Tracing shifts of oceanic fronts using the cryptic diversity of the planktonic foraminifera <i>Globorotalia inflata</i>

Morard, Raphaël; Reinelt, Melanie; Chiessi, Cristiano Mazur; Groeneveld, Jeroen; Kučera, Michal

doi:10.1002/2016pa002977

Cited by 27 publications

(21 citation statements)

References 39 publications

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“…This would skew the analyses of either one of the proxies toward “colder” values preventing a linear relationship between the averages from different locations (Figure S4). The relationship between the variability displayed by Mg/Ca and δ 18 O also argues against a strong influence of vital effects (De Nooijer et al, ) or genetic variations (Morard et al, ; Sadekov et al, ) on the variability of Mg/Ca and δ 18 O in single specimens. These mechanisms could only explain our findings by simultaneously influencing δ 18 O and Mg/Ca with the relative amount of this effect for both proxies following the temperature calibrations, which is unlikely as a vital effect is usually thought to only affect a specific component like the Mg inclusion.…”

Section: Resultsmentioning

confidence: 99%

Deciphering the Variability in Mg/Ca and Stable Oxygen Isotopes of Individual Foraminifera

Groeneveld

Mackensen

et al. 2019

Paleoceanog and Paleoclimatol

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Foraminifera are commonly used in paleoclimate reconstructions as they occur throughout the world's oceans and are often abundantly preserved in the sediments. Traditionally, foraminifera‐based proxies like δ 18 O and Mg/Ca are analyzed on pooled specimens of a single species. Analysis of single specimens of foraminifera allows reconstructing climate variability on timescales related to El Niño–Southern Oscillation or seasonality. However, quantitative calibrations between the statistics of individual foraminifera analyses (IFA) and climate variability are still missing. We performed Mg/Ca and δ 18 O measurements on single specimens from core top sediments from different settings to better understand the signal recorded by individual foraminifera. We used three species of planktic foraminifera ( Globigerinoides ruber (s.s.), T . sacculifer , and N . dutertrei ) from the Indo‐Pacific Warm Pool and one species ( G . ruber (pink)) from the Gulf of Mexico. Mean values for the different species of Mg/Ca versus calculated δ 18 O temperatures agree with published calibration equations. IFA statistics (both mean and standard deviation) of Mg/Ca and δ 18 O between the different sites show a strong relationship indicating that both proxies are influenced by a common factor, most likely temperature variations during calcification. This strongly supports the use of IFA to reconstruct climate variability. However, our combined IFA data for the different species only show a weak relationship to seasonal and interannual temperature changes, especially when seasonal variability increases at a location. This suggests that the season and depth habitat of the foraminifera strongly affect IFA variability, such that ecology needs to be considered when reconstructing past climate variability.

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Section: Resultsmentioning

confidence: 99%

Deciphering the Variability in Mg/Ca and Stable Oxygen Isotopes of Individual Foraminifera

Groeneveld

Mackensen

et al. 2019

Paleoceanog and Paleoclimatol

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“…In planktonic foraminifera, heritability has yet to be measured for any morphological trait, although it is likely to vary amongst traits as it does in all other organisms studied to date (Visscher et al, 2008). In this context, it is interesting to note that genetic-species of planktonic foraminifera are often found in distinct environments (i.e., different biomes or different depth habitats) (Huber et al, 1997;de Vargas et al, 2001;Darling & Wade, 2008;Morard et al, 2009;Quillévéré et al, 2011;Morard et al, 2013;Morard et al, 2016). While evidence for high heritability of wall thickness and porosity is lacking, both 325 porosity and wall thickness have been observed to vary with environmental conditions in culture and across environments gradients (this study; Colombo & Cita, 1980;Caron, 1987a-b;Bijma et al, 1990;Lea et al, 1999;Spero et al, 1997;Russell et al, 2004;Lombard et al, 2009;Kuroyanagi et al, 2013;Spero et al, 2015;Henehan et al, 2017).…”

Section: Discussionmentioning

confidence: 87%

Factors Influencing Porosity in Planktonic Foraminifera

Burke¹,

Renema²,

Henehan³

et al. 2018

Preprint

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Abstract. The clustering of mitochondria near pores in the test walls of foraminifera suggests that these perforations play a critical role in metabolic gas exchange. As such, pore measurements could provide a novel means of tracking changes in metabolic rate in the fossil record. However, in planktonic foraminifera, variation in pore size, density, and porosity have been 20 variously attributed to environmental, biological, and taxonomic drivers, complicating such an interpretation. Here we examine the environmental, biological, and evolutionary determinants of porosity in 718 individuals representing 17 morphospecies of planktonic foraminifera from 6 core tops in the North Atlantic. Using random forest models, we find that porosity is primarily correlated to size and habitat temperature, two key factors in determining metabolic rates. In order to test if this correlation arose spuriously through the association of cryptic species with distinct biomes, we cultured Globigerinoides ruber in three 25 different temperature conditions, and found that porosity increased with temperature. Crucially, these results show that porosity can be plastic: changing in response to environmental drivers within the lifetime of an individual foraminifer. This demonstrates the potential of porosity as a proxy for foraminiferal metabolic rates, with significance for interpreting geochemical data and the physiology of foraminifera in non-analog environments. It also highlights the importance of phenotypic plasticity (i.e., ecophenotypy) in accounting for some aspects of morphological variation in the modern and fossil 30 record.

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“…The unmixing algorithm used in this paper gives the probability of each distinct population, using each population and their calculated mean and standard deviation, to generate a normal distribution for the populations determined via statistical unmixing (Hammer et al, 2001;Wit et al, 2013). Using these data, it is possible to model the theoretical effect of sample size on the resultant stable isotope measurements (Morard et al, 2016). For simplicity, we assume that each specimen contributes an equal weighting to the overall pooled stable isotope value; of course, in reality, each specimen will contribute an amount of CO 2 equal to its weight.…”

Section: Sedimentary Processes: Dissolution and Bioturbationmentioning

confidence: 99%

Modal shift in North Atlantic seasonality during the last deglaciation

et al. 2020

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Abstract. Changeover from a glacial to an interglacial climate is considered as transitional between two stable modes. Palaeoceanographic reconstructions using the polar foraminifera Neogloboquadrina pachyderma highlight the retreat of the Polar Front during the last deglaciation in terms of both its decreasing abundance and stable oxygen isotope values (δ18O) in sediment cores. While conventional isotope analysis of pooled N. pachyderma and G. bulloides shells shows a warming trend concurrent with the retreating ice, new single-shell measurements reveal that this trend is composed of two isotopically different populations that are morphologically indistinguishable. Using modern time series as analogues for interpreting downcore data, glacial productivity in the mid-North Atlantic appears limited to a single maximum in late summer, followed by the melting of drifting icebergs and winter sea ice. Despite collapsing ice sheets and global warming during the deglaciation, a second “warm” population of N. pachyderma appears in a bimodal seasonal succession, separated by the subpolar G. bulloides. This represents a shift in the timing of the main plankton bloom from late to early summer in a “deglacial” intermediate mode that persisted from the glacial maximum until the start of the Holocene. When seawater temperatures exceeded the threshold values, first the “cold” (glacial) then the “warm” (deglacial) populations of N. pachyderma disappeared, whilst G. bulloides with a greater tolerance to higher temperatures persisted throughout the Holocene to the present day in the midlatitude North Atlantic. Single-specimen δ18O of polar N. pachyderma reveals a steeper rate of ocean warming during the last deglaciation than appears from conventional pooled δ18O average values.

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Tracing shifts of oceanic fronts using the cryptic diversity of the planktonic foraminifera Globorotalia inflata

Cited by 27 publications

References 39 publications

Deciphering the Variability in Mg/Ca and Stable Oxygen Isotopes of Individual Foraminifera

Deciphering the Variability in Mg/Ca and Stable Oxygen Isotopes of Individual Foraminifera

Factors Influencing Porosity in Planktonic Foraminifera

Modal shift in North Atlantic seasonality during the last deglaciation

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