Three-dimensional architecture and surface functionality of coccolith base plates
Bartosz MarzecJessica M. WalkerM. PanagopoulouYasmeen JhonsDaniel K. ClareAnn P. WheelerMichael P. ShaverFabio Nudelman
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Coccolith
Base (topology)
Coccolith index distribution pattern(the relationship between coccolith abundance and water depth)in submarine sand ridges of the south Yellow Sea is built up based on the coccolithophore ecological character.According to the pattern,the former water depth and its changes during the latest 35 thousand years are obtained in the light of coccolith distribution in the SMK core,this provides a new method in quantitative study of former water depth.
Coccolith
Coccolithophore
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Culture experiments were used to assess the applicability of Emiliania huxleyi coccolith morphology as a palaeo‐sea‐surface salinity (SSS) proxy. Coccolith morphology was dependent on salinity over a range reflecting present day marine conditions; both coccolith size and the number of coccolith elements increased linearly with increasing salinity. Using regression analysis, the effect of salinity on coccolith morphology was compared to those previously observed in sediment core‐top and plankton data. No significant differences were found between the slopes of these data, suggesting that salinity is the primary control on E. huxleyi coccolith size and element number in the ocean. However, the intercepts of the culture data were significantly higher. A combination of experimental and literature analysis indicated that temperature and nutrients were unlikely to be the causes of this discrepancy. Literature analysis also highlighted that coccolith size data from marginal environments displayed different intercepts to those from the open‐ocean data. This suggests that discrete morphotypes exist in these marginal locations. We, therefore, recommend that the original E. huxleyi coccolith morphology palaeo‐SSS transfer function requires further evaluation before being routinely applied.
Coccolith
Emiliania huxleyi
Coccolithophore
paleoceanography
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Coccolith
Coccolithophore
Emiliania huxleyi
Cell size
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Citations (18)
Coccolith
Coccolithophore
Emiliania huxleyi
paleoceanography
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Citations (4)
Coccoliths are calcite platelets produced inside coccolithophore cells and extruded to form a covering on the cell surface called a coccosphere. The size of coccoliths is an important parameter often used to identify species, and observations on extant species have shown an influence of abiotic parameters (e.g., CO2, light, nutrient concentration) on coccolith size. However, the sometimes large range of coccolith sizes occurring within a single coccosphere questions the mechanisms controlling coccolith size. A link was previously shown between cell/coccosphere size and coccolith size called the “coccolithophore size rule”. In this study, we query the mechanisms controlling the size of a coccolith during coccolithogenesis. Two working hypotheses are formulated: (1) coccolith size is smaller than cell diameter, and (2) coccolithogenesis mainly occurs during a specific growth phase (G1 interphase). We propose two numerical models (each with two variants) to test the constraining effect of these hypotheses on coccolith size distribution within a population. Neither model can accurately reproduce the size distribution of an empirical coccolith population, indicating that additional factors likely influence coccolith size. According to both hypotheses, the comparison of coccolith size and cell size is only pertinent at the time of formation of a coccolith. In light of these results, we suggest that application of the coccolithophore size rules model should be limited to multipopulational studies, and we confirm the basis of the link between coccolith number and cell cycle. The coccolith size rule model proposed here requires verification with further observations of coccolithophore and coccolith growth data.
Coccolith
Coccolithophore
Cell size
Emiliania huxleyi
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Abstract. Coccolithophores play a key role in the marine carbon cycle and ecosystem. The carbonate shells produced by coccolithophore, named as coccolith, could be well preserved in the marine sediment for millions of years and become an excellent archive for paleoclimate studies. The micro-filtering and sinking–decanting methods have been successfully designed for coccolith separation and promoted the development of geochemistry studies on coccolith, such as the stable isotopes and Sr / Ca ratio. However, these two methods are still not efficient enough for the sample-consuming methods. In this study, the trajectory of coccolith movement during a centrifugation process was calculated in theory and carefully tested by separations in practice. We offer a MATLAB code to estimate the appropriate parameter, angular velocity at a fixed centrifugation duration, for separating certain coccolith size fractions from bulk sediment. This work could improve the efficiency of coccolith separation, especially for the finest size fraction, and make it possible to carry out the clumped isotope and radio carbon analyses on coccoliths in sediment.
Coccolith
Coccolithophore
Pelagic sediment
Emiliania huxleyi
Settling
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Abstract. The fossil record of coccolithophores dates back approximately 225 million years and the production of their calcite platelets (coccoliths) contributes to the global carbon cycle over short and geological time scales. Variations in coccolithophore parameters (e.g., community composition, morphology, size and coccolith mass) have been used as paleoproxy to understand past oceanographic conditions. Coccolith mass has been frequently estimated with different methods with electron microscopy the most applied. Here, we compared the electron microscopy (EM) method with the Coulter Multisizer (CM) (i.e., electric field disturbance) and Bidirectional Circular Polarization (BCP) methods to estimate coccolith masses in controlled laboratory experiments with two ecotypes of Emiliania huxleyi. Average coccolith mass estimates were in good agreement with literature data. However, mass estimates from CM were slightly overestimated compared to EM and BCP estimates and a correction factor (cf = 0.8) is suggested to compensate for this discrepancy. The relative change in coccolith mass triggered by morphotype specific structures and environmental parameters (i.e., seawater carbonate chemistry) was suitably captured by each of the three techniques.
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Coccolithophore
Emiliania huxleyi
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Coccolith
Assemblage (archaeology)
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Abstract The marine biological calcification and photosynthesis, which can produce particulate inorganic and organic carbon (PIC and POC), have the opposite effects on seawater p CO 2 . Coccolithophores are a kind of marine unicellular algae with both of the two biological processes, and PIC and POC productions of them can shape the water column rain ratio as a dominant driver for Earth's carbon cycle. Thus, the changes in ancient coccolithophore PIC:POC can be important for the paleoceanographic and paleoclimatic studies of carbon cycle modeling. However, ancient coccolithophore PIC:POC is poorly constrained because of the occasional occurrences of intact coccospheres in deep ocean sediments, as detached coccoliths are commonly the remnants of fossilized coccolithophores. Here, we carry out the biometric analysis of coccosphere and coccolith from the living cells of Emiliania huxleyi and Gephyrocapsa oceanica in the South China Sea, and confirm a significant correlationship between their PIC:POC and lateral coccolith aspect ratio ( AR L ). AR L here is defined by the ratio of mean coccolith thickness with respect to coccolith length. A linear regression is given, ( R 2 = 0.59, n = 121), for the reconstruction of ancient Noelaerhabdaceae coccolithophore PIC:POC based on individual coccoliths in marine sediments. Based on this equation, we reconstruct ancient Noelaerhabdaceae coccolithophore PIC:POC since 14 million years ago (Ma) using published coccolith data, which reveal a long‐term decrease in PIC:POC from 7 to 4 Ma. We suggest that such a change in coccolithophore physiology may be induced by a simultaneous long‐term decline in seawater calcium concentration.
Coccolith
Coccolithophore
Emiliania huxleyi
paleoceanography
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Abstract. Coccolithophore play a key role in the marine carbon cycle and ecosystem. The carbonate shells produced by coccolithophore, named as coccolith, could be well preserved in the marine sediment for million years and become an excellent archive for paleoclimate studies. The micro filtering and sinking-decanting method have been successfully designed for coccolith separation and promoted the development of geochemistry studies on coccolith, such as the stable isotopes and Sr / Ca ratio. However, these two methods are still not efficient enough for the sample-consuming methods. In this study, the trajectory of coccoliths movement during a centrifugation process was calculated in theory and carefully tested by separations in practice. We offer a matlab code to estimate the appropriate parameter, angular velocity at a fixed centrifugation duration, for separating certain coccolith size fractions from bulk sediment. This work could improve the efficiency of coccolith separation, especially for the finest size fraction and make it possible to carry the clumped isotope and radio carbon analysis on coccolith in sediment.
Coccolith
Coccolithophore
Pelagic sediment
Emiliania huxleyi
Settling
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