Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean: a stable isotope approach DOI Creative Commons
Anna Belcher, Sian F. Henley, Katharine Hendry

et al.

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(16), P. 3573 - 3591

Published: Aug. 25, 2023

Abstract. The biological carbon pump is responsible for much of the decadal variability in ocean dioxide (CO2) sink, driving transfer from atmosphere to deep ocean. A mechanistic understanding ecological drivers particulate organic (POC) flux key both assessment magnitude CO2 sink and accurate predictions as how this will change with changing climate. This particularly important Southern Ocean, a region uptake supply nutrients global thermocline. In study we examine sediment-trap-derived particle fluxes stable isotope signatures (C), nitrogen (N), biogenic silica (BSi) at site biologically productive waters northern Scotia Sea Ocean. Both (2000 m) shallow (400 sediment traps exhibited two main peaks POC, N, BSi flux: one austral spring summer, reflecting periods high surface productivity. Particulate isotopic compositions were similar traps, highlighting that most remineralisation occurred upper 400 m water column. Differences seasonal cycles C, Si provide insights into degree coupling these nutrients. We measured increasing enrichment POC spring, consistent fractionation during uptake. Since observed isotopically light material suggest physically mediated replenishment lighter isotopes depth, enabling full expression associated nutrient regimes, indicated by different summer periods, suggests source reaching shifts phytoplankton community structure. This, combined occurrence advective inputs certain times year, highlights need make synchronous measurements physical processes improve our ability track changes regions sinking material. also highlight conduct particle-specific (e.g. faecal pellets, detritus, zooplankton moults) analysis use tool assessing composition develop biogeochemical fluxes.

Language: Английский

Oxygen isotope ensemble reveals Earth’s seawater, temperature, and carbon cycle history DOI
Terry T. Isson, Sofia Rauzi

Science, Journal Year: 2024, Volume and Issue: 383(6683), P. 666 - 670

Published: Feb. 8, 2024

Earth's persistent habitability since the Archean remains poorly understood. Using an oxygen isotope ensemble approach-comprising shale, iron oxide, carbonate, silica, and phosphate records-we reconcile a multibillion-year history of seawater δ

Language: Английский

Citations

20
Active Silica Diagenesis in the Deepest Hadal Trench Sediments DOI Open Access
Min Luo,

Weiding Li,

Sonja Geilert

et al.

Geophysical Research Letters, Journal Year: 2022, Volume and Issue: 49(14)

Published: July 19, 2022

Abstract Porewater dissolved silicic acid (DSi) concentrations and stable Si isotope compositions (δ 30 Si) together with biogenic silica (bSiO 2 ) contents of sediments in five sediment cores collected from the southern Mariana Trench are presented. These data suggest occurrence bSiO dissolution concomitant authigenic clay formation three ‐bearing cores. A reaction‐transport model constrained by measured geochemical was applied to quantify rates turnover. Model results predicted greatest both at trench axis core that displayed low abundant detrital materials, suggesting materials may be a limiting factor for diagenesis. further ∼40%–70% DSi generated is consumed formation. This first study demonstrates active diagenesis hadal realm has implications understanding benthic cycling deep‐sea settings.

Language: Английский

Citations

17
Impact of Diagenesis on Biogenic Silica‐ Structural, Chemical, and Isotope Proxies DOI Creative Commons
Franziska M. Stamm, Rebecca A. Pickering, Patrick Frings

et al.

Journal of Geophysical Research Biogeosciences, Journal Year: 2025, Volume and Issue: 130(2)

Published: Feb. 1, 2025

Abstract The silicon isotope composition (δ 30 Si) of biogenic silica is often used as an archive past environmental conditions. For example, sponge spicule δ Si known to be related seawater‐dissolved concentrations. Such a proxy application requires that the not diagenetically altered—or at least any alteration can identified and accounted for. Yet preservation pristine signals during (early) diagenesis challenged by observations structural changes amorphous (opal‐A) toward more stable phase (opal‐CT). This transformation associated with resetting oxygen 18 O) values but unclear implications for other geochemical signatures. was investigated using modern Cretaceous siliceous spicules. Modern spicules collected from different ocean basins were uniformly transparent opal‐A, whereas exhibited two states: visually similar or clearly altered milky, translucent composition. A comparison O both categories within single samples reveals individuals are offset thus presumably unsuitable palaeoenvironmental applications. suite analyses (XRD, Raman spectroscopy, FT‐IR spectroscopy) demonstrate even clear subtly their counterparts, implying caution required when interpreting proxies in ancient silica.

Language: Английский

Citations

0
Silicate Weathering and Diagenetic Reaction Balances in Deltaic Muds DOI
Gerrit Müller, Robert C. Aller, Appy Sluijs

et al.

American Journal of Science, Journal Year: 2025, Volume and Issue: unknown

Published: May 19, 2025

Reactions between terrigenous sediments, marine-biogenic substances and seawater modulate multiple biogeochemical cycles, but the dynamics factors governing these reactions are poorly constrained. Deltaic mobile muds a major sedimentary facies along river-dominated ocean margins through which most sediment transits mixes with matter, representing efficient globally significant batch reactors. Here, we present process-based model that combines equilibrium aqueous chemistry kinetic concepts from biogeochemistry mineral sciences to explore solution-mediated interplay of organic inorganic matter alteration in episodically reworked deltaic muds. The reproduces observed diagenetic conditions product suites over seasonal timescales relevant systems indicates systematic dynamic coupling cycles H + , C, P, Fe, S, Si, Mg, K, Ca. We used combination published field observations authigenic occurrences develop generalized explanatory framework for silicate weathering fluxes reaction balances marine sediments. Diagenetic is represented by continuum acid (reverse) alkaline (forward) endmembers moderated sources, determine sediment’s potential depositional environments, govern expression this potential. Reverse dominates seasonally reworked, low-latitude muds, where green clays form rapidly lateritic river sediments biogenic silica under suboxic conditions. High precipitation rates protracted remobilization drive large solute from/to Net forward becomes more likely steady, sustained anoxic conditions, particularly volcanically-influenced settings at minimal pre-weathering sources. These results further our understanding role play global Earth system evolution, can aid targeted ‘enhanced weathering’ strategies environmental governance.

Language: Английский

Citations

0
Upwelling-driven biogenic silica accumulation in the Yangtze Sea, South China during Late Ordovician to Early Silurian time: A possible link with the global climatic transitions DOI
Bowen Zan,

Chuanlong Mou,

Gary G. Lash

et al.

Sedimentary Geology, Journal Year: 2024, Volume and Issue: 461, P. 106571 - 106571

Published: Jan. 8, 2024

Language: Английский

Citations

3
Diatom silicon isotope ratios in Quaternary research: Where do we stand? DOI Creative Commons
Patrick Frings, Virginia N. Panizzo, Jill Sutton

et al.

Quaternary Science Reviews, Journal Year: 2024, Volume and Issue: 344, P. 108966 - 108966

Published: Sept. 16, 2024

Language: Английский

Citations

3
Tools to trace past productivity and ocean nutrients DOI
Jesse R. Farmer, Jennifer S. Fehrenbacher, Tristan J. Horner

et al.

Elsevier eBooks, Journal Year: 2024, Volume and Issue: unknown, P. 111 - 151

Published: July 2, 2024

Language: Английский

Citations

2
Silicon isotopes reveal the impact of fjordic processes on the transport of reactive silicon from glaciers to coastal regions DOI Creative Commons
Tong Wang, Hong Chin Ng, Jade E. Hatton

et al.

Chemical Geology, Journal Year: 2024, Volume and Issue: 670, P. 122403 - 122403

Published: Sept. 11, 2024

Language: Английский

Citations

1
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean: a stable isotope approach DOI Creative Commons
Anna Belcher, Sian F. Henley, Katharine Hendry

et al.

Biogeosciences, Journal Year: 2023, Volume and Issue: 20(16), P. 3573 - 3591

Published: Aug. 25, 2023

Abstract. The biological carbon pump is responsible for much of the decadal variability in ocean dioxide (CO2) sink, driving transfer from atmosphere to deep ocean. A mechanistic understanding ecological drivers particulate organic (POC) flux key both assessment magnitude CO2 sink and accurate predictions as how this will change with changing climate. This particularly important Southern Ocean, a region uptake supply nutrients global thermocline. In study we examine sediment-trap-derived particle fluxes stable isotope signatures (C), nitrogen (N), biogenic silica (BSi) at site biologically productive waters northern Scotia Sea Ocean. Both (2000 m) shallow (400 sediment traps exhibited two main peaks POC, N, BSi flux: one austral spring summer, reflecting periods high surface productivity. Particulate isotopic compositions were similar traps, highlighting that most remineralisation occurred upper 400 m water column. Differences seasonal cycles C, Si provide insights into degree coupling these nutrients. We measured increasing enrichment POC spring, consistent fractionation during uptake. Since observed isotopically light material suggest physically mediated replenishment lighter isotopes depth, enabling full expression associated nutrient regimes, indicated by different summer periods, suggests source reaching shifts phytoplankton community structure. This, combined occurrence advective inputs certain times year, highlights need make synchronous measurements physical processes improve our ability track changes regions sinking material. also highlight conduct particle-specific (e.g. faecal pellets, detritus, zooplankton moults) analysis use tool assessing composition develop biogeochemical fluxes.

Language: Английский

Citations

3