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Ion Beam Analysis: Analytical Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Three isotopes of carbon are present in nature; 12C, 13C and 14C. 12C accounts for ~99.8% of all carbon atoms, 13C accounts for ~1% of carbon atoms while 14C represents only 1 ppb (one part per billion) of natural carbon. Carbon isotope 14C is radioactive and has a half-life of 5730 years. Because this decay is constant it can be used as a “clock” to measure elapsed time assuming the starting amount is known. A unique characteristic of 14C is that it is constantly formed in the upper atmosphere where neutrons from cosmic rays knock a proton from 14N atoms. These newly formed 14C atoms rapidly oxidize to form 14CO2 that is chemically indistinguishable from 12CO2 and 13CO2. Photosynthesis incorporates 14C into plants and therefore animals that eat the plants. 14C enters the dissolved inorganic carbon pool in the oceans, lakes and rivers. From there it is incorporated into shell, corals and other marine organisms. When a plant or animal dies it no longer exchanges CO2 with the atmosphere. This starts the radioactive decay “clock”. 14C decays by emitting an electron, which converts a neutron to a proton, converting it back to its original 14N form.
Organic Matter
Published in Michael J. Kennish, Ecology of Estuaries Physical and Chemical Aspects, 2019
The concentration of inorganic material usually exceeds that of both DOM and POM. The total amount of dissolved salt in river water (120 mg/ℓ), for example, is significantly greater than the DOM content, which falls between 10 and 20 mg C per liter. Likewise, the dissolved salt content of seawater (35 g/ℓ) is many times greater than the DOM content (0.5 to 5 mg C per liter). Most of the carbon in seawater exists as dissolved inorganic carbon.19
Carbon Dioxide Sequestration by Microalgae
Published in Gokare A. Ravishankar, Ranga Rao Ambati, Handbook of Algal Technologies and Phytochemicals, 2019
G.V. Swarnalatha, Ajam Shekh, P.V. Sijil, C.K. Madhubalaji, Vikas Singh Chauhan, Ravi Sarada
The phosphoglycolate is dephosphorylated to glycolate by the enzyme phosphoglycolate phosphatase; otherwise it inhibits the carboxylase activity of RuBisCO. This glycolate via photorespiration enters into further metabolism (Beardall and Raven 2004; J. A. Raven 2000), or it is lost by excretion from algal cells. In some algae, dissolved inorganic carbon assimilation from the environment occurs by alternative pathways.
A Bayesian conditional model for bivariate mixed ordinal and skew continuous longitudinal responses using quantile regression
Published in Journal of Applied Statistics, 2018
S. Ghasemzadeh, M. Ganjali, T. Baghfalaki
This criterion attempts to identify the most parsimonious model by providing a balance between the likelihood and the number of parameters that exist in the model. One needs two quantities for computing of the DIC that can be easily approximated using MCMC methods. One of these quantities is posterior mean of usual deviance measure m. The DIC is defined as follows: θ, respectively. Also θ is the vector of model parameters. The lowest DIC leads us to the best model fit.
Environmental post-processing increases the adhesion strength of mussel byssus adhesive
Published in Biofouling, 2018
Matthew N. George, Emily Carrington
pH electrodes were calibrated using NBS standards before use in each treatment. Bottle samples were collected at three time points throughout each 20-day treatment (1, 12, and 20 days) and poisoned with 0.02% saturated mercuric chloride (HgCl2) to halt all biological activity. All samples that contained mercuric chloride were handled and disposed of in accordance with NIOSH guidelines. For each bottle, total alkalinity (TA) was measured in μmol kg−1 using end-point titration (DL15 titrator, Mettler Toledo, Schwerzenbach, Switzerland; accuracy ± 50 μmol kg−1) following SOP 3b from Dickson et al. (2007). Treatment averages for pCO2 (μatm) and total dissolved inorganic carbon (TC) were calculated using CO2Calc (Van Heuven et al. 2011) with the following constants: CO2: Mehrbach et al. (1973); KHSO4: Dickson (1990); and Boron: Uppström (1974). Means (± SD) for each treatment are listed in Table 1.
Still challenging: the ecological function of the cyanobacterial toxin microcystin – What we know so far
Published in Toxin Reviews, 2018
Azam Omidi, Maranda Esterhuizen-Londt, Stephan Pflugmacher
Recent studies demonstrated a correlation between dissolved inorganic carbon (DIC) and the growth and MC production of M. aeruginosa. In a competitive study, the effect of low and high DIC (0.365 and 7.658 mmol l−1 KHCO3) on M. aeroginosa toxic and non-toxic strains, FACHB 912 and FACHB 469, co-cultured with green algae Chlamydomonas microsphaera were investigated. The growth of M. aeruginosa toxic and non-toxic strains was negatively affected by DIC without any significant changes in the chlorophyl content; however, the photosynthesis efficiency and chlorophyl content of green algae decreased. The results proposed that M. aeruginosa might be more adapted to low DIC condition (Zhang et al., 2012). Increased dissolved inorganic carbon had an adverse effect on the frequency of toxic Microcystis and MCs concentration in Lake Chaohu, China as well (Yu et al., 2014). Deficiency of intracellular inorganic carbon resulted in an increase in MC production of M. aeruginosa PCC 7806. Moreover, the toxic wild type contained greater chlorophyl a content and consequently displayed higher photosynthetic efficiency compared with the mcyB− mutant, suggesting a role of MCs in environmental adaptation (Jähnichen et al., 2007).