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To determine the benthic transformation pathways and fate of carbon associated with secondary-treated pulp and paper mill (PPM) effluent, (13)C-labeled activated sludge biomass (ASB) and phytoplankton (PHY) were added, separately, to estuarine intertidal sediments. Over 28 days, (13)C was traced into sediment organic carbon, fauna, seagrass, bacteria, and microphytobenthos and into fluxes of dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) from inundated sediments, and carbon dioxide (CO2(g)) from exposed sediments. There was greater removal of PHY carbon from sediments (~85% over 28 days) compared to ASB (~75%). Although there was similar (13)C loss from PHY and ASB plots via DIC (58% and 56%, respectively) and CO2(g) fluxes (<1%), DOC fluxes were more important for PHY (41%) than ASB (12%). Faster downward transport and loss suggest that fauna prefer PHY, due to its lability and/or toxins associated with ASB; this may account for different carbon pathways. Secondary-treated PPM effluent has lower oxygen demand than primary-treated effluent, but ASB accumulation may contribute to sediment anoxia, and respiration of ASB and PHY-derived DOC may make the water column more heterotrophic. This highlights the need to optimize secondary-treatment processes to control the quality and quantity of organic carbon associated with PPM effluent.

Lacustrine carbonates are a powerful archive of paleoenvironmental information but are susceptible to post-depositional alteration. Microbial metabolisms can drive such alteration by changing carbonate saturation in situ, thereby driving dissolution or precipitation. The net impact these microbial processes have on the primary δ 18 O, δ 13 C, and Δ 47 values of lacustrine carbonate is not fully known. We studied the evolution of microbial community structure and the porewater and sediment geochemistry in the upper ~30 cm of sediment from two shoreline sites at Green Lake, Fayetteville, NY over 2 years of seasonal sampling. We linked seasonal and depth-based changes of porewater carbonate chemistry to microbial community composition, in situ carbon cycling (using δ 13 C values of carbonate, dissolved inorganic carbon (DIC), and organic matter), and dominant allochems and facies. We interpret that microbial processes are a dominant control on carbon cycling within the sediment, affecting porewater DIC, aqueous carbon chemistry, and carbonate carbon and clumped isotope geochemistry. Across all seasons and sites, microbial organic matter remineralization lowers the δ 13 C of the porewater DIC. Elevated carbonate saturation states in the sediment porewaters (Ω > 3) were attributed to microbes from groups capable of sulfate reduction, which were abundant in the sediment below 5 cm depth. The nearshore carbonate sediments at Green Lake are mainly composed of microbialite intraclasts/oncoids, charophytes, larger calcite crystals, and authigenic micrite-each with a different origin. Authigenic micrite is interpreted to have precipitated in situ from the supersaturated porewaters from microbial metabolism. The stable carbon isotope values (δ 13 C carb ) and clumped isotope values (Δ 47 ) of bulk carbonate sediments from the same depth horizons and site varied depending on both the sampling season and the specific location within a site, indicating localized (μm to mm) controls on carbon and clumped isotope values. Our results suggest that biological processes are a dominant control on carbon chemistry within the sedimentary subsurface of the shorelines of Green Lake, from actively forming microbialites to pore space organic matter remineralization and micrite authigenesis. A combination of biological activity, hydrologic balance, and allochem composition of the sediments set the stable carbon, oxygen, and clumped isotope signals preserved by the Green Lake carbonate sediments., (© 2024 The Author(s). Geobiology published by John Wiley & Sons Ltd.)

A preparation of organic working standards for the online measurement of 13C/12C and 18O/16O ratios in biological material is presented. The organic working standards are simple and inexpensive C3 and C4 carbohydrates (sugars or cellulose) from distinct geographic origin, including white sugar, toilet and XEROX papers from Switzerland, maize from Ivory Coast, cane sugar from Brazil, papyrus from Egypt, and the core of the stem of a Cyperus papyrus plant from Kenya. These photosynthetic products were compared with International Atomic Energy standards CH-3 and CH-6 and other calibration materials. The presented working standards cover a 15% range of 13C/12C ratios and 9% for 18O/16O, with a precision<+/-0.2% for n>10.

The bomb-peak signal preserved in the Arches® cotton paper was used to detect art forgeries imitating the work of Chinese artist T'ang Haywen (1927–1991). The dating of seven legitimate T'ang Haywen art pieces showed that the timing of the paper production was consistent with the artist's use of Arches® paper starting in the early 1980s. The measured F14C of the paper from the 14 suspected forged paintings shows that the support material was produced in the last decade (2008–2011), therefore the art pieces could not be genuine T'ang Haywen works. [ABSTRACT FROM AUTHOR]

When undertaking any study of the isotope abundance values of a bulk material, consideration should be given to the source materials and how they are combined to reach the final product being measured. While it is demonstrative to measure and record the values of clean papers, such as the results published as part one of this series, the majority of forensic casework samples would have undergone some form of writing or printing process prior to examination. Understanding the effects of these processes on the δ13C values of paper is essential for interpretation and comparison with clean samples, for example in cases where printed documents need to be compared to paper from an unprinted suspect ream. This study was undertaken so that the source materials, the effects of the production process and the effects of printing and forensic testing could be observed with respect to 80 gsm white office papers. Samples were taken sequentially from the paper production facility at the Australian Paper Mill (Maryvale, VIC). These samples ranged from raw wood chips through the pulping, whitening and refinement steps to the final formed and packed paper. Cellulose was extracted from each sample to observe both fractionation and mixing steps and their effect on the δ13C values. Overall, the mixing steps were observed to have a larger effect on the isotopic values of the bulk materials than any potential fractionation. Printing of papers using toner and inkjet printing processes and forensic testing were observed to have little effect on δ13C. These experiments highlighted considerations for sampling and confirmed the need for a holistic understanding of sample history to inform the interpretation of results. [ABSTRACT FROM AUTHOR]

A Jurassic negative carbon isotope excursion (CIE), co-evolved with Toarcian Oceanic Anoxic Event (OAE) at ~183 Ma, is suggested to be linked to a global carbon-cycle perturbation and is well documented for Toarcian terrestrial fossil woods and marine sediments around the globe. A theoretically coupled δ 13 C carb -δ 13 C org pattern due to such dubbed global carbon-cycle event from the negative CIE in Dotternhausen Toarcian stratigraphic profile (southwest Germany) is unexpectedly disturbed by two-step δ 13 C carb -δ 13 C org decoupling in which the last step, upper in the stratigraphic order, is of higher magnitude. However, the trigger(s) for these sudden decoupling disturbances are still poorly constrained. Here, connecting new carbon and oxygen isotope data with documentary lipid biomarkers shows that the global carbon cycle during the Toarcian OAE was disturbed by enhanced green sulfur bacteria (GSB) metabolisms and early diagenesis at local scales. The first step δ 13 C carb -δ 13 C org decoupling was induced in the initial stage of the GSB bloom. The second step of much larger δ 13 C carb -δ 13 C org decoupling arising from a GSB prosperity was, however, exaggerated by early diagenesis through the respiration of sulfate-reducing bacteria (SRB). Paleo-geographically distinct localities of the Tethys region show contrasting decoupled δ 13 C carb -δ 13 C org patterns, which implies that the second-order carbon-cycle perturbations have pervasively and independently impacted the global carbon event during the Toarcian OAE., (© 2020 The Authors. Geobiology published by John Wiley & Sons Ltd.)

The recently published Lethaia paper by Bergström et al. (https://doi.org/10.1111/let.12269) on the age of the Ordovician Winneshiek Shale (Iowa, USA), and the impact that formed the Decorah crater which hosts this rock unit, is an interesting scientific contribution, although there are a number of problems with the interpretations and data presentation that merit comment. Due mainly to a lack of adequate critical assessment of δ13C data and biostratigraphical control, we contend that the conclusions of Bergström et al. are poorly founded and should not be cursorily accepted and propagated in future scientific literature. [ABSTRACT FROM AUTHOR]

Reid, Della F. (University of Hawaii, Honolulu), and Hilmer A. Frank. Isotopic method for estimating microbial cell volumes. J. Bacteriol. 92:639-644. 1966.-A sensitive isotopic method was developed for estimating the mean cell volume in small numbers of bacterial spores by measuring directly the extracellular fluid volume when cells are present in a saturated inulin solution containing inulin-C(14) at low specific activity. The method minimizes errors due to solute adsorption to the cells and avoids errors arising from differences in cell packing. The effects of these sources of error on cell volume and intercellular space estimations made with nonpenetrating solutes are discussed.