Authigenic minerals reflect microbial control on pore waters in a ferruginous analogue
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Keywords: ferruginous sediment, millerite, siderite, vivianite, magnetite, pore water geochemistry, microbial mediation, early diagenesis, Lake Towuti
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Abstract
Comprehensive pore water geochemistry, high resolution geochemical core profiles, and electron microscopy of authigenic minerals revealed in situ formation of magnetite, millerite, and abundant siderite and vivianite along a 100 m long sequence. Framboidal magnetites represent primary pelagic precipitates, whereas millerite, a sulfide mineral often overlooked under sulfate-poor conditions, shows acicular aggregates entangled with siderite and vivianite resulting from saturated pore waters and continuous growth during burial. These phases act as biosignatures of microbial iron and sulfate reduction, fermentation and methanogenesis, processes clearly traceable in pore water profiles.
Variability in metal and organic substrates attests to environment driven processes, differentially sustaining microbial processes along the stratigraphy. Geochemical profiles resulting from microbial activity over 200 kyr after deposition provide constraints on the depth and age of mineral formation within ferruginous records.
Figures
 Figure 1 Site description of Lake Towuti. (a) World map displaying the location of Sulawesi Island, with close up on the Indonesia archipelago and location of the Malili Lake System. (b) Map of Sulawesi illustrating the (ultra)mafic and lateritic geology of the Malili Lake catchment. (c) Bathymetric map of Lake Towuti with position of drill site TDP-1A (156 m water depth), dissolved oxygen, iron, sulfate and pH profiles of Lake Towuti’s water column (Bauer et al., 2020), and gravity cores retrieved from 60 and 200 m water depth illustrating redox conditions at the water-sediment interface. |  Figure 2 EDX point analyses and SEM images of diagenetic minerals. (Top) Ternary plots show: (a) magnetites and coextracted iron oxides (goethite, wüstite), (b) millerites with incorporation of Fe2+ traces, (c) siderites and (d) vivianites with substitution of Mn2+ for Fe2+. Smelter particles represent airborne contaminants from the nearby mine. (Bottom) (a) Magnetites in framboidal habits; (b) millerites in acicular spherules and aggregates, sometimes entangled and overgrown by siderites; (c) siderites aggregating into twins and mosaic monocrystals; and (d) vivianites in tabular habit developing into rosettes. The crystal section shows inclusions of millerite and siderite. |  Figure 3 Depth profiles for pore water geochemistry and stability diagrams for Fe-bearing phases. (a) Lithology of Lake Towuti’s upper 25 mblf including tephras (T) and vivianites (V); potential sulfate reduction rates (SRR); pore water concentrations for sulfate, ferrous iron, manganese, arsenic, cobalt, nitrate, ammonium, phosphate, formate, acetate, lactate, butyrate, methane, dissolved inorganic carbon (DIC), pore water pH, calcium, magnesium, potassium and sodium. Data points represent averaged triplicates (reproducibility <5 %). The dotted line signifies the base of the 14C ages, i.e. 44.7 ka (Russell et al., 2020). (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005), respectively. |  Figure 4 Depth profiles for bulk sediment, and pore water geochemistry. (Left to right) Stratigraphy of site TDP-1A with tephras (T) and vivianites (V); XRF core scanning profiles for Ni, S, Fe, Mn and P in bulk sediment overlain by pore water concentrations for SO42−, Fe2+, Mn2+ and PO43−; siderite concentration based on coulometry; total organic carbon (TOC). XRF core scanning profiles represent point analyses with moving averages at 5 mm and 2 cm resolution, respectively. Data points represent averaged triplicates (reproducibility <5 %). |
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Introduction
Ferruginous conditions (iron-rich, sulfate-poor) were widespread in the Archean and Proterozoic oceans and resulted in the deposition of ancient iron formations (Canfield et al., 2008
Canfield, D.E., Poulton, S.W., Knoll, A.H., Narbonne, G.M., Ross, G., Goldberg, T., Strauss, H. (2008) Ferruginous Conditions Dominated Later Neoproterozoic Deep-Water Chemistry. Science 321, 949–952. https://doi.org/10.1126/science.1154499
). Precambrian iron formations are composed of diverse iron oxides and carbonates thought to have formed as primary pelagic precipitates from the recrystallisation of ferric-ferrous iron (oxyhydr)oxides (Halevy et al., 2017Halevy, I., Alesker, M., Schuster, E.M., Popovitz-Biro, R., Feldman, Y. (2017) A key role for green rust in the Precambrian oceans and the genesis of iron formations. Nature Geoscience 10, 135–139. https://doi.org/10.1038/ngeo2878
). Sulfides are also occasionally reported to occur, but only in minor quantities due to the scarcity of seawater sulfate at the time (Fakhraee et al., 2019Fakhraee, M., Hancisse, O., Canfield, D.E., Crowe, S.A., Katsev, S. (2019) Proterozoic seawater sulfate scarcity and the evolution of ocean–atmosphere chemistry. Nature Geoscience 12, 375–380. https://doi.org/10.1038/s41561-019-0351-5
). Although the Proterozoic Earth was an essentially microbial world, mineral phases precipitated by microbial biogeochemical cycling of iron, sulfur and carbon remain poorly constrained in terms of early diagenetic imprints prior to sediment lithification (Posth et al., 2014Posth, N.R., Canfield, D.E., Kappler, A. (2014) Biogenic Fe(III) minerals: From formation to diagenesis and preservation in the rock record. Earth-Science Reviews 135, 103–121. https://doi.org/10.1016/j.earscirev.2014.03.012
). Characterising and identifying such mineral phases is therefore paramount in order to employ their signatures as recorders of past ferruginous environments and as tracers of microbial processes of the Earth’s early oceans (Tosca et al., 2019Tosca, N.J., Jiang, C.Z., Rasmussen, B., Muhling, J. (2019) Products of the iron cycle on the early Earth. Free Radical Biology and Medicine 140, 138–153. https://doi.org/10.1016/j.freeradbiomed.2019.05.005
).Modern analogues to Earth’s early oceans (Swanner et al., 2020
Swanner, E.D., Lambrecht, N., Wittkop, C., Harding, C., Katsev, S., Torgeson, J., Poulton, S.W. (2020) The biogeochemistry of ferruginous lakes and past ferruginous oceans. Earth-Science Reviews 211, 103430. https://doi.org/10.1016/j.earscirev.2020.103430
) that allow the study of both modern pore water geochemistry and short term diagenetic evolution of ferruginous sediments are scarce. One such environment is the ferruginous sediments deposited in the Malili Lakes (Russell et al., 2016Russell, J.M., Bijaksana, S., Vogel, H., Melles, M., Kallmeyer, J., Ariztegui, D., Crowe, S.A., Fajar, S., Hafidz, A., Haffner, D., Hasberg, A., Ivory, S., Kelly, C., King, J., Kirana, K., Morlock, M., Noren, A., O’Grady, R., Ordonez, L., Stevenson, J., von Rintelen, T., Vuillemin, A., Watkinson, I., Wattrus, N., Wicaksono, S., Wonik, T., Bauer, K., Deino, A., Friese, A., Henny, C., Imran, Marwoto, R., Ngkoimani, L.O., Nomosatryo, S., Safiuddin, L.O., Simister, R., Tamuntuan, G. (2016) The Towuti Drilling Project: paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake. Scientific Drilling 21, 29–40. https://doi.org/10.5194/sd-21-29-2016
), a chain of five interconnected tectonic lakes hosted in variably weathered (ultra)mafic rocks on Sulawesi, Indonesia (Fig. 1a, b). Lateritic erosion of the catchment supplies considerable amounts of iron (oxyhydr)oxides, but little sulfate, to the lakes (Morlock et al., 2018Morlock, M.A., Vogel, H., Nigg, V., Ordoñez, L.G., Hasberg, A.K.M., Melles, M., Russell, J.M., Bijaksana, S., the TDP Science Team (2018) Climatic and tectonic controls on source-to-sink processes in the tropical, ultramafic catchment of Lake Towuti, Indonesia. Journal of Paleolimnology 61, 279–295. https://doi.org/10.1007/s10933-018-0059-3
). Lake Towuti (2.5° S, 121° E), with a maximum water depth of ca. 200 m, is presently oxygen depleted below 130 m depth (Fig. 1c) displaying a persistent monimolimnion wherein primary ferric iron phases, mostly ferrihydrite (Fe2O3 · 0.5H2O), undergo reductive dissolution (Bauer et al., 2020Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
). Subsequent sediment (trans)formation during early diagenesis (Vuillemin et al., 2019Vuillemin, A., Wirth, R., Kemnitz, H., Schleicher, A.M., Friese, A., Bauer, K.W., Simister, R., Nomosatryo, S., Ordoñez, L., Ariztegui, D., Henny, C., Crowe, S.A., Benning, L.G., Kallmeyer, J., Russell, J.M., Bijaksana, S., Vogel, H., the Towuti Drilling Project Science Team (2019) Formation of diagenetic siderite in modern ferruginous sediments. Geology 47, 540–544. https://doi.org/10.1130/G46100.1
, 2020Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordoñez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science Team (2020) Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955–1973. https://doi.org/10.5194/bg-17-1955-2020
) precipitates secondary mineral phases, such as siderite (FeCO3) and vivianite (Fe3[PO4]2 · 8H2O). Geomicrobiological investigations have shown that iron-, sulfur- and methane-related biogeochemical processes coexist in Lake Towuti sediments (Vuillemin et al., 2016Vuillemin, A., Friese, A., Alawi, M., Henny, C., Nomosatryo, S., Wagner, D., Crowe, S.A., Kallmeyer, J. (2016) Geomicrobiological Features of Ferruginous Sediments from Lake Towuti, Indonesia. Frontiers in Microbiology 7, 1007. https://doi.org/10.3389/fmicb.2016.01007
, 2018Vuillemin, A., Horn, F., Friese, A., Winkel, M., Alawi, M., Wagner, D., Henny, C., Orsi, W.D., Crowe, S.A., Kallmeyer, J. (2018) Metabolical potential of microbial communities from ferruginous sediments. Environmental Microbiology 20, 4297–4313. https://doi.org/10.1111/1462-2920.14343
). Due to extremely low sulfate concentrations (<20 μM), sediment organic matter (OM) remineralisation proceeds mainly through methanogenesis (Friese et al., 2021Friese, A., Bauer, K., Glombitza, C., Ordoñez, L., Ariztegui, D., Heuer, V.B., Vuillemin, A., Henny, C., Nomosatryo, S., Simister, R., Wagner, D., Bijaksana, S., Vogel, H., Melles, M., Russell, J.M., Crowe, S.A., Kallmeyer, J. (2021) Organic matter mineralization in modern and ancient ferruginous sediments. Nature Communications 12, 2216. https://doi.org/10.1038/s41467-021-22453-0
). These sedimentary conditions make Lake Towuti a unique ferruginous analogue in which to study the evolution of pore water geochemistry under the influence of microbial reduction and mineral (trans)formations prior to sediment lithification (Vuillemin et al., 2023Vuillemin, A., Mayr, C., Schuessler, J.A., Friese, A., Bauer, K.W., Lücke, A., Heuer, V.B., Glombitza, C., Henny, C., von Blanckenburg, F., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J. (2023) A one-million-year isotope record from siderites formed in modern ferruginous sediments. GSA Bulletin 135, 504–522. https://doi.org/10.1130/B36211.1
).Figure 1 Site description of Lake Towuti. (a) World map displaying the location of Sulawesi Island, with close up on the Indonesia archipelago and location of the Malili Lake System. (b) Map of Sulawesi illustrating the (ultra)mafic and lateritic geology of the Malili Lake catchment. (c) Bathymetric map of Lake Towuti with position of drill site TDP-1A (156 m water depth), dissolved oxygen, iron, sulfate and pH profiles of Lake Towuti’s water column (Bauer et al., 2020
Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
), and gravity cores retrieved from 60 and 200 m water depth illustrating redox conditions at the water-sediment interface.Here, we analyse one 100 m long sediment sequence to investigate the link between putative microbial processes and geochemical gradients under which authigenic minerals precipitate. We present detailed pore water geochemistry and high resolution geochemical core profiles down to a basal age of about ∼1 Ma (Russell et al., 2020
Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). Using transmitted light and scanning electron microscopy (SEM), we illustrate characteristic authigenic mineral phases, namely magnetite (Fe3O4), millerite (NiS), siderite and vivianite, which occur in varying quantities throughout the stratigraphy. Together these data document the direct precipitation of successive phases from pore waters, highlight microbial processes of sediment remineralisation underlying reductive diagenesis, and allow us to establish mineral biosignatures in ferruginous records.top
Methods
The Towuti Drilling Project (TDP) coring operations were carried out by the International Continental Scientific Drilling Program (ICDP) in spring-summer 2015, using the Deep Lakes Drilling System (Russell et al., 2016
Russell, J.M., Bijaksana, S., Vogel, H., Melles, M., Kallmeyer, J., Ariztegui, D., Crowe, S.A., Fajar, S., Hafidz, A., Haffner, D., Hasberg, A., Ivory, S., Kelly, C., King, J., Kirana, K., Morlock, M., Noren, A., O’Grady, R., Ordonez, L., Stevenson, J., von Rintelen, T., Vuillemin, A., Watkinson, I., Wattrus, N., Wicaksono, S., Wonik, T., Bauer, K., Deino, A., Friese, A., Henny, C., Imran, Marwoto, R., Ngkoimani, L.O., Nomosatryo, S., Safiuddin, L.O., Simister, R., Tamuntuan, G. (2016) The Towuti Drilling Project: paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake. Scientific Drilling 21, 29–40. https://doi.org/10.5194/sd-21-29-2016
). Hole TDP-1A (156 m water depth) was drilled with a contamination tracer to aid geomicrobiological sampling (Friese et al., 2017Friese, A., Kallmeyer, J., Kitte, J.A., Montaño Martínez, I., Bijaksana, S., Wagner, D., the ICDP Lake Chalco Drilling Science Team, the ICDP Towuti Drilling Science Team (2017) A simple and inexpensive technique for assessing contamination during drilling operations. Limnology and Oceanography: Methods 15, 200–211. https://doi.org/10.1002/lom3.10159
). In the field, pristine core sections were transferred into an anaerobic chamber for pore water extraction, using Rhizon samplers for soft sediment, and an IODP-style titanium cylinder and hydraulic press for compact samples deeper than 10 m below lake floor (mblf). Alkalinity, pH, and Fe2+, Mn2+ and PO43− concentrations were determined via colorimetric titration, potentiometry and spectrophotometry, respectively. Dissolved inorganic carbon (DIC) was calculated by solving the carbonate system using the pH and alkalinity profiles and borehole temperatures. Major dissolved elements and volatile fatty acids (VFAs) were analysed by ion chromatography. Pore water trace metals were quantified by ICP-MS. Potential sulfate reduction rates (pSRRs) were determined by sediment incubation with radioactive 35SO42− (Friese et al., 2021Friese, A., Bauer, K., Glombitza, C., Ordoñez, L., Ariztegui, D., Heuer, V.B., Vuillemin, A., Henny, C., Nomosatryo, S., Simister, R., Wagner, D., Bijaksana, S., Vogel, H., Melles, M., Russell, J.M., Crowe, S.A., Kallmeyer, J. (2021) Organic matter mineralization in modern and ancient ferruginous sediments. Nature Communications 12, 2216. https://doi.org/10.1038/s41467-021-22453-0
).All cores from TDP site 1 were split and scanned at the National Lacustrine Core Facility (LacCore), described macroscopically and microscopically to determine their stratigraphy and composition. A composite core was established based on visual alignment of lithologic features and magnetic susceptibility measurements (Russell et al., 2020
Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). The upper 100 m of the composite cores were scanned at 5 mm resolution on an XRF core scanner (ITRAX, Cox Ltd.) equipped with chromium and molybdenum X-ray tubes to resolve high atomic mass elements (Morlock et al., 2021Morlock, M.A., Vogel, H., Russell, J.M., Anselmetti, F.S., Bijaksana, S. (2021) Quaternary environmental changes in tropical Lake Towuti, Indonesia, inferred from end-member modelling of X-ray fluorescence core-scanning data. Journal of Quaternary Science 36, 1040–1051. https://doi.org/10.1002/jqs.3338
). The remainder of core TDP-1A was subsampled for heavy mineral extraction (≥2.9 g cm−3) via density and magnetic separation. Heavy mineral extracts were fixed onto SEM aluminium stubs and carbon coated (∼20 nm layer), using a Leica EM ACE600 high vacuum sputter coater. Morphological investigation and elemental point analyses were performed on a Zeiss Ultra 55 Plus field SEM and FEI Quanta 3D FEG, both coupled to energy dispersive X-ray spectrometres (EDX). All methods are detailed in the Supplementary Information.top
Results and Discussion
Authigenic mineral shapes and compositions can be employed to trace changes in redox controlled variations in water and pore fluid geochemistry associated with microbial processes in the upper sediment sequence. If mineral precipitation continues during burial, their signatures deviate from the stratigraphic context.
Pore water geochemical evolution and mineral precipitation. Reducible iron oxides in sediments originate from lateritic weathering of Towuti’s (ultra)mafic catchment (Morlock et al., 2018
Morlock, M.A., Vogel, H., Nigg, V., Ordoñez, L.G., Hasberg, A.K.M., Melles, M., Russell, J.M., Bijaksana, S., the TDP Science Team (2018) Climatic and tectonic controls on source-to-sink processes in the tropical, ultramafic catchment of Lake Towuti, Indonesia. Journal of Paleolimnology 61, 279–295. https://doi.org/10.1007/s10933-018-0059-3
) and authigenic oxidation of ferrous iron in the water column (Sheppard et al., 2019Sheppard, R.Y., Milliken, R.E., Russell, J.M., Dyar, M.D., Sklute, E.C., Vogel, H., Melles, M., Bijaksana, S., Morlock, M.A., Hasberg, A.K.M. (2019) Characterization of iron in Lake Towuti sediment. Chemical Geology 512, 11–30. https://doi.org/10.1016/j.chemgeo.2019.02.029
). Consequently, alternating red and green sediments reflect variations in the composition, abundance and changes in iron oxidation state through time (Russell et al., 2020Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). During settling when the water column is stratified, particulate iron undergoes partial reductive dissolution in the monimolimnion (Bauer et al., 2020Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
), precipitating pelagic framboidal magnetites (Fig. 2a). Currently bottom waters contain ca. 20 to 12 μM sulfate (Vuillemin et al., 2016Vuillemin, A., Friese, A., Alawi, M., Henny, C., Nomosatryo, S., Wagner, D., Crowe, S.A., Kallmeyer, J. (2016) Geomicrobiological Features of Ferruginous Sediments from Lake Towuti, Indonesia. Frontiers in Microbiology 7, 1007. https://doi.org/10.3389/fmicb.2016.01007
), promoting sulfate reduction rates (SRR) that are highest at the sediment water interface (SWI) and drastically drop within the upper 20 cmblf (Fig. 3a). In contrast to euxinic conditions under which Fe sulfides (e.g., mackinawite) act as the primary Ni-hosting phases (Mansor et al., 2019Mansor, M., Winkler, C., Hochella Jr., M.F., Xu, J. (2019) Nanoparticulate Nickel-Hosting Phases in Sulfidic Environments: Effects of Ferrous Iron and Bacterial Presence on Mineral Formation Mechanism and Solid-Phase Nickel Distribution. Frontiers in Earth Science 7, 151. https://doi.org/10.3389/feart.2019.00151
), iron sulfides were not observed. Under the present ferruginous conditions, sulfate reduction with organic carbon as the reductant produces sulfide that reacts with nickel (Fig. 4) and precipitates millerite (NiS). The habits of millerites identified at 0.2 mblf and deeper suggest both pelagic precipitation and post-depositional growth at the SWI and in shallow sediments during active sulfate reduction (Fig. 2b).Figure 2 EDX point analyses and SEM images of diagenetic minerals. (Top) Ternary plots show: (a) magnetites and coextracted iron oxides (goethite, wüstite), (b) millerites with incorporation of Fe2+ traces, (c) siderites and (d) vivianites with substitution of Mn2+ for Fe2+. Smelter particles represent airborne contaminants from the nearby mine. (Bottom) (a) Magnetites in framboidal habits; (b) millerites in acicular spherules and aggregates, sometimes entangled and overgrown by siderites; (c) siderites aggregating into twins and mosaic monocrystals; and (d) vivianites in tabular habit developing into rosettes. The crystal section shows inclusions of millerite and siderite.
Figure 3 Depth profiles for pore water geochemistry and stability diagrams for Fe-bearing phases. (a) Lithology of Lake Towuti’s upper 25 mblf including tephras (T) and vivianites (V); potential sulfate reduction rates (SRR); pore water concentrations for sulfate, ferrous iron, manganese, arsenic, cobalt, nitrate, ammonium, phosphate, formate, acetate, lactate, butyrate, methane, dissolved inorganic carbon (DIC), pore water pH, calcium, magnesium, potassium and sodium. Data points represent averaged triplicates (reproducibility <5 %). The dotted line signifies the base of the 14C ages, i.e. 44.7 ka (Russell et al., 2020
Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003Maher, B.A., Alekseev, A., Alekseeva, T. (2003) Magnetic mineralogy of soils across the Russian Steppe: climatic dependence of pedogenic magnetite formation. Palaeogeography, Palaeoclimatology, Palaeoecology 201, 321–341. https://doi.org/10.1016/S0031-0182(03)00618-7
) corresponding to (1) the monimolimnion (Roh et al., 2003Roh, Y., Zhang, C.-L., Vali, H., Lauf, R.J., Zhou, J., Phelps, T.J. (2003) Biogeochemical and environmental factors in Fe biomineralization: magnetite and siderite formation. Clays and Clay Minerals 51, 83–95. https://doi.org/10.1346/CCMN.2003.510110
), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014Craw, D., Bowell, R.J. (2014) The Characterization of Arsenic in Mine Waste. Reviews in Mineralogy and Geochemistry 79, 473–505. https://doi.org/10.2138/rmg.2014.79.10
), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002Zachara, J.M., Kukkapadu, R.V., Fredrickson, J.K., Gorby, Y.A., Smith, S.C. (2002) Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB). Geomicrobiology Journal 19, 179–207. https://doi.org/10.1080/01490450252864271
) and phosphate-saturated conditions (Morton and Edwards, 2005Morton, S.C., Edwards, M. (2005) Reduced Phosphorus Compounds in the Environment. Critical Reviews in Environmental Science and Technology 35, 333–364. https://doi.org/10.1080/10643380590944978
), respectively.Figure 4 Depth profiles for bulk sediment, and pore water geochemistry. (Left to right) Stratigraphy of site TDP-1A with tephras (T) and vivianites (V); XRF core scanning profiles for Ni, S, Fe, Mn and P in bulk sediment overlain by pore water concentrations for SO42−, Fe2+, Mn2+ and PO43−; siderite concentration based on coulometry; total organic carbon (TOC). XRF core scanning profiles represent point analyses with moving averages at 5 mm and 2 cm resolution, respectively. Data points represent averaged triplicates (reproducibility <5 %).
Due to stratification in ferruginous Lake Towuti, the main terminal electron acceptors (i.e. O2, NO3−, SO42−) are rapidly depleted in the sediment (Figs. 1, 3a), which implies that anaerobic OM degradation should proceed via mineral ferric iron and CO32− reduction. Reductive dissolution of hydrous ferric oxides (e.g., ferrihydrite) continues in shallow sediments releasing substantial amounts of Fe2+ (278 μM) to the pore water (Fig. 3a). Below 50 cmblf, because goethite and magnetite represent the main reducible ferric phases remaining in sediments (Figs. 2a, S-1), fermentation is preferentially performed over microbial respiration of less reactive substances (Friese et al., 2021
Friese, A., Bauer, K., Glombitza, C., Ordoñez, L., Ariztegui, D., Heuer, V.B., Vuillemin, A., Henny, C., Nomosatryo, S., Simister, R., Wagner, D., Bijaksana, S., Vogel, H., Melles, M., Russell, J.M., Crowe, S.A., Kallmeyer, J. (2021) Organic matter mineralization in modern and ancient ferruginous sediments. Nature Communications 12, 2216. https://doi.org/10.1038/s41467-021-22453-0
). Nevertheless, steadily increasing metal concentrations in pore water (Mn, As, Co) suggests that Fe reduction concomitant with fermentation (Fig. 3a) continues at slow rates, promoting the dissolution of less reactive ferric-ferrous phases during burial.From 1 to 10 mblf, pore water NH4+, PO43− and VFA concentrations provide concomitant evidence of microbial OM degradation (Fig. 3a). Between 30 cmblf and 5 mblf, formate, lactate, acetate and butyrate concentrations vary with metabolic production and consumption (i.e. acidogenesis, acetogenesis). Below 5 mblf, persistently low VFA concentrations (<20 μM) indicate complete remineralisation to methane (Friese et al., 2021
Friese, A., Bauer, K., Glombitza, C., Ordoñez, L., Ariztegui, D., Heuer, V.B., Vuillemin, A., Henny, C., Nomosatryo, S., Simister, R., Wagner, D., Bijaksana, S., Vogel, H., Melles, M., Russell, J.M., Crowe, S.A., Kallmeyer, J. (2021) Organic matter mineralization in modern and ancient ferruginous sediments. Nature Communications 12, 2216. https://doi.org/10.1038/s41467-021-22453-0
) accompanied by a decrease in microbial uptake of PO43−. Such stepwise fermentation and steady increase in DIC delimit the depth at which pore waters reach siderite saturation (Vuillemin et al., 2019Vuillemin, A., Wirth, R., Kemnitz, H., Schleicher, A.M., Friese, A., Bauer, K.W., Simister, R., Nomosatryo, S., Ordoñez, L., Ariztegui, D., Henny, C., Crowe, S.A., Benning, L.G., Kallmeyer, J., Russell, J.M., Bijaksana, S., Vogel, H., the Towuti Drilling Project Science Team (2019) Formation of diagenetic siderite in modern ferruginous sediments. Geology 47, 540–544. https://doi.org/10.1130/G46100.1
). The pore water pH (7.1–7.5) implies that this biogenic DIC reacts in the form of HCO3− with dissolved Fe2+ to consistently precipitate siderite between 50 cmblf and 5 mblf (Table S-1), whereas CO2 fixation via hydrogenotrophic methanogenesis subsequently reduces DIC activity in pore waters (Fig. 3b).The increasing pore water Na+, Ca2+ and Mg2+ concentrations with depth (Fig. 3) indicate that (ultra)mafic sheet silicates (e.g., serpentine) partially dissolve after burial (Table S-1). Ca2+ and Mg2+ concentrations are predicted to decrease the solubility of PO43− in ferruginous solutions (Kubeneck et al., 2023
Kubeneck, L.J., ThomasArrigo, L.K., Rothwell, K.A., Kaegi, R., Kretzschmar, R. (2023) Competitive incorporation of Mn and Mg in vivianite at varying salinity and effects on crystal structure and morphology. Geochimica et Cosmochimica Acta 346, 231–244. https://doi.org/10.1016/j.gca.2023.01.029
), thereby influencing pore water chemical equilibrium. Their presence in pore water could exert control over the onset of vivianite precipitation (Fig. 2d) after siderite (Vuillemin et al., 2020Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordoñez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science Team (2020) Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955–1973. https://doi.org/10.5194/bg-17-1955-2020
). Ca2+ and Mg2+ concentrations drop around 15 mblf, suggesting that PO43− supplants CO32− for precipitation with Fe2+ and Mn2+ available in pore water (Fig. 3).Pore water geochemical profiles in Lake Towuti’s upper sediment column stem from microbial activity and dissolution-precipitation of specific mineral phases (Figs. 2, 3). We observe a characteristic succession of authigenic mineral precipitation as a function of chemical equilibration of ferruginous pore waters (Jiang and Tosca, 2019
Jiang, C.Z., Tosca, N.J. (2019) Fe(II)-carbonate precipitation kinetics and the chemistry of anoxic ferruginous seawater. Earth and Planetary Science Letters 506, 231–242. https://doi.org/10.1016/j.epsl.2018.11.010
) during anaerobic respiration of terminal electron acceptors and sediment OM remineralisation. Namely, magnetite, millerite, siderite and vivianite represent biosignatures of microbial iron and sulfate reduction, fermentation and methanogenesis lasting 200 kyr after deposition.Geochemical gradient and continuous mineral overgrowth. Based on the geochemical gradient that developed in Lake Towuti’s upper 25 m of sediment (Fig. 3a) and pH-Eh stability fields for authigenic minerals (Fig. 3b), we estimated that the initial environments of formation for magnetite, millerite, siderite and vivianite correspond to the monimolimnion, SWI, shallow (<1–5 mblf) and deep sediments (>15 mblf), respectively. These precipitation stages, which are inherent to microbial processes, can overlap according to the geochemical gradient that develops in anoxic waters and sediments (Fig. 3a, b).
In Lake Towuti, some framboidal magnetites form as pelagic precipitates in the chemocline (Fig. 1c) during periods of water column stratification (Bauer et al., 2020
Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
) and are preserved as such in the sediment (Fig. 2a). Even at low sulfate concentrations (<20 μM), microbial sulfate reduction in the vicinity of the SWI produces HS− in pore water which preferentially reacts with Ni2+ over Fe2+ to form millerite, incorporating minor Fe and trace metals (Figs. 2b, S-2 and S-3). The spherical habits fused into acicular aggregates of authigenic millerites originating from microbial sulfate reduction appear in places with early siderite phases, or fully overgrown by siderite (Figs. 2b, S-3). Furthermore, millerite aggregates within siderite-rich zones (Fig. S-4) suggest increased millerite precipitation during deeper mixing phases and oxygenation of the sediment water interface, sulfate reduction taking place predominantly around the redox front within the upper few centimetres of the sediment column (Fig. S-5).Crystallisation of successive phases from pore waters and the entangled habits that we observe (Fig. 2) reveal a certain degree of Ostwald ripening where smaller precursor crystals dissolve and re-precipitate allowing larger crystal nuclei to further grow over time of burial (Benning and Waychunas, 2008
Benning, L.G., Waychunas, G.A. (2008) Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls. In: Brantley, S., Kubicki, J., White, A. (Eds.) Kinetics of Water-Rock Interaction. Springer, New York, 259–333. https://doi.org/10.1007/978-0-387-73563-4_7
). As demonstrated for redox (trans)formation of green rust (Halevy et al., 2017Halevy, I., Alesker, M., Schuster, E.M., Popovitz-Biro, R., Feldman, Y. (2017) A key role for green rust in the Precambrian oceans and the genesis of iron formations. Nature Geoscience 10, 135–139. https://doi.org/10.1038/ngeo2878
), pore water solutions become saturated with ferrous colloids (Moens et al., 2021Moens, C., Montalvo, D., Smolders, E. (2021) The concentration and size distribution of iron-rich colloids in pore waters are related to soil organic matter content and pore water calcium concentration. European Journal of Soil Science 72, 2199–2214. https://doi.org/10.1111/ejss.13104
) that react with either carbonate or phosphate ions over time to form siderite monocrystals (Vuillemin et al., 2019Vuillemin, A., Wirth, R., Kemnitz, H., Schleicher, A.M., Friese, A., Bauer, K.W., Simister, R., Nomosatryo, S., Ordoñez, L., Ariztegui, D., Henny, C., Crowe, S.A., Benning, L.G., Kallmeyer, J., Russell, J.M., Bijaksana, S., Vogel, H., the Towuti Drilling Project Science Team (2019) Formation of diagenetic siderite in modern ferruginous sediments. Geology 47, 540–544. https://doi.org/10.1130/G46100.1
) and vivianite nodules (Vuillemin et al., 2020Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordoñez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science Team (2020) Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955–1973. https://doi.org/10.5194/bg-17-1955-2020
). Siderite SEM images document diagenetic growth from micritic phases into twins and aggregates, forming spherules of mosaic monocrystals (Fig. 2c) promoted by saturated pore water conditions during burial (Table S-1). Similarly, vivianite SEM images reveal crystal growth from tabular habits into rosettes (Fig. 2d), forming macroscopic crystals due to diagenetic diffusion during burial, indicating that vivianite constitutes an important sink for Fe2+, Mn2+ and Mg2+ in pore waters that reached saturation in specific sedimentary layers. Millerite and siderite inclusions identified in a vivianite crystal cross section suggest that these phases precipitated first (Fig. 2d). Finally, EDX results (Figs. 2, S-2) show that magnetites have minor trace metal concentrations, millerites incorporate some Fe2+, siderites substitute Mn2+ in their initial growth phase, while later forming vivianites have an overall manganoan composition substituting both Mn2+ and Mg2+ (Kubeneck et al., 2023Kubeneck, L.J., ThomasArrigo, L.K., Rothwell, K.A., Kaegi, R., Kretzschmar, R. (2023) Competitive incorporation of Mn and Mg in vivianite at varying salinity and effects on crystal structure and morphology. Geochimica et Cosmochimica Acta 346, 231–244. https://doi.org/10.1016/j.gca.2023.01.029
).Mineral biosignatures in their recent and ancient stratigraphic context. The mineralogy of Lake Towuti presents an alternation of dark green to reddish-grey clays, considered to reflect detrital iron fluxes to the lake, stratification regimes, and redox conditions at the SWI (Russell et al., 2016
Russell, J.M., Bijaksana, S., Vogel, H., Melles, M., Kallmeyer, J., Ariztegui, D., Crowe, S.A., Fajar, S., Hafidz, A., Haffner, D., Hasberg, A., Ivory, S., Kelly, C., King, J., Kirana, K., Morlock, M., Noren, A., O’Grady, R., Ordonez, L., Stevenson, J., von Rintelen, T., Vuillemin, A., Watkinson, I., Wattrus, N., Wicaksono, S., Wonik, T., Bauer, K., Deino, A., Friese, A., Henny, C., Imran, Marwoto, R., Ngkoimani, L.O., Nomosatryo, S., Safiuddin, L.O., Simister, R., Tamuntuan, G. (2016) The Towuti Drilling Project: paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake. Scientific Drilling 21, 29–40. https://doi.org/10.5194/sd-21-29-2016
, 2020Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). Variations in the burial of ferric iron and OM, their availability as substrates and the pore water geochemistry (Fig. 4) ensuing microbial breakdown, can imprint different mineral biosignatures during early diagenesis (Morlock et al., 2021Morlock, M.A., Vogel, H., Russell, J.M., Anselmetti, F.S., Bijaksana, S. (2021) Quaternary environmental changes in tropical Lake Towuti, Indonesia, inferred from end-member modelling of X-ray fluorescence core-scanning data. Journal of Quaternary Science 36, 1040–1051. https://doi.org/10.1002/jqs.3338
). Each of these minerals, whether forming in the water column, near surface sediments or from pore waters, acts as a discrete sink for selective solutes (i.e. Ni2+, Mn2+, Fe2+, CO32−, HS−, PO43−). Pore water profiles thereby provide constraints on the depth of formation and age difference with the stratigraphy. Yet their abundance along the stratigraphic record results from past depositional modes and redox biogeochemistry.Iron inflows deposited under oxygenated conditions formed reddish clays containing abundant, but poorly reactive, detrital magnetites and diagenetic siderites (Vuillemin et al., 2023
Vuillemin, A., Mayr, C., Schuessler, J.A., Friese, A., Bauer, K.W., Lücke, A., Heuer, V.B., Glombitza, C., Henny, C., von Blanckenburg, F., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J. (2023) A one-million-year isotope record from siderites formed in modern ferruginous sediments. GSA Bulletin 135, 504–522. https://doi.org/10.1130/B36211.1
). Millerites were also found in red clays in which slightly more sulfate was available for microbial reduction at the time of deposition (i.e. ∼20 μM). These magnetites and millerites were progressively overgrown by diagenetic siderite during burial. While framboidal magnetites and spherical millerites represented pelagic precipitates forming under stratified conditions, vivianites nucleated from diffusive pore waters in greenish clays. To conclude, we could show that millerite precipitates in ferruginous anoxic waters and shallow sediments at sulfate levels relevant to sulfur cycling in Earth’s early oceans (Farquhar et al., 2010Farquhar, J., Wu, N., Canfield, D.E., Oduro, H. (2010) Connections between Sulfur Cycle Evolution, Sulfur Isotopes, Sediments, and Base Metal Sulfide Deposits. Economic Geology 105, 509–533. https://doi.org/10.2113/gsecongeo.105.3.509
). Whereas vivianite preservation over a geologic scale is compromised, continuous precipitation of siderite from saturated pore waters forms spheroids that can coalesce into lithified bands like those documented in ancient red beds.top
Acknowledgements
The financial, logistic and administrative support of the International Continental Scientific Drilling Program (ICDP), U.S. National Science Foundation (NSF), German Research Foundation (DFG), Swiss National Science Foundation (SNSF), PT Vale Indonesia, Ministry of Research, Education, and Higher Technology of Indonesia (RISTEK), U.S. National Lacustrine Core Repository, DOSECC Exploration Services, and GFZ German Research Centre for Geosciences is acknowledged. This study was financed through DFG grants of the ICDP priority program to JK (KA 2293/8-1) and AV (VU 94/1-1, VU 94/3-1), SNSF grants to AV (P2GEP2_148621) and HV (20FI21_153054/1, 200021_153053/1). AP and LGB acknowledge financial support from the Helmholtz Recruiting Initiative (I-044-16-01) for access to the Potsdam Imaging and Spectral Analyses (PISA) facility.
Editor: Andreas Kappler
top
References
Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
Show in context Lake Towuti (2.5° S, 121° E), with a maximum water depth of ca. 200 m, is presently oxygen depleted below 130 m depth (Fig. 1c) displaying a persistent monimolimnion wherein primary ferric iron phases, mostly ferrihydrite (Fe2O3 · 0.5H2O), undergo reductive dissolution (Bauer et al., 2020).
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(c) Bathymetric map of Lake Towuti with position of drill site TDP-1A (156 m water depth), dissolved oxygen, iron, sulfate and pH profiles of Lake Towuti’s water column (Bauer et al., 2020), and gravity cores retrieved from 60 and 200 m water depth illustrating redox conditions at the water-sediment interface.
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During settling when the water column is stratified, particulate iron undergoes partial reductive dissolution in the monimolimnion (Bauer et al., 2020), precipitating pelagic framboidal magnetites (Fig. 2a).
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In Lake Towuti, some framboidal magnetites form as pelagic precipitates in the chemocline (Fig. 1c) during periods of water column stratification (Bauer et al., 2020) and are preserved as such in the sediment (Fig. 2a).
View in article
Benning, L.G., Waychunas, G.A. (2008) Nucleation, Growth, and Aggregation of Mineral Phases: Mechanisms and Kinetic Controls. In: Brantley, S., Kubicki, J., White, A. (Eds.) Kinetics of Water-Rock Interaction. Springer, New York, 259–333. https://doi.org/10.1007/978-0-387-73563-4_7
Show in context Crystallisation of successive phases from pore waters and the entangled habits that we observe (Fig. 2) reveal a certain degree of Ostwald ripening where smaller precursor crystals dissolve and re-precipitate allowing larger crystal nuclei to further grow over time of burial (Benning and Waychunas, 2008).
View in article
Canfield, D.E., Poulton, S.W., Knoll, A.H., Narbonne, G.M., Ross, G., Goldberg, T., Strauss, H. (2008) Ferruginous Conditions Dominated Later Neoproterozoic Deep-Water Chemistry. Science 321, 949–952. https://doi.org/10.1126/science.1154499
Show in context Ferruginous conditions (iron-rich, sulfate-poor) were widespread in the Archean and Proterozoic oceans and resulted in the deposition of ancient iron formations (Canfield et al., 2008).
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Craw, D., Bowell, R.J. (2014) The Characterization of Arsenic in Mine Waste. Reviews in Mineralogy and Geochemistry 79, 473–505. https://doi.org/10.2138/rmg.2014.79.10
Show in context (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005).
View in article
Fakhraee, M., Hancisse, O., Canfield, D.E., Crowe, S.A., Katsev, S. (2019) Proterozoic seawater sulfate scarcity and the evolution of ocean–atmosphere chemistry. Nature Geoscience 12, 375–380. https://doi.org/10.1038/s41561-019-0351-5
Show in context Sulfides are also occasionally reported to occur, but only in minor quantities due to the scarcity of seawater sulfate at the time (Fakhraee et al., 2019).
View in article
Farquhar, J., Wu, N., Canfield, D.E., Oduro, H. (2010) Connections between Sulfur Cycle Evolution, Sulfur Isotopes, Sediments, and Base Metal Sulfide Deposits. Economic Geology 105, 509–533. https://doi.org/10.2113/gsecongeo.105.3.509
Show in context To conclude, we could show that millerite precipitates in ferruginous anoxic waters and shallow sediments at sulfate levels relevant to sulfur cycling in Earth’s early oceans (Farquhar et al., 2010).
View in article
Friese, A., Kallmeyer, J., Kitte, J.A., Montaño Martínez, I., Bijaksana, S., Wagner, D., the ICDP Lake Chalco Drilling Science Team, the ICDP Towuti Drilling Science Team (2017) A simple and inexpensive technique for assessing contamination during drilling operations. Limnology and Oceanography: Methods 15, 200–211. https://doi.org/10.1002/lom3.10159
Show in context Hole TDP-1A (156 m water depth) was drilled with a contamination tracer to aid geomicrobiological sampling (Friese et al., 2017).
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Friese, A., Bauer, K., Glombitza, C., Ordoñez, L., Ariztegui, D., Heuer, V.B., Vuillemin, A., Henny, C., Nomosatryo, S., Simister, R., Wagner, D., Bijaksana, S., Vogel, H., Melles, M., Russell, J.M., Crowe, S.A., Kallmeyer, J. (2021) Organic matter mineralization in modern and ancient ferruginous sediments. Nature Communications 12, 2216. https://doi.org/10.1038/s41467-021-22453-0
Show in context Due to extremely low sulfate concentrations (<20 μM), sediment organic matter (OM) remineralisation proceeds mainly through methanogenesis (Friese et al., 2021).
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Pore water trace metals were quantified by ICP-MS. Potential sulfate reduction rates (pSRRs) were determined by sediment incubation with radioactive 35SO42− (Friese et al., 2021).
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Below 50 cmblf, because goethite and magnetite represent the main reducible ferric phases remaining in sediments (Figs. 2a, S-1), fermentation is preferentially performed over microbial respiration of less reactive substances (Friese et al., 2021).
View in article
Between 30 cmblf and 5 mblf, formate, lactate, acetate and butyrate concentrations vary with metabolic production and consumption (i.e. acidogenesis, acetogenesis). Below 5 mblf, persistently low VFA concentrations (<20 μM) indicate complete remineralisation to methane (Friese et al., 2021) accompanied by a decrease in microbial uptake of PO43−
View in article
Halevy, I., Alesker, M., Schuster, E.M., Popovitz-Biro, R., Feldman, Y. (2017) A key role for green rust in the Precambrian oceans and the genesis of iron formations. Nature Geoscience 10, 135–139. https://doi.org/10.1038/ngeo2878
Show in context Precambrian iron formations are composed of diverse iron oxides and carbonates thought to have formed as primary pelagic precipitates from the recrystallisation of ferric-ferrous iron (oxyhydr)oxides (Halevy et al., 2017).
View in article
As demonstrated for redox (trans)formation of green rust (Halevy et al., 2017), pore water solutions become saturated with ferrous colloids (Moens et al., 2021) that react with either carbonate or phosphate ions over time to form siderite monocrystals (Vuillemin et al., 2019) and vivianite nodules (Vuillemin et al., 2020).
View in article
Jiang, C.Z., Tosca, N.J. (2019) Fe(II)-carbonate precipitation kinetics and the chemistry of anoxic ferruginous seawater. Earth and Planetary Science Letters 506, 231–242. https://doi.org/10.1016/j.epsl.2018.11.010
Show in context We observe a characteristic succession of authigenic mineral precipitation as a function of chemical equilibration of ferruginous pore waters (Jiang and Tosca, 2019) during anaerobic respiration of terminal electron acceptors and sediment OM remineralisation.
View in article
Kubeneck, L.J., ThomasArrigo, L.K., Rothwell, K.A., Kaegi, R., Kretzschmar, R. (2023) Competitive incorporation of Mn and Mg in vivianite at varying salinity and effects on crystal structure and morphology. Geochimica et Cosmochimica Acta 346, 231–244. https://doi.org/10.1016/j.gca.2023.01.029
Show in context The increasing pore water Na+, Ca2+ and Mg2+ concentrations with depth (Fig. 3) indicate that (ultra)mafic sheet silicates (e.g., serpentine) partially dissolve after burial (Table S-1). Ca2+ and Mg2+ concentrations are predicted to decrease the solubility of PO43− in ferruginous solutions (Kubeneck et al., 2023), thereby influencing pore water chemical equilibrium.
View in article
Finally, EDX results (Figs. 2, S-2) show that magnetites have minor trace metal concentrations, millerites incorporate some Fe2+, siderites substitute Mn2+ in their initial growth phase, while later forming vivianites have an overall manganoan composition substituting both Mn2+ and Mg2+ (Kubeneck et al., 2023).
View in article
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Show in context (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005).
View in article
Mansor, M., Winkler, C., Hochella Jr., M.F., Xu, J. (2019) Nanoparticulate Nickel-Hosting Phases in Sulfidic Environments: Effects of Ferrous Iron and Bacterial Presence on Mineral Formation Mechanism and Solid-Phase Nickel Distribution. Frontiers in Earth Science 7, 151. https://doi.org/10.3389/feart.2019.00151
Show in context In contrast to euxinic conditions under which Fe sulfides (e.g., mackinawite) act as the primary Ni-hosting phases (Mansor et al., 2019), iron sulfides were not observed.
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Moens, C., Montalvo, D., Smolders, E. (2021) The concentration and size distribution of iron-rich colloids in pore waters are related to soil organic matter content and pore water calcium concentration. European Journal of Soil Science 72, 2199–2214. https://doi.org/10.1111/ejss.13104
Show in context As demonstrated for redox (trans)formation of green rust (Halevy et al., 2017), pore water solutions become saturated with ferrous colloids (Moens et al., 2021) that react with either carbonate or phosphate ions over time to form siderite monocrystals (Vuillemin et al., 2019) and vivianite nodules (Vuillemin et al., 2020).
View in article
Morlock, M.A., Vogel, H., Nigg, V., Ordoñez, L.G., Hasberg, A.K.M., Melles, M., Russell, J.M., Bijaksana, S., the TDP Science Team (2018) Climatic and tectonic controls on source-to-sink processes in the tropical, ultramafic catchment of Lake Towuti, Indonesia. Journal of Paleolimnology 61, 279–295. https://doi.org/10.1007/s10933-018-0059-3
Show in context Lateritic erosion of the catchment supplies considerable amounts of iron (oxyhydr)oxides, but little sulfate, to the lakes (Morlock et al., 2018).
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Reducible iron oxides in sediments originate from lateritic weathering of Towuti’s (ultra)mafic catchment (Morlock et al., 2018) and authigenic oxidation of ferrous iron in the water column (Sheppard et al., 2019).
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Morlock, M.A., Vogel, H., Russell, J.M., Anselmetti, F.S., Bijaksana, S. (2021) Quaternary environmental changes in tropical Lake Towuti, Indonesia, inferred from end-member modelling of X-ray fluorescence core-scanning data. Journal of Quaternary Science 36, 1040–1051. https://doi.org/10.1002/jqs.3338
Show in context The upper 100 m of the composite cores were scanned at 5 mm resolution on an XRF core scanner (ITRAX, Cox Ltd.) equipped with chromium and molybdenum X-ray tubes to resolve high atomic mass elements (Morlock et al., 2021).
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Variations in the burial of ferric iron and OM, their availability as substrates and the pore water geochemistry (Fig. 4) ensuing microbial breakdown, can imprint different mineral biosignatures during early diagenesis (Morlock et al., 2021).
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Morton, S.C., Edwards, M. (2005) Reduced Phosphorus Compounds in the Environment. Critical Reviews in Environmental Science and Technology 35, 333–364. https://doi.org/10.1080/10643380590944978
Show in context (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005).
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Posth, N.R., Canfield, D.E., Kappler, A. (2014) Biogenic Fe(III) minerals: From formation to diagenesis and preservation in the rock record. Earth-Science Reviews 135, 103–121. https://doi.org/10.1016/j.earscirev.2014.03.012
Show in context Although the Proterozoic Earth was an essentially microbial world, mineral phases precipitated by microbial biogeochemical cycling of iron, sulfur and carbon remain poorly constrained in terms of early diagenetic imprints prior to sediment lithification (Posth et al., 2014).
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Roh, Y., Zhang, C.-L., Vali, H., Lauf, R.J., Zhou, J., Phelps, T.J. (2003) Biogeochemical and environmental factors in Fe biomineralization: magnetite and siderite formation. Clays and Clay Minerals 51, 83–95. https://doi.org/10.1346/CCMN.2003.510110
Show in context (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005).
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Russell, J.M., Bijaksana, S., Vogel, H., Melles, M., Kallmeyer, J., Ariztegui, D., Crowe, S.A., Fajar, S., Hafidz, A., Haffner, D., Hasberg, A., Ivory, S., Kelly, C., King, J., Kirana, K., Morlock, M., Noren, A., O’Grady, R., Ordonez, L., Stevenson, J., von Rintelen, T., Vuillemin, A., Watkinson, I., Wattrus, N., Wicaksono, S., Wonik, T., Bauer, K., Deino, A., Friese, A., Henny, C., Imran, Marwoto, R., Ngkoimani, L.O., Nomosatryo, S., Safiuddin, L.O., Simister, R., Tamuntuan, G. (2016) The Towuti Drilling Project: paleoenvironments, biological evolution, and geomicrobiology of a tropical Pacific lake. Scientific Drilling 21, 29–40. https://doi.org/10.5194/sd-21-29-2016
Show in context Modern analogues to Earth’s early oceans (Swanner et al., 2020) that allow the study of both modern pore water geochemistry and short term diagenetic evolution of ferruginous sediments are scarce. One such environment is the ferruginous sediments deposited in the Malili Lakes (Russell et al., 2016), a chain of five interconnected tectonic lakes hosted in variably weathered (ultra)mafic rocks on Sulawesi, Indonesia (Fig. 1a, b).
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The Towuti Drilling Project (TDP) coring operations were carried out by the International Continental Scientific Drilling Program (ICDP) in spring-summer 2015, using the Deep Lakes Drilling System (Russell et al., 2016).
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The mineralogy of Lake Towuti presents an alternation of dark green to reddish-grey clays, considered to reflect detrital iron fluxes to the lake, stratification regimes, and redox conditions at the SWI (Russell et al., 2016, 2020).
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Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
Show in context We present detailed pore water geochemistry and high resolution geochemical core profiles down to a basal age of about ∼1 Ma (Russell et al., 2020).
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A composite core was established based on visual alignment of lithologic features and magnetic susceptibility measurements (Russell et al., 2020).
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Consequently, alternating red and green sediments reflect variations in the composition, abundance and changes in iron oxidation state through time (Russell et al., 2020).
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The dotted line signifies the base of the 14C ages, i.e. 44.7 ka (Russell et al., 2020).
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The mineralogy of Lake Towuti presents an alternation of dark green to reddish-grey clays, considered to reflect detrital iron fluxes to the lake, stratification regimes, and redox conditions at the SWI (Russell et al., 2016, 2020).
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Sheppard, R.Y., Milliken, R.E., Russell, J.M., Dyar, M.D., Sklute, E.C., Vogel, H., Melles, M., Bijaksana, S., Morlock, M.A., Hasberg, A.K.M. (2019) Characterization of iron in Lake Towuti sediment. Chemical Geology 512, 11–30. https://doi.org/10.1016/j.chemgeo.2019.02.029
Show in context Reducible iron oxides in sediments originate from lateritic weathering of Towuti’s (ultra)mafic catchment (Morlock et al., 2018) and authigenic oxidation of ferrous iron in the water column (Sheppard et al., 2019).
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Swanner, E.D., Lambrecht, N., Wittkop, C., Harding, C., Katsev, S., Torgeson, J., Poulton, S.W. (2020) The biogeochemistry of ferruginous lakes and past ferruginous oceans. Earth-Science Reviews 211, 103430. https://doi.org/10.1016/j.earscirev.2020.103430
Show in context Modern analogues to Earth’s early oceans (Swanner et al., 2020) that allow the study of both modern pore water geochemistry and short term diagenetic evolution of ferruginous sediments are scarce. One such environment is the ferruginous sediments deposited in the Malili Lakes (Russell et al., 2016), a chain of five interconnected tectonic lakes hosted in variably weathered (ultra)mafic rocks on Sulawesi, Indonesia (Fig. 1a, b).
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Tosca, N.J., Jiang, C.Z., Rasmussen, B., Muhling, J. (2019) Products of the iron cycle on the early Earth. Free Radical Biology and Medicine 140, 138–153. https://doi.org/10.1016/j.freeradbiomed.2019.05.005
Show in context Characterising and identifying such mineral phases is therefore paramount in order to employ their signatures as recorders of past ferruginous environments and as tracers of microbial processes of the Earth’s early oceans (Tosca et al., 2019).
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Vuillemin, A., Friese, A., Alawi, M., Henny, C., Nomosatryo, S., Wagner, D., Crowe, S.A., Kallmeyer, J. (2016) Geomicrobiological Features of Ferruginous Sediments from Lake Towuti, Indonesia. Frontiers in Microbiology 7, 1007. https://doi.org/10.3389/fmicb.2016.01007
Show in context Geomicrobiological investigations have shown that iron-, sulfur- and methane-related biogeochemical processes coexist in Lake Towuti sediments (Vuillemin et al., 2016, 2018).
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Currently bottom waters contain ca. 20 to 12 μM sulfate (Vuillemin et al., 2016), promoting sulfate reduction rates (SRR) that are highest at the sediment water interface (SWI) and drastically drop within the upper 20 cmblf (Fig. 3a).
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Vuillemin, A., Horn, F., Friese, A., Winkel, M., Alawi, M., Wagner, D., Henny, C., Orsi, W.D., Crowe, S.A., Kallmeyer, J. (2018) Metabolical potential of microbial communities from ferruginous sediments. Environmental Microbiology 20, 4297–4313. https://doi.org/10.1111/1462-2920.14343
Show in context Geomicrobiological investigations have shown that iron-, sulfur- and methane-related biogeochemical processes coexist in Lake Towuti sediments (Vuillemin et al., 2016, 2018).
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Vuillemin, A., Wirth, R., Kemnitz, H., Schleicher, A.M., Friese, A., Bauer, K.W., Simister, R., Nomosatryo, S., Ordoñez, L., Ariztegui, D., Henny, C., Crowe, S.A., Benning, L.G., Kallmeyer, J., Russell, J.M., Bijaksana, S., Vogel, H., the Towuti Drilling Project Science Team (2019) Formation of diagenetic siderite in modern ferruginous sediments. Geology 47, 540–544. https://doi.org/10.1130/G46100.1
Show in context Subsequent sediment (trans)formation during early diagenesis (Vuillemin et al., 2019, 2020) precipitates secondary mineral phases, such as siderite (FeCO3) and vivianite (Fe3[PO4]2 · 8H2O).
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Such stepwise fermentation and steady increase in DIC delimit the depth at which pore waters reach siderite saturation (Vuillemin et al., 2019).
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As demonstrated for redox (trans)formation of green rust (Halevy et al., 2017), pore water solutions become saturated with ferrous colloids (Moens et al., 2021) that react with either carbonate or phosphate ions over time to form siderite monocrystals (Vuillemin et al., 2019) and vivianite nodules (Vuillemin et al., 2020).
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Vuillemin, A., Friese, A., Wirth, R., Schuessler, J.A., Schleicher, A.M., Kemnitz, H., Lücke, A., Bauer, K.W., Nomosatryo, S., von Blanckenburg, F., Simister, R., Ordoñez, L.G., Ariztegui, D., Henny, C., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J., the Towuti Drilling Project Science Team (2020) Vivianite formation in ferruginous sediments from Lake Towuti, Indonesia. Biogeosciences 17, 1955–1973. https://doi.org/10.5194/bg-17-1955-2020
Show in context Subsequent sediment (trans)formation during early diagenesis (Vuillemin et al., 2019, 2020) precipitates secondary mineral phases, such as siderite (FeCO3) and vivianite (Fe3[PO4]2 · 8H2O).
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Their presence in pore water could exert control over the onset of vivianite precipitation (Fig. 2d) after siderite (Vuillemin et al., 2020).
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As demonstrated for redox (trans)formation of green rust (Halevy et al., 2017), pore water solutions become saturated with ferrous colloids (Moens et al., 2021) that react with either carbonate or phosphate ions over time to form siderite monocrystals (Vuillemin et al., 2019) and vivianite nodules (Vuillemin et al., 2020).
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Vuillemin, A., Mayr, C., Schuessler, J.A., Friese, A., Bauer, K.W., Lücke, A., Heuer, V.B., Glombitza, C., Henny, C., von Blanckenburg, F., Russell, J.M., Bijaksana, S., Vogel, H., Crowe, S.A., Kallmeyer, J. (2023) A one-million-year isotope record from siderites formed in modern ferruginous sediments. GSA Bulletin 135, 504–522. https://doi.org/10.1130/B36211.1
Show in context These sedimentary conditions make Lake Towuti a unique ferruginous analogue in which to study the evolution of pore water geochemistry under the influence of microbial reduction and mineral (trans)formations prior to sediment lithification (Vuillemin et al., 2023).
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Iron inflows deposited under oxygenated conditions formed reddish clays containing abundant, but poorly reactive, detrital magnetites and diagenetic siderites (Vuillemin et al., 2023).
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Zachara, J.M., Kukkapadu, R.V., Fredrickson, J.K., Gorby, Y.A., Smith, S.C. (2002) Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB). Geomicrobiology Journal 19, 179–207. https://doi.org/10.1080/01490450252864271
Show in context (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003) corresponding to (1) the monimolimnion (Roh et al., 2003), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002) and phosphate-saturated conditions (Morton and Edwards, 2005).
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Supplementary Information
The Supplementary Information includes:
- Supplementary Methods
- Figures S-1 to S-8
- Table S-1
- Supplementary Information References
Download the Supplementary Information (PDF)
Figures
Figure 1 Site description of Lake Towuti. (a) World map displaying the location of Sulawesi Island, with close up on the Indonesia archipelago and location of the Malili Lake System. (b) Map of Sulawesi illustrating the (ultra)mafic and lateritic geology of the Malili Lake catchment. (c) Bathymetric map of Lake Towuti with position of drill site TDP-1A (156 m water depth), dissolved oxygen, iron, sulfate and pH profiles of Lake Towuti’s water column (Bauer et al., 2020
Bauer, K.W., Byrne, J.M., Kenward, P., Simister, R.L., Michiels, C.C., Friese, A., Vuillemin, A., Henny, C., Nomosatryo, S., Kallmeyer, J., Kappler, A., Smit, M.A., Francois, R., Crowe, S.A. (2020) Magnetite biomineralization in ferruginous waters and early Earth evolution. Earth and Planetary Science Letters 549, 116495. https://doi.org/10.1016/j.epsl.2020.116495
), and gravity cores retrieved from 60 and 200 m water depth illustrating redox conditions at the water-sediment interface.
Figure 2 EDX point analyses and SEM images of diagenetic minerals. (Top) Ternary plots show: (a) magnetites and coextracted iron oxides (goethite, wüstite), (b) millerites with incorporation of Fe2+ traces, (c) siderites and (d) vivianites with substitution of Mn2+ for Fe2+. Smelter particles represent airborne contaminants from the nearby mine. (Bottom) (a) Magnetites in framboidal habits; (b) millerites in acicular spherules and aggregates, sometimes entangled and overgrown by siderites; (c) siderites aggregating into twins and mosaic monocrystals; and (d) vivianites in tabular habit developing into rosettes. The crystal section shows inclusions of millerite and siderite.
Figure 3 Depth profiles for pore water geochemistry and stability diagrams for Fe-bearing phases. (a) Lithology of Lake Towuti’s upper 25 mblf including tephras (T) and vivianites (V); potential sulfate reduction rates (SRR); pore water concentrations for sulfate, ferrous iron, manganese, arsenic, cobalt, nitrate, ammonium, phosphate, formate, acetate, lactate, butyrate, methane, dissolved inorganic carbon (DIC), pore water pH, calcium, magnesium, potassium and sodium. Data points represent averaged triplicates (reproducibility <5 %). The dotted line signifies the base of the 14C ages, i.e. 44.7 ka (Russell et al., 2020
Russell, J.M., Vogel, H., Bijaksana, S., Melles, M., Deino, A., Hafidz, A., Haffner, D., Hasberg, A.K.M., Morlock, M., von Rintelen, T., Sheppard, R., Stelbrink, B., Stevenson, J. (2020) The late quaternary tectonic, biogeochemical, and environmental evolution of ferruginous Lake Towuti, Indonesia. Palaeogeography, Palaeoclimatology, Palaeoecology 556, 109905. https://doi.org/10.1016/j.palaeo.2020.109905
). (b) Stability diagram tracing the measured pH and decreasing Eh during sedimentation and burial, successively focusing on conditions (red square) observed during in vitro microbial Fe3+ reduction (Maher et al., 2003Maher, B.A., Alekseev, A., Alekseeva, T. (2003) Magnetic mineralogy of soils across the Russian Steppe: climatic dependence of pedogenic magnetite formation. Palaeogeography, Palaeoclimatology, Palaeoecology 201, 321–341. https://doi.org/10.1016/S0031-0182(03)00618-7
) corresponding to (1) the monimolimnion (Roh et al., 2003Roh, Y., Zhang, C.-L., Vali, H., Lauf, R.J., Zhou, J., Phelps, T.J. (2003) Biogeochemical and environmental factors in Fe biomineralization: magnetite and siderite formation. Clays and Clay Minerals 51, 83–95. https://doi.org/10.1346/CCMN.2003.510110
), (2) sediment water interface (SWI) wherein millerite replaces pyrite (Craw and Bowell, 2014Craw, D., Bowell, R.J. (2014) The Characterization of Arsenic in Mine Waste. Reviews in Mineralogy and Geochemistry 79, 473–505. https://doi.org/10.2138/rmg.2014.79.10
), (3) shallow and (4) deep sediments under carbonate- (Zachara et al., 2002Zachara, J.M., Kukkapadu, R.V., Fredrickson, J.K., Gorby, Y.A., Smith, S.C. (2002) Biomineralization of Poorly Crystalline Fe(III) Oxides by Dissimilatory Metal Reducing Bacteria (DMRB). Geomicrobiology Journal 19, 179–207. https://doi.org/10.1080/01490450252864271
) and phosphate-saturated conditions (Morton and Edwards, 2005Morton, S.C., Edwards, M. (2005) Reduced Phosphorus Compounds in the Environment. Critical Reviews in Environmental Science and Technology 35, 333–364. https://doi.org/10.1080/10643380590944978
), respectively.
Figure 4 Depth profiles for bulk sediment, and pore water geochemistry. (Left to right) Stratigraphy of site TDP-1A with tephras (T) and vivianites (V); XRF core scanning profiles for Ni, S, Fe, Mn and P in bulk sediment overlain by pore water concentrations for SO42−, Fe2+, Mn2+ and PO43−; siderite concentration based on coulometry; total organic carbon (TOC). XRF core scanning profiles represent point analyses with moving averages at 5 mm and 2 cm resolution, respectively. Data points represent averaged triplicates (reproducibility <5 %).