April and August Northeast Atlantic surface water masses reflected in planktic foraminifera

Ottens, Janneke J.

doi:10.1016/0077-7579(92)90031-9

Cited by 41 publications

(34 citation statements)

References 33 publications

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“…As G. ruber lives during the warm season and G. inflata at the BST, of which temperature is close to that of winter condition, this interpretation fits well with our concept. The development of this species during warm season at midlatitude is confirmed by the plankton nets of Ottens [1992] collected between 30°N and 60°N in the Atlantic. Recently, living G. inflata were sampled in the SW‐African margin water column during austral summer [ Wilke et al , 2006].…”

Section: Results and Discussion: A Modern Ecological Conceptmentioning

confidence: 65%

Deep‐dwelling foraminifera as thermocline temperature recorders

Cléroux

Cortijo

Duplessy

et al. 2007

Geochem Geophys Geosyst

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[1] We measured the oxygen isotopic composition of the deep-dwelling foraminiferal species G. inflata, G. truncatulinoides dextral and sinistral, and P. obliquiloculata in 29 modern core tops raised from the North Atlantic Ocean. We compared calculated isotopic temperatures with atlas temperatures and defined ecological models for each species. G. inflata and G. truncatulinoides live preferentially at the base of the seasonal thermocline. Under temperature stress, i.e., when the base of the seasonal thermocline is warmer than 16°C, G. inflata and G. truncatulinoides live deeper in the main thermocline. P. obliquiloculata inhabits the seasonal thermocline in warm regions. We tested our model using 10 cores along the Mauritanian upwelling and show that the comparison of d 18 O variations registered by the surficial species G. ruber and G. bulloides and the deep-dwelling species G. inflata evidences significant glacialinterglacial shifts of the Mauritanian upwelling cells.

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Section: Results and Discussion: A Modern Ecological Conceptmentioning

confidence: 65%

Deep‐dwelling foraminifera as thermocline temperature recorders

Cléroux

Cortijo

Duplessy

et al. 2007

Geochem Geophys Geosyst

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“…Apart from their possibly different preferences in prey, it has been consistently reported from the North Atlantic (Kipp 1976;Ottens 1992) and the SW Pacific (Thiede et al 1997) that G. falconensis lives at the warm 'edge' of the distribution of G. bulloides, thus indicating a preference for slightly warmer waters than G. bdloides. If we compare the flux patterns of the two species in the northern Arabian Sea (Figs.…”

Section: Julian Daysmentioning

confidence: 97%

Planktic foraminifera, particle flux and oceanic productivity off Pakistan, NE Arabian Sea: modern analogues and application to the palaeoclimatic record

Schulz

Rad

Ittekkot

2002

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We use the flux of bulk sediment (CaC03, biogenic opal, organic carbon, lithogenic material), and of planktic foraminifera (PF) and other shell-bearing plankton from sediment trap EPT-2 off Pakistan to (1) constrain the seasonal pattern of regional productivity and (2) search for indications of the NE monsoon winter situation that may serve as a modem analogue to better reveal the seasonal climatic signals preserved in the sedimentary record of the Arabian Sea. Our trap data show a clear seasonality of fluxes that can also be traced in the composition of non-bioturbated (varved) summer and winter sediment laminae preserved within the oxygen minimum zone. In EPT-2, the flux of PF is low during summer, but during winter and late spring it is higher, as at trap station WAST, in the upwelling area of the western Arabian Sea. Globigerina bulloides, a PF species linked to summer upwelling and high productivity, is of minor importance off Pakistan. In contrast, Globigerina falconensis dominates in flux and relative abundance, and is indicative of winter mixing, when NE monsoonal winds cool the highly saline surface waters and break up stratification. An enhanced horizontal flux of suspended sediments stirred up on the shelf and upper slope is clearly shown by the peak in occurrence of small benthic foraminifera during winter. Altogether, our data suggest that the particle flux in the northeastern Arabian Sea is determined by local sediment resuspcnsion and winter productivity rather than by summer monsoonal upwelling, representing a 'nonupwelling' environment, in contrast to the 'summer upwelling' regime off Oman, Somalia and southern India. We used this evidence to reconstruct the seasonal intensity of both monsoons for the past 25 ka: the SW and NE monsoon both were weak during the last glacial period. The NE monsoon peaked during the cool phases of the glacial to interglacial climatic transition (i.e. during the Younger Dryas (YD) and Heinrich Event Hl). The SW monsoon was reinforced after the YD. Both monsoons were enhanced during early Holocene time, when summer insolation and hence atmospheric forcing was at a maximum.

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“…). According to plankton net studies from the eastern sub‐polar North Atlantic within the Norwegian Atlantic Current (NwAC), the stable isotope composition of G. inflata records the physical properties (temperature/salinity) of the ambient water‐masses, which are controlled by deep winter‐time mixing (Ottens ; Chapman ). Accordingly, depleted δ 18 O values of this species reflect the occurrence of warmer and saltier waters at our study site.…”

Section: Ecological Preferences Of Planktic Foraminifers In the Sub‐pmentioning

confidence: 99%

Subarctic Front migration at the Reykjanes Ridge during the mid‐ to late Holocene: evidence from planktic foraminifera

Perner

Moros

Jansen

et al. 2017

Boreas

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Prins, M. A. 2018 (January): Subarctic Front migration at the Reykjanes Ridge during the mid-to late Holocene: evidence from planktic foraminifera. Boreas, Vol. 47, pp. 175-188. https://doi.org/10.1111/bor.12263. ISSN 0300-9483.Expansion of fresh and sea-ice loaded surface waters from the Arctic Ocean into the sub-polar North Atlantic is suggested to modulate the northward heat transport within the North Atlantic Current (NAC). The Reykjanes Ridge south of Iceland is a suitable area to reconstruct changes in the mid-to late Holocene fresh and sea-ice loaded surface water expansion, which is marked by the Subarctic Front (SAF). Here, shifts in the location of the SAF result from the interaction of freshwater expansion and inflow of warmer and saline (NAC) waters to the Ridge. Using planktic foraminiferal assemblage and concentration data from a marine sediment core on the eastern Reykjanes Ridge elucidates SAF location changes and thus, changes in the water-mass composition (upper~200 m) during the last c. 5.8 ka BP. Our foraminifer data highlight a late Holocene shift (at c. 3.0 ka BP) in water-mass composition at the Reykjanes Ridge, which reflects the occurrence of cooler and fresher surface waters when compared to the midHolocene. We document two phases of SAF presence at the study site: from (i) c. 5.5 to 5.0 ka BP and (ii) c. 2.7 to 1.5 ka BP. Both phases are characterized by marked increases in the planktic foraminiferal concentration, which coincides with freshwater expansions and warm subsurface water conditions within the sub-polar North Atlantic. We link the SAF changes, from c. 2.7 to 1.5 ka BP, to a strengthening of the East Greenland Current and awarming in the NAC, as identified by various studies underlying these two currents. From c. 1.5 ka BP onwards, we record a prominent subsurface cooling and continued occurrence of fresh and sea-ice loaded surface waters at the study site. This implies that the SAF migrated to the southeast of our core site during the last millennium.

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April and August Northeast Atlantic surface water masses reflected in planktic foraminifera

Cited by 41 publications

References 33 publications

Deep‐dwelling foraminifera as thermocline temperature recorders

Deep‐dwelling foraminifera as thermocline temperature recorders

Planktic foraminifera, particle flux and oceanic productivity off Pakistan, NE Arabian Sea: modern analogues and application to the palaeoclimatic record

Subarctic Front migration at the Reykjanes Ridge during the mid‐ to late Holocene: evidence from planktic foraminifera

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