Significantly dominant warm-core eddies: An ecological indicator of the basin-scale low biological production in the Bay of Bengal

Jyothibabu, R.; Karnan, C.; Arunpandi, N.; Krishnan, S. Santhi; Balachandran, K.K.; Sahu, K. C.

doi:10.1016/j.ecolind.2020.107016

Cited by 13 publications

(5 citation statements)

References 27 publications

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“…Recent studies also shown that the presence of cyclonic eddies in the AS increases the intensity of surface chlorophyll (Nukapothula et al ., 2018; Wang et al ., 2020; Shafeeque et al ., 2021; Peter et al ., 2022; Smitha et al ., 2022). The strong chlorophyll anomalies are evident in the AS when compared with the BoB is associated with the presence of strong upwelling zones, intense mixing of surface waters due to stronger winds that are weak or absent in the BoB (Ajith Joseph et al ., 2019; Jayaram et al ., 2021; Jyothibabu et al ., 2021; Lahiri and Vissa, 2022). Recently, Smitha et al .…”

Section: Resultsmentioning

confidence: 99%

Mesoscale eddies with anomalous sea surface temperature and its relation with atmospheric convection over the North Indian Ocean

Gulakaram

Anandh

Bhaskaran

2023

Intl Journal of Climatology

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Mesoscale eddies are the important phenomenon of world oceans that play a prominent role in influencing the near-surface atmosphere and transport of heat. Ocean and atmosphere responses due to the presence of oceanic mesoscale eddies are not well studied in the Northern Indian Ocean (NIO) region.The present study analysed the ocean and atmospheric response due to the presence of mesoscale eddies using a composite analysis. Generally, it is assumed that the anti-cyclonic eddies are associated with the positive anomalies of sea surface temperature (SST), and cyclonic eddies are accompanied by negative anomalies. However, for the two marginal seas in the NIO, that is, the Bay of Bengal (BoB) and Arabian Sea (AS), the composite picture of SST anomalies associated with mesoscale eddies showed an abnormal response of SST. This unusual behaviour of cold SST near anti-cyclonic eddies and warm SST near cyclonic eddies in BoB and AS is analysed with the mean composites of precipitation, outgoing longwave radiation (OLR), and turbulent fluxes. The mean composites over all anti-cyclonic eddies reveal the presence of enhanced precipitation and convection (low OLR), whereas over cyclonic eddies, suppressed convection and negative precipitation anomalies are evident. The composites of latent heat flux (LHF), precipitation and OLR near surface cold anticyclonic eddies indicate the loss of heat from the ocean to the atmosphere, intense precipitation along with cloudy conditions are responsible for the cooling of the ocean. Along with this, stronger winds are also evident during cloudy conditions could play a role in anomalous cooling of SST observed near anti-cyclonic through intense surface mixing. Similarly, vice versa is observed near the surface warm cyclonic eddies. The overlying atmosphere and abnormal response of SST near oceanic eddies are essential for understanding the significant role of oceanic mesoscale eddies in influencing the large-scale circulation of the atmosphere and climate.

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Section: Resultsmentioning

confidence: 99%

Mesoscale eddies with anomalous sea surface temperature and its relation with atmospheric convection over the North Indian Ocean

Gulakaram

Anandh

Bhaskaran

2023

Intl Journal of Climatology

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“…The abundant mesoscale eddies that occur in this bay can change the dynamic conditions within the stratified water (Chen et al, 2012;Cheng et al, 2013Cheng et al, , 2018Cui et al, 2016;Dandapat & Chakraborty, 2016;Li et al, 2017;Yang et al, 2013) and have a crucial role in the transport of heat and substance (Chen et al, 2012(Chen et al, , 2021Dong et al, 2014;Gonaduwage et al, 2019), as well as air-sea interactions (Chow & Liu, 2012;Greaser et al, 2020). The strong vertical stratification in the upper layer of the BoB means that cyclonic (anticyclonic) eddy-induced upwelling (downwelling) brings sufficient (deficient) nutrients and greatly increases (decreases) the primary productivity (Gauns et al, 2005;Gomes et al, 2000;Jyothibabu et al, 2008Jyothibabu et al, , 2021Madhupratap et al, 2003;Sarma et al, 2018Sarma et al, , 2019Vidya & Kumar, 2013;Yang et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Because of receiving a significant amount of freshwater discharge from large rivers, the strong vertical stratification in the upper layer of the BoB inhibits heat and substances transport from ocean depth to the surface in the BoB (Gauns et al., 2005; Gomes et al., 2000; Jyothibabu et al., 2008; Madhupratap et al., 2003). In this scenario, the eddies inducing the upper ocean mixing can increase heat and substances exchange between the sea surface and subsurface (Jyothibabu et al., 2021; Nuncio & Kumar, 2012; Prasanna Kumar et al., 2007; Sarma et al., 2019; Vidya & Kumar, 2013; Yang et al., 2020). Periodic eddies occur almost annually in fixed time frames with similar patterns and trajectories (Chu et al., 2020).…”

Section: Introductionmentioning

confidence: 99%

An Eddy Pair in the Northwestern Bay of Bengal: Characteristics, Dynamics and Interannual Variability

Zhong,

Chen,

Chu

2024

JGR Oceans

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Mesoscale eddies are active in the Bay of Bengal and have profound effects on the dynamic conditions, the transport of heat and salt, and the primary productivity. We report a pair of periodic eddies in the Bay of Bengal and examine their characteristics, dynamic mechanisms and interannual variability based on satellite observations and a nonlinear 1.5‐layer reduced‐gravity model. The eddy pair mainly occupies the northwestern Bay of Bengal from March to May and consists of a cyclonic eddy in the north and an anticyclonic eddy in the south. The anticyclonic eddy is generated by local wind forcing, whereas the cyclonic eddy is significantly contributed by equatorial and coastal Kelvin waves. On an interannual scale, the eddy pair was exceptionally weak in 1999, 2000 and 2008 due to the extreme La Niña events in these years when the westerly wind anomaly over the equatorial Indian Ocean weakened the local wind forcing and coastal Kelvin waves. This study provides new knowledge on periodic eddies in the Bay of Bengal and advances our understanding of the dynamic connections between this marginal sea and the equator.

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“…During spring, the surface Bay experiences high temperature and salinity owing to heat gain by the sea and excess evaporation, respectively (Narvekar and Kumar 2006). Weaker winds and prolonged ACEs hinder the supply of subsurface nutrients to the euphotic zone, which leads to ultraoligotrophy in the Bay (Jyothibabu et al 2021). These changing environmental conditions can affect the phytoplankton growth and thereby their elemental stoichiometry during spring.…”

Section: Introductionmentioning

confidence: 99%

“…The changing environmental conditions and associated biogeochemical processes such as N 2 fixation might also affect the elemental stoichiometry. Third, ACEs prevail dominantly during spring (Jyothibabu et al 2021). Furthermore, the age of an eddy is another aspect to look at in biological context as a time lag always exists between ocean physical process and its manifestation on productivity.…”

Section: Introductionmentioning

confidence: 99%

Role of eddies and N2 fixation in regulating C:N:P proportions in the Bay of Bengal

et al. 2021

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Recent observations and numerical simulations have profoundly established that the C:N:P ratios in the ocean deviate from the canonical Redfield Ratio (106:16:1). Physical and biogeochemical processes have been hypothesized to be responsible for this deviation. However, a paucity of concurrent observations on biogeochemical and physical parameters have barred us to understand their exact role on the C:N:P ratios. For this purpose, we have sampled the Bay of Bengal for its C, N, and P contents in the organic and inorganic pools from 5 to 2000 m depth at eight stations (five coastal and three open ocean) during boreal spring 2019. Mesoscale anticyclonic eddies were identified at two of the sampling stations, where nutrient concentrations were lower in the top layer (5 m to the depth of chlorophyll maximum) compared to those at the non-eddy stations. Mean (NO 3 -?NO 2 -):PO 4 3ratio was lower at the anticyclonic eddy stations compared to that at the non-eddy stations in the top layer. Yet C:N:P ratios in the particulate and dissolved organic matter in the top layer were the same at anticyclonic eddy and non-eddy stations. Overall the mean C:N:P ratios were 249:39:1 in particulate organic matter and 2338:146:1 in dissolved organic matter in the top layer. Biological N 2 fixation was not a driver in controlling the N:P ratio of the export flux and the subsurface water nutrient ratios during spring. Although the Bay of Bengal receives large riverine influx, its influence in changing the C:N:P ratios was small during this study.

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Significantly dominant warm-core eddies: An ecological indicator of the basin-scale low biological production in the Bay of Bengal

Cited by 13 publications

References 27 publications

Mesoscale eddies with anomalous sea surface temperature and its relation with atmospheric convection over the North Indian Ocean

Mesoscale eddies with anomalous sea surface temperature and its relation with atmospheric convection over the North Indian Ocean

An Eddy Pair in the Northwestern Bay of Bengal: Characteristics, Dynamics and Interannual Variability

Role of eddies and N2 fixation in regulating C:N:P proportions in the Bay of Bengal

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