Seasonal changes in species composition, numbers, mass, size, and isotopic composition of planktonic foraminifera settling into the deep sargasso sea

Deuser, W. G.; Ross, E. H.; Hemleben, Christoph; Spindler, Michael

doi:10.1016/0031-0182(81)90034-1

Cited by 240 publications

(118 citation statements)

References 11 publications

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“…A similar interpretation may apply to a large set of published and unpublished planktic data from sediment traps and core tops in ocean regions as different as the northern and equatorial Atlantic [e.g., Simstich, 1998;Deuser et al, 1981aDeuser et al, , 1981bGanssen, 1983], the Arabian Sea, and South China Sea [Wang et al, 1999]. Overall, the spatial distribution patterns of these data suggest that d 13 C values of various planktic foraminifera species primarily reflect the nutrient concentrations in ocean surface water ambient to shell calcification, besides various secondary forcings such as air-sea exchange of CO 2 , sea surface temperature, secular d 13 C variations, and vital and metabolic effects.…”

Section: Tracers Of Nutrient Concentration and Bottom Water Ventilationmentioning

confidence: 70%

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Gebhardt¹,

Sarnthein²,

et al. 2008

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[1] Our study addresses fundamental questions of the mode and timing of orbital and millennial-scale changes in the meridional overturning circulation (MOC) of the subarctic North Pacific. Particular concerns are the vertical mixing, the present and past abundance of nutrients in surface waters despite strong stratification, and the North Pacific-North Atlantic seesaw of oscillations in sea surface temperature (SST). We do this by generating and interpreting multiple records for glacial terminations I-V down two long piston cores, one each from the western and eastern subarctic Pacific. Chlorins and biogenic opal are proxies for surface water productivity; d 13 C of epibenthic foraminifera is a record of deepwater ventilation; and the d 13 C of N. pachyderma sin. is a tracer of nutrients in subsurface waters that extend up to the sea surface during times of vertical mixing. The degree of mixing is traced by pairing SST and d 18 O records of planktic surface and subsurface (pycnocline) dwellers. Tight age control is deduced from a suite of age-calibrated 14 C plateau boundaries for Termination I and benthic d 18 O and geomagnetic events for the last 800 ka. Carbon 14 paleoreservoir ages record the ages of surface and deep waters to uncover short-term changes in MOC over Termination I. We have defined a standard sequence of short-term productivity events for Termination I, also evident during terminations II to V and subsequent interglacials over the last 450 ka. The peak glacial regime of stable stratification and low productivity terminated, together with the end of ice rafting and melting, near 17 ka, $2000 years after the onset of Termination I. Pulses of vertical mixing and incursion of warm surface waters from the subtropics followed. Convected young water masses finally penetrated down to 3600-m water depth at 17.0 to less than 14.5 ka, significantly improving bottom water ventilation through the late deglacial and earliest interglacial. Mixing with upwelled nutrients from the pycnocline induced short-term maxima in algal production of chlorins and biogenic opal near 17-15 and 15-12 ka, respectively. Deglacial meltwater incursions in the Aleutian Current and silica input from North American rivers also promoted East Pacific productivity after 15.5 ka. Productivity decreased during the late deglacial and early interglacial, coeval with an exceptional peak in CaCO 3 preservation caused by both low organic flux and well-ventilated deepwater. Subsequently, low salinity and cool surface waters and in turn, stratification were gradually restored. A second, opaldominated productivity maximum marked the ends of interglacials. The deglacial pulses of vertical mixing around 17-11 ka imply an important contribution of the North Pacific to the coeval release of oceanic CO 2 into the atmosphere and support the east-west seesaw model of climate change.Citation: Gebhardt, H., M. Sarnthein, P. M. Grootes, T. Kiefer, H. Kuehn, F. Schmieder, and U. Röhl (2008), Paleonutrient and productivity records from the subarctic North ...

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Section: Tracers Of Nutrient Concentration and Bottom Water Ventilationmentioning

confidence: 70%

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Gebhardt¹,

Sarnthein²,

et al. 2008

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“…As a result of these interspecies differences, which are generally attributed to vital effects or ecological factors such as depth habitat and/or seasonal preferences, species-specific proxy calibrations are necessary in order to produce the most reliable estimates of past ocean conditions (Hemleben et al, 1989;Spero et al, 1997;Bijma et al, 1998;Bemis et al, 2002). Despite attempts to differentiate between morphologically defined species, the paleoceanographic community has long recognized the existence of morphotypes within species of planktonic foraminifera, often finding a large range in morphologies within a single population (Kennett, 1976;Deuser et al, 1981;Bé et al, 1983;Deuser, 1987;Deuser and Ross, 1989). A handful of studies report significant stable isotopic and trace element differences among different morphotypes of some species of planktonic foraminifera (Deuser et al, 1981;Healy-William et al, 1985;Deuser, 1987;Bijma et al, 1998;Wang, 2000;Steinke et al, 2005;Richey et al, 2012).…”

Section: Overviewmentioning

confidence: 99%

“…Despite attempts to differentiate between morphologically defined species, the paleoceanographic community has long recognized the existence of morphotypes within species of planktonic foraminifera, often finding a large range in morphologies within a single population (Kennett, 1976;Deuser et al, 1981;Bé et al, 1983;Deuser, 1987;Deuser and Ross, 1989). A handful of studies report significant stable isotopic and trace element differences among different morphotypes of some species of planktonic foraminifera (Deuser et al, 1981;Healy-William et al, 1985;Deuser, 1987;Bijma et al, 1998;Wang, 2000;Steinke et al, 2005;Richey et al, 2012). Marine Micropaleontology 120 (2015) [46][47][48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][64] However, the significance of morphological variation was not apparent until the first genetic studies of foraminifera.…”

Section: Overviewmentioning

confidence: 99%

Morphometric and stable isotopic differentiation of Orbulina universa morphotypes from the Cariaco Basin, Venezuela

Marshall

Thunell

Spero

et al. 2015

Marine Micropaleontology

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Biometric characteristics of Orbulina universa (d'Orbigny) were used to differentiate two morphotypes present in sediment trap samples collected from the Cariaco Basin, Venezuela. Specifically, wall thickness and weight-area relationships were used to separate shells into thin (M thin ) and thick (M thick ) morphotypes. M thick (mean thickness = 19-41 μm) comprises 75% of the total O. universa in these samples and has morphometric characteristics similar to that of the previously described Type I Caribbean genotype, whereas M thin (mean thickness = 6-22 μm) is comparable to the Type III Mediterranean genotype. The flux of M thick increases during periods of upwelling, whereas M thin flux shows no systematic relationship with changing hydrographic regimes in the basin. The δ 18O and δ 13 C of M thick are on average 0.34‰ higher and 0.38‰ lower, respectively, than those of M thin , suggesting that they calcify their final spherical chamber at different depths in the water column and/or differ in their vital effects on shell geochemistry. Additionally, the absolute offset in the stable isotopic compositions of the two morphotypes varies as a function of surface ocean stratification. During periods of upwelling, the δ

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“…In the Sargasso Sea, white G. ruber is abundant in sediment traps throughout the year (with fluxes >50 tests m − 2 day − 1 during all months) (Deuser et al, 1981;Deuser, 1987;Deuser and Ross, 1989), suggesting that G. ruber (white) is representative of mean annual sea-surface conditions in the sediment record. Data indicate that G. ruber (pink) exhibits peak abundances from April-October (with fluxes of >5 tests m − 2 day − 1 ), and fluxes drop to nearly 0 during the winter (December-April).…”

Section: Comparison Of Downcore Geochemical Records For Pink and Whitmentioning

confidence: 99%

Ecological controls on the shell geochemistry of pink and white Globigerinoides ruber in the northern Gulf of Mexico: Implications for paleoceanographic reconstruction

Richey

Poore

Flower

et al. 2012

Marine Micropaleontology

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Seasonal changes in species composition, numbers, mass, size, and isotopic composition of planktonic foraminifera settling into the deep sargasso sea

Cited by 240 publications

References 11 publications

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Paleonutrient and productivity records from the subarctic North Pacific for Pleistocene glacial terminations I to V

Morphometric and stable isotopic differentiation of Orbulina universa morphotypes from the Cariaco Basin, Venezuela

Ecological controls on the shell geochemistry of pink and white Globigerinoides ruber in the northern Gulf of Mexico: Implications for paleoceanographic reconstruction

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