Ion Beam Analysis: Analytical Applications
Vlado Valković in 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.
Radionuclide Concentrations in Water
Michael Pöschl, Leo M. L. Nollet in Radionuclide Concentrations in Food and the Environment, 2006
Dating old groundwater begins with the determination that they are tritium free, and so have no modern component. Tritium-free groundwater can be considered submodern (recharged more than 50 years ago) or older and have not incorporated any significant amount of modern water during discharge. The only absolute, albeit indirect, dating techniques for groundwater involve the decay (or in-growth) of long-lived radionuclides. By far the most routinely applied is 14C, which is transported as dissolved inorganic carbon (DIC) or dissolved organic carbon (DOC).
Carbon Dioxide Sequestration by Microalgae
Gokare A. Ravishankar, Ranga Rao Ambati in Handbook of Algal Technologies and Phytochemicals, 2019
Temperature is one of the vital factors in microalgal growth, particularly in the maintenance of cell morphology and physiology. The metabolic activities of the culture may increase or decrease as a function of temperature. Economic cultivation of microalgae for biomass production is combined with CO2 capture. Enhanced biomass production is associated with availability of dissolved inorganic carbon in the nutrient medium. However, CO2 solubility is influenced by culture/atmospheric temperature. An ideal temperature range for microalgal biomass production is reported to be 25–35°C. The optimal growth of microalgae is determined by the intracellular enzyme activity and reaction rates which in turn are dependent on temperature. Various microalgal species have their optimal growth temperature in the range of 15–26°C (Kumar et al. 2010). Since the temperature of the flue gas from power plants is around 120°C, thermotolerant microalgae can be employed to sequester the CO2 from flue gas. The thermotolerant microalgae has the ability to tolerate and grow up to the temperature of 55°C with more than 40% CO2 (Wang et al. 2008). Some species, viz. Cyanidiium caldarim, Galdieria partita, and Cyanidioschyzon melorae, have been identified as thermotolerant and can grow at 50°C (Kurano et al. 1995). Thermotolerant Synechococcus (a unicellular cyanobacterium) is known to grow at the temperature range of 48–55°C (Eberly and Ely 2012). According to Henry’s law, at 50°C Henry’s constant is 1.817 × 10−2 mol/atm, whereas with lowering temperatures the constant increases to 2.965 × 10−2 mol/atm (Eberly and Ely 2012), leading to higher CO2 availability and fixation by microalgae (Eberly and Ely 2012). Increase in temperature decreases the solubility, and it will be balanced with the increased metabolic rates.
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).
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.
Metabarcoding and metabolomics offer complementarity in deciphering marine eukaryotic biofouling community shifts
Published in Biofouling, 2018
Jean-François Briand, Xavier Pochon, Susanna A. Wood, Christine Bressy, Cédric Garnier, Karine Réhel, Félix Urvois, Gérald Culioli, Anastasija Zaiko
A strong Spearman’s rank pairwise correlation was observed between temperature and lead (Pb) (r = 0.905, p = 0.005, n = 8) and dissolved inorganic carbon (DIC) (r = 0.881, p = 0.007, n = 8). A correlation was observed between nitrates, silicates (r = 0.881, p = 0.007, n = 8) and dissolved organic carbon (DOC) (r = 0.876, p = 0.037, n = 8). Consequently, temperature was chosen as a proxy for Pb and DIC, and nitrates for silicates and DOC for further CCA. Eukaryotic communities displayed two clusters depending on site (Figure 4). Communities at Toulon were clearly associated with high temperature, Pb and salinity. Conversely, communities at Lorient were significantly associated with high concentrations of nutrients (phosphates, nitrates and silicates), and DOC, but also copper (Cu) and cadmium (Cd). The cumulative percentage of variance of the species/environment relationship indicates that the first and second canonical axis explained 26.8% and 18.8%, respectively.
Related Knowledge Centers
- Alkalinity
- Fugacity
- Inorganic Compound
- Nucleic Acid
- Protein
- Lipid
- Carbohydrate
- Carbon
- Solution
- Bjerrum Plot