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Regression models.

Regression models.

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We analysed the morphology of Emiliania huxleyi from globally distributed plankton samples and demonstrate that the size of E. huxleyi placoliths is highly correlated with in-situ sea surface water salinity. A standard step-wise multiple linear regression analysis was used to link morphological parameters of E. huxleyi to in-situ salinity and in-si...

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... models obtained from set 9 and 10 both produce a skewed distribution of their residuals along the salinity range from 32.6 to 38.8 indicating that the error of un- known values is biased towards the ends of the distribution. However, the model of subset 4 shows evenly distributed residuals and therefore, we consider this model the most valid and robust model to predict unknown values although the R 2 of this model is lower than the R 2 of model 9 and 10, respectively ( Fig. 4; Tables 2, 3). The multiple regression model of subset 4 yielded an R 2 = 0.84 with a standard residual error of 0.67 for in-situ salinity (Fig. 4C). ...
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... multiple regression model of subset 4 yielded an R 2 = 0.84 with a standard residual error of 0.67 for in-situ salinity (Fig. 4C). The most significant explaining variables of the model are the length of the distal shield (DL), the width of the central area (CAW), and the area of the central area (CAA) ( Table 2). Multiple linear regression analysis of tempera- ture and morphological parameters revealed no robust model. ...
Context 3
... their stepwise regression analysis of the sediment data set revealed that width and not length (as was found in this study) of the distal shield was the significant explaining variable. The analysis of the p-values for length and width in our data set revealed that the differences between both parameters are small and the resulting differences in the regression model appear to be negligible ( Fig. 4B; Table 2). ...

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... When applying biometry studies with paleoenvironmental goals (e. g., to reconstruct temperature (Bollmann, 1997), salinity (Bollmann et al., 2009) 3.) within a population should be sampled to estimate the intra-populational coccolith size variation induced by the cell growth. The dataset should also include several populations or species with different size ranges. ...
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... Our algorithm is described in detail in the Supporting Information S1. Briefly, we compile coccolith size and abundance data from published core-top and water column surveys ( Figure 1b) (Andruleit & Rogalla, 2002;Balestra et al., 2010;Baumann et al., 2000;Bendle et al., 2005;Boeckel, 2003;Boeckel & Baumann, 2004;Boeckel et al., 2006;Bollmann, 1997;Bollmann et al., 2009;Bollmann & Herrle, 2007;Bollmann et al., 2002;CLIMAP Project Members, 1976;Cortés et al., 2001;Findlay & Giraudeau, 2000;Frenz et al., 2005;Geitzenauer et al., 1976;Hagino & Okada, 2006;Haidar & Thierstein, 2001;Herrmann et al., 2012;Horigome et al., 2014;Kinkel et al., 2000;Saavedra-Pellitero & Baumann, 2015;Saavedra-Pellitero et al., 2010Schiebel et al., 2004Schiebel et al., , 2011Schwab et al., 2012). Using the coccolith size range defining each species as reported by the Nannotax3 database (Young et al., 2017), we estimate a biomass-weighted ("BMW") coccolith length for the alkenone-producing population at every sample location in Figure 1b. ...
... temperature, salinity, irradiance, CO 2 , NO 3 , PO 4 ) were recognized to influence E. huxleyi morphotypes growth, calcification rates (Zondervan, 2007;Feng et al., 2017). Few studies attributed variation in E. huxleyi coccolith size to changes in the seawater salinity (e.g., Bollmann and Herrle, 2007;Bollmann et al., 2009). This study documents smaller E. huxleyi coccospheres in the SSTF and PF containing larger coccoliths, and larger coccosphere in the SAF containing smaller coccoliths (Figs. ...
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... Several morphometric studies on extant coccolithophores have been carried out on Emiliania huxleyi (e.g., Colmenero-Hidalgo et al. 2002;Bollmann et al. 2009;Young et al. 2014), Calcidiscus leptoporus (e.g., Knappertsbusch et al. 1997;Baumann and Sprengel 2000;Renaud and Klaas 2001;Renaud et al. 2002;Quinn et al. 2004), and Coccolithus pelagicus (e.g., Geisen et al. 2002;Parente et al. 2004;Narciso et al. 2006, Cubillos et al. 2012). The last taxon has been documented as two distinct entities in the modern nannoflora, with culture studies and molecular genetics showing that these are genotypically discrete but very closely related as sub-species Geisen et al. 2004: C. pelagicus subsp. ...
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... Coccolithophores are known to be sensitive to seawater conditions such as SST, SSS, nutrient and the ocean carbonate system and respond with changes in their calcification and coccolith length (e.g., Feng et al., 2008;Bollmann et al., 2009;Grelaud et al., 2009;Beaufort et al., 2011). Analysis of our dataset revealed that the coccolith lengths (GEO and SPC) were not strongly correlated with the environmental variables, whilst no significant correlations were found between the SSS and the coccolith morphological parameters ( Table 1). ...
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... Reconstructing past salinities can be accomplished with several different techniques, e.g., diatom and dinoflagellate species composition (Zonneveld et al., 2001), morphology and the size of placoliths from Emiliania huxleyi (Bollmann et al., 2009), Ba/Ca ratios in foraminiferal calcite (Weldeab et al., 2007), the strontium isotope composition of bivalves (Israelson and Buchardt, 1999), the process length of di-noflagellate cysts (Mertens et al., 2009), the hydrogen isotope composition of alkenones (van der Meer et al., 2007;Schouten et al., 2006), or temperature-corrected (Mg/Ca, TEX 86 ) oxygen isotopes (Elderfield and Ganssen, 2000). While some of these proxies may yield reliable results (e.g., coupled Mg/Ca and oxygen isotopes - Elderfield et al., 2012;Lear et al., 2000) others suffer from rather large uncertainties introduced by modeled parameters or require a good knowledge of the regional oceanography (Wit et al., 2013). ...
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... To achieve this, strains of the two species Emiliania huxleyi and Gephyrocapsa oceanica were grown under different salinity conditions, as salinity is known to affect E. huxleyi coccolith length (e.g. [34][35][36][37][38][39]). By measuring coccolith thickness with increasing coccolith length, the relationship between coccolith length and thickness in E. huxleyi and G. oceanica could be investigated and the usefulness of the k s model for estimating the mass of these two species evaluated. ...
... The salinity effect on E. huxleyi coccolith length is well documented from both culture, plankton, and sediment studies [34][35][36][37][38][39]. In this study, salinity also affected coccolith length in the E. huxleyi strains RCC 868, RCC 1210, RCC 1824, and SAG 33.90. ...
... Furthermore, [36] found that coccoliths sampled from areas with salinities outside a typical open ocean range (33-38 salinity) deviated from the typical salinity response. For this reason, [37] hypothesized that open ocean populations of E. huxleyi display a more marked morphological response to salinity than coastal populations, as the larger salinity fluctuations in coastal regions may have led to different adaptations to changing salinity in coastal E. huxleyi populations. In this regard it is interesting to note that while most strains used in this study were isolated from a coastal region (Fig 1), the strain isolated furthest from the coast, RCC 868, was among the two E. huxleyi strains with the greatest increase in length with salinity. ...
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Coccolith mass is an important parameter for estimating coccolithophore contribution to carbonate sedimentation, organic carbon ballasting and coccolithophore calcification. Single coccolith mass is often estimated based on the ks model, which assumes that length and thickness increase proportionally. To evaluate this assumption, this study compared coccolith length, thickness, and mass of seven Emiliania huxleyi strains and one Gephyrocapsa oceanica strain grown in 25, 34, and 44 salinity artificial seawater. While coccolith length increased with salinity in four E. huxleyi strains, thickness did not increase significantly with salinity in three of these strains. Only G. oceanica showed a consistent increase in length with salinity that was accompanied by an increase in thickness. Coccolith length and thickness was also not correlated in 14 of 24 individual experiments, and in the experiments in which there was a positive relationship r2 was low (<0.4). Because thickness did not increase with length in E. huxleyi, the increase in mass was less than expected from the ks model, and thus, mass can not be accurately estimated from coccolith length alone.
... They showed that, the E. huxleyi coccolith size varies significantly within the salinity range of 33-38 psu with a standard error of 0.49 psu. In addition, in situ studies in the Atlantic, Pacific, and Southern Ocean showed significant relationship between SSS and E. huxleyi placolith size 62 . Their plankton-derived multiple regression models for in situ salinity varied from that of the previous studies of the Holocene sediment samples. ...
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Coccolithophores are one of the major groups of marine carbonate producers and are the most important pelagic unicellular calcifying organisms those play a pivotal role in the marine biogeochemical cycles. Since past few decades coccolithophores have gained immense attention due to their unique role in the global carbon cycle and particularly due to their combined effects on the biological carbon and carbonate counter pumps. Owing to their high diversity, better preservation, fast turnover rate and significant role in the marine biogeochemical cycles, coccolithophores are identified as a potential proxy to reconstruct paleoceanographic changes. In this review, a broad introduction of the biology and biogeography of extant coccolithophores is discussed by brief overview on the preservation of the coccoliths and their applications. This includes how coccolith abundance, diversity and morphometric studies are used to reconstruct paleotemperature, paleosalinity, paleoproductivity and paleocirculation. In addition, implications of coccolithophores in isotopic studies for the estimation of paleotemperature and paleoproductivity are also discussed.
... We use a centennially-resolved, phytoplankton-based Sea Surface Salinity (SSS) record based on an Emiliania huxleyi transfer-function outlined by ref. 13 (see Method section) from a sediment core (GeoTÜ SL152) located in the Aegean Sea approximately 130 km west from the opening of the Marmara Sea. The core is ideally located to monitor the outflow of low salinity Black Sea surface water into the Northern Aegean Sea through the Marmara Sea (Fig. 1C,D). ...
... we used the methods as outline by ref. 13 . All SSS estimates presented here are based on transfer-function subset 4 of ref. 13 in which all coccoliths of Emiliania huxleyi larger than 4 µm were excluded. ...
... we used the methods as outline by ref. 13 . All SSS estimates presented here are based on transfer-function subset 4 of ref. 13 in which all coccoliths of Emiliania huxleyi larger than 4 µm were excluded. Our results are presented as deviation from the average mean annual SSS of the presented interval (sea surface salinity anomaly, Supplement Data Table 2), in practical salinity units to record relative SSS anomalies. ...
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During the Holocene, North American ice sheet collapse and rapid sea-level rise reconnected the Black Sea with the global ocean. Rapid meltwater releases into the North Atlantic and associated climate change arguably slowed the pace of Neolithisation across southeastern Europe, originally hypothesized as a catastrophic flooding that fueled culturally-widespread deluge myths. However, we currently lack an independent record linking the timing of meltwater events, sea-level rise and environmental change with the timing of Neolithisation in southeastern Europe. Here, we present a sea surface salinity record from the Northern Aegean Sea indicative of two meltwater events at ~8.4 and ~7.6 kiloyears that can be directly linked to rapid declines in the establishment of Neolithic sites in southeast Europe. The meltwater events point to an increased outflow of low salinity water from the Black Sea driven by rapid sea level rise >1.4 m following freshwater outbursts from Lake Agassiz and the final decay of the Laurentide ice sheet. Our results shed new light on the link between catastrophic sea-level rise and the Neolithisation of southeastern Europe, and present a historical example of how coastal populations could have been impacted by future rapid sea-level rise.
... Other environmental variables have been described as factors influencing calcification in laboratory experiments (Båtvik et al., 1997;Bollmann et al., 2009;Fielding et al., 2009;De Bodt et al., 2010). Although temperature was not completely discarded by Smith et al. (2012), no statistical relationship with coccolith morphometrics was obtained. ...
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Abstract Lack of information about carbonate chemistry in inshore waters is a ‘knowledge gap’ in assessing the impacts of changing carbonate chemistry on the marine environment. Assessing the response of calcifying phytoplankton to this changing carbonate chemistry requires a greater understanding of temporal variation. This study provides a description of the variability of carbonate parameters at a monitoring site in the eastern coast of Scotland. Four-years of monthly data were analysed to assess the diversity, abundance and morphometrics of coccolithophores in relation to carbonate chemistry and environmental variables. The seasonality in carbonate parameters reflected the seasonal cycle in phytoplankton activity, with higher total alkalinity concentrations and pH and lower dissolved inorganic carbon concentrations during the growing season. The dominant coccolithophore at the site was Emiliania huxleyi which showed a clear seasonal pattern, being more abundant in mid-summer when warmer and nutrient-depleted conditions restricted the annual diatom bloom. This study revealed the presence of three morphotypes of E. huxleyi, type A, type A overcalcified (type AO) and type B, which were seasonally distributed throughout the year. The less calcified form was mainly observed in spring while heavily calcified morphotypes overlapped during summer. Autumn and winter months were dominated by the most calcified form (type AO). These results indicate that the seasonal pattern of E. huxleyi morphotypes was not related to the carbonate concentration at the site. This study reflects the strong interannual variability in carbonate chemistry and the complexity associated with coccolithophore calcification, and highlights the need of long-term data to understand the potential impact of ocean acidification on calcifying phytoplankton.