in the southern NEAS is inhibited by the poleward advection of low-salinity water from the south by the West India Coastal Current (WICC). Using an Ocean General Circulation Model coupled with an ecosystem model, we investigate the consequences of the inhibition of mixed-layer deepening for winter phytoplankton bloom in the NEAS. We show that, during the winter monsoon, the shallow ML inhibits the entrainment of nutrients in the southern NEAS. Strong (weak) positive nitrate tendency in the northern (southern) NEAS seen in the model during the winter monsoon is maintained by strong (weak) entrainment. As a result, the chlorophyll integrated to 200 m depth from the surface is lower in the southern NEAS than in the northern NEAS. The inhibition of mixed-layer deepening in the south affects the size-based distribution of small and large phytoplankton, nutrient limitation terms and growth rate, and their elemental composition. The WICC, which inhibits the deepening of the ML and affects the winter bloom in the NEAS, is driven by coastal Kelvin waves generated by remote winds. This paper demonstrates a mechanism by which remotely forced coastal Kelvin waves impact the biology in the north Indian Ocean.

Ecological Informatics, May 1, 2023

ASEAN journal on science & technology for development, Sep 15, 2018

The Ballast Water Risk Assessment serves as a "Decision Support System" for any given port to tak... more The Ballast Water Risk Assessment serves as a "Decision Support System" for any given port to take appropriate ballast water management actions. Risk assessment involves collation of data from the ballast water reporting forms to identify the source of ballast water. The environmental characteristics of the source and recipient ports are utilized to evaluate the similarities. This is then combined with other risk factors, including voyage duration and risk species to gain a preliminary indication of the overall risk posed by each source port. The results will help in evaluating the risk posed by ballast water introductions, and decide whether to apply a blanket or selective ballast water management regime. The experience in India with ballast water risk assessment showed that manually submitted ballast water reporting forms were ridden with inaccuracies. Hence, self-validating electronic ballast water reporting forms (e-BWRF) were introduced to overcome such inaccuracies. Our experience with the risk assessment conducted in an Indian port Visakhapatnam, suggests that the local ports pose higher risk of introduction. However, under such circumstances a risk reduction factor was introduced in the method to counter geographical proximities. The paper provides an overview of lessons learnt through ballast water risk assessment in India and the necessary corrective actions taken thereof.

Aquatic Sciences, 2021

Sea surface temperature fronts in the Northeastern Arabian Sea (NEAS) facilitate nutrient enhance... more Sea surface temperature fronts in the Northeastern Arabian Sea (NEAS) facilitate nutrient enhancement in the surface layers, resulting in high primary production. Such high production areas contribute to the accumulation of fresh organic matter rich in carbohydrates, thereby supporting higher heterotrophic metabolism. Transparent exopolysaccharides (TEP) are one of the carbohydrate polymers released as exudates during primary production or decaying process and their breakdown is mediated by a set of ectoenzymes that includes glucosidases and chitinases. Observations were carried out in different aged NEAS fronts to elucidate the influence of frontal age on the abundance of TEP, bacterial nucleic acid content (high nucleic acid content, HNA and low nucleic acid content, LNA), and ectoenzymatic activities. The fronts were classified as younger and older, depending on their first appearance and sampling day. A clear transition from HNA to LNA bacteria, variations in TEP and related ectoenzymatic activities in the fronts was influenced by the frontal age. The younger fronts were dominated by HNA bacteria, α-glucosidase, and chitinase activity. In contrast, an acceleration in β-glucosidase activity, bacterial production, which was related to TEP concentration, was evident in the older fronts. Further, a significant increase in protist numbers in older fronts was related to effective grazing on HNA bacteria and TEP. The active turnover of TEP by bacteria and protists facilitates strong microbial loop in NEAS frontal regions. Elucidating contribution of such changes in the frontal areas will provide a basis for a better understanding of microbial carbon cycling.

ASEAN journal on science & technology for development, Sep 15, 2018

The Decision Support System (DSS) for ballast water management in any given port is dependent on ... more The Decision Support System (DSS) for ballast water management in any given port is dependent on the availability of information on ballast water carried by a ship in advance. Collation of information through Ballast Water Reporting Forms (BWRF) has been adopted by several countries. This paper provides a comparison of the reporting forms adopted by some of the countries and the International Maritime Organization (IMO) recommended BWRF. The manually submitted reporting forms have several limitations and India has developed a self-validating Electronic Ballast Water Reporting Form (e-BWRF) to overcome such issues. In addition, the possible direction for reporting in the future is also presented.

Progress in Oceanography, Mar 1, 2019

Environmental Monitoring and Assessment, Apr 4, 2023

NARA eBooks, Jul 27, 2017

The user has requested enhancement of the downloaded file.

Prawn seed resources of Sunkeri. Hack Waters indicated the availability oC Penacus iudicus (H. Mi... more Prawn seed resources of Sunkeri. Hack Waters indicated the availability oC Penacus iudicus (H. Milne Edward":.), Penacus monodon (Fabricius) Metape-!U:tells dobsoni (Miers), and lvletapenueus monoceros (Fabricius). The monthly variation in seed c:ompositiop, its correlntion w1th environmental pan\~ meters and the aquaculture poteiltialiti.-.s are being r~ported.

Esta publicacion ha sido preparada por las Asociaciones GloBallast, la IOI, el CSIR-NIO y la UICN... more Esta publicacion ha sido preparada por las Asociaciones GloBallast, la IOI, el CSIR-NIO y la UICN para que sirva de orientacion a quienes tienen previsto hacer un reconocimiento biologico portuario de referencia, en especial en relacion con la gestion del agua de lastre.

Destruction on mango wood (Mangifera indica Linn.) panels in the Mandovi estuary of Goa at 5 diff... more Destruction on mango wood (Mangifera indica Linn.) panels in the Mandovi estuary of Goa at 5 different depths was studied for different seasons. The causative organisms were found to be Lyrodus pedicel/atus Quatrefages and Martesia striata L. Maximum incidence of wood boring organisms was during Sept. and Oct. of the study period.

Offshore marine environment can very well be utilized for mass storage of liquids which are not h... more Offshore marine environment can very well be utilized for mass storage of liquids which are not harmful to that environment. Improper placement of large tanks on the seabed, to store large quantities of liquids, would adversely affect the hydrodynamics of adjoining environment. Thorough understanding on the hydrodynamics of the adjoining environment is thus required before and after placing such tanks so as to properly plan the placement of these large tanks. A two dimensional numerical hydrodynamic model is used to study influence of placing large number of tanks in a dynamic marine environment. Cylindrical tanks (5 m dia.) are arranged in three rows with 50 tanks placed in each row with their length (100 m) aligned perpendicular to the coast. These tanks cover an area of about 36000 m 2 and are placed on seabed in water depths about 15 m. Hydrodynamic simulations carried out with tidal forcing for cases of (a) before and (b) after placement of tanks showed that current speeds increase up to 65% in the region where the tanks are placed compared to currents without placement of tanks. However, up to 85% increase in current speeds is observed in regions beyond the tanks. In this manuscript results of the effects on the hydrodynamics of a region due to placing large number of tanks in shallow waters are presented.

Marine Pollution Bulletin, Feb 1, 2023

Marine Pollution Bulletin, Nov 1, 2021

Port environments are highly dynamic and hotspots for marine bioinvasion. This study investigated... more Port environments are highly dynamic and hotspots for marine bioinvasion. This study investigated the bacterial diversity at two geographically distant ports (Mangalore-marine port; and Haldia-riverine port) using next-generation sequencing during southwest monsoon and non-monsoon (Pre-monsoon) seasons. During southwest monsoon, at both marine and riverine ports, operational taxonomic units (OTUs) affiliated to bacteria reported to have hydrocarbon degrading ability were observed. Whereas during pre-monsoon, a significant increase in benthic bacterial OTUs was evident at the marine port, and the riverine port was characterized by oceanic species OTUs. Results suggest that the dynamics of prevalent environmental conditions, driven by seasons, led to emergence of ecologically relevant bacteria, many of which have been observed for the first time in Indian coastal waters. Their presence could be used as indicators of prevailing environmental conditions and nature of anthropogenic influence in port ecosystems. Unravelling functional roles of such ecologically relevant species is a way forward.

Journal of Marine Systems, Nov 1, 2019

Abstract The westward propagating Rossby waves and associated currents transport low salinity nut... more Abstract The westward propagating Rossby waves and associated currents transport low salinity nutrient-rich water mass from the Bay of Bengal into the southeastern Arabian Sea (SEAS) during winter monsoon, and ensuing changes in physicochemical properties of water column regulate phytoplankton distribution in the latter region. Herein, we elucidate the influence of Rossby wave propagation on picophytoplankton community composition in the SEAS. We compare the picophytoplankton community structure between the Rossby front (low saline, high nitrate concentration and strong current) and the surrounding non-frontal regions (high saline, low nitrate and weak current) along a cruise track in the SEAS during early winter monsoon (November 2016). The higher abundance of phycoerythrin-rich Synechococcus (‘dim’ and ‘bright’ types) and lower abundance of Prochlorococcus in the frontal region than the non-frontal regions suggest that salinity and nitrate concentration in the water column significantly influence the picophytoplankton community dynamics. We argue that the advection of low saline water mass from the Bay of Bengal associated with Rossby wave propagation introduces a ‘dim’ phycoerythrin-rich Synechococcus group in the frontal region, and the ensuing physicochemical changes in water column favor their growth, whereas low cell abundance of Prochlorococcus and Phycocyanin-rich Synechococcus suggests restricted growth of both the groups. These inferences indicate that Rossby wave associated circulation pattern and physicochemical changes in the water column regulate picophytoplankton community composition and its contribution to food web dynamics in the SEAS.

Journal of Marine Systems, Apr 1, 2018

Abstract The deepening of mixed layer and ensuing changes in optical and physicochemical properti... more Abstract The deepening of mixed layer and ensuing changes in optical and physicochemical properties of euphotic zone can influence phytoplankton community dynamics in the northeastern Arabian Sea during winter monsoon. The response of picophytoplankton community to such changes during winter convective mixing is not well understood. Herein, we have compared variations in the picophytoplankton community structure during early (November–December 2012), peak (end-January 2014) and late (mid-February 2015) winter monsoon from three separate cruises in the southern northeastern Arabian Sea. The higher Synechococcus abundance owing to entrainment of nutrients in mixed layer was observed during peak winter monsoon, while the concomitant changes in nitrate concentration, light and oxygen environment restricted Prochlorococcus growth resulting in lower abundance during the same period. This highlights the diverse responses of picophytoplankton groups to physicochemical changes of water column during winter convective mixing. The divinyl chlorophyll b/a ratio (marker for Prochlorococcus ecotypes) indicated prevalence of one low-light adapted ecotype (sensitive to light shock) in sub-surface water, one high-light adapted ecotype in surface water during early winter monsoon and both disappeared during intense mixing period in peak winter monsoon. Subsequently, a distinct low-light adapted ecotype, capable to tolerate light shock, was noticed during late winter monsoon and we argue that this ecotype is introduced to southern northeastern Arabian Sea through advection from north by sub-surface circulation. The total picophytoplankton biomass available to microbial loop is restored during late winter monsoon, when stratification begins, with a higher abundance of Synechococcus and the re-occurrence of Prochlorococcus population in the region. These inferences indicate that variability in picophytoplankton community structure and their contribution to the microbial loop are driven by convective mixing and advection, which in turn influence ecosystem functioning and trophodynamics of the southern northeastern Arabian Sea.

Marine Pollution Bulletin, Feb 1, 2017

Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, I... more Dinoflagellate community structure from two semi-enclosed areas along the South Andaman region, India, was investigated to assess the anthropogenic impact on coastal water quality. At the densely inhabited Port Blair Bay, the dominance of mixotrophs in water and Protoperidinoids in sediments was attributed to anthropogenic nutrient enrichment and prey availability. A significant decrease in dinoflagellate abundance from inner to outer bay emphasize the variation in nutrient availability. The dominance of autotrophs and Gonyaulacoid cysts at the North Bay highlight low nutrient conditions with less anthropogenic pressure. The occurrence of oceanic Ornithocercus steinii and Diplopsalis sp. could evince the oceanic water intrusion into the North Bay. Nine potentially harmful and red-tide-forming species including Alexandrium tamarense complex, A. minutum were identified in this study. Although there are no harmful algal bloom (HABs) incidences in this region so far, increasing coastal pollution could support their candidature towards the future HABs initiation and development.

Journal Of Geophysical Research: Oceans, Sep 1, 2016

The intense winter phytoplankton bloom during November-February in the northeastern Arabian Sea (... more The intense winter phytoplankton bloom during November-February in the northeastern Arabian Sea (NEAS) was thought, until recently, to be controlled only by a convective deepening of the mixed layer (ML) owing to cool and dry northeasterlies. But, a recent study has shown that the deepening of the ML in the southern NEAS is inhibited by the poleward advection of low-salinity water from the south by the West India Coastal Current (WICC). Using an Ocean General Circulation Model coupled with an ecosystem model, we investigate the consequences of the inhibition of mixed-layer deepening for winter phytoplankton bloom in the NEAS. We show that, during the winter monsoon, the shallow ML inhibits the entrainment of nutrients in the southern NEAS. Strong (weak) positive nitrate tendency in the northern (southern) NEAS seen in the model during the winter monsoon is maintained by strong (weak) entrainment. As a result, the chlorophyll integrated to 200 m depth from the surface is lower in the southern NEAS than in the northern NEAS. The inhibition of mixed-layer deepening in the south affects the size-based distribution of small and large phytoplankton, nutrient limitation terms and growth rate, and their elemental composition. The WICC, which inhibits the deepening of the ML and affects the winter bloom in the NEAS, is driven by coastal Kelvin waves generated by remote winds. This paper demonstrates a mechanism by which remotely forced coastal Kelvin waves impact the biology in the north Indian Ocean.

Ecological Informatics, May 1, 2023

ASEAN journal on science & technology for development, Sep 15, 2018

The Ballast Water Risk Assessment serves as a "Decision Support System" for any given port to tak... more The Ballast Water Risk Assessment serves as a "Decision Support System" for any given port to take appropriate ballast water management actions. Risk assessment involves collation of data from the ballast water reporting forms to identify the source of ballast water. The environmental characteristics of the source and recipient ports are utilized to evaluate the similarities. This is then combined with other risk factors, including voyage duration and risk species to gain a preliminary indication of the overall risk posed by each source port. The results will help in evaluating the risk posed by ballast water introductions, and decide whether to apply a blanket or selective ballast water management regime. The experience in India with ballast water risk assessment showed that manually submitted ballast water reporting forms were ridden with inaccuracies. Hence, self-validating electronic ballast water reporting forms (e-BWRF) were introduced to overcome such inaccuracies. Our experience with the risk assessment conducted in an Indian port Visakhapatnam, suggests that the local ports pose higher risk of introduction. However, under such circumstances a risk reduction factor was introduced in the method to counter geographical proximities. The paper provides an overview of lessons learnt through ballast water risk assessment in India and the necessary corrective actions taken thereof.

Aquatic Sciences, 2021

Sea surface temperature fronts in the Northeastern Arabian Sea (NEAS) facilitate nutrient enhance... more Sea surface temperature fronts in the Northeastern Arabian Sea (NEAS) facilitate nutrient enhancement in the surface layers, resulting in high primary production. Such high production areas contribute to the accumulation of fresh organic matter rich in carbohydrates, thereby supporting higher heterotrophic metabolism. Transparent exopolysaccharides (TEP) are one of the carbohydrate polymers released as exudates during primary production or decaying process and their breakdown is mediated by a set of ectoenzymes that includes glucosidases and chitinases. Observations were carried out in different aged NEAS fronts to elucidate the influence of frontal age on the abundance of TEP, bacterial nucleic acid content (high nucleic acid content, HNA and low nucleic acid content, LNA), and ectoenzymatic activities. The fronts were classified as younger and older, depending on their first appearance and sampling day. A clear transition from HNA to LNA bacteria, variations in TEP and related ectoenzymatic activities in the fronts was influenced by the frontal age. The younger fronts were dominated by HNA bacteria, α-glucosidase, and chitinase activity. In contrast, an acceleration in β-glucosidase activity, bacterial production, which was related to TEP concentration, was evident in the older fronts. Further, a significant increase in protist numbers in older fronts was related to effective grazing on HNA bacteria and TEP. The active turnover of TEP by bacteria and protists facilitates strong microbial loop in NEAS frontal regions. Elucidating contribution of such changes in the frontal areas will provide a basis for a better understanding of microbial carbon cycling.

ASEAN journal on science & technology for development, Sep 15, 2018

The Decision Support System (DSS) for ballast water management in any given port is dependent on ... more The Decision Support System (DSS) for ballast water management in any given port is dependent on the availability of information on ballast water carried by a ship in advance. Collation of information through Ballast Water Reporting Forms (BWRF) has been adopted by several countries. This paper provides a comparison of the reporting forms adopted by some of the countries and the International Maritime Organization (IMO) recommended BWRF. The manually submitted reporting forms have several limitations and India has developed a self-validating Electronic Ballast Water Reporting Form (e-BWRF) to overcome such issues. In addition, the possible direction for reporting in the future is also presented.

Progress in Oceanography, Mar 1, 2019

Environmental Monitoring and Assessment, Apr 4, 2023

NARA eBooks, Jul 27, 2017

The user has requested enhancement of the downloaded file.

Prawn seed resources of Sunkeri. Hack Waters indicated the availability oC Penacus iudicus (H. Mi... more Prawn seed resources of Sunkeri. Hack Waters indicated the availability oC Penacus iudicus (H. Milne Edward":.), Penacus monodon (Fabricius) Metape-!U:tells dobsoni (Miers), and lvletapenueus monoceros (Fabricius). The monthly variation in seed c:ompositiop, its correlntion w1th environmental pan\~ meters and the aquaculture poteiltialiti.-.s are being r~ported.

Esta publicacion ha sido preparada por las Asociaciones GloBallast, la IOI, el CSIR-NIO y la UICN... more Esta publicacion ha sido preparada por las Asociaciones GloBallast, la IOI, el CSIR-NIO y la UICN para que sirva de orientacion a quienes tienen previsto hacer un reconocimiento biologico portuario de referencia, en especial en relacion con la gestion del agua de lastre.

Destruction on mango wood (Mangifera indica Linn.) panels in the Mandovi estuary of Goa at 5 diff... more Destruction on mango wood (Mangifera indica Linn.) panels in the Mandovi estuary of Goa at 5 different depths was studied for different seasons. The causative organisms were found to be Lyrodus pedicel/atus Quatrefages and Martesia striata L. Maximum incidence of wood boring organisms was during Sept. and Oct. of the study period.

Offshore marine environment can very well be utilized for mass storage of liquids which are not h... more Offshore marine environment can very well be utilized for mass storage of liquids which are not harmful to that environment. Improper placement of large tanks on the seabed, to store large quantities of liquids, would adversely affect the hydrodynamics of adjoining environment. Thorough understanding on the hydrodynamics of the adjoining environment is thus required before and after placing such tanks so as to properly plan the placement of these large tanks. A two dimensional numerical hydrodynamic model is used to study influence of placing large number of tanks in a dynamic marine environment. Cylindrical tanks (5 m dia.) are arranged in three rows with 50 tanks placed in each row with their length (100 m) aligned perpendicular to the coast. These tanks cover an area of about 36000 m 2 and are placed on seabed in water depths about 15 m. Hydrodynamic simulations carried out with tidal forcing for cases of (a) before and (b) after placement of tanks showed that current speeds increase up to 65% in the region where the tanks are placed compared to currents without placement of tanks. However, up to 85% increase in current speeds is observed in regions beyond the tanks. In this manuscript results of the effects on the hydrodynamics of a region due to placing large number of tanks in shallow waters are presented.