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The recognized biogenic production corresponds to corporal materials, and ethological structures (ichnofossils). Ethological structures include bioturbation, bioerosion, and biogenic granule-classification structures. Biogenic materials and structures traditionally include biogenic aggregates (such as fecal pellets or castings and coprolite grapstones); bioturbation structures or ichno-structures (burrows, tracks, trails, and root penetration structures); biogenic granulo-classification or biostratification structures (algal and bacterial stromatolites of graded bedding of biogenic origin); bioerosion structures (borings, scrapings, and bitings); and biolitites (e.g., reef structures). This paper presents a new classification system for biogenic materials applicable to the fossil record. It summarizes our efforts to standardize terminology, use new and existing terms, correct any contradictions in some terms, and facilitate teaching and learning processes related to this subject. In our proposal, biogenic production is used for any materials or structures produced, built, modified, or used by living organisms. Biogenic production includes the following five groups: direct production (corporal, biodeposition, bioexhudation, and bioclaustration materials and structures); bio-modified materials and structures (predation, bioerosion, and bioturbation); bio-built materials and structures (biofoodcaches, bioconstructions, and biostratification structures); microbial induced materials and structures; and biotools. All types of biogenic production have examples in the sedimentary record.

The sequential extraction routes of biogenic materials from sewage sludge (SS) were investigated. Physical methods (ultrasound, heating) and chemical methods (sodium hydroxide, sodium carbonate) were used to extract extracellular polymeric substances (EPS) and alginate-like extracellular polymers (ALEs) from SS. The residues after extraction were further subjected to physical methods (heating) and chemical methods (sulfuric acid, sodium hydroxide) for protein extraction. A comparison was made between sequential extraction routes and direct extraction of biomaterials from sludge in terms of extraction quantity, material properties, and applicability. The results showed that sequential extraction of biomaterials is feasible. The highest extraction quantities were obtained when using sodium carbonate for EPS and ALE extraction and sodium hydroxide for protein, reaching 449.80 mg/gVSS, 109.78 mg/gVSS, and 5447.08 mg/L, respectively. Sequential extraction procedures facilitate the extraction of biomaterials. Finally, suitable extraction methods for different application scenarios were analyzed.

This study examines carbohydrates, amino acids, and lipids as important contributors to organic carbon (OC) in the tropical Atlantic Ocean at the Cape Verde Atmospheric Observatory (CVAO). The above compounds were measured in both surface seawater and in ambient sub-micron aerosol particles to investigate their sea-to-air transfer, including their enrichment in the sea surface microlayer (SML), potential atmospheric in situ formation or degradation, and their oceanic contribution to the ambient marine aerosol particles. In bulk seawater and the SML, similar distributions among species were found for the lipids and carbohydrates with moderate SML enrichments (enrichment factors EFSML = 1.3 ± 0.2 and 1.1 ± 0.5 respectively). In contrast, the amino acids exhibited a higher enrichment in the SML with an average EFSML of 2.3 ± 0.4, although they are less surface-active than lipids. The same compounds studied in the seawater were found on the ambient sub-micron aerosol particles, whereas the lipids' enrichment was more pronounced (EFaer.=1.6×105) compared to the amino acids and carbohydrates (EFaer.=1.5×103 and 1.3×103 respectively), likely due to their high surface activity and/or the lipophilic character. Detailed molecular analysis of the seawater and aerosol particles revealed changes in the relative abundance of the individual organic compounds. They were most pronounced for the amino acids and are likely related to an in situ atmospheric processing by biotic and/or abiotic reactions. On average, 49 % of the OC on the aerosol particles (=∧97 ng m−3) could be attributed to the specific components or component groups investigated in this study. The majority (43 %) was composed of lipids. Carbohydrates and amino acids made up less than 1 % of the OC. This shows that carbohydrates, at least when resolved via molecular measurements of single sugars, do not comprise a very large fraction of OC on marine aerosol particles, in contrast to other studies. However, carbohydrate-like compounds are also present in the high lipid fraction (e.g. as glycolipids), but their chemical composition could not be revealed by the measurements performed here. Previously determined OC components at the CVAO, specifically amines, oxalic acid, and carbonyls, comprised an OC fraction of around 6 %. Since the identified compounds constituted about 50 % of the OC and belong to the rather short-lived biogenic material probably originating from the surface ocean, a pronounced coupling between ocean and atmosphere was indicated for this oligotrophic region. The remaining, non-identified OC fraction might in part contain recalcitrant OC; however, this fraction does not constitute the vast majority of OC in the aerosol particles investigated here.

The copper-nickel(-platinum-group element) sulfide resources of the Duluth Complex, Minnesota, USA, formed by assimilation of sulfur from the Virginia Formation black shale. In the normal black shale of the Virginia Formation, sulfur is mainly hosted in disseminated pyrite, whereas mm-scale pyrrhotite laminae dominate in the sulfur-rich Bedded Pyrrhotite Unit. The Bedded Pyrrhotite Unit was the main supply of sulfur in some of the magmatic sulfide deposits but its origin has not been studied in detail. Using Raman spectroscopy, we show that the carbonaceous material within the regionally metamorphosed normal black shale is graphitized biogenic material. The Bedded Pyrrhotite Unit contains pyrobitumen that represents residues of oil that accumulated to porous horizons, which formed due to dissolution of precursor sedimentary clasts. Replacement of the clasts by quartz and sulfides facilitated the formation of the pyrrhotite laminae of the Bedded Pyrrhotite Unit, which likely occurred during regional metamorphism. The pyrite-bearing normal black shale experienced loss of H 2 O, C org , and sulfur during devolatilization caused by the Duluth Complex. The contact-metamorphosed Bedded Pyrrhotite Unit shows no systematic depletion of volatiles and is the most C org and sulfur-rich part of the Virginia Formation. During devolatilization, sulfur was preserved because unlike pyrite, pyrrhotite was stable. Consequently, magmatic assimilation of sulfur from the Bedded Pyrrhotite Unit required partial melting. Retrograde hydration introduced H 2 O, and possibly C org , and sulfur, to the contact-metamorphosed Bedded Pyrrhotite Unit, which further affected the volatile budget. Our findings highlight why constraining diagenetic and regional metamorphic processes is important to understand magma-sediment interaction processes.

Biogenic varves as well as the biogenic component of clastic–biogenic varves have great potential as climate and environmental proxies but the response of biogenic lamina thickness to variations in growing-season climate is not well known. The connection of biogenic lamina thickness with growing-season or open-water season climate has been the focus of a limited number of studies. We examined biogenic laminae deposited during the past 100 years in five Finnish lakes representing different catchment types. We compared variations in biogenic lamina thicknesses with growing-season temperature records and open-water-season precipitation records. Statistical analyses for the whole study period reveal that the studied lakes generally respond positively to variations in growing-season temperature and open-water season precipitation. This suggests that warm summers intensify primary production while precipitation enhances transportation of allochthonous biogenic material and nutrients into the lake. Both mechanisms lead to enhanced biogenic lamina thickness. Two lakes reveal a more complex relationship to climate. Biogenic lamina thicknesses record a distinguishable climate signal despite human activities in the catchments, such as peatland drainage and forest cutting. We conclude that variations in biogenic lamina thickness of such boreal (clastic)–biogenic varves show potential for growing-season climate reconstructions. However, the response of each lake to climate parameters should be tested and understood separately.

Tubular fossils are a unique metazoan group emerging in the late Ediacaran Period and demonstrating early skeletogenesis and an increase in the diversity of early biocommunities. Among the known records, Sinotubulites is widely distributed and distinct in morphology and ultrastructure, holding important evolutionary and stratigraphic significance comparable to the well-known Cloudina. However, its biological affinity remains unclear until now. Among various reasons, taphonomic bias is one of the major factors responsible for this, as it not only altered the primary morphology but also modified the ultrastructure and composition of the fossil. Thus, a further study on its taphonomic process would help to decode the biological affinity of Sinotubulites. For this purpose, we conducted a taphonomic study on Sinotubulites from the top of the Shibantan Member of the Dengying Formation at the Zhongling section in the Yangtze Gorges area (Hubei Province, China). We applied electron backscatter diffraction (EBSD) and cathodoluminescence (CL) to reveal its mineralogical features. EBSD and CL analyses demonstrate that both the fossils and matrix are composed of unoriented calcite, and the matrix shows slight dolomitization with sporadic dolomite grains. The calcite crystals within the Sinotubulites tubes are significantly larger than those in the matrix, indicating that the tubular structure provided sufficient space for crystal growth. The absence of lamellar structures in the tubular walls further suggests that the original biogenic material may have been dissolved during diagenetic calcification. The absence of dolomitization in the fossils indicates that this process may have been inhibited by either their large calcite crystals or the enclosed space confined by the outer shell. The identical non-luminescent features of the matrix and fossils suggest that their calcification likely occurred during the same stage. This study demonstrates that taphonomic biases must be accounted for when analyzing the original structure and composition. Additionally, this research documents the occurrence of Sinotubulites in the Shibantan Member, representing its lowest stratigraphic horizon in the Yangtze Block.

Experiments conducted in the olivine–serpentine–anthracene–metal (FeNi) system have shown that the recrystallization of olivines occurs under substantially reduced conditions with active participation of hydrocarbons, especially paraffins; moreover, their amount increases with increasing pressure and temperature. During the decomposition of serpentine, a large amount of water is released; therefore, the fluid at relatively low P-T parameters (2 GPa, 1100 °C) has mainly water–hydrocarbon composition. With an increase in pressure up to 3–4.5 GPa and temperature up to 1300–1400 °C, the composition of the fluid changes greatly towards an increase in the relative amount of hydrocarbons, while the main share is occupied by light (C1–C4) aliphatic hydrocarbons. Therefore, a biogenic material with a carbon–hydrogen composition can make a certain contribution to the carbon budget in subduction processes when falling into the subduction zones and may affect the oxygen fugitivity in the subducted slab.

Strontium isotope ratios (87Sr ∕ 86Sr) of biogenic material such as bones and teeth reflect the local sources of strontium ingested as food and drink during their formation. This has led to the use of strontium isotope ratios as a geochemical tracer in a wide range of fields including archaeology, ecology, food studies and forensic sciences. In order to utilise strontium as a geochemical tracer, baseline data of bioavailable 87Sr ∕ 86Sr in the region of interest are required, and a growing number of studies have developed reference maps for this purpose in various geographic regions, and over varying scales. This study presents a new data set of bioavailable strontium isotope ratios from rock and soil samples across Israel, as well as from sediment layers from seven key archaeological sites. This data set may be viewed and accessed both in an Open Science Framework repository (https://doi.org/10.17605/OSF.IO/XKJ5Y, Moffat et al., 2020) or via the IRHUM (Isotopic Reconstruction of Human Migration) database.

To assess the effects of dust deposition on the strength of the biological pump in the Mediterranean Sea by acting as fertilizer and/or ballasting agent, we analyzed fluxes of mineral dust, particulate organic carbon (POC) and inorganic carbon (PIC), and source-specific lipid biomarkers (i.e., higher plant-derived long-chain fatty acids and phytoplankton-derived alkenones, C 30 1,15 diols, and sterols) in sinking particles. Sinking particles were collected at ten-day intervals by a sediment-trap mooring deployed in the Ionian Basin from April 2017 to May 2018 at 2340 m water depth. High POC fluxes occur during summer, when surface ocean primary production is lowest due to thermal stratification. Notably, these high POC fluxes coincide with pulses of substantial dust deposition, suggesting that POC export is primarily driven by dust deposition and subsequent ballasting. However, the lipid composition, and thereby that of the phytoplankton community, differs between dust events. (Seasonal) variations in the properties of the deposited dust, presumably associated with its provenance, likely control the effect of dust deposition on phytoplankton response and export in the Ionian Basin. Although POC export is associated with dust deposition, the net effect of dust deposition on the biological pump is more ambiguous as not all dust events are associated with an increase in POC export, and most dust events are also associated with PIC export that has a counteracting effect on the biological pump. Multi-year time series of dust deposition and biogenic export are required to validate the seasonal variations in dust-driven export of biogenic material observed here, and to account for effects of interannual variations in dust fluxes and phytoplankton production on the strength of the biological pump.

Late Holocene sediments have been recovered in a core from the central Chukchi Sea to reconstruct their accumulation conditions. The sediments consist mainly of terrigenous and just partly of biogenic material. Fine sand is dominated by up to 99.8% light fraction minerals, whereas heavy minerals account for not more than 1.4%. Results of magnetic susceptibility, related to the sand and heavy mineral content, decrease from the bottom to the top of the core. The species composition of pollen spectra varies insignificantly throughout the core and, on the whole, reflects the modern vegetation of the Chukchi Sea coast. The increased number of cysts of dinoflagellates and other aquatic palynomorphs, as well as some increased content of coarse-grained material at the upper part of the sediment core, is presumably caused by recent climate warming conditions. Two peaks of 137 Cs activity at the 7.5 and 1.5 cm in the core are related to radioactive fallout, caused by the accidents at the Chernobyl nuclear power plant in 1986 and the Fukushima nuclear power plant in 2011. The resulting sedimentation rates of 2.5–3 mm/yr correspond well to rates of sedimentation determined by 210 Pb dating (2.0 mm/yr).