Fluctuations of Mediterranean Outflow Water circulation in the Gulf of Cadiz during MIS 5 to 7: Evidence from benthic foraminiferal assemblage and stable isotope records

Singh, Arun D.; Rai, A.K.; Tiwari, Manish; Naidu, Pothuri Divakar; Verma, Komal; Chaturvedi, Madan M.; Niyogi, A.; Pandey, Dhananjai K.

doi:10.1016/j.gloplacha.2015.08.005

Cited by 34 publications

(24 citation statements)

References 95 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A more sluggish bottom current could indicate either the absence of MOW above Site U1387 or MOW being less dense and neutrally buoyant already in the vicinity of the Faro Drift. The latter scenario would agree with Singh et al (2015) who deduce upper MOW presence at Site U1387 during the insolation maxima of MIS 5 and MIS 7 from their benthic foraminifer data.…”

Section: Upper Mow Variations On Orbital Time-scalessupporting

confidence: 89%

“…The early Pleistocene climate records of IODP Site U1387 revealed that the history of the upper MOW encompasses a complex interplay of orbital and millennial-scale forcing. Precession (insolation) forcing on MOW ventilation is now clearly established, not only by this study but also for other Expedition 339 Sites and time periods (e.g., Lebreiro et al, submitted;Singh et al, 2015). The impacts of insolation maxima (minima) were independent of glacial and interglacial climate conditions and mostly related to Mediterranean climate conditions as clearly demonstrated by the coincidence of sapropel layers in the eastern Mediterranean Sea and poor ventilation in the upper MOW.…”

Section: Discussionsupporting

confidence: 76%

“…7). Flow velocity increases of the upper and lower MOW cores during North Atlantic ice-rafting events and/or Greenland stadials are well known from the last glacial cycle (Llave et al, 2006;Toucanne et al, 2007;Voelker et al, 2006) and have recently also been described for late MIS 6 and MIS 7 (Bahr et al, 2014;Singh et al, 2015). Voelker et al (2006) linked these events to periods of enhanced deep convection in the western Mediterranean Sea and more recently, Toucanne et al (2012) showed that better ventilation and faster flow also occurred at the level of the LIW in the western Mediterranean Sea.…”

Section: Upper Mow Responses To Millennial-scale Climate Changementioning

confidence: 86%

See 2 more Smart Citations

Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020–1135 ka)

Voelker

Salgueiro

Rodrigues

et al. 2015

Global and Planetary Change

View full text Add to dashboard Cite

Centennial-to-millennial scale records from IODP Site U1387, drilled during IODP Expedition 339 into the Faro Drift at 558 m water depth, now allow evaluating the climatic history of the upper core of the Mediterranean Outflow (MOW) and of the surface waters in the northern Gulf of Cadiz during the early Pleistocene. This study focuses on the period from Marine Isotope Stages (MIS) 29 to 34, i.e. the interval surrounding extreme interglacial MIS 31. Conditions in the upper MOW reflect obliquity, precession and millennial-scale variations. The benthic δ 18 O signal follows obliquity with the exception of an additional, smaller δ 18 O peak that marks the MIS 32/31 transition. Insolation maxima (precession minima) led to poor ventilation and a sluggish upper MOW core, whereas insolation minima were associated with enhanced ventilation and often also increased bottom current velocity. Millennial-scale periods of colder sea-surface temperatures (SST) were associated with short-term maxima in flow velocity and better ventilation, reminiscent of conditions known from MIS 3. A prominent contourite layer, coinciding with insolation cycle 100, was formed during MIS 31 and represents one of the few contourites developing within an interglacial period. MIS 31 surface water conditions were characterized by an extended period (1065-1091 ka) of warm SST, but SST were not much warmer than during MIS 33. Interglacial to glacial transitions experienced 2 to 3 stadial/interstadial cycles, just like their mid-to-late Pleistocene counterparts. Glacial MIS 30 and 32 recorded periods of extremely cold (b12°C) SST that in their climatic impact were comparable with the Heinrich events of the mid and late Pleistocene. Glacial MIS 34, on the other hand, was a relative warm glacial period off southern Portugal. Overall, surface water and MOW conditions at Site U1387 show a strong congruence with Mediterranean climate, whereas millennial-scale variations are closely linked to North Atlantic circulation changes.

show abstract

Section: Upper Mow Variations On Orbital Time-scalessupporting

confidence: 89%

Section: Discussionsupporting

confidence: 76%

Section: Upper Mow Responses To Millennial-scale Climate Changementioning

confidence: 86%

See 1 more Smart Citation

Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020–1135 ka)

Voelker

Salgueiro

Rodrigues

et al. 2015

Global and Planetary Change

View full text Add to dashboard Cite

show abstract

“…Because of the net loss of water in the Mediterranean (evaporation exceeding precipitation plus runoff) and the cold winds reaching the northern margins of the basin the density of Mediterranean water at Gibraltar is much higher than that of the Atlantic surface water, resulting in a Mediterranean Outflow at depth and an Atlantic inflow at surface (Bethoux & Gentili, 1999; Bryden et al, 1994). A series of studies have investigated the evolution of the MOW by analyzing changes in the physical or geochemical properties of the sediments in various sites along the Gulf of Cadiz contourite depositional system (Bahr et al, 2015; Bryden & Kinder, 1991; Bryden & Stommel, 1982; Kaboth et al, 2016; Kaboth, de Boer, et al, 2017; Kaboth, Grunert, et al, 2017; Kaboth‐Bahr et al, 2018; Lebreiro et al, 2015, 2018; Llave et al, 2006; Singh et al, 2015; Stow et al, 2013; Toucanne et al, 2007; Voelker et al, 2006, 2015). Most of them point to the straight relationship between the intensity of MOW and Northern Hemisphere climate variability.…”

Section: Introductionmentioning

confidence: 99%

Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets

Sierro

Hodell

Andersen

et al. 2020

Paleoceanog and Paleoclimatol

View full text Add to dashboard Cite

To investigate past changes in the Mediterranean Overflow Water (MOW) to the Atlantic, we analyzed the strength of the MOW and benthic δ 13 C along the last 250 kyr at Integrated Ocean Drilling Program (IODP) Site U1389 in the Gulf of Cadiz, near the Strait of Gibraltar. Both the strength of the MOW and the benthic δ 13 C were mainly driven by precession-controlled fluctuations in the Mediterranean hydrologic budget. Reduced/enhanced Nile discharge and lower/higher Mediterranean annual rainfall at precession maxima/minima resulted in higher/lower MOW strengths at Gibraltar and stronger/weaker Mediterranean overturning circulation. At millennial scale, the higher heat and freshwater loss to the atmosphere during Greenland stadials increased buoyancy loss in the eastern Mediterranean. This enhanced the density gradient with Atlantic water, resulting in a higher MOW velocity in the Gulf of Cadiz. Unlike non-Heinrich stadials, a lower-amplitude increase in velocity was seen during Heinrich stadials (HSs), and a significant drop in velocity was recorded in the middle phase. This weak MOW was especially recognized in Termination I and II during HS1 and HS11. These lower velocities at the depth of Site U1389 were triggered by MOW deepening due to the lower densities of Atlantic intermediate water caused by freshwater released from the Laurentide and Eurasian ice sheets. The intrusion of salt and heat at deeper depths in the Atlantic during HSs and its shoaling at the end could have contributed to drive the changes in the Atlantic Meridional Overturning Circulation during Terminations.

show abstract

“…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%

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

2021

View full text Add to dashboard Cite

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.

show abstract

Fluctuations of Mediterranean Outflow Water circulation in the Gulf of Cadiz during MIS 5 to 7: Evidence from benthic foraminiferal assemblage and stable isotope records

Cited by 34 publications

References 95 publications

Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020–1135 ka)

Mediterranean Outflow and surface water variability off southern Portugal during the early Pleistocene: A snapshot at Marine Isotope Stages 29 to 34 (1020–1135 ka)

Mediterranean Overflow Over the Last 250 kyr: Freshwater Forcing From the Tropics to the Ice Sheets

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

Contact Info

Product

Resources

About