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Antarctic Marine Biodiversity: Adaptations, Environments and Responses to Change
Published in S. J. Hawkins, A. J. Evans, A. C. Dale, L. B. Firth, I. P. Smith, Oceanography and Marine Biology, 2018
Human outputs of CO2 since the industrial revolution have increased global temperatures by absorbing radiation from the Earth that would otherwise have passed out of the atmosphere. A second major consequence is that around 30% of the CO2 released has been absorbed by the oceans, which has resulted in a decrease of ocean pH of around 0.1 units, and the major part of this change has occurred in the last 50 years (Caldeira & Wickett 2003, 2005, IPCC 2014). Carbonate solubility varies strongly with pH, temperature and pressure, with higher solubility at lower pH, higher pressure and lower temperature. Thus, for the same amounts dissolved per unit seawater and the same concentrations, the solubility state is lower in all three cases. This results in the deep oceans being undersaturated and the polar oceans having lower carbonate saturation at the surface than oceans at lower latitudes (Orr et al. 2005, Fabry et al. 2009). Future predictions are that acidification will continue to be strongest in the polar regions, especially in Antarctica such that surface waters will be undersaturated for aragonite, the more soluble of the common forms of carbonate, by the middle of this century (Figure 21, McNeil & Matear 2008, Feely et al. 2009a,b, 2012). This undersaturation will occur first in winter, which has colder conditions than summer, and there is already a seasonal signal in carbonate saturation in the Southern Ocean (McNeil et al. 2011, Hauri et al. 2016, Legge et al. 2017).
Water Management
Published in L.B. (Bert) McCarty, Golf Turf Management, 2018
Two measurements are used for assessing the carbonate level of irrigation water: the direct measurement of carbonate and bicarbonate and the residual sodium carbonate equation. It is not the absolute levels of bicarbonates or carbonates present in the irrigation water that is most important, but rather their relative concentrations compared to Ca, Mg, and Na levels. RSC specifically measures the presence of excess carbonate (CO3−2) and bicarbonate HCO3− content over calcium (Ca+2) and magnesium (Mg+2) ions expressed as milliequivalents per liter.
Recycling of Metalworking Fluids
Published in Jerry P. Byers, Metalworking Fluids, Third Edition, 2018
A carbonate is a salt of carbonic acid characterized by the presence of the carbonate ion, CO2−. Soluble carbonates such as sodium carbonate have minimal effect on metalworking fluids and tend to buffer the solutions to a pH of 8.6.
Indications of the sedimentary environments by the sedimentary characteristics and trace elements of Ordovician Majiagou Formation, Northern Shaanxi salt basin
Published in Geosystem Engineering, 2020
LinLin Wang, Tao Shi, Dawei Chang, Haitao Zhang
Combining the regional structure and sedimentary background, core observation and rock slice identification from 8 wells were carried out, including Zhen Jia Well 1 and Shaanjia Well 1. The results show that sedimentary rocks in Ordovician Majiagou Formation is mainly carbonates and evaporites (Figure 2). Other sedimentary rocks such as clastic rocks are less developed. Carbonate rocks include limestone and dolomite. The limestone is further divided into particle-lime mudstone and metasomatic limestone, and dolomite is further divided into dolomicrite, dolosiltite, saccharoidal dolomite, concrete-anhydrock dolomite, and lamellar gypsodolomite. The evaporites include gypsum rock and salt rock, and the gypsum rock is subdivided into primary gypsum rock and metasomatic gypsum rock. There are some bedding and sedimentary structures in the carbonate formation of Majiagou Formation, mainly including horizontal burrows, biological burrow structure, stromatolite structure, filling structure, horizontal bedding, deformed bedding and massive bedding. Based on the identification of rock types, beddings and sedimentary structures, the sedimentary facies types on Majiagou Formation carbonate platform in the study area are established, and the platform is further classified into open platform and restricted platform.
Low-temperature synthesis of SrCrO4 nanorod particles from strontium sulfate
Published in Journal of Dispersion Science and Technology, 2020
SrCO3 was observed in the product phase, although no carbonation agent was added to the system. This is because the CO2 gas in the air acts as a carbonator when dissolved in water/solution medium. First, the CO2 gas enters the solution phase, whereupon it becomes soluble and then carboxylic acid, a polybasic acid, forms. Carbonic acid, which is a weak acid with two steps of ionization in the aqueous solution, forms bicarbonate in the first step and carbonate ions in the second step. However, the formation of these species strongly depends on the pH of the solution. Initially, when the medium is acidic, the concentration of carbonic acid decreases over time with the addition of sodium hydroxide and ends at approximately pH= 9. At this point, the concentration of bicarbonate ions reaches its maximum value. Finally, at about pH > 11, all of the bicarbonate ions turn into carbonate ions. Some of the free Sr2+ ions in the solution are precipitated as SrCO3 (Ksp: 5.6x1010 for SrCO3).[29]
Study of adhesion characteristics of different bitumen–aggregate combinations using bitumen bond strength test
Published in Journal of the Chinese Institute of Engineers, 2018
Syeda Aamara Asif, Naveed Ahmed, Aneeqa Hayat, Sabahat Hussan, Faisal Shabbir, Khalid Mehmood
The results from Figure 8 indicate that limestone and marble have better bonding properties in comparison to other moisture conditioned aggregates. Generally, aggregates are classified into two groups; basic aggregates and acidic aggregates. Basic aggregates are less sensitive to moisture, i.e. are more resistant against stripping, than the acidic ones. As basic aggregates form better bonds with bitumen, it is comparatively harder for water to penetrate through the bitumen film and remove it from the surface of the aggregates. Hence, there is less possibility of stripping in case of basic aggregates. Limestone and marble are composed of calcite carbonates. Carbonates (CaCO3) raise pH of water if in contact. Calcareous aggregates give free calcium ions which form strong water-resistant bonds with bitumen (Yin et al. 2017).