Rates of peptide bond hydrolysis and other diagenetic reactions are not favourable for Mesozoic p... more Rates of peptide bond hydrolysis and other diagenetic reactions are not favourable for Mesozoic protein survival. Proteins hydrolyse into peptide fragments and free amino acids that, in open systems such as bone, can leach from the specimen and be further degraded. However, closed systems are more likely to retain degradation products derived from endogenous proteins. Amino acid racemisation data in experimental and subfossil material suggests that mollusc shell and avian eggshell calcite crystals can demonstrate closed system behaviour, retaining endogenous amino acids. Here, high-performance liquid chromatography reveals that the intra-crystalline fraction of Late Cretaceous (estimated ~80 Ma) titanosaur sauropod eggshell is enriched in some of the most stable amino acids (Glx, Gly, Ala, and possibly Val) and those that racemise are fully racemic, despite being some of the slowest racemising amino acids. These results are consistent with degradation trends deduced from modern, the...
Organic systems, integrated crop–livestock systems (ICL) and leys are posited as strategies to in... more Organic systems, integrated crop–livestock systems (ICL) and leys are posited as strategies to increase soil carbon (C) stocks. However, previous studies have: (i) only considered one driver of change; (ii) evaluated soil C content instead of stocks; (iii) been limited to the 0.20 m depth; (iv) used short‐term leys; and (v) rarely assessed the distribution of C among soil organic matter (SOM) fractions, which relates to C stabilization. The aim of this study was to investigate the impact of conventional vs. organic agricultural systems, grazing regimes (non‐grazed vs. grazed) and different proportions of temporary grass‐clover leys in crop rotations (ley time proportion – LTP) on soil C stocks and C distribution among SOM fractions down to 0.60 m soil depth. SOM fractions assessed were particulate organic matter (POM > 53 μm), heavy fraction (HF > 53 μm) and mineral‐associated silt and clay fraction (SC < 53 μm). There were no differences in soil C stocks between the conven...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2020
The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanograp... more The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanographic conditions and extensive sea ice loss, which can lead to large, yet unquantified disruptions to ecosystem functioning. This key region hosts a large fraction of Arctic primary productivity. However, processes governing benthic and pelagic coupling are not mechanistically understood, limiting our ability to predict the impacts of future perturbations. We combine field observations with a reaction-transport model approach to quantify organic matter (OM) processing and disentangle its drivers. Sedimentary OM reactivity patterns show no gradients relative to sea ice extent, being mostly driven by seafloor spatial heterogeneity. Burial of high reactivity, marine-derived OM is evident at sites influenced by Atlantic Water (AW), whereas low reactivity material is linked to terrestrial inputs on the central shelf. Degradation rates are mainly driven by aerobic respiration (40–75%), being gre...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2020
Process-based, mechanistic investigations of organic matter transformation and diagenesis directl... more Process-based, mechanistic investigations of organic matter transformation and diagenesis directly beneath the sediment–water interface (SWI) in Arctic continental shelves are vital as these regions are at greatest risk of future change. This is in part due to disruptions in benthic–pelagic coupling associated with ocean current change and sea ice retreat. Here, we focus on a high-resolution, multi-disciplinary set of measurements that illustrate how microbial processes involved in the degradation of organic matter are directly coupled with inorganic and organic geochemical sediment properties (measured and modelled) as well as the extent/depth of bioturbation. We find direct links between aerobic processes, reactive organic carbon and highest abundances of bacteria and archaea in the uppermost layer (0–4.5 cm depth) followed by dominance of microbes involved in nitrate/nitrite and iron/manganese reduction across the oxic-anoxic redox boundary (approx. 4.5–10.5 cm depth). Sulfate re...
Soil quality (SQ) is the ability of soil to provide ecosystem functions and services. Implementat... more Soil quality (SQ) is the ability of soil to provide ecosystem functions and services. Implementation of a certain agricultural system can affect SQ and therefore play an essential role in achieving sustainable agriculture. The aim of this study was to explore how agricultural systems (conventional vs. organic), grazing regime (non‐grazed vs. grazed) and the different proportions of temporary grass‐clover leys in crop rotations (ley time proportion, LTP) affect SQ within a mixed (cropping and pasture/dairy system) commercial farming enterprise in the UK. Seven SQ indicators were evaluated, including chemical (pH; available phosphorus (P); potassium (K)), physical (bulk density, BD; aggregate stability, AS) and biological (total carbon (C); microbial biomass carbon, MBC) sectors. All SQ indicators were measured at three depth intervals (0–0.15, 0.15–0.30, 0.30–0.60 m), except for AS and MBC, which were only considered for the topsoil (0–0.15 m). The findings reflected existing knowled...
Fossils were long thought to lack original organic material, but the discovery of organic molecul... more Fossils were long thought to lack original organic material, but the discovery of organic molecules in fossils and sub-fossils, thousands to millions of years old, has demonstrated the potential of fossil organics to provide radical new insights into the fossil record. How long different organics can persist remains unclear, however. Non-avian dinosaur bone has been hypothesised to preserve endogenous organics including collagen, osteocytes, and blood vessels, but proteins and labile lipids are unstable during diagenesis or over long periods of time. Furthermore, bone is porous and an open system, allowing microbial and organic flux. Some of these organics within fossil bone have therefore been identified as either contamination or microbial biofilm, rather than original organics. Here, we use biological and chemical analyses of Late Cretaceous dinosaur bones and sediment matrix to show that dinosaur bone hosts a diverse microbiome. Fossils and matrix were freshly-excavated, aseptic...
Fossils were thought to lack original organic molecules, but chemical analyses show that some can... more Fossils were thought to lack original organic molecules, but chemical analyses show that some can survive. Dinosaur bone has been proposed to preserve collagen, osteocytes, and blood vessels. However, proteins and labile lipids are diagenetically unstable, and bone is a porous open system, allowing microbial/molecular flux. These ‘soft tissues’ have been reinterpreted as biofilms. Organic preservation versus contamination of dinosaur bone was examined by freshly excavating, with aseptic protocols, fossils and sedimentary matrix, and chemically/biologically analyzing them. Fossil ‘soft tissues’ differed from collagen chemically and structurally; while degradation would be expected, the patterns observed did not support this. 16S rRNA amplicon sequencing revealed that dinosaur bone hosted an abundant microbial community different from lesser abundant communities of surrounding sediment. Subsurface dinosaur bone is a relatively fertile habitat, attracting microbes that likely utilize i...
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2016
The solar system contains large quantities of organic compounds that can form complex molecular s... more The solar system contains large quantities of organic compounds that can form complex molecular structures. The processing of organic compounds by biological systems leads to molecules with distinctive structural characteristics; thus, the detection and characterization of organic materials could lead to a high degree of confidence in the existence of extra-terrestrial life. Given the nature of the surface of most planetary bodies in the solar system, evidence of life is more likely to be found in the subsurface where conditions are more hospitable. Basalt is a common rock throughout the solar system and the primary rock type on Mars and Earth. Basalt is therefore a rock type that subsurface life might exploit and as such a suitable material for the study of methods required to detect and analyze organic material in rock. Telluric basalts from Earth represent an analog for extra-terrestrial rocks where the indigenous organic matter could be analyzed for molecular biosignatures. This...
The soils beneath the rainforest of Guyana have the potential to hold, and release, large stores ... more The soils beneath the rainforest of Guyana have the potential to hold, and release, large stores of carbon under land use and climate change. Little is known about soil carbon stocks or molecular dynamics in this region. This study therefore aims to elucidate differences in the molecular (lignin and tannin) and bulk soil organic carbon (SOC) stocks in different ‘sub-environments’ along a rainforest-savannah boundary, setting a framework for further investigation into the soil carbon dynamics of the region. Bulk SOC analysis shows that Gleysols have the highest stocks, particularly those under rainforest vegetation (swamp and island forests surrounded by savannah), whereas Plinthosols have significantly lower SOC stocks. Texture and soil water content analysis indicates that predominantly clay soils play a role in high SOC stocks, whilst predominantly sandy soils prevent SOC stocks from accumulating. Clay and sand are present in both Gleysols and Plinthosols, to different extents. An...
Rates of peptide bond hydrolysis and other diagenetic reactions are not favourable for Mesozoic p... more Rates of peptide bond hydrolysis and other diagenetic reactions are not favourable for Mesozoic protein survival. Proteins hydrolyse into peptide fragments and free amino acids that, in open systems such as bone, can leach from the specimen and be further degraded. However, closed systems are more likely to retain degradation products derived from endogenous proteins. Amino acid racemisation data in experimental and subfossil material suggests that mollusc shell and avian eggshell calcite crystals can demonstrate closed system behaviour, retaining endogenous amino acids. Here, high-performance liquid chromatography reveals that the intra-crystalline fraction of Late Cretaceous (estimated ~80 Ma) titanosaur sauropod eggshell is enriched in some of the most stable amino acids (Glx, Gly, Ala, and possibly Val) and those that racemise are fully racemic, despite being some of the slowest racemising amino acids. These results are consistent with degradation trends deduced from modern, the...
Organic systems, integrated crop–livestock systems (ICL) and leys are posited as strategies to in... more Organic systems, integrated crop–livestock systems (ICL) and leys are posited as strategies to increase soil carbon (C) stocks. However, previous studies have: (i) only considered one driver of change; (ii) evaluated soil C content instead of stocks; (iii) been limited to the 0.20 m depth; (iv) used short‐term leys; and (v) rarely assessed the distribution of C among soil organic matter (SOM) fractions, which relates to C stabilization. The aim of this study was to investigate the impact of conventional vs. organic agricultural systems, grazing regimes (non‐grazed vs. grazed) and different proportions of temporary grass‐clover leys in crop rotations (ley time proportion – LTP) on soil C stocks and C distribution among SOM fractions down to 0.60 m soil depth. SOM fractions assessed were particulate organic matter (POM > 53 μm), heavy fraction (HF > 53 μm) and mineral‐associated silt and clay fraction (SC < 53 μm). There were no differences in soil C stocks between the conven...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2020
The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanograp... more The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanographic conditions and extensive sea ice loss, which can lead to large, yet unquantified disruptions to ecosystem functioning. This key region hosts a large fraction of Arctic primary productivity. However, processes governing benthic and pelagic coupling are not mechanistically understood, limiting our ability to predict the impacts of future perturbations. We combine field observations with a reaction-transport model approach to quantify organic matter (OM) processing and disentangle its drivers. Sedimentary OM reactivity patterns show no gradients relative to sea ice extent, being mostly driven by seafloor spatial heterogeneity. Burial of high reactivity, marine-derived OM is evident at sites influenced by Atlantic Water (AW), whereas low reactivity material is linked to terrestrial inputs on the central shelf. Degradation rates are mainly driven by aerobic respiration (40–75%), being gre...
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences, 2020
Process-based, mechanistic investigations of organic matter transformation and diagenesis directl... more Process-based, mechanistic investigations of organic matter transformation and diagenesis directly beneath the sediment–water interface (SWI) in Arctic continental shelves are vital as these regions are at greatest risk of future change. This is in part due to disruptions in benthic–pelagic coupling associated with ocean current change and sea ice retreat. Here, we focus on a high-resolution, multi-disciplinary set of measurements that illustrate how microbial processes involved in the degradation of organic matter are directly coupled with inorganic and organic geochemical sediment properties (measured and modelled) as well as the extent/depth of bioturbation. We find direct links between aerobic processes, reactive organic carbon and highest abundances of bacteria and archaea in the uppermost layer (0–4.5 cm depth) followed by dominance of microbes involved in nitrate/nitrite and iron/manganese reduction across the oxic-anoxic redox boundary (approx. 4.5–10.5 cm depth). Sulfate re...
Soil quality (SQ) is the ability of soil to provide ecosystem functions and services. Implementat... more Soil quality (SQ) is the ability of soil to provide ecosystem functions and services. Implementation of a certain agricultural system can affect SQ and therefore play an essential role in achieving sustainable agriculture. The aim of this study was to explore how agricultural systems (conventional vs. organic), grazing regime (non‐grazed vs. grazed) and the different proportions of temporary grass‐clover leys in crop rotations (ley time proportion, LTP) affect SQ within a mixed (cropping and pasture/dairy system) commercial farming enterprise in the UK. Seven SQ indicators were evaluated, including chemical (pH; available phosphorus (P); potassium (K)), physical (bulk density, BD; aggregate stability, AS) and biological (total carbon (C); microbial biomass carbon, MBC) sectors. All SQ indicators were measured at three depth intervals (0–0.15, 0.15–0.30, 0.30–0.60 m), except for AS and MBC, which were only considered for the topsoil (0–0.15 m). The findings reflected existing knowled...
Fossils were long thought to lack original organic material, but the discovery of organic molecul... more Fossils were long thought to lack original organic material, but the discovery of organic molecules in fossils and sub-fossils, thousands to millions of years old, has demonstrated the potential of fossil organics to provide radical new insights into the fossil record. How long different organics can persist remains unclear, however. Non-avian dinosaur bone has been hypothesised to preserve endogenous organics including collagen, osteocytes, and blood vessels, but proteins and labile lipids are unstable during diagenesis or over long periods of time. Furthermore, bone is porous and an open system, allowing microbial and organic flux. Some of these organics within fossil bone have therefore been identified as either contamination or microbial biofilm, rather than original organics. Here, we use biological and chemical analyses of Late Cretaceous dinosaur bones and sediment matrix to show that dinosaur bone hosts a diverse microbiome. Fossils and matrix were freshly-excavated, aseptic...
Fossils were thought to lack original organic molecules, but chemical analyses show that some can... more Fossils were thought to lack original organic molecules, but chemical analyses show that some can survive. Dinosaur bone has been proposed to preserve collagen, osteocytes, and blood vessels. However, proteins and labile lipids are diagenetically unstable, and bone is a porous open system, allowing microbial/molecular flux. These ‘soft tissues’ have been reinterpreted as biofilms. Organic preservation versus contamination of dinosaur bone was examined by freshly excavating, with aseptic protocols, fossils and sedimentary matrix, and chemically/biologically analyzing them. Fossil ‘soft tissues’ differed from collagen chemically and structurally; while degradation would be expected, the patterns observed did not support this. 16S rRNA amplicon sequencing revealed that dinosaur bone hosted an abundant microbial community different from lesser abundant communities of surrounding sediment. Subsurface dinosaur bone is a relatively fertile habitat, attracting microbes that likely utilize i...
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 2016
The solar system contains large quantities of organic compounds that can form complex molecular s... more The solar system contains large quantities of organic compounds that can form complex molecular structures. The processing of organic compounds by biological systems leads to molecules with distinctive structural characteristics; thus, the detection and characterization of organic materials could lead to a high degree of confidence in the existence of extra-terrestrial life. Given the nature of the surface of most planetary bodies in the solar system, evidence of life is more likely to be found in the subsurface where conditions are more hospitable. Basalt is a common rock throughout the solar system and the primary rock type on Mars and Earth. Basalt is therefore a rock type that subsurface life might exploit and as such a suitable material for the study of methods required to detect and analyze organic material in rock. Telluric basalts from Earth represent an analog for extra-terrestrial rocks where the indigenous organic matter could be analyzed for molecular biosignatures. This...
The soils beneath the rainforest of Guyana have the potential to hold, and release, large stores ... more The soils beneath the rainforest of Guyana have the potential to hold, and release, large stores of carbon under land use and climate change. Little is known about soil carbon stocks or molecular dynamics in this region. This study therefore aims to elucidate differences in the molecular (lignin and tannin) and bulk soil organic carbon (SOC) stocks in different ‘sub-environments’ along a rainforest-savannah boundary, setting a framework for further investigation into the soil carbon dynamics of the region. Bulk SOC analysis shows that Gleysols have the highest stocks, particularly those under rainforest vegetation (swamp and island forests surrounded by savannah), whereas Plinthosols have significantly lower SOC stocks. Texture and soil water content analysis indicates that predominantly clay soils play a role in high SOC stocks, whilst predominantly sandy soils prevent SOC stocks from accumulating. Clay and sand are present in both Gleysols and Plinthosols, to different extents. An...
Petrification is a process, but it also can be understood as a concept. This volume takes the fir... more Petrification is a process, but it also can be understood as a concept. This volume takes the first steps to manifest, materialize or “petrify” the concept of “petrification” and turn it into a tool for analyzing material and social processes. The wide array of approaches to petrification as a process assembled here is more of a collection of possibilities than an attempt to establish a firm, law-generating theory. Divided into three parts, this volume’s twenty-plus authors explore petrification both as a theoretical concept and as a contextualized material and social process across geological, prehistoric and historic periods. Topics connecting the various papers are properties of materials, preferences and choices of actors, the temporality of matter, being and becoming, the relationality between actors, matter, things and space (landscape, urban space, built space), and perceptions of the following generations dealing with the petrified matter, practices, and social relations. Contributors to this volume study specifically whether particular processes of petrification are confined to the material world or can be seen as mirroring, following, triggering, or contradicting changes in social life and general world views. Each of the authors explores – for a period or a specific feature – practices and changes that led to increased conformity and regularity. Some authors additionally focus on the methods and scrutinize them and their applications for their potential to create objects of investigation: things, people, periods, in order to raise awareness for these or to shape or “invent” categories. This volume is of interest to archaeologists, geologists, architectural historians, conservationists, and historians.
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Topics connecting the various papers are properties of materials, preferences and choices of actors, the temporality of matter, being and becoming, the relationality between actors, matter, things and space (landscape, urban space, built space), and perceptions of the following generations dealing with the petrified matter, practices, and social relations. Contributors to this volume study specifically whether particular processes of petrification are confined to the material world or can be seen as mirroring, following, triggering, or contradicting changes in social life and general world views. Each of the authors explores – for a period or a specific feature – practices and changes that led to increased conformity and regularity. Some authors additionally focus on the methods and scrutinize them and their applications for their potential to create objects of investigation: things, people, periods, in order to raise awareness for these or to shape or “invent” categories. This volume is of interest to archaeologists, geologists, architectural historians, conservationists, and historians.