Stable Isotope

ABSTRACT Understanding the transformation of unconsolidated sediments into their lithified equivalents is an essential concept in geology, and is especially complex for coral reef deposits accumulating at marine and terrestrial interfaces. Because corals are used as paleoclimatic and paleoenvironmental proxies, it is important to identify the extent of alteration to their skeletons.

Palaios, 2003

inhabiting deep reef environments, and increased nutrient availability in the deep reefs sampled. Clear gradients in the degree of taphonomic alteration of reef corals with reef habitat indicate the utility of corals as taphofacies indicators in ancient reef settings. In contrast to shallow-water reefs on the Great Barrier Reef, taphonomic alteration of corals in the Florida Keys was equitable across growth forms.

Marshal, P., J. Johnson, and D. …, 2007

Chapter 22: Using the past to understand the future: Palaeoecology of coral reefs 22.2 Vulnerability of coral reefs to climate change 22.2.1 Exposure

Coral Reefs, 1991

Time-series •180 and 013C records from cohabiting massive coral Porites australiensis and giant clam Tridacna gigas from the Great Barrier Reef of Australia, and from calcareous green algae in a core through modern Halimeda bioherm accreting in the eastern Java Sea, provide insights into the complex links between environmental factors and stable isotopes imprinted in these reef skeletal materials. The aragonitic coral and giant clam offer 20 years and 15 years of growth history, respectively. The giant clam yields mean 6180 and 613C values of-0.5_+0.5%0 and 2.2+0.2%o (n=67), which agree well with the predicted equilibrium values. The coral yields mean 618 O and 613C values of-5.6 + 0.5%0 and-1.8 __. 0.7%0 (n = 84), offering a striking example of kinetic and metabolic fractionation effects. Although both the coral and giant clam harbor symbionts and were exposed to a uniform ambient environment during their growth histories, their distinct isotopic compositions demonstrate dissimilar calcification pathways. The ~ 18 O records contain periodicities corresponding to the alternating annual density bands revealed by X-radiography and optical transmitted light. Attenuation of the 6180 seasonal amplitudes occurring in the giant clam record 8 years after skeletal growth commenced is attributed to a changeover from fast to slow growth rates. Extreme seasonal 6180 amplitudes of up to 2.2%o discerned in both the coral and giant clam records exceed the equivalent seasonal temperature contrast in the reef environment, and are caused by the combined effect of rainfall and evaporation during the monsoon and dry seasons, respectively. Thus in addition of being useful temperature recorders, reef skeletal material of sufficient longevity, such as Porites and Tridacna, may also indicate rainfall variations. Changing growth rates, determined from the annual growth bands, may exert a primary control on the coral 613C record which shows a remarkable negative shift of 1.7%o over its growth history, by comparison with only 0.15%o negative shift in the contemporaneous giant clam record. Use of coral 613 C records as proxies of fossil fuel COz uptake by the ocean must be regarded with caution. The 6180 and ~3C records from Halimeda are remarkably uniform over 1000 years of bioherm accretion history (6180 =-1.7 _+ 0.2%0; 613C=3.9_+0.1%o, n= 28), in spite of variable Mg-calcite cements present in the utricles. Most of the cement infilling is probably syndepositional, and both the Halimeda aragonite and the Mgcalcite cements containing 12.3 mole % MgCO3 are deposited in isotopic equilibrium. Therefore, in favorable circumstances these algal skeletal remains may act as the shallow water analogs of benthic foraminifera in deep sea sediments in recording ambient sea water isotopic composition and temperature.

Marine Biology, 1999

Stable-isotope and growth records of coral skeletons are often used to reconstruct tropical paleoclimate, yet few surveys have systematically examined the natural variability in coral skeletal d 13 C, d 18 O and maximum linear skeletal extension (MLSE) across depth. Here, interspeci®c, intraspeci®c, and geographical variations in coral skeletal d 13 C, d 18 O, and MLSE were examined in the corals Porites compressa, P. lobata, and Montipora verrucosa grown at 1.7, 5.0, and 8.3 m depth from August 1996 to March 1997 at The Point Reef and Patch Reef #41 ®eld sites in Kaneohe Bay, Hawaii. Coral skeletal d 13 C values signi®cantly decreased with depth and diered between species, but did not vary between ®eld sites. d 18 O values were not signi®cantly dierent across depth within a species, but did dier among species and ®eld sites. High-resolution analysis of the intra-annual variation in skeletal d 13 C and d 18 O in P. compressa at 2.0 m depth con®rms that these isotopes re¯ect changes in solar irradiance and temperature, respectively. Changes in MLSE across depth were consistent within, but highly variable among, species. Peak MLSE occurred at 1.7, 5.0, and 8.3 m for P. lobata, P. compressa, and M. verrucosa, respectively. Such interspeci®c variation in MLSE patterns may be attributable to one or more of the following: increases in zooplankton in the diet, changes in metabolic processes, or changes in growth form with depth. Overall, these results imply that natural inter-and intraspeci®c vari-ability in coral skeletal d 13 C, d 18 O, and MLSE should be considered when interpreting and comparing coralbased tropical paleoclimate data from various coral species, depths, and ®eld sites.

Geochimica et Cosmochimica Acta, 2011

The integrity of coral-based reconstructions of past climate variability depends on a comprehensive knowledge of the effects of post-depositional alteration on coral skeletal geochemistry. Here we combine millimeter-scale and micro-scale coral Sr/Ca data, scanning electron microscopy (SEM) images, and X-ray diffraction with previously published d 18 O records to investigate the effects of submarine and subaerial diagenesis on paleoclimate reconstructions in modern and young sub-fossil corals from the central tropical Pacific. In a 40-year-old modern coral, we find secondary aragonite is associated with relatively high coral d 18 O and Sr/Ca, equivalent to sea-surface temperature (SST) artifacts as large as À3 and À5°C, respectively. Secondary aragonite observed in a 350-year-old fossil coral is associated with relatively high d 18 O and Sr/Ca, resulting in apparent paleo-SST offsets of up to À2 and À4°C, respectively. Secondary Ion Mass Spectrometry (SIMS) analyses of secondary aragonite yield Sr/Ca ratios ranging from 10.78 to 12.39 mmol/mol, significantly higher compared to 9.15 ± 0.37 mmol/mol measured in more pristine sections of the same fossil coral. Widespread dissolution and secondary calcite observed in a 750-year-old fossil coral is associated with relatively low d 18 O and Sr/Ca. SIMS Sr/Ca measurements of the secondary calcite (1.96-9.74 mmol/mol) are significantly lower and more variable than Sr/Ca values from more pristine portions of the same fossil coral (8.22 ± 0.13 mmol/mol). Our results indicate that while diagenesis has a much larger impact on Sr/Ca-based paleoclimate reconstructions than d 18 O-based reconstructions at our site, SIMS analyses of relatively pristine skeletal elements in an altered coral may provide robust estimates of Sr/Ca which can be used to derive paleo-SSTs.

Sustainability, 2023

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY

The use of sustainable technologies for buildings, with the goal of creating an environment for living and working that uses fewer resources and generates less waste, also aims to retrofit existing buildings to be more efficient in terms of energy and water. Many cities are following this way targeting both commercial and municipal buildings. These cities are called smart cities where all life processes and nerve centers of social life are read, in order to radically improve quality of life, opportunity, prosperity, social and economic development, thanks to the use of technology. This paper deals with the study of smart buildings within smart cities, namely the use in an integrated project of computer and telematics tools with automation organized systems and passive bioclimatic strategies in architecture, determining a socio-technical management of intelligent building. The article is the result of a research carried out within the framework of intelligent buildings in the last generation cities, such as those ones with zero emissions that are taking place in the Middle East countries (Dubai, Masdar, Tiajin, and Kochi). The topic deals with the issues of building automation as a form of technological intelligence and the study of those smart technologies integrated into the building envelope that improve its performances, making it more sustainable. The research methodology has provided a bibliographic retrieval on the state of the art and the latest technological trends in the building field, later has followed a theoretical and comparative approach of the examined technologies, which led to the development of reasoning on operation, performance and functional capabilities of a building that is both sustainable and home automation, to arrive at the final concept of sustainable intelligent building, able to combine the artificial intelligence, home automation, and technological devices of the architectural project to enhance the building energy performance. In conclusion, the proposed result is that of an integrated intelligent building in which artificial intelligence will become part of the shell-building in order to achieve high levels of energy efficiency and thus environmental sustainability. . 1 Information and communications technology (ICT) is a term often used as an extended synonym for information technology. It stresses the role of unified communications and the integration of telecommunications (telephone lines and wireless signals), computers as well as necessary enterprise software, storage, and audio-visual systems, which enable users to access, store, transmit, and manipulate information.

Autoimmunity, 2012

A dual role of B cells in experimental autoimmune encephalomyelitis (EAE), the animal model of the human autoimmune disease multiple sclerosis (MS), has been established. In the first role, B cells contribute to the pathogenesis of EAE through the production of anti-myelin antibodies that contribute to demyelination. On the contrary, B cells have also been shown to have protective functions in that they play an essential role in the spontaneous recovery from EAE. In this review, we summarize studies conducted in a number of species demonstrating the conditions under which B cells are pathogenic in EAE. We also discuss the phenotype and anti-inflammatory mechanisms of regulatory B cells.

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