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

Marshall, Brittney J.; Thunell, Robert C.; Spero, Howard J.; Henehan, Michael J.; Lorenzoni, Laura; Astor, Yrene

doi:10.1016/j.marmicro.2015.08.001

Cited by 43 publications

(47 citation statements)

References 75 publications

(151 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, shell size can vary within a studied sieve range (Beer et al, 2010a). Many later studies circumvented this issue by directly measuring the major axis length (Barker and Elderfield, 2002;Aldridge et al, 2012;Beer et al, 2010a) or cross-sectional area (Beer et al, 2010b;Marshall et al, 2013Marshall et al, , 2015Osborne et al, 2016;Weinkauf et al, 2013Weinkauf et al, , 2016 of each individual within a sampled population. However, as discussed by Weinkauf et al (2016), an assumption common to most shell-weight studies is that SNW metrics themselves do not vary as a function of size -which is unlikely to be true.…”

Section: Introductionmentioning

confidence: 99%

Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

et al. 2017

Self Cite

View full text Add to dashboard Cite

Abstract. The response of the marine carbon cycle to changes in atmospheric CO 2 concentrations will be determined, in part, by the relative response of calcifying and non-calcifying organisms to global change. Planktonic foraminifera are responsible for a quarter or more of global carbonate production, therefore understanding the sensitivity of calcification in these organisms to environmental change is critical. Despite this, there remains little consensus as to whether, or to what extent, chemical and physical factors affect foraminiferal calcification. To address this, we directly test the effect of multiple controls on calcification in culture experiments and core-top measurements of Globigerinoides ruber. We find that two factors, body size and the carbonate system, strongly influence calcification intensity in life, but that exposure to corrosive bottom waters can overprint this signal post mortem. Using a simple model for the addition of calcite through ontogeny, we show that variable body size between and within datasets could complicate studies that examine environmental controls on foraminiferal shell weight. In addition, we suggest that size could ultimately play a role in determining whether calcification will increase or decrease with acidification. Our models highlight that knowledge of the specific morphological and physiological mechanisms driving ontogenetic change in calcification in different species will be critical in predicting the response of foraminiferal calcification to future change in atmospheric pCO 2 .

show abstract

Section: Introductionmentioning

confidence: 99%

Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

et al. 2017

Self Cite

View full text Add to dashboard Cite

show abstract

“…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). This raises the interesting possibility that some of the morphological differences between different genetic species are driven primarily by differences in the environment in which they occur, rather than by heritable genetic differences.…”

Section: Discussionmentioning

confidence: 67%

“…Differences in porosity have been observed among genetic species within two morphospecies complexes: Orbulina universa and Globigerinella siphonifera (Huber et al, 1997;de Vargas et al, 1999;Morard et al, 2009;Morard et al, 2013;Marshall et al, 2015;Weiner et al, 2015). In fact, it is the sole characteristic by which two cryptic species of Globigerinella siphonifera can be identified in empty tests (Huber et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

“…In fact, it is the sole characteristic by which two cryptic species of Globigerinella siphonifera can be identified in empty tests (Huber et al, 1997). In Orbulina universa, variation in areal aperture density and placement distinguish among the three cryptic species, along with variation in wall-thickness in Orbulina 305 universa (Morard et al, 2009;Marshall et al, 2015). We examined this, by culturing individuals of Globigerinoides ruber to test whether, and to what extent, porosity could vary based on environmental conditions at the time of chamber formation.…”

Section: Discussionmentioning

confidence: 99%

“…Ecophenotypy in planktonic foraminifera has largely fallen out of favor as an explanation for variation in morphology, with the observations that ecophenotypes often align with different genetic complexes (Huber et al, 1997;de Vargas et al, 1999;de Vargas et al, 2001;Morard et al, 2009;Quillévéré et al, 2011;Morard et al, 2013;Marshall et al, 2015;Weiner et al, 2015). However, it is well-established that the expression of any phenotypic trait is a product of both its genes and its environment (e.g.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Factors Influencing Porosity in Planktonic Foraminifera

Burke¹,

Renema²,

Henehan³

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

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.

show abstract

Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin

et al. 2016

Self Cite

View full text Add to dashboard Cite

Planktonic foraminiferal calcification intensity, reflected by shell wall thickness, has been hypothesized to covary with the carbonate chemistry of seawater. Here we use both sediment trap and box core samples from the Santa Barbara Basin to evaluate the relationship between the calcification intensity of the planktonic foraminifera species Globigerina bulloides, measured by area density (µg/µm2), and the carbonate ion concentration of seawater ([CO32−]). We also evaluate the influence of both temperature and nutrient concentration ([PO43−]) on foraminiferal calcification and growth. The presence of two G. bulloides morphospecies with systematically different calcification properties and offset stable isotopic compositions was identified within sampling populations using distinguishing morphometric characteristics. The calcification temperature and by extension calcification depth of the more abundant “normal” G. bulloides morphospecies was determined using δ18O temperature estimates. Calcification depths vary seasonally with upwelling and were used to select the appropriate [CO32−], temperature, and [PO43−] depth measurements for comparison with area density. Seasonal upwelling in the study region also results in collinearity between independent variables complicating a straightforward statistical analysis. To address this issue, we use additional statistical diagnostics and a down core record to disentangle the respective roles of each parameter on G. bulloides calcification. Our results indicate that [CO32−] is the primary variable controlling calcification intensity while temperature influences shell size. We report a modern calibration for the normal G. bulloides morphospecies that can be used in down core studies of well‐preserved sediments to estimate past [CO32−].

show abstract

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

Cited by 43 publications

References 75 publications

Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

Size-dependent response of foraminiferal calcification to seawater carbonate chemistry

Factors Influencing Porosity in Planktonic Foraminifera

Calcification of the planktonic foraminifera Globigerina bulloides and carbonate ion concentration: Results from the Santa Barbara Basin

Contact Info

Product

Resources

About