Changes in standing stock and vertical distribution of benthic foraminifera along a depth gradient (58–2750 m) in the southeastern Arabian Sea

Singh, D. K.; Saraswat, Rajeev; Kaithwar, Amrata

doi:10.1007/s12526-017-0823-z

Cited by 14 publications

(7 citation statements)

References 60 publications

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“…The region has an extensive relict carbonate platform, with the age of the overlying sediments varying from 7.3 to 8.4 ka (Rao et al 2003). The sediments are sandy on the continental shelf, gradually dominated by the silt and clay on the slope and further deeper regions (Hashimi et al 1981; 1982; Singh et al 2018). The inner shelf sediments are dominated by CaCO 3 of biogenic origin (foraminifera, molluscs, pteropods) (Hashimi et al 1982).…”

Section: Study Areamentioning

confidence: 99%

“…The inner shelf sediments are dominated by CaCO 3 of biogenic origin (foraminifera, molluscs, pteropods) (Hashimi et al 1982). The C org in surface sediments varies from 1.5 % to 6.9 % (Singh et al 2018). The dissolved oxygen varies from 0.48 mL L −1 to 3.84 mL L −1 , with the oxygen-deficient zone (<2 mL L −1 ) between 152 and 1550 m (Singh et al 2018).…”

Section: Study Areamentioning

confidence: 99%

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Persistent increase in carbon burial in the Gulf of Mannar, during the Meghalayan Age: Influence of primary productivity and better preservation

et al. 2023

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The oceans store a substantial fraction of carbon as calcium carbonate (CaCO3) and organic carbon (Corg) and constitute a significant component of the global carbon cycle. The Corg and CaCO3 flux depends on productivity and is strongly modulated by the Asian monsoon in the tropics. Anthropogenic activities are likely to influence the monsoon and thus it is imperative to understand its implications on carbon burial in the oceans. We have reconstructed multi-decadal CaCO3 and Corg burial changes and associated processes during the last 4.9 ky, including the Meghalayan Age, from the Gulf of Mannar. The influence of monsoon on carbon burial is reconstructed from the absolute abundance of planktic foraminifera and relative abundance of Globigerina bulloides. Both Corg and CaCO3 increased throughout the Meghalayan Age, except between 3.0–3.5 ka and the last millennium. The increase in Corg burial during the Meghalayan Age was observed throughout the eastern Arabian Sea. The concomitant decrease in the Corg to nitrogen ratio suggests increased contribution of marine organic matter. Although the upwelling was intense until 1.5 ka, the lack of a definite increasing trend suggests that the persistent increase in Corg and CaCO3 during the early Meghalayan Age was mainly driven by higher productivity during the winter season coupled with better preservation in the sediments. Both the intervals (3.0–3.5 ka and the last millennium) of nearly constant carbon burial coincide with a steady sea-level. The low carbon burial during the last millennium is attributed to the weaker-upwelling-induced lower productivity.

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Section: Study Areamentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

Persistent increase in carbon burial in the Gulf of Mannar, during the Meghalayan Age: Influence of primary productivity and better preservation

et al. 2023

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“…Half of the sediment from each section was immediately preserved in ethanol rose-Bengal solution (2 g rose-Bengal per liter of ethanol), to stain living benthic foraminifera. The top two sections (0-2 cm) were analyzed, as they contain the majority of the living benthic foraminifera in the northern Indian Ocean (Singh et al, 2018). The use of rose-Bengal stained living benthic foraminifera has been widely discussed since its introduction by Walton (1952).…”

Section: Field Samplingmentioning

confidence: 99%

“…The stained sediments were stored in cold-storage (4 • C) for a minimum of 2 weeks and were then processed following the standard procedure (Manasa et al, 2016;Singh et al, 2018;Suokhrie et al, 2020). The excess ethanol rose-Bengal was removed, and the sediments were freeze-dried.…”

Section: Laboratory Analysismentioning

confidence: 99%

“…The salinity and temperature are the major factors in riverine influx dominated continental shelves (Manasa et al, 2016). However, the deeper depth continental slope assemblages are mainly controlled by the availability of food and dissolved oxygen concentration (Gooday, 1986;Corliss and Chen, 1988;Mackensen and Douglas, 1989;Corliss and Emerson, 1990;Barmawidjaja et al, 1992;Jorissen et al, 1992;Rosoff and Corliss, 1992;Rathburn and Corliss, 1994;Nisha and Singh, 2012;Singh et al, 2015aSingh et al, , 2018Verma et al, 2018). Benthic foraminiferal abundance, diversity, species richness and evenness also depend on ambient conditions (Gibson and Buzas, 1973;Buzas and Culver, 1991;Murray, 2006;Singh et al, 2015a,b).…”

Section: Introductionmentioning

confidence: 99%

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Multiple Ecological Parameters Affect Living Benthic Foraminifera in the River-Influenced West-Central Bay of Bengal

2021

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The huge riverine influx and associated processes decrease the ambient salinity, stratify the water column, modulate the oxygen-deficient zone, and are also responsible for the recent acidification in the Bay of Bengal. Here, we have studied the effect of these riverine influx-dominated ecological parameters on living benthic foraminifera in the west-central Bay of Bengal. We report that the pH below 7.6 in front of the Krishna river, reduces the diversity and the richness of living benthic foraminifera on the adjacent shelf and the slope. A similar decreased diversity and richness is also observed in front of the Godavari River. We delineate three prominent assemblages, representing different depth zones with associated distinct physico-chemical conditions. The shallow water assemblage (∼27–100 m) is represented by Nonionella labradorica, Hanzawaia nipponica, Brizalina dilatata, Ammonia tepida, and Nonionella limbato-striata. These species are adapted to relatively warmer temperatures and more oxygenated waters. The deepwater assemblage (∼1,940–2,494 m) includes Bulimina cf. delreyensis, Bulimina marginata, Hormosinella guttifera, Cassidulina laevigata, and Gyroidinoides subzelandica and can tolerate a relatively colder temperature. The intermediate-depth assemblage (∼145–1,500 m) dominated by Eubuliminella exilis, Bolivinellina earlandi, Fursenkoina spinosa, Bolivinellina lucidopunctata, Globobulimina globosa, Fursenkoina spinosa, Eubuliminella cassandrae, Uvigerina peregrina, Rotaliatinopsis semiinvoluta, and Cassidulina laevigata, represents oxygen-deficient and organic carbon-rich environment. Besides the pH, temperature, dissolved oxygen and organic matter, we also report a strong influence of bathymetry, coarse fraction (CF) and the type of organic matter on a few living benthic foraminifera. The ecological preferences of 40 such dominant living benthic foraminifera, each representing a specific environment, have also been reported for site-specific proxy. We conclude that although the huge riverine influx affects living benthic foraminifera on the shelf, the dissolved oxygen and organic carbon mostly control benthic foraminiferal distribution in the deeper west-central Bay of Bengal.

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A highly diverse living benthic foraminiferal assemblage in the oxygen deficient zone of the southeastern Arabian Sea

2020

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Changes in standing stock and vertical distribution of benthic foraminifera along a depth gradient (58–2750 m) in the southeastern Arabian Sea

Cited by 14 publications

References 60 publications

Persistent increase in carbon burial in the Gulf of Mannar, during the Meghalayan Age: Influence of primary productivity and better preservation

Persistent increase in carbon burial in the Gulf of Mannar, during the Meghalayan Age: Influence of primary productivity and better preservation

Multiple Ecological Parameters Affect Living Benthic Foraminifera in the River-Influenced West-Central Bay of Bengal

A highly diverse living benthic foraminiferal assemblage in the oxygen deficient zone of the southeastern Arabian Sea

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