A High Precision Method for Calcium Determination in Seawater Using Ion Chromatography

He, Hangqi; Li, Yifan; Wang, Shuyuan; Ma, Qianwei; Pan, Yiwen

doi:10.3389/fmars.2020.00231

Cited by 14 publications

(7 citation statements)

References 36 publications

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“…However, while the values in that table are derived from historic data ( see Millero et al 2008; Table 2), they represent a chemical construct, that is, a model of IAPSO that relates its conductivity to the Practical Salinity Scale, but not its exact composition. In fact, He et al (2020) recently showed, in the context of designing a high‐precision method for measuring seawater Ca concentrations, that the composition of IAPSO varies significantly from batch to batch, a fact also discussed by Pawlowicz (2010). Steiner et al (2020) used a single batch of IAPSO to prepare their calibration standards and derived its Sr/Ca ratio via TIMS with double‐spike ID as 8.545 ± 0.021 mmol mol −1 .…”

Section: Normalization and The Problem Of The Seawater Reference Standardmentioning

confidence: 87%

An ICP‐AES method for routine high‐precision measurement of seawater Sr/Ca ratios to validate coral paleothermometry calibrations

Khare

Hughes

Kilbourne

et al. 2021

Limnology & Ocean Methods

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A new inductively coupled plasma atomic emission spectrometry (ICP‐AES) method is presented for rapid and routine analysis of Sr/Ca molar ratios in seawater, with a long‐term precision of < 0.2%. It is an adaptation of a method widely employed for the analysis of coral aragonite Sr/Ca ratios in marine paleothermometry studies, which are based on the assumption that the seawater Sr/Ca ratio is constant in space and time. While prior studies have shown variations of up to 1% with depth, smaller variations at the ocean surface are generally accounted for via empirical, species‐specific calibrations of coral Sr/Ca vs. temperature. We found Sr/Ca variations in some coastal waters to be even larger, with distinct periodicity, complicating this approach. Although the high precision necessary for measurements of seawater Sr/Ca has previously relied on advanced mass spectrometry, long analysis times, and expensive isotopic spikes, our method uses more accessible instrumentation and is both time‐ and cost‐saving. The intricate composition of seawater, relative to coral aragonite solutions, requires an intensity ratio calibration technique combined with rigorous normalization to a suitable seawater standard. Key aspects of our method are discussed, including the choice of wavelengths, instrument parameters, accuracy, precision, and matrix effects. Special attention is given to the need for a certified seawater Sr/Ca reference standard, which does not presently exist. Analytical validation is provided by concurrent sharp gradients in Sr/Ca and δ18O, coinciding with the Florida landfall of hurricane Irma, as recorded at near‐daily resolution in a continuous seawater sample collected with an osmotic pump.

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Section: Normalization and The Problem Of The Seawater Reference Standardmentioning

confidence: 87%

An ICP‐AES method for routine high‐precision measurement of seawater Sr/Ca ratios to validate coral paleothermometry calibrations

Khare

Hughes

Kilbourne

et al. 2021

Limnology & Ocean Methods

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“…In nature, calcium is considered an easily available element as it is among the most abundant cations in water and soil. Nevertheless, concentrations of Ca 2+ ions vary depending on the environment, typically reaching ~10 mM in open ocean water ( 33 ) and ranging between 0.01 and ~1.9 mM in freshwater, with the average at ~0.1–0.35 mM and much higher concentrations observed in the vicinity of carbonate rocks ( 34 ). Calcium concentrations in the soil solutions were reported to reach up to 20 mM ( 35 ) and strongly depend on the type of soil.…”

Section: Discussionmentioning

confidence: 99%

Evolution of the T4 phage virion is driven by selection pressure from non-bacterial factors

Majewska,

Miernikiewicz,

Szymczak

et al. 2023

Microbiol Spectr

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Bacteriophages colonize animal and human bodies, propagating on sensitive bacteria that are symbionts, commensals, or pathogens of animals and humans. T4-like phages are dependent on abundant symbionts such as Escherichia coli , commonly present in animal and human gastrointestinal (GI) tracts. Bacteriophage T4 is one of the most complex viruses, and its intricate structure, particularly the capsid head protecting the phage genome, likely contributes substantially to the overall phage fitness in diverse environments. We investigated how individual head proteins—gp24, Hoc, and Soc—affect T4 phage survival under pressure from non-bacterial factors. We constructed a panel of T4 phage variants defective in these structural proteins: T4∆Soc, T4∆24byp24, T4∆Hoc∆Soc, T4∆Hoc∆24byp24, T4∆Soc∆24byp24, and T4∆Hoc∆Soc∆24byp24 (byp = bypass). These variants were investigated for their sensitivity to selected environmental conditions relevant to the microenvironment of the GI tract, including pH, temperature, and digestive enzymes. The simple and “primitive” structure of the phage capsid (∆24byp24) was significantly less stable at low pH and more sensitive to inactivation by digestive enzymes, and the simultaneous lack of gp24 and Soc resulted in a notable decrease in phage activity at 37°C. Gp24 was also found to be highly resistant to thermal and chemical denaturation. Thus, gp24, which was acquired relatively late in evolution, seems to play a key role in T4 withstanding environmental conditions, including those related to the animal/human GI tract, and Soc is a molecular glue that enhances this protective effect. IMPORTANCE Bacteriophages are important components of animal and human microbiota, particularly in the gastrointestinal tract, where they dominate the viral community and contribute to shaping microbial balance. However, interactions with bacterial hosts are not the only element of the equation in phage survival—phages inhabiting the GI tract are constantly exposed to increased temperature, pH fluctuations, or digestive enzymes, which raises the question of whether and how the complex structure of phage capsids contributes to their persistence in the specific microenvironment of human/animal bodies. Here we address this phage-centric perspective, identifying the role of individual head proteins in T4 phage survival in GI tract conditions. The selection pressure driving the evolution of T4-like phages could have come from the external environment that affects phage virions with increased temperature and variable pH; it is possible that in the local microenvironment along the GI tract, the phage benefits from stability-protecting proteins.

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“…B. belcheri xiamen has 25 EF-CaBP genes, B. belcheri beihai has 19 genes, B. floridae has 17 genes, and B. lanceolatum has only 12 genes. Marine salinity is linearly correlated with the calcium ion concentration (He et al 2020). Therefore, we further explored the relationship of the gene number variation of these proximally arrayed EF-CaBP genes and the sea surface salinity of the collection locations (Fig.…”

Section: Calcium Balancementioning

confidence: 99%

Gene Novelties in Amphioxus Illuminate the Early Evolution of Deuterostomes

Xiong

Yang

Zeng

et al. 2022

Preprint

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Horizontal gene transfer (HGT) enables novel gene establishment but has rarely been reported in the genomes of deuterostomes. Using the genomes of four amphioxi, massive HGT events were identified that introduced novel genes in different functional groups. Innate immunity of amphioxi that have no adaptative immune system was enriched by HGT genes. Anaerobic adaptation of amphioxi may have been enabled by the HGT of genes for alcohol dehydrogenase and ferredoxin. A proximally arrayed cluster of EF-hand calcium-binding protein genes, of which the copy number was linearly correlated to the sea salinity of the collection region, may foster their survival at different calcium concentrations. Combining phylogenetic analysis and conservation among deuterostomes, this comprehensive analysis of HGT in amphioxi revealed insights into the early evolution of deuterostomes.

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A High Precision Method for Calcium Determination in Seawater Using Ion Chromatography

Cited by 14 publications

References 36 publications

An ICP‐AES method for routine high‐precision measurement of seawater Sr/Ca ratios to validate coral paleothermometry calibrations

An ICP‐AES method for routine high‐precision measurement of seawater Sr/Ca ratios to validate coral paleothermometry calibrations

Evolution of the T4 phage virion is driven by selection pressure from non-bacterial factors

Gene Novelties in Amphioxus Illuminate the Early Evolution of Deuterostomes

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