An empirical method for absolute calibration of coccolith thickness

González-Lemos, Saúl; Guitián, José; Fuertes, Miguel Ángel; Flores, José-Abel; Stoll, Heather

doi:10.5194/bg-2017-249

Cited by 6 publications

(9 citation statements)

References 15 publications

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“…On the other hand, the present study appears to contradict, for example, [8], who reported that E. huxleyi coccolith mass was driven by variation in E. huxleyi morphotype relative abundance. The reason for this contradiction lies in part in the applied method of [8], which has been shown to have significant flaws detailed in [61,[82][83][84][85][86]. In addition, [8] measured only coccolith mass at a family level (Gephyrocapsa oceanica plus E. huxleyi) without analyzing the coccolith mass of individual E. huxleyi morphotypes.…”

Section: Comparison With Other Studiesmentioning

confidence: 99%

Coccolith mass and morphology of different Emiliania huxleyi morphotypes: A critical examination using Canary Islands material

Johnsen

Bollmann

2020

PLoS ONE

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Different morphotypes of the abundant marine calcifying algal species Emiliania huxleyi are commonly linked to various degrees of E. huxleyi calcification, but few studies have been done to validate this assumption. This study investigated therefore whether E. huxleyi morphotypes can be related to coccolithophore calcification and coccolith mass. Samples from January (high productivity) and September (low productivity) 1997 at an open ocean and a coastal site near the Canary Islands were analysed using a combination of thickness measurements (Circular Polarizer Retardation estimates (CPR) method), Scanning Electron Microscope imaging, and Markov Chain Monte Carlo (MCMC) models. Mean E. huxleyi coccolith mass varied from a maximum of 2.9pg at the open ocean station in January to a minimum of 1.7pg in September at both stations. In contrast, overall calcite produced by E. huxleyi (assuming 23 coccoliths/cell) varied from a maximum of 2.6 μgL-1 at the coastal station in January to a minimum of 0.5 μgL-1 in September at the open ocean site. The relative abundance of "Overcalcified" Type A, Type A, Group B and malformed coccoliths was determined from SEM images. The mean coccolith mass of "Overcalcified" Type A was 2.0pg using the CPR-method, while mean mass of Type A and Group B coccoliths was determined using coccolith length measurements from SEM images and MCMC models relating thickness measurements to morphotype relative abundance. Type A cocccolith mass varied from a 1.6pg to 2.6pg and Group B coccolith mass varied from 1.5pg to 2.0pg. These results demonstrate that the coccolith mass of Type A, "Overcalcified" Type A, and Group B do not differ systematically and there is no systematic relationship between relative abundance of a morphotype and the overall calcite production of E. huxleyi. Therefore, morphotype appearance and relative abundance can not be uniformly used as reliable indicators of E. huxleyi calcification or calcite production.

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Section: Comparison With Other Studiesmentioning

confidence: 99%

Coccolith mass and morphology of different Emiliania huxleyi morphotypes: A critical examination using Canary Islands material

Johnsen

Bollmann

2020

PLoS ONE

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“…The advantages of this approach are that: (i) it directly measures complete coccoliths with no assumptions regarding their shape or thickness and (ii) it allows for quantification of calcite losses associated with missing parts or etching of the coccoliths. Disadvantages of this technique are the errors associated with the coccolith-calcite calibration and their consequent effect on the coccolith mass estimates (Fuertes et al, 2014;González Lemos et al, 2018). The morphometric approach, on the other hand, allows better taxonomic identification of the coccoliths and has smaller errors in the length measurements (~0.1 to 0.2 μm; Poulton et al 2011).…”

Section: Determination Of Coccolith Mass and Sizementioning

confidence: 99%

Coccolithophore biodiversity controls carbonate export in the Southern Ocean

Rigual-Hernández¹,

Trull²,

Nodder³

et al. 2019

Preprint

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Abstract. Southern Ocean waters are projected to undergo profound changes in their physical and chemical properties in the coming decades. Coccolithophore blooms in the Southern Ocean are thought to account for a major fraction of the global marine calcium carbonate (CaCO3) production and export to the deep sea. Therefore, changes in the composition and abundance of Southern Ocean coccolithophore populations are likely to alter the marine carbon cycle, with feedbacks to the rate of global climate change. However, the contribution of coccolithophores to CaCO3 export in the Southern Ocean is uncertain, particularly in the circumpolar Subantarctic Zone that represents about half of the areal extent of the Southern Ocean and where coccolithophores are most abundant. Here, we present measurements of annual CaCO3 flux and quantitatively partition them amongst coccolithophore species and heterotrophic calcifiers at two sites representative of a large portion of the Subantarctic Zone. We find that coccolithophores account for a major fraction of the annual CaCO3 export with highest contributions in waters with low algal biomass accumulations. Notably, our analysis reveals that although Emiliania huxleyi is an important vector for CaCO3 export to the deep sea, less abundant but larger species account for most of the annual coccolithophore CaCO3 flux. This observation contrasts with satellite remote sensing images that mostly reflect E. huxleyi blooms as a result of its higher cell abundance and detachment of its relatively small liths. It appears likely that the climate-induced migration of oceanic fronts will initially result in the poleward expansion of large coccolithophore species increasing CaCO3 production. However, subantarctic coccolithophore populations will eventually diminish as acidification overwhelms those changes. Overall, our analysis emphasizes the need for species-centred studies to improve our ability to project future changes in phytoplankton communities and their influence on marine biogeochemical cycles.

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“…At least 200 coccolith and 10 fields of view were counted for the coccolith abundance and accumulation rate analyses. The coccolith mass was estimated on the circular polarized microscope with the gray-level method following the method 50,51 , in which the intensity of light was calibrated via a well measured calcite wedge. About 40 pictures were taken from the same slider made for coccolith counting.…”

Section: Coccolith Analysesmentioning

confidence: 99%

High and low latitude controls on Mid-Brunhes coccolithophore bloom and its implications on ocean carbon cycle

Zhang

Liu

Hernández‐Almeida

et al. 2021

Preprint

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Periodic ~400 kyr orbital scale variations in the ocean carbon cycle, manifest in indicators of deep sea dissolution and benthic 13C, have been observed throughout the Cenozoic but the driving mechanisms remain under debate. Changes in coccolithophore productivity may change the global rain ratio (Corganic: Cinorganic fluxes from ocean into sediment) and the balance of ocean carbonate system and thereby, potentially contributing to the ~400 kyr oscillation of the marine carbon cycle. Some evidence suggests that Pleistocene coccolithophore productivity was characterized by “bloom” events of high productivity coincident with the orbital benthic 13C signal. However, there is no consensus on the mechanism responsible for bloom events nor whether they were regional or global phenomena. In this study, we investigate the timing and spatial pattern of the most recent purported coccolithophore bloom event, which occurred during the Mid-Brunhes period. We find that maximum coccolithophore productivity is diachronous, peaking in the Southern Ocean sub-Antarctic zone with eccentricity minimum (~430 ka), peaking in upwelling zones some ~28 kyr later, and finally peaking in the western tropical Pacific occurred some ~80 kyr later. Simple globally homogeneous mechanisms of driving productivity such as temperature or light duration are not consistent with this pattern. Rather, we propose a dual high and low latitude control on blooms. Coincident with eccentricity minimum, increased high-latitude diatom silica consumption lowers the Si/P, leading to coccolithophorid blooms in the Southern Ocean north of the polar front. Coincident with increasing eccentricity, stronger tropical monsoons deliver higher fluvial nutrients to surface waters, increasing total (diatom and coccolithophore) productivity. Most of the tropical and subtropical locations are influenced by both processes with varying degrees, through the effect of silicic acid leakage on tropical thermocline waters and monsoon-related nutrient supply. Moreover, we propose that the high latitude processes have intensified over the Pleistocene, extending the 405 kyr carbon cycle to about 500 kyr.

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An empirical method for absolute calibration of coccolith thickness

Cited by 6 publications

References 15 publications

Coccolith mass and morphology of different Emiliania huxleyi morphotypes: A critical examination using Canary Islands material

Coccolith mass and morphology of different Emiliania huxleyi morphotypes: A critical examination using Canary Islands material

Coccolithophore biodiversity controls carbonate export in the Southern Ocean

High and low latitude controls on Mid-Brunhes coccolithophore bloom and its implications on ocean carbon cycle

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