This file was created by the TYPO3 extension publications --- Timezone: CEST Creation date: 2026-04-23 Creation time: 15:00:05 --- Number of references 39 article Ekram2025 Article 2025 10.3390/microorganisms13051005 Microorganisms 13 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105016186250&doi=10.3390%2fmicroorganisms13051005&partnerID=40&md5=03759e0bd94ac76700dab6ff00b4324f Cited by: 1; All Open Access, Gold Open Access Md Akhtar-E Ekram Cornelia Wuchter Satria Bijaksana Kliti Grice James Russell Janelle Stevenson Hendrik Vogel Marco J. L. Coolen article Park2025741 Article 2025 10.1002/jqs.3730 Journal of Quaternary Science 40 741 – 746 5 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105008247517&doi=10.1002%2fjqs.3730&partnerID=40&md5=bcf3659b1ccdd417de214952d48279d5 Cited by: 0; All Open Access, Green Open Access, Hybrid Gold Open Access Jinheum Park Christine S. Lane Clive Oppenheimer Céline-Marie Vidal Christina J. Manning Francesca Forni Hendrik Vogel Satria Bijaksana James M. Russell article Ruiz-Blas2025 Article 2025 10.1007/s00248-025-02559-4 Microbial Ecology 88 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-105007215529&doi=10.1007%2fs00248-025-02559-4&partnerID=40&md5=8340f2022ccc916c73bed1c80d9177b5 Cited by: 0 Fatima Ruiz-Blas André Friese Alexander Bartholomäus Cynthia Henny James M. Russell Jens Kallmeyer Aurèle Vuillemin article Ferruginous conditions prevailed through Earth’s early oceans history, yet our understanding of biogeochemical cycles in anoxic iron-rich, sulfate-poor sediments remains elusive in terms of redox processes and organic matter remineralization. Using comprehensive geochemistry, cell counts and metagenomic data, we investigated the taxonomic and functional distribution of the microbial subsurface biosphere in Lake Towuti, a stratified ferruginous analogue. Below the zone in which pore water becomes depleted in electron acceptors, cell densities exponentially decreased while microbial assemblages shifted from iron- and sulfate-reducing bacterial populations to fermentative anaerobes and methanogens, mostly selecting Bathyarchaeia below the sulfate reduction zone. Bathyarchaeia encode metabolic machinery to cycle and assimilate polysulfides via sulfhydrogenase, sulfide dehydrogenase and heterodisulfide reductase, using dissimilatory sulfite reductase subunit E and rubredoxin as carriers. Their metagenome-assembled genomes showed that carbon fixation could proceed through the complete methyl-branch Wood-Ljungdahl pathway, conducting (homo)acetogenesis in the absence of methyl coenzyme M reductase. Further, their partial carbonyl-branch, assumed to act in tetrahydrofolate interconversions of C1 and C2 compounds, could support close interactions with methylotrophic methanogens in the fermentation zone. Thus, Bathyarchaeia appeared capable of coupling sulfur-redox reactions with fermentative processes, using electron bifurcation in a redox-conserving (homo)acetogenic Wood-Ljungdahl pathway, and revealing geochemical ferruginous conditions at the transition between the sulfate reduction and fermentation zone as their preferential niche. 2024 09 2730-6151 10.1093/ismeco/ycae112 ISME Communications https://doi.org/10.1093/ismeco/ycae112 Fatima Ruiz-Blas Alexander Bartholomäus Sizhong Yang Dirk Wagner Cynthia Henny James M Russell Jens Kallmeyer Aurèle Vuillemin article RN71 Studying past ecosystems from ancient environmental DNA preserved in lake sediments (sedaDNA) is a rapidly expanding field. This research has mainly involved Holocene sediments from lakes in cool climates, with little known about the suitability of sedaDNA to reconstruct substantially older ecosystems in the warm tropics. Here, we report the successful recovery of chloroplast trnL (UAA) sequences (trnL-P6 loop) from the sedimentary record of Lake Towuti (Sulawesi, Indonesia) to elucidate changes in regional tropical vegetation assemblages during the lake's Late Quaternary paleodepositional history. After the stringent removal of contaminants and sequence artifacts, taxonomic assignment of the remaining genuine trnL-P6 reads showed that native nitrogen-fixing legumes, C3 grasses, and shallow wetland vegetation (Alocasia) were most strongly associated with >1-million-year-old (>1 Ma) peats and silts (114–98.8 m composite depth; mcd), which were deposited in a landscape of active river channels, shallow lakes, and peat-swamps. A statistically significant shift toward partly submerged shoreline vegetation that was likely rooted in anoxic muddy soils (i.e., peatland forest trees and wetland C3 grasses (Oryzaceae) and nutrient-demanding aquatic herbs (presumably Oenanthe javanica)) occurred at 76 mcd (~0.8 Ma), ~0.2 Ma after the transition into a permanent lake. This wetland vegetation was most strongly associated with diatom ooze (46–37 mcd), thought to be deposited during maximum nutrient availability and primary productivity. Herbs (Brassicaceae), trees/shrubs (Fabaceae and Theaceae), and C3 grasses correlated with inorganic parameters, indicating increased drainage of ultramafic sediments and laterite soils from the lakes' catchment, particularly at times of inferred drying. Downcore variability in trnL-P6 from tropical forest trees (Toona), shady ground cover herbs (Zingiberaceae), and tree orchids (Luisia) most strongly correlated with sediments of a predominantly felsic signature considered to be originating from the catchment of the Loeha River draining into Lake Towuti during wetter climate conditions. However, the co-correlation with dry climate-adapted trees (i.e., Castanopsis or Lithocarpus) plus C4 grasses suggests that increased precipitation seasonality also contributed to the increased drainage of felsic Loeha River sediments. This multiproxy approach shows that despite elevated in situ temperatures, tropical lake sediments potentially comprise long-term archives of ancient environmental DNA for reconstructing ecosystems, which warrants further exploration. © 2024 The Authors. Geobiology published by John Wiley & Sons Ltd. Article 2024 10.1111/gbi.12599 Geobiology 22 John Wiley and Sons Inc e12599 3 Greater Sunda Islands; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; catchment; ground cover; Holocene; landscape ecology; nutrient availability; ooze; paleoecology; paleoenvironment; peatland; seasonality; tropical forest https://www.ncbi.nlm.nih.gov/pubmed/38745401 Cited by: 0; All Open Access, Hybrid Gold Open Access M. A. Ekram M. Campbell S. H. Kose C. Plet R. Hamilton S. Bijaksana K. Grice J. Russell J. Stevenson H. Vogel M. J. L. Coolen article Ageli2024 Article 2024 10.1016/j.jglr.2023.09.001 Journal of Great Lakes Research 50 3 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85171973485&doi=10.1016%2fj.jglr.2023.09.001&partnerID=40&md5=d134f86bcff08204cd9cb420f17e14f1 Cited by: 1 Mariam K. Ageli Paul B. Hamilton Andrew J. Bramburger James Russell Hendrik Vogel Satria Bijaksana G. Douglas Haffner article RN97 2024 10.1093/femsec/fiae140 FEMS Microbiol Ecol https://www.ncbi.nlm.nih.gov/pubmed/39384533 A. Vuillemin F. Ruiz-Blas S. Yang A. Bartholomaus C. Henny J. Kallmeyer article Vuillemin2023504 Ancient iron formations hold important records of environmental conditions during the Precambrian eons. Reconstructions of past oceanic systems require investigation of modern ferruginous analogs to disentangle water column and diagenetic signals recorded in iron-bearing minerals. We analyzed oxygen, iron, and carbon isotopes in siderite, a ferrous carbonate phase commonly used as an environmental proxy, from a 100-m-long record spanning a 1 Ma depositional history in ferruginous Lake Towuti, Indonesia. Combining bulk sediment and pore water geochemistry, we traced processes controlling siderite isotope signatures. We show that siderite oxygen isotope compositions (δ18O) reflect in-lake hydrological and depositional conditions. Low iron isotope values (δ56Fe) record water column oxygenation events over geological timescales, with minor diagenetic partitioning of Fe isotopes by microbial iron reduction after deposition. The carbon isotope compositions (δ13C) reflect the incorporation of biogenic HCO3 –, which is consistent with sediment organic matter remineralization lasting over ca. 200 ka after burial. Positive δ13C excursions indicate an increased production of biogenic methane that escaped the sediment during low lake levels. Diffusion across the sediment–water interface during initial formation of siderites tends to align the isotope signatures of bottom waters to those of pore waters. As microbial reduction of ferric iron and oxidation of organic matter proceed and saturate pore water conditions with respect to siderite, overgrowth on nuclei partially mutes the environmental signal inherited from past bottom waters over ca. 1 Ma. Because high depositional fluxes of ferric iron and organic matter in early oceans would have promoted similar microbial processes in ferruginous deposits prior to lithification, the environmental record contained in siderite grains can successively integrate depositional and early diagenetic signals over short geological timescales. © 2022 Geological Society of America Article 2023 English 00167606 10.1130/B36211.1 Bulletin of the Geological Society of America 135 Geological Society of America 504 – 522 1-2 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biogeochemistry; Deposition; Geology; Iron; Iron ores; Isotopes; Organic compounds; Oxygen; Sediments; Water; Biogenics; Bottom water; Diagenetics; Geological timescales; Iron isotopes; Isotope record; Isotope signatures; Pore waters; Water columns; δ13C; carbon isotope; depositional environment; iron; isotopic composition; oxygen; oxygenation; Precambrian; sediment chemistry; sediment-water interface; siderite; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85143396496&doi=10.1130%2fB36211.1&partnerID=40&md5=8445726b48462a7e05fb31da2b295465 Cited by: 1; All Open Access, Green Open Access Aurèle Vuillemin Christoph Mayr Jan A. Schuessler André Friese Kohen W. Bauer Andreas Lücke Verena B. Heuer Clemens Glombitza Cynthia Henny Friedhelm Blanckenburg James M. Russell Satria Bijaksana Hendrik Vogel Sean A. Crowe Jens Kallmeyer article WOS:001177567400001 2023 10.7185/geochemlet.2339 GEOCHEMICAL PERSPECTIVES LETTERS 28 20-26 A. Vuillemin M. Morlock A. Paskin L. G. Benning C. Henny J. Kallmeyer J. M. Russell H. Vogel article RN10 Located at the triple junction of the Pacific, Eurasian and Sunda plates, the Island of Sulawesi in Indonesia is one of the most tectonically active places on Earth. This is highlighted by the recurrence of devastating earthquakes such as the 2018 Mw 7.5 earthquake that damaged the city of Palu and caused several thousand fatalities in central Sulawesi. The majority of large-magnitude earthquakes on Sulawesi are related to stress release along major strike-slip faults such as the Palu-Koro Fault and its southern extensions, the Matano and Lawanopo Faults. To date, information on the frequency and magnitude of past major events on these faults is limited to instrumental records and historical sources restricted to the last century, whereas information from natural archives is completely lacking. Lake-sediment records can fill this gap, but a detailed assessment of the various factors that influence the sensitivity of sediment successions to past earthquakes is required to evaluate their suitability. Lake Towuti, situated in Eastern Sulawesi, is known for its paleoclimate record and also promises to be a key site to generate a paleoseismology record for Sulawesi. The lake lies close to the highly active Matano and Lawanopo strike-slip faults and thereby is an ideal archive for past earthquakes that have occurred in the surrounding area. Here we combine high-resolution chirp seismic data with lithostratigraphic and petrophysical data of sediment piston cores to assess the recurrence of seismically generated mass-transport and turbidite deposits. Three major seismic-stratigraphic units are distinguished in the upper ∼10 m of the sediment succession and linked to differences in the frequency of mass-wasting during the past 60 kyrs. The evidence of a more turbidite-prone period between 12 and 40 ka is roughly coincident with a dry phase and associated lake-level lowstand during the last glacial period at Lake Towuti. Hence, we suggest that climate strongly influences the sensitivity of slopes to fail during seismic shaking in this tropical setting as a consequence of lowstand-forced sediment redeposition from the shelves onto the slopes and into the basins. As climate significantly impacts the sensitivity of the lacustrine sediments to record earthquake-related mass wasting deposits, we suggest that the frequency of mass-transport deposits can additionally be employed as a quantitative indicator for past changes in hydroclimate in these tropical settings. © 2023 The Authors Article 2023 English 02773791 10.1016/j.quascirev.2023.108015 Quaternary Science Reviews 305 Elsevier Ltd Catchments; Earth system models; Earthquakes; Fault slips; Sediments; Stratigraphy; Strike-slip faults; Tropics; Indonesia; Lake level changes; Lake sediments; Late Pleistocene; Mass transport deposit; Mass wasting; Paleoclimates; Paleoseismology; Seismic stratigraphy; Sulawesi/indonesia; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85149434395&doi=10.1016%2fj.quascirev.2023.108015&partnerID=40&md5=999ae654fcd6bf6c1b23f876f358e095 Cited by: 0; All Open Access, Hybrid Gold Open Access Nicolas Tournier Stefano C. Fabbri Flavio S. Anselmetti Sri Yudawati Cahyarini Satria Bijaksana Nigel Wattrus James M. Russell Hendrik Vogel article Ageli2022 Many large, ancient lakes support primarily planktonic-driven food webs. In contrast, the lowest trophic levels of the Malili Lakes of Sulawesi Island, Indonesia are dominated by benthic diatom communities composed mainly of endemic species. Centric diatoms are not observed in the current diatom assemblage and pennate pelagic species are rare. Using two deep drill-cores from Lake Towuti, we investigated whether the lake has always been dominated by benthic primary production. Despite the ultra-oligotrophic conditions observed in the lake today, we observed state changes characterized by productive planktonic communities and less productive, benthic-dominated diatom assemblages. Two periods of planktonic production, each lasting approximately 50 kyr, were dominated by a complex mixture of Aulacoseira spp., with valve densities >1.0 × 109 valves/g with a maximum biovolume of 3.5 × 1012 μm3/g. A similar planktonic assemblage was observed at much lower abundances (<107valves/g) in the deeper sediments (>1 Ma), during the earliest stages of lake formation. Two periods of increased benthic primary production of approximately ~11 kyr in duration, originating from the littoral zone of the lake, were also observed, one between the two planktonic phases and one above the last planktonic maxima. The benthic periods were dominated by Cymbopleura spp., with valve densities of approximately 2.0 × 108 valves/g and a maximum biovolume of 1.2 × 1011 μm3/g. Nonmetric multidimensional scaling analysis of sediment chemistry revealed that the benthic and pelagic states clustered with distinct chemical environments. The benthic phases were associated with well-mixed conditions in the lake whereas the planktonic phases were related to rapidly reoccurring water column mixing followed by intense stratification that generate nutrient recycling events. We conclude that lake mixing and nutrient cycling regimes regulated, in part, the switch between benthic and pelagic states in Lake Towuti. © 2022 Article 2022 English 00310182 10.1016/j.palaeo.2022.110937 Palaeogeography, Palaeoclimatology, Palaeoecology 594 Elsevier B.V. Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; benthic-pelagic coupling; plankton; primary production; sediment chemistry; trophic level https://www.scopus.com/inward/record.uri?eid=2-s2.0-85127109089&doi=10.1016%2fj.palaeo.2022.110937&partnerID=40&md5=c3d1e956aa984d029a95e099469dca2f Cited by: 0 Mariam K. Ageli Paul B. Hamilton Andrew J. Bramburger R. Paul Weidman Zhuoyan Song James Russell Satria Bijaksana G. Douglas Haffner article Ulfers2021377 Lake Towuti is located on central Sulawesi/Indonesia, within the Indo Pacific Warm Pool, a globally important region for atmospheric heat and moisture budgets. In 2015 the Towuti Drilling Project recovered more than 1000 m of drill core from the lake, along with downhole geophysical logging data from two drilling sites. The cores constitute the longest continuous lacustrine sediment succession from the Indo Pacific Warm Pool. We combined lithological descriptions with borehole logging data and used multivariate statistics to better understand the cyclic sequence, paleoenvironments, and geochronology of these sediments. Accurate chronologies are crucial to analyze and interpret paleoclimate records. Astronomical tuning can help build age-depth models and fill gaps between age control points. Cyclostratigraphic investigations were conducted on a downhole magnetic susceptibility log from the lacustrine facies (10–98 m below lake floor) from a continuous record of sediments in Lake Towuti. This study provides insights into the sedimentary history of the basin between radiometric ages derived from dating a tephra layer (~ 797 ka) and C14-ages (~ 45 ka) in the cores. We derived an age model that spans from late marine isotope stage (MIS) 23 to late MIS 6 (903 ± 11 to 131 ± 67 ka). Although uncertainties caused by the relatively short record and the small differences in the physical properties of sediments limited the efficacy of our approach, we suggest that eccentricity cycles and/or global glacial-interglacial climate variability were the main drivers of local variations in hydroclimate in central Indonesia. We generated the first nearly complete age-depth model for the lacustrine facies of Lake Towuti and examined the potential of geophysical downhole logging for time estimation and lithological description. Future lake drilling projects will benefit from this approach, since logging data are available just after the drilling campaign, whereas core descriptions, though more resolved, only become available months to years later. © 2021, The Author(s). Article 2021 English 09212728 10.1007/s10933-020-00171-9 Journal of Paleolimnology 65 Springer Science and Business Media B.V. 377 – 392 4 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; borehole logging; cyclostratigraphy; eccentricity; facies analysis; lacustrine deposit; magnetic susceptibility; marine isotope stage; moisture content; paleoclimate; proxy climate record; tephra; warm pool https://www.scopus.com/inward/record.uri?eid=2-s2.0-85100995329&doi=10.1007%2fs10933-020-00171-9&partnerID=40&md5=5a081a525c5d24340e0c426e30322de6 Cited by: 3; All Open Access, Green Open Access, Hybrid Gold Open Access A. Ulfers K. Hesse C. Zeeden J.M. Russell H. Vogel S. Bijaksana T. Wonik article Sheppard2021 Iron is the most abundant redox-sensitive element on the Earth's surface, and the oxidation state, mineral host, and crystallinity of Fe-rich phases in sedimentary systems can record details of water-rock interactions and environmental conditions. However, we lack a complete understanding of how these Fe-rich materials are created, maintained, and oxidized or reduced in sedimentary environments, particularly those with mafic sources. The catchment of Lake Towuti, Indonesia, is known to contain a wide range of abundant crystalline Fe oxide, and the lake has a long sedimentary history. Here, we study a ∼100 m long drill core from the lake to understand patterns of sedimentation and how young iron-rich sediments are affected by diagenesis through geologic time. We use visible/near infrared and Mössbauer spectroscopy, X-ray diffraction, bulk chemistry measurements, and statistical cluster analysis to characterize the core sediment. We find that the core sediment can be divided into three statistically different zones dominated by Mg serpentine, Al clay minerals, and Fe2+ carbonate, respectively. The entire core is rich in nanophase Fe, and elemental correlations and Fe mineralogy vary between these zones. The nanophase Fe is highly complex with both ferrous and ferric components, and contributes to, but does not dictate, variations in sediment color. We propose that the distinctive zones are the result of structural basin changes (notably river capture and shifting drainage patterns), and diagenetic overprinting caused by deep burial of reactive Fe. This complex record has implications for disentangling depositional and diagenetic trends in other mafic lacustrine systems. © 2021. American Geophysical Union. All Rights Reserved. Article 2021 English 15252027 10.1029/2020GC009582 Geochemistry, Geophysics, Geosystems 22 John Wiley and Sons Inc 8 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Catchments; Chemical analysis; Cluster analysis; Crystallinity; Drills; Infill drilling; Iron oxides; Lakes; Nanocrystalline materials; Runoff; Sedimentary rocks; Sedimentology; Sediments; Serpentine; Drainage patterns; Environmental conditions; Lacustrine systems; Redox sensitives; Sedimentary environment; Sedimentary systems; Visible/near infrared; Water rock interactions; diagenesis; iron oxide; lacustrine deposit; mineralogy; sediment chemistry; sediment core; sedimentation; Core drilling https://www.scopus.com/inward/record.uri?eid=2-s2.0-85113753437&doi=10.1029%2f2020GC009582&partnerID=40&md5=20c2e0e060f5681bfadd583832697d3a Cited by: 0; All Open Access, Bronze Open Access, Green Open Access Rachel Y. Sheppard Ralph E. Milliken James M. Russell Elizabeth C. Sklute M. Darby Dyar Satria Bijaksana Ascelina K. M. Hasberg Marina A. Morlock article Friese2021 Article 2021 10.1038/s41467-021-22453-0 Nature Communications 12 1 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85104316745&doi=10.1038%2fs41467-021-22453-0&partnerID=40&md5=d90e3f0bf3f2ae016577ce5836e19a88 Cited by: 46; All Open Access, Gold Open Access, Green Open Access André Friese Kohen Bauer Clemens Glombitza Luis Ordoñez Daniel Ariztegui Verena B. Heuer Aurèle Vuillemin Cynthia Henny Sulung Nomosatryo Rachel Simister Dirk Wagner Satria Bijaksana Hendrik Vogel Martin Melles James M. Russell Sean A. Crowe Jens Kallmeyer article Morlock20211040 Continental and marine sediments are composed of a mixture from different sources and are influenced by a variety of environmental factors and transport processes prior to deposition. For analysis and interpretation, these sources and processes are often challenging to disentangle. We show that end-member modelling of X-ray fluorescence (XRF) core-scanning data helps to overcome these challenges by unmixing different environmental signals from high-resolution sediment geochemical records. We apply this approach to a 100 m long lacustrine succession from Lake Towuti, Indonesia, to separate the regional climate and tectonic history from local ecological and diagenetic processes. The resulting six end-members (EMs) are interpreted to represent changes in ecological (EM1), climatic (EMs 2–4), tectonic (EM 5) and geomorphic (EM6) processes determining changes in sediment composition. Because end-member analysis allows for the tracking of transient and overlapping processes, climatic changes can be followed throughout the 100 m-long succession, suggesting alternating wet and dry periods in Central Sulawesi over long (several 100 000 years) time scales. We show that end-member analysis on elemental data sets offers a detailed and objective means to disentangle depositional processes in sedimentary successions resulting from varying tectonic and environmental factors involved in sediment formation and deposition. © 2021 John Wiley & Sons, Ltd. Article 2021 English 02678179 10.1002/jqs.3338 Journal of Quaternary Science 36 John Wiley and Sons Ltd 1040 – 1051 6 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; data set; depositional environment; environmental change; geochemistry; marine sediment; Quaternary; sediment analysis; sediment transport; X-ray fluorescence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85110376909&doi=10.1002%2fjqs.3338&partnerID=40&md5=176711daa48b6cea40181303e99cf223 Cited by: 4 Marina A. Morlock James M. Russell Satria Bijaksana article Bauer2020 Burial of large quantities of magnetite (Fe(II)Fe(III)2O4) in iron formations (IFs) likely contributed to the protracted oxidation of Earth's surface during the Precambrian Eons. Magnetite can form through a diversity of biological and abiotic pathways and its preservation in IFs may thus be variably interpreted as the result of some combination of these processes. Such interpretations give rise to divergent pictures of the Precambrian Earth system and models for its evolution through time. New knowledge on the contribution of specific magnetite formation pathways is, therefore, needed to accurately tether our conceptual and numerical models to the geologic record. To constrain pathways of magnetite formation under ferruginous conditions, we conducted geochemical and multi-method microspectroscopic analyses on particles obtained from the water columns and sediments of ferruginous lakes Matano and Towuti, in Indonesia. We find that biologically reactive Fe(III) mineral phases are reduced in the anoxic waters of both lakes, causing the formation of primary authigenic magnetite, directly in the water column. This water column magnetite often takes conspicuous framboidal forms, which given the link to microbial Fe(III) reduction, may provide a biological signature on early Earth and by extension, other planetary bodies. The consumption of more biologically reactive forms of Fe(III) and the resulting delivery of primary magnetite to underlying sediments promotes the burial of oxidized equivalents and implies that primary magnetite formation could have been a principal pathway of Fe delivery to IFs. Combined, the removal of Fe from Earth's surface through biologically induced magnetite formation and subsequent burial in IFs, suggests that seawater chemistry and the microbially mediated reactions that cause magnetite formation played key roles in Earth system evolution and in setting the pace for planetary oxidation through the Precambrian Eons. © 2020 Article 2020 English 0012821X 10.1016/j.epsl.2020.116495 Earth and Planetary Science Letters 549 Elsevier B.V. Greater Sunda Islands; Lake Matano; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biology; Biomineralization; Geologic models; Lakes; Magnetite; Ore reduction; Oxidation; Abiotic pathways; Biological signatures; Earth's surface; Magnetite formation; Mediated reactions; Planetary bodies; Precambrian eons; Seawater chemistry; biomineralization; early Earth; evolution; lacustrine deposit; magnetite; mass spectrometry; oxidation; Precambrian; water column; Iron compounds https://www.scopus.com/inward/record.uri?eid=2-s2.0-85089556687&doi=10.1016%2fj.epsl.2020.116495&partnerID=40&md5=29b4c47bce8584158d0568916a2c7765 Cited by: 6; All Open Access, Green Open Access K.W. Bauer J.M. Byrne P. Kenward R.L. Simister C.C. Michiels A. Friese A. Vuillemin C. Henny S. Nomosatryo J. Kallmeyer A. Kappler M.A. Smit R. Francois S.A. Crowe article Hamilton2020 Any palynologist who has worked in the tropics has undoubtedly dealt with the frustration of trying to classify small, tricolporate pollen into meaningful taxonomic groups. While this is not a significant issue where coarse-scale identifications represent similar habitat indicators or “unknown” types are rare, it poses a problem when one of these “unknowns” overwhelm the record. This is the case with unknown “type 69” – a small, tricolporate pollen grain encountered within a 60,000-year sediment sequence from Lake Towuti in Sulawesi, Indonesia. This type comprises up to 35% of the pollen count for some Last Glacial Maximum (LGM) samples (highlighting its climatic sensitivity) but could not be identified by experts in the field. This study thus aimed to compare the metrics of “type 69” with reference pollen from Sulawesi to aid with its identification. In doing so, we present a pollen atlas of 63 maritime southeast Asian pollen types. Our results show that “type 69” aligns with metrics taken from Saurauia pollen. While detailed ecological data on Saurauia species in Sulawesi are lacking, they appear to favor higher elevations and riverbank settings, and are post-disturbance colonizers. Proliferation of this pollen type during the LGM is therefore linked to a combination of downslope range expansion of Saurauia species under a cooler climate and potentially, out competition of upland everwet forest taxa. This study demonstrates an approach to managing important unknown fossil pollen types in tropical records and, through the ensuing pollen atlas, provides a tool for progressing palynology in southeast Asia. © 2019 Elsevier B.V. Article 2020 English 00346667 10.1016/j.revpalbo.2019.104146 Review of Palaeobotany and Palynology 273 Elsevier B.V. Greater Sunda Islands; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Saurauia; colonization; fossil record; Last Glacial Maximum; palynology; range expansion; river bank; sedimentary sequence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85075997785&doi=10.1016%2fj.revpalbo.2019.104146&partnerID=40&md5=35e09bd5879c1ba2a0c9e4771da010a8 Cited by: 1 R. Hamilton J. Stevenson article Russell2020 There is a paucity of long and continuous continental records from South East Asia suitable to inform on past changes and underlying causes of the region's climate and associated diverse ecosystem evolution during the late Quaternary. In 2015, the Towuti Drilling Project (TDP) collected a series of sedimentary drill cores from the tectonic, ferruginous, and highly biodiverse Lake Towuti, Sulawesi, one of Indonesia's oldest lakes. The drill cores contain ~1 Myr of uninterrupted lacustrine sedimentation to document long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediment. Here we use lithostratigraphic, mineralogical, geochemical, and geochronological datasets to elucidate Lake Towuti's tectonic emergence and its biogeochemical responses to climatic and volcanic forcings since lake formation. Our data document that Lake Towuti emerged during a phase of accelerated tectonic subsidence from a landscape characterized by active river channels, shallow lakes and swamps into a permanent lake at ~1 Ma. The lacustrine sediments feature quasi-rhythmic alternations of green organic rich and red sideritic clay beds reflecting changes in lake mixing and biogeochemistry as a response to temperature and hydrological changes driven by orbital-scale changes in insolation and continental ice volume through the mid- to late Pleistocene. Clay deposition is interrupted by two beds of diatomaceous oozes composed primarily of planktonic diatoms that reflect phases of substantially increased primary productivity. The occurrence of these diatomaceous oozes in close association with multiple tephra beds suggests a trophic state change driven by the addition of volcanically sourced P, possibly in combination with a lake mixing state that supports recycling of P. Data on lake age and ontogeny are also in agreement with molecular-clock estimates of ~0.7 Ma (0.18–1.37 Ma) for the divergence of Lake Towuti's Telmatherinid fishes from a riverine ancestor. Our data therefore are compatible with an evolutionary model in which Lake Towuti's endemic fauna is a result of geographic speciation in the Malili Lakes, a set of large lakes in Southeast Sulawesi, driven by physical or chemical dispersal limits imposed by the regional rivers and lakes. More detailed chronological constraints and refined climate and environmental proxy datasets are currently in preparation and will help to paint a more detailed history of the region's climate and environmental history in future studies. © 2020 Elsevier B.V. Article 2020 English 00310182 10.1016/j.palaeo.2020.109905 Palaeogeography, Palaeoclimatology, Palaeoecology 556 Elsevier B.V. Far East; Greater Sunda Islands; Lake Towuti; Malili Lakes; Pacific Ocean; Pacific Ocean (West); South Sulawesi; Sulawesi; Sunda Isles; Bacillariophyta; Pisces; Telmatherinidae; biogeochemistry; climate variation; diatom; dispersal; lacustrine deposit; Pleistocene; Quaternary; speciation (biology); subsidence https://www.scopus.com/inward/record.uri?eid=2-s2.0-85087995636&doi=10.1016%2fj.palaeo.2020.109905&partnerID=40&md5=2a2ce03ed0a0376342b00a48e94c95db Cited by: 8; All Open Access, Green Open Access James M. Russell Satria Bijaksana Alan Deino Abdul Hafidz Doug Haffner Ascelina K.M. Hasberg Marina Morlock Thomas Rintelen Rachel Sheppard Björn Stelbrink Janelle Stevenson article Vuillemin20201955 Ferruginous lacustrine systems, such as Lake Towuti, Indonesia, are characterized by a specific type of phosphorus cycling in which hydrous ferric iron (oxyhydr) oxides trap and precipitate phosphorus to the sediment, which reduces its bioavailability in the water column and thereby restricts primary production. The oceans were also ferruginous during the Archean, thus understanding the dynamics of phosphorus in modern-day ferruginous analogues may shed light on the marine biogeochemical cycling that dominated much of Earth’s history. Here we report the presence of large crystals ( > 5 mm) and nodules (> 5 cm) of vivianite – a ferrous iron phosphate – in sediment cores from Lake Towuti and address the processes of vivianite formation, phosphorus retention by iron and the related mineral transformations during early diagenesis in ferruginous sediments. Core scan imaging, together with analyses of bulk sediment and pore water geochemistry, document a 30m long interval consisting of sideritic and non-sideritic clayey beds and diatomaceous oozes containing vivianites. Highresolution imaging of vivianite revealed continuous growth of crystals from tabular to rosette habits that eventually form large (up to 7 cm) vivianite nodules in the sediment. Mineral inclusions like millerite and siderite reflect diagenetic mineral formation antecedent to the one of vivianite that is related to microbial reduction of iron and sulfate. Together with the pore water profiles, these data suggest that the precipitation of millerite, siderite and vivianite in soft ferruginous sediments stems from the progressive consumption of dissolved terminal electron acceptors and the typical evolution of pore water geochemistry during diagenesis. Based on solute concentrations and modeled mineral saturation indices, we inferred vivianite formation to initiate around 20m depth in the sediment. Negative 56Fe values of vivianite indicated incorporation of kinetically fractionated light Fe2C into the crystals, likely derived from active reduction and dissolution of ferric oxides and transient ferrous phases during early diagenesis. The size and growth history of the nodules indicate that, after formation, continued growth of vivianite crystals constitutes a sink for P during burial, resulting in long-term P sequestration in ferruginous sediment. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Article 2020 English 17264170 10.5194/bg-17-1955-2020 Biogeosciences 17 Copernicus GmbH 1955 – 1973 7 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; diagenesis; electron; geochemistry; iron oxide; phosphate; phosphorus; porewater; saturation; sediment analysis; siderite; vivianite; water column https://www.scopus.com/inward/record.uri?eid=2-s2.0-85083457042&doi=10.5194%2fbg-17-1955-2020&partnerID=40&md5=d15dddd5415f1948dde1ece4c0385f52 Cited by: 15; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin André Friese Richard Wirth Jan A. Schuessler Anja M. Schleicher Helga Kemnitz Andreas Lücke Kohen W. Bauer Sulung Nomosatryo Friedhelm Von Blanckenburg Rachel Simister Luis G. Ordoñez Daniel Ariztegui Cynthia Henny James M. Russell Satria Bijaksana Hendrik Vogel Sean A. Crowe Jens Kallmeyer conference Andika2019 Multiple attenuation effect study in Lake Towuti seismic data is based on limited offset recording. The goal of this study is to better understand the sediments structure of Lake Towuti that layered above East Sulawesi ophiolitic and metamorphic rocks for stratigraphic interpretation. Surface-related multiple and internal multiple are a common noise signal that recorded in this seismic data, alongside the primary signal from the sediments layer. In order to get a representative subsurface image of the lake, a combination of some de-multiple method to suppress this noise signal has been applied in previous study. However, the line seismic that used in this seismic recording is less than 100 m. From our perspective, this limited offset line fact have to be considered carefully. It's because some application of de-multiple method in this case will not effectively suppress the noise. In this study, we give an alternative combination method in function to put out the surface-related multiple of the case. First, we enhance the S/N ratio and velocity analysis of the data by Common Reflection Surface (CRS) method. From this enhancement, CRS can give a direct advantage when applying some de-multiple method, especially in Predictive Deconvolution and SRME method. Moreover, we combine the application of de-multiple theory with the strict arrangement of Predictive Deconvolution, Surface-Related Multiple Elimination (SRME), and the last is F-K filter. Those combination methods precisely give a better imaging of Lake Towuti sediments layer in this seismic processing study. © 2019 Published under licence by IOP Publishing Ltd. Conference paper 2019 English 17551307 10.1088/1755-1315/279/1/012033 IOP Conference Series: Earth and Environmental Science 279 Institute of Physics Publishing Azis M.I. 1 Metamorphic rocks; Sediments; Seismic prospecting; Seismic response; Seismic waves; Stratigraphy; Combination method; Common reflection surfaces; Multiple attenuation; Predictive deconvolution; Seismic processing; Seismic recording; Subsurface images; Surface-related multiple elimination; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85072639481&doi=10.1088%2f1755-1315%2f279%2f1%2f012033&partnerID=40&md5=acd394e15740c12592d71ce5edbab714 Cited by: 0; All Open Access, Bronze Open Access Ryan Bobby Andika Wahyu Triyoso Satria Bijaksana Abd. Hafidz James M. Russell Nigel Watruss article Hasberg2019675 Lake Towuti on Sulawesi Island, Indonesia, is located within the heart of the Indo-Pacific Warm Pool. This tropical lake is surrounded by ultramafic (ophiolitic) rocks and lateritic soils that create a unique ferruginous depositional setting. In order to understand modern sediment deposition in Lake Towuti, a set of 84 lake surface sediment samples was collected from across the entirety of the lake and samples were analyzed for their physical, chemical, mineralogical and biological constituents. End-member analyses were carried out to elucidate modern sediment origin, transport and depositional processes. This study found that allochthonous sediment, characterized by the concentrations of the elements Mg, Fe, Si and Al, as well as the clay and serpentine minerals, is dominated by fluvial supply from five distinct source areas. Granulometric data and the occurrence of organic matter of a terrestrial origin suggest that, in the southern and north-eastern parts of the lake the near-shore sediments may additionally be influenced by mass wasting. This is due at least partly to the particularly steep slopes in these areas. Furthermore, sediment composition suggests that sediment transport into deeper parts of the lake, particularly in the northern basin, is partly controlled by gravitational and density-driven processes such as turbidity currents. Directional sediment transport by persistent lake currents, in contrast, appears to be less important. Organic matter deposition in the ultra-oligotrophic lake, albeit limited, is dominated by autochthonous production, but with some contribution of fluvial and gravitational supply. Biogenic silica deposition, primarily from diatom frustules and sponge spicules, is very limited and is concentrated in only a few areas close to the shoreline that are characterized by shallow waters, but away from the areas of high suspension loads at the mouths of the major inlets. The results of this study build upon current and published work on short piston cores from Lake Towuti. Conversely, the results will support the interpretation of the depositional history and past climatic and environmental conditions derived from the composition of much longer records, which were obtained by the Towuti Drilling Project in May 2015 and are currently under investigation. © 2018 The Authors. Sedimentology © 2018 International Association of Sedimentologists Article 2019 English 00370746 10.1111/sed.12503 Sedimentology 66 Blackwell Publishing Ltd 675 – 698 2 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Bacillariophyta; Biogeochemistry; Biological materials; Chemical analysis; Gravitation; Ocean currents; Organic compounds; Sediment transport; Sedimentation; Serpentine; Silica; Silicate minerals; Surficial sediments; Suspensions (fluids); Depositional process; Environmental conditions; Pacific warm pool; Provenance analysis; Redox condition; Sediment composition; Sedimentation process; Tropical lakes; depositional environment; lacustrine deposit; provenance; redox conditions; sediment transport; sedimentation; shallow water; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-85052403974&doi=10.1111%2fsed.12503&partnerID=40&md5=f4a62f810d995f41dfae24a779bc0f74 Cited by: 18; All Open Access, Green Open Access Ascelina K. M. Hasberg Satria Bijaksana Peter Held Janna Just Marina A. Morlock Stephan Opitz James M. Russell article Sheppard201911 Sediments collected from Lake Towuti, an ultramafic-hosted lake in Indonesia, preserve a visible alternating pattern of red and green sediments due to variations in clay mineral and Fe-oxide composition and abundance consistent with changes in iron oxidation state through time. Spectral, mineralogical, and chemical analyses on soils, river, and sediment samples from across the lake and its catchment were carried out to better understand the starting composition of these sediments and the processes that affected them before and after deposition. Despite high Fe abundances in all samples and abundant Fe oxides in lateritic source regions, mineralogical analyses (X-ray diffraction (XRD) and Mössbauer spectroscopy) of the modern lake sediment show almost no well-crystalline iron oxides. In addition, sequential Fe extractions suggest an increasing proportion of easily extractable, poorly crystalline (X-ray amorphous) material with burial depth. XRD, bulk chemistry, and visible-near infrared (VNIR) spectral reflectance measurements demonstrate that clay mineralogy and bulk chemistry can be inferred from VNIR data. These results provide evidence for variations in Fe mineralogy and crystallinity based on location in this source to sink system. Understanding how the mineralogy and chemistry of sediments within a ferruginous lake basin are affected by transport, chemical alteration, physical alteration, and deposition from source to sink on Earth, and the degree to which these trends and underlying processes can be inferred from chemical and spectral properties, may provide useful direction in assessing paleoenvironmental conditions in other terrestrial lakes as well as ancient lacustrine environments preserved in the stratigraphic record of Mars. © 2019 Elsevier B.V. Article 2019 English 00092541 10.1016/j.chemgeo.2019.02.029 Chemical Geology 512 Elsevier B.V. 11 – 30 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Catchments; Chemical analysis; Clay minerals; Crystalline materials; Crystallinity; Deposition; Infrared devices; Lakes; Sedimentation; Sediments; Stratigraphy; X ray diffraction; Fe oxide; Mars analogue; Mineralogical analysis; Modern lake sediments; Spectral reflectance measurements; Ssbauer spectroscopies; Stratified lakes; Stratigraphic records; iron oxide; lacustrine deposit; Mars; paleoenvironment; redox conditions; sediment analysis; sediment chemistry; sedimentation; X-ray diffraction; Iron oxides https://www.scopus.com/inward/record.uri?eid=2-s2.0-85062414349&doi=10.1016%2fj.chemgeo.2019.02.029&partnerID=40&md5=6691785ad26224a94f0ade0ccac63ee5 Cited by: 10; All Open Access, Bronze Open Access Rachel Y. Sheppard Ralph E. Milliken James M. Russell M. Darby Dyar Elizabeth C. Sklute Satria Bijaksana Marina A. Morlock Ascelina K.M. Hasberg article Vuillemin2019540 Ferruginous conditions prevailed in the world's deep oceans during the Archean and Proterozoic Eons. Sedimentary iron formations deposited at that time may provide an important record of environmental conditions, yet linking the chemistry and mineralogy of these sedimentary rocks to depositional conditions remains a challenge due to a dearth of information about the processes by which minerals form in analogous modern environments. We identified siderites in ferruginous Lake Towuti, Indonesia, which we characterized using high-resolution microscopic and spectroscopic imaging combined with microchemical and geochemical analyses. We infer early diagenetic growth of siderite crystals as a response to sedimentary organic carbon degradation and the accumulation of dissolved inorganic carbon in pore waters. We suggest that siderite formation proceeds through syntaxial growth on preexisting siderite crystals, or possibly through aging of precursor carbonate green rust. Crystal growth ultimately leads to spar-sized ( > 50 μm) mosaic single siderite crystals that form twins, bundles, and spheroidal aggregates during burial. Early-formed carbonate was detectable through microchemical zonation and the possible presence of residual phases trapped in siderite interstices. This suggests that such microchemical zonation and mineral inclusions may be used to infer siderite growth histories in ancient sedimentary rocks including sedimentary iron formations. © 2019 Geological Society of America. Article 2019 English 00917613 10.1130/G46100.1 Geology 47 Geological Society of America 540 – 544 6 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Analytical geochemistry; Iron; Iron ores; Organic carbon; Sedimentology; Depositional condition; Diagenetic growth; Dissolved inorganic carbon; Environmental conditions; Geochemical analysis; Mineral inclusions; Proterozoic eons; Spectroscopic imaging; diagenesis; dissolved inorganic carbon; formation mechanism; iron; mineralogy; organic carbon; porewater; sediment analysis; sediment chemistry; sedimentary rock; siderite; Sedimentary rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066434739&doi=10.1130%2fG46100.1&partnerID=40&md5=4eff5b8101f8d25ca5b2040986aa53d6 Cited by: 27; All Open Access, Green Open Access, Hybrid Gold Open Access Aurèle Vuillemin Helga Kemnitz André Friese Kohen W. Bauer Rachel Simister Sulung Nomosatryo Luis Ordoñez Daniel Ariztegui Cynthia Henny Sean A. Crowe Liane G. Benning Jens Kallmeyer James M. Russell Satria Bijaksana The Towuti Drilling Project Science Team article Ordoñez201932 Qualitative and quantitative changes of organic and carbonate carbon in sedimentary records are frequently used to reconstruct past environments, paleoproductivity and sediment provenance. Amongst the most commonly used proxies are Total Organic Carbon (TOC), Mineral Carbon (MinC), as well as Hydrogen (HI) and Oxygen Indices (OI) of organic matter (OM). Rock Eval pyrolysis enables the assessment of these quantitative and qualitative parameters with a single analysis. This is achieved through transient pyrolysis of the samples up to 650 °C followed by combustion up to 850 °C, with hydrocarbons, CO and CO2 measured during the thermal decomposition of both OM and carbonate minerals. Carbonate minerals with low thermal cracking temperatures, such as siderite (<400 °C), can induce significant matrix effects which bias the TOC, MinC and OI Rock-Eval parameters. Here we assess the applicability of End-Member Analysis (EMA) as a means of correcting Rock-Eval thermograms for siderite matrix effects. For this, we performed Rock-Eval pyrolysis on sideritic sediments of Lake Towuti (Indonesia). New thermal boundaries were constrained in Rock-Eval thermograms using EMA to limit siderite matrix effects and improve TOC, MinC and OI calculations. Our approach allowed us to: (1) evaluate the influence of siderite matrix effects on Rock-Eval thermograms; (2) properly exploit a Rock-Eval dataset to characterize the type and sources of OM in siderite-rich sediments and (3) identify the OM behind degradation and mineralization processes. The Rock-Eval dataset revealed sediments with a substantial amount of refractory OM, especially in those where TOC is high and HI characteristic of autochthonous biomass. These results, associated to alternative indices used to assess OM preservation, suggest that refractory OM is residually enriched following strong degradation of labile compounds. Finally, relatively labile and refractory organic fractions may be consumed in the formation of siderite during this sequential process of OM mineralization. © 2019 The Authors Article 2019 English 01466380 10.1016/j.orggeochem.2019.05.002 Organic Geochemistry 134 Elsevier Ltd 32 – 44 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; Biogeochemistry; Biological materials; Carbonate minerals; Carbonation; Iron ores; Lakes; Mineralogy; Organic carbon; Pyrolysis; Refractory materials; Sediments; Temperature measuring instruments; Thermoanalysis; Thermography (temperature measurement); Endmembers; Mineralization process; Qualitative parameters; Quantitative changes; Rock-Eval pyrolysis; Siderite; Total Organic Carbon; Tropical lakes; degradation; lacustrine deposit; lacustrine environment; mineralization; organic matter; paleoproductivity; provenance; pyrolysis; sediment chemistry; siderite; thermal decomposition; total organic carbon; Rocks https://www.scopus.com/inward/record.uri?eid=2-s2.0-85066755224&doi=10.1016%2fj.orggeochem.2019.05.002&partnerID=40&md5=ad1c6c2c3d863f52257d7ae994768b67 Cited by: 11; All Open Access, Green Open Access, Hybrid Gold Open Access Luis Ordoñez David Sebag Daniel Ariztegui Thierry Adatte James M. Russell Jens Kallmeyer Aurèle Vuillemin André Friese Sean A. Crowe Kohen W. Bauer Rachel Simister Cynthia Henny Sulung Nomosatryo Satria Bijaksana article Morlock2019279 Humid tropical landscapes are subject to intense weathering and erosion, which strongly influence sediment mobilisation and deposition. In this setting, we aimed to understand how geomorphology and hydroclimate altered the style and intensity of erosion and sediment composition in a tropical lake and its tectonically active catchment. Lake Towuti (2.75°S, 121.5°E) is one of the oldest and deepest lakes in Indonesia, with uninterrupted lacustrine sedimentation over several glacial–interglacial cycles. Here we present results from a novel set of Lake Towuti surface sediment, bedrock and soil samples from the catchment, and two existing sediment cores that extend to 30,000 and 60,000 years before present. We studied the catchment morphology, soil properties, geochemistry, and clay and bulk mineralogy. Results from several river long profiles show clear signs of tectonic activity, which enhances river incision, favours mass movement processes, and together with remobilisation of fluvial deposits, strongly influences modern sedimentation in the lake. Material from the Mahalona River, the lake’s largest inflow, dominates modern sediment composition in Towuti’s northern basin. The river transports Al-poor and Mg-rich sediments (mainly serpentines) to the lake, indicating river incision into the Mg-rich serpentinised peridotite bedrock. Relatively small, but important additional contributions of material, come from direct laterite-derived input and the Loeha River, which both provide Al-rich and Mg-poor sediment to the lake. Over time, the Al/Mg and kaolinite-to-serpentine ratios varied strongly, primarily in response to lake-level fluctuations driven by hydroclimatic changes. In the past 60,000 years, both the Al/Mg and kaolinite-to-serpentine ratios showed variations sensitive to changes in climate boundary conditions across glacial-interglacial cycles, while tectonic activity had less influence on changes in sediment composition on these short time-scales. © 2018, Springer Nature B.V. Article 2019 English 09212728 10.1007/s10933-018-0059-3 Journal of Paleolimnology 61 Springer Netherlands 279 – 295 3 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; bank erosion; bedrock; catchment; climate effect; geomorphology; hydrological regime; lacustrine deposit; lake level; paleoclimate; peridotite; sedimentation rate; source-sink dynamics; tectonic setting; tropical region; weathering rate https://www.scopus.com/inward/record.uri?eid=2-s2.0-85055054448&doi=10.1007%2fs10933-018-0059-3&partnerID=40&md5=14b79789fe5aaf9e2b5b6c13f68b006b Cited by: 10; All Open Access, Green Open Access Marina A. Morlock Valentin Nigg Luis Ordoñez Ascelina K. M. Hasberg James M. Russell Satria Bijaksana article Kirana20189 Past changes in the Earth's magnetic field can be highlighted through reconstructions of magnetic paleointensity. Many magnetic field variation features are global, and can be used for the detailed correlation and dating of sedimentary records. On the other hand, sedimentary magnetic records also exhibit features on a regional, rather than a global scale. Therefore, the development of regional scale magnetic field reconstructions is necessary to optimize magnetic paleointensity dating. In this paper, a 60 thousand year (kyr) paleointensity record is presented, using the core TOW10-9B of Lake Towuti, located in the island of Sulawesi, Indonesia, as a part of the ongoing research towards understanding the Indonesian environmental history, and reconstructing a high-resolution regional magnetic record from dating the sediments. Located in the East Sulawesi Ophiolite Belt, the bedrock surrounding Lake Towuti consists of ultramafic rocks that render the lake sediments magnetically strong, creating challenges in the reconstruction of the paleointensity record. These sediment samples were subject to a series of magnetic measurements, followed by testing the obtained paleointensity records resulting from normalizing natural remanent magnetization (NRM) against different normalizing parameters. These paleointensity records were then compared to other regional, as well as global, records of magnetic paleointensity. The results show that for the magnetically strong Lake Towuti sediments, an anhysteretic remanent magnetization (ARM) is the best normalizer. A series of magnetic paleointensity excursions are observed during the last 60 kyr, including the Laschamp excursion at 40 kyr BP, that provide new information about the magnetic history and stratigraphy of the western tropical Pacific region. We conclude that the paleointensity record of Lake Towuti is reliable and in accordance with the high-quality regional and global trends. © 2017 Elsevier B.V. Article 2018 English 00319201 10.1016/j.pepi.2017.12.007 Physics of the Earth and Planetary Interiors 275 Elsevier B.V. 9 – 18 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; Geomagnetism; Lakes; Lithology; Magnetic fields; Magnetization; Repair; Sedimentology; Sediments; Stratigraphy; Anhysteretic remanent magnetizations; Earth's magnetic field; Environmental history; Laschamp excursions; Magnetic field variations; Natural remanent magnetization; Normalizing parameters; Relative paleointensity; geological record; geomagnetic field; lacustrine deposit; magnetic intensity; ophiolite; paleoenvironment; paleointensity; paleomagnetism; reconstruction; stratigraphic correlation; Magnetism https://www.scopus.com/inward/record.uri?eid=2-s2.0-85040597017&doi=10.1016%2fj.pepi.2017.12.007&partnerID=40&md5=6f6281912666780ac5eb7aef8b091d27 Cited by: 3 Kartika Hajar Kirana Satria Bijaksana John King Gerald Hendrik Tamuntuan James Russell La Ode Ngkoimani Darharta Dahrin Silvia Jannatul Fajar article Friese2017200 Subsurface exploration relies on drilling. Normally drilling requires a drilling fluid that will infiltrate into the drill core. Drilling fluid contains non-indigenous materials and microbes from the surface, so its presence renders a sample unsuitable for microbiological and many other analyses. Because infiltration cannot be avoided, it is of paramount importance to assess the degree of contamination to identify uncontaminated samples for geomicrobiological investigations. To do this, usually a tracer is mixed into the drilling fluid. In past drilling operations a variety of tracers have been used, each has specific strengths and weaknesses. For microspheres the main problem was the high price, which limited their use to spot checks or drilling operations that require only small amounts of drilling fluid. Here, we present a modified microsphere tracer approach that uses an aqueous fluorescent pigment dispersion with a similar concentration of fluorescent particles as previously used microsphere tracers. However, it costs four orders of magnitude less, allowing for a more liberal use even in large operations. Its applicability for deep drilling campaigns was successfully tested during two drilling campaigns of the International Continental Drilling Program (ICDP) at Lake Towuti, Sulawesi, Indonesia, and Lake Chalco, Mexico. Quantification of the tracer requires only a fluorescence microscope or a flow cytometer. The latter allowing for high-resolution data to be obtained directly on-site within minutes and with minimal effort, decreasing sample processing times substantially relative to traditional tracer methods. This approach offers an inexpensive, rapid, but powerful alternative technique for contamination assessment during drilling campaigns. © 2017 Association for the Sciences of Limnology and Oceanography. Article 2017 English 15415856 10.1002/lom3.10159 Limnology and Oceanography: Methods 15 Wiley Blackwell 200 – 211 2 https://www.scopus.com/inward/record.uri?eid=2-s2.0-85012942108&doi=10.1002%2flom3.10159&partnerID=40&md5=3510ecc7a8321f77eb30ea0e69c59c51 Cited by: 19; All Open Access, Green Open Access, Hybrid Gold Open Access André Friese Jens Kallmeyer Jan Axel Kitte Ivan Montaño Martínez Satria Bijaksana Dirk Wagner article Kallmeyer201761 Drilling is an integral part of subsurface exploration. Because almost all drilling operations require the use of a drill fluid, contamination by infiltration of drill fluid into the recovered core material cannot be avoided. Because it is impossible to maintain sterile conditions during drilling the drill fluid will contain surface microbes and other contaminants. As contamination cannot be avoided, it has to be tracked to identify those parts of the drill core that were not infiltrated by the drill fluid. This is done by the addition of tracer compounds. A great variety of tracers is available, and the choice depends on many factors. This review will first explain the basic principles of drilling before presenting the most common tracers and discussing their strengths and weaknesses. The final part of this review presents a number of key questions that have to be addressed in order to find the right tracer for a particular drilling operation. © 2017 Elsevier Inc. Article 2017 English 00652164 10.1016/bs.aambs.2016.09.003 Advances in Applied Microbiology 98 Academic Press Inc. 61 – 91 Bacteria; Ecosystem; Extraction and Processing Industry; Geologic Sediments; Humans; fluorescent dye; fluorocarbon; microsphere; tracer; Article; drill; ecological procedures; extended core barrel; gravity; hydraulic piston coring; microbial contamination; nonhuman; rotary drilling; tube; wireline coring; bacterium; chemistry; devices; ecosystem; genetics; growth, development and aging; human; isolation and purification; microbiology; mining; procedures; sediment https://www.scopus.com/inward/record.uri?eid=2-s2.0-85005991804&doi=10.1016%2fbs.aambs.2016.09.003&partnerID=40&md5=cf94c86c1e4af01a4407c6a5b4b9b682 Cited by: 10; All Open Access, Green Open Access J. Kallmeyer article Vuillemin2017 Extracellular DNA is ubiquitous in soil and sediment and constitutes a dominant fraction of environmental DNA in aquatic systems. In theory, extracellular DNA is composed of genomic elements persisting at different degrees of preservation produced by processes occurring on land, in the water column and sediment. Extracellular DNA can be taken up as a nutrient source, excreted or degraded by microorganisms, or adsorbed onto mineral matrices, thus potentially preserving information from past environments. To test whether extracellular DNA records lacustrine conditions, we sequentially extracted extracellular and intracellular DNA from anoxic sediments of ferruginous Lake Towuti, Indonesia. We applied 16S rRNA gene Illumina sequencing on both fractions to discriminate exogenous from endogenous sources of extracellular DNA in the sediment. Environmental sequences exclusively found as extracellular DNA in the sediment originated from multiple sources. For instance, Actinobacteria, Verrucomicrobia, and Acidobacteria derived from soils in the catchment. Limited primary productivity in the water column resulted in few sequences of Cyanobacteria in the oxic photic zone, whereas stratification of the water body mainly led to secondary production by aerobic and anaerobic heterotrophs. Chloroflexi and Planctomycetes, the main degraders of sinking organic matter and planktonic sequences at the water-sediment interface, were preferentially preserved during the initial phase of burial. To trace endogenous sources of extracellular DNA, we used relative abundances of taxa in the intracellular DNA to define which microbial populations grow, decline or persist at low density with sediment depth. Cell lysis became an important additional source of extracellular DNA, gradually covering previous genetic assemblages as other microbial genera became more abundant with depth. The use of extracellular DNA as nutrient by active microorganisms led to selective removal of sequences with lowest GC contents. We conclude that extracellular DNA preserved in shallow lacustrine sediments reflects the initial environmental context, but is gradually modified and thereby shifts from its stratigraphic context. Discrimination of exogenous and endogenous sources of extracellular DNA allows simultaneously addressing in-lake and post-depositional processes. In deeper sediments, the accumulation of resting stages and sequences from cell lysis would require stringent extraction and specific primers if ancient DNA is targeted. © 2017 Vuillemin, Horn, Alawi, Henny, Wagner, Crowe and Kallmeyer. Article 2017 English 1664302X 10.3389/fmicb.2017.01440 Frontiers in Microbiology 8 Frontiers Media S.A. JUL cell DNA; RNA 16S; Acidobacteria; Actinobacteria; Alphaproteobacteria; Article; cell count; Chloroflexi; controlled study; cytolysis; Deltaproteobacteria; DNA base composition; DNA extraction; DNA sequence; high throughput sequencing; hydrothermal vent species; Nitrospirae; nonhuman; phylogenetic tree; phylogeny; Planctomycetes; polymerase chain reaction; population abundance; preservation; sediment; Thaumarchaeota; Thermoplasmatales; Verrucomicrobia https://www.scopus.com/inward/record.uri?eid=2-s2.0-85026413976&doi=10.3389%2ffmicb.2017.01440&partnerID=40&md5=b5b219e03dab07bda04a33cac0e4e707 Cited by: 42; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin Fabian Horn Mashal Alawi Cynthia Henny Dirk Wagner Sean A. Crowe Jens Kallmeyer article Wilke2016118 Sedimentary sequences in ancient or long-lived lakes can reach several thousands of meters in thickness and often provide an unrivalled perspective of the lake's regional climatic, environmental, and biological history. Over the last few years, deep-drilling projects in ancient lakes became increasingly multi- and interdisciplinary, as, among others, seismological, sedimentological, biogeochemical, climatic, environmental, paleontological, and evolutionary information can be obtained from sediment cores. However, these multi- and interdisciplinary projects pose several challenges. The scientists involved typically approach problems from different scientific perspectives and backgrounds, and setting up the program requires clear communication and the alignment of interests. One of the most challenging tasks, besides the actual drilling operation, is to link diverse datasets with varying resolution, data quality, and age uncertainties to answer interdisciplinary questions synthetically and coherently. These problems are especially relevant when secondary data, i.e., datasets obtained independently of the drilling operation, are incorporated in analyses. Nonetheless, the inclusion of secondary information, such as isotopic data from fossils found in outcrops or genetic data from extant species, may help to achieve synthetic answers. Recent technological and methodological advances in paleolimnology are likely to increase the possibilities of integrating secondary information. Some of the new approaches have started to revolutionize scientific drilling in ancient lakes, but at the same time, they also add a new layer of complexity to the generation and analysis of sediment-core data. The enhanced opportunities presented by new scientific approaches to study the paleolimnological history of these lakes, therefore, come at the expense of higher logistic, communication, and analytical efforts. Here we review types of data that can be obtained in ancient lake drilling projects and the analytical approaches that can be applied to empirically and statistically link diverse datasets to create an integrative perspective on geological and biological data. In doing so, we highlight strengths and potential weaknesses of new methods and analyses, and provide recommendations for future interdisciplinary deep-drilling projects. © 2016 Elsevier B.V. Review 2016 English 09218181 10.1016/j.gloplacha.2016.05.005 Global and Planetary Change 143 Elsevier B.V. 118 – 151 Biology; Geology; Paleolimnology; Analytical approach; Ancient lakes; Deep drilling; Evolutionary biology; Evolutionary information; Interdisciplinary project; Methodology; Sedimentary sequence; biological survey; core analysis; data quality; deep drilling; evolutionary biology; fossil record; geological theory; integrated approach; lacustrine environment; outcrop; paleolimnology; technological change; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84975523752&doi=10.1016%2fj.gloplacha.2016.05.005&partnerID=40&md5=65b5fcf6cccc099d292cd51ee6749ff8 Cited by: 26; All Open Access, Bronze Open Access, Green Open Access Thomas Wilke Bert Van Bocxlaer Christian Albrecht Daniel Ariztegui Diana Delicado Alexander Francke Mathias Harzhauser Torsten Hauffe Jens Holtvoeth Janna Just Zlatko Levkov Kirsty Penkman Laura Sadori Alister Skinner Björn Stelbrink Hendrik Vogel Frank Wesselingh Thomas Wonik article Vuillemin2016 Lake Towuti is a tectonic basin, surrounded by ultramafic rocks. Lateritic soils form through weathering and deliver abundant iron (oxy)hydroxides but very little sulfate to the lake and its sediment. To characterize the sediment biogeochemistry, we collected cores at three sites with increasing water depth and decreasing bottom water oxygen concentrations. Microbial cell densities were highest at the shallow site-a feature we attribute to the availability of labile organic matter (OM) and the higher abundance of electron acceptors due to oxic bottom water conditions. At the two other sites, OM degradation and reduction processes below the oxycline led to partial electron acceptor depletion. Genetic information preserved in the sediment as extracellular DNA (eDNA) provided information on aerobic and anaerobic heterotrophs related to Nitrospirae, Chloroflexi, and Thermoplasmatales. These taxa apparently played a significant role in the degradation of sinking OM. However, eDNA concentrations rapidly decreased with core depth. Despite very low sulfate concentrations, sulfate-reducing bacteria were present and viable in sediments at all three sites, as confirmed by measurement of potential sulfate reduction rates. Microbial community fingerprinting supported the presence of taxa related to Deltaproteobacteria and Firmicutes with demonstrated capacity for iron and sulfate reduction. Concomitantly, sequences of Ruminococcaceae, Clostridiales, and Methanomicrobiales indicated potential for fermentative hydrogen and methane production. Such first insights into ferruginous sediments showed that microbial populations perform successive metabolisms related to sulfur, iron, and methane. In theory, iron reduction could reoxidize reduced sulfur compounds and desorb OM from iron minerals to allow remineralization to methane. Overall, we found that biogeochemical processes in the sediments can be linked to redox differences in the bottom waters of the three sites, like oxidant concentrations and the supply of labile OM. At the scale of the lacustrine record, our geomicrobiological study should provide a means to link the extant subsurface biosphere to past environments. © 2016 Vuillemin, Friese, Alawi, Henny, Nomosatryo, Wagner, Crowe and Kallmeyer. Article 2016 English 1664302X 10.3389/fmicb.2016.01007 Frontiers in Microbiology 7 Frontiers Research Foundation JUN organic matter; organic nitrogen; oxidizing agent; anoxia; Article; atomic absorption spectrometry; biogeochemistry; biosphere; Chloroflexi; Clostridiales; controlled study; Deltaproteobacteria; denaturing gradient gel electrophoresis; Firmicutes; fluorescent lighting; gene sequence; ion chromatography; lake sediment; Methanomicrobiales; microbial community; Nitrospirae; nonhuman; nucleic acid analysis; oxidation reduction reaction; oxygen concentration; phylogeny; polymerase chain reaction; Ruminococcaceae; sulfate reducing bacterium; Thermoplasmatales; total organic carbon https://www.scopus.com/inward/record.uri?eid=2-s2.0-84980398286&doi=10.3389%2ffmicb.2016.01007&partnerID=40&md5=97c709482982702e15c9d16888a4b992 Cited by: 27; All Open Access, Gold Open Access, Green Open Access Aurèle Vuillemin André Friese Mashal Alawi Cynthia Henny Sulung Nomosatryo Dirk Wagner Sean A. Crowe Jens Kallmeyer article Weber2015253 We tested the use of visible to near-infrared (VNIR) reflectance spectroscopy to characterize the relative abundances of clay minerals in sediments from Lake Towuti, a large tectonic lake in Sulawesi, Indonesia. We measured VNIR spectra of lake and river sediments from Lake Towuti and its catchment to identify clay minerals, fit major VNIR absorption features with a modified Gaussian model to estimate relative abundances of these minerals, and compared these absorptions to the samples’ chemistry to test the utility of VNIR spectroscopy to characterize sediment compositional variations. We found that major absorptions are caused by vibrations of Al–OH in kaolinite (2.21 μm), Fe–OH in nontronite (2.29 μm), Mg–OH in saponite and serpentine (2.31 μm), and Mg–OH in serpentine (2.34 μm). This was confirmed with X-ray diffraction data. The correlations between absorption band areas for Fe–OH, Al–OH, and Mg–OH vibrations and Fe, Al and Mg concentrations, respectively, are statistically significant, varying between r = 0.51 and r = 0.90, and spatial variations in inferred clay mineralogy within the lake are consistent with variations in the geology of the catchment. We conclude that VNIR spectroscopy is an effective way to characterize the clay mineralogy of lake sediments, and can be used to investigate changes in mineral inputs to lake deposits. © 2015, Springer Science+Business Media Dordrecht. Article 2015 English 09212728 10.1007/s10933-015-9844-4 Journal of Paleolimnology 54 Kluwer Academic Publishers 253 – 261 2-3 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; clay mineral; fluvial deposit; lacustrine deposit; paleolimnology; relative abundance; spatial variation; spectroscopy https://www.scopus.com/inward/record.uri?eid=2-s2.0-84941416465&doi=10.1007%2fs10933-015-9844-4&partnerID=40&md5=378488154e33dc6021afb8c421f0f478 Cited by: 6 Andrea K. Weber James M. Russell Timothy A. Goudge Mark R. Salvatore John F. Mustard Satria Bijaksana article Vogel2015359 Lake Towuti (2.5°S, 121.5°E) is a long-lived, tectonic lake located on the Island of Sulawesi, Indonesia, and in the center of the Indo-Pacific warm pool (IPWP). Lake Towuti is connected with upstream lakes Matano and Mahalona through the Mahalona River, which constitutes the largest inlet to the lake. The Mahalona River Delta is prograding into Lake Towuti’s deep northern basin thus exerting significant control on depositional processes in the basin. We combine high-resolution seismic reflection and sedimentological datasets from a 19.8-m-long sediment piston core from the distal edge of this delta to characterize fluctuations in deltaic sedimentation during the past ~29 kyr BP and their relation to climatic change. Our datasets reveal that, in the present, sedimentation is strongly influenced by deposition of laterally transported sediments sourced from the Mahalona River Delta. Variations in the amount of laterally transported sediments, as expressed by coarse fraction amounts in pelagic muds and turbidite recurrence rates and cumulative thicknesses, are primarily a function of lake-level induced delta slope instability and delta progradation into the basin. We infer lowest lake-levels between ~29 and 16, a gradual lake level rise between ~16 and 11, and high lake-levels between ~11 and 0 kyr BP. Periods of highest turbidite deposition, ~26 to 24 and ~18 to 16 kyr BP coincide with Heinrich events 2 and 1, respectively. Our lake-level reconstruction therefore supports previous observations based on geochemical hydroclimate proxies of a very dry last glacial and a wet Holocene in the region, and provides new evidence of millennial-scale variations in moisture balance in the IPWP. © 2015, Springer Science+Business Media Dordrecht. Article 2015 English 09212728 10.1007/s10933-015-9857-z Journal of Paleolimnology 54 Kluwer Academic Publishers 359 – 377 4 Greater Sunda Islands; Lake Mahalona; Lake Matano; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sulawesi; Sunda Isles; climate change; deltaic sedimentation; depositional environment; Heinrich event; Holocene; lacustrine deposit; Last Glacial; pool; reconstruction; sedimentology; turbidity https://www.scopus.com/inward/record.uri?eid=2-s2.0-84945448673&doi=10.1007%2fs10933-015-9857-z&partnerID=40&md5=eef60ceaf1d31a38b9457d2a5d449f11 Cited by: 25; All Open Access, Green Open Access James M. Russell Sri Yudawati Cahyarini Satria Bijaksana Nigel Wattrus Janet Rethemeyer article Costa2015467 The Indo-Pacific Warm Pool (IPWP) is an important driver of global climate, but its response to and involvement in paleoclimate change is poorly constrained. We generated a new record of sediment geochemistry from Lake Towuti (2.5°S, 121.5°E), Indonesia, located in the heart of the IPWP, to investigate changes in hydrological connectivity with upstream lakes and the extent of lake mixing and oxygenation during paleoclimate changes over the last 60,000. years BP (60. ka). Lake Towuti is located at the downstream end of the Malili Lakes, a chain of large, ancient, and biologically diverse tectonic lakes occupying a geologically heterogeneous terrain in central Sulawesi, Indonesia. Major and trace element data from river and lake sediments suggest no changes in sediment provenance during the Last Glacial Maximum (LGM), indicating that some of the Malili Lakes remained hydrologically open despite a regionally drier climate. However, samples from the LGM are uniformly less enriched in trace elements than samples from the Holocene and Marine Isotope Stage 3 (MIS3), which suggests a decrease in weathering intensity during the LGM, likely in response to decreased precipitation and temperature. Changes in Fe and other redox-sensitive trace element concentrations indicate changes in water column oxygenation, with the highest oxygen availability occurring during the LGM (15-35. ka) likely due to more frequent and/or deeper mixing of Lake Towuti's water column. The glacial-interglacial trend in lake oxygenation corresponds with changes in regional precipitation and associated changes in the seasonal cycle. The high degree of faunal endemism in these lakes may be related to changes in the lake geochemistry associated with glacial-interglacial environmental variability driven by changing inputs and redox variability. © 2014 Elsevier B.V. Article 2015 English 00310182 10.1016/j.palaeo.2014.10.009 Palaeogeography, Palaeoclimatology, Palaeoecology 417 Elsevier 467 – 475 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; climate variation; connectivity; glacial-interglacial cycle; mixing; oxygenation; paleoclimate; paleolimnology; provenance; seasonal variation; trace element https://www.scopus.com/inward/record.uri?eid=2-s2.0-84918508289&doi=10.1016%2fj.palaeo.2014.10.009&partnerID=40&md5=c2a9befb55919ad23eb144f81dd8fc13 Cited by: 38 K.M. Costa J.M. Russell H. Vogel S. Bijaksana article Tamuntuan2015163 We investigated the mineral-magnetic behavior of sediments from Lake Towuti located in the Eastern Sulawesi Ophiolite belt, Indonesia. Rock magnetic analysis supplemented by X-ray diffraction and scanning electron microscopy analysis were performed on sediment core TOW10-9B from the north basin of Lake Towuti to give insights on the environmental and sedimentary processes controlling the magnetic properties of the sediment and its paleoclimatic significance. The results show that the core has three distinct zones of varying magnetic properties. Careful examination demonstrates that these zones correspond to varying levels of iron oxide dissolution and magnetite precipitation that are climatically and environmentally dependent. The magnetically strongest zone is characterized by weak iron oxide dissolution and intense magnetite precipitation, likely driven by changes in the stratification and/or water level of the lake during dry conditions in Marine Isotope Stage 2 (MIS2) period, whereas the two magnetically weaker zones are characterized by signs of dissolution and correspond to relatively wet conditions, respectively, during Marine Isotope Stage 3 (MIS3) and the Holocene. Although our data show that major changes in concentration dependent parameters, such as magnetic susceptibility and saturation isothermal remanent magnetization (SIRM), in Lake Towuti sediment correlate with changes in regional rainfall, many of the concentration changes are more strongly affected by in situ chemical processes than by changes in erosion and terrestrial sediment supply. These findings urge caution in the interpretation of magnetic mineral concentration profiles as indicators of clastic sediment inputs. © 2014 Elsevier B.V. Article 2015 English 00310182 10.1016/j.palaeo.2014.12.008 Palaeogeography, Palaeoclimatology, Palaeoecology 420 Elsevier 163 – 172 Greater Sunda Islands; Lake Towuti; Malili Lakes; South Sulawesi; Sulawesi; Sunda Isles; clastic sediment; core analysis; depositional environment; dissolution; Holocene; lacustrine deposit; magnetic mineral; magnetic property; marine isotope stage; ophiolite; paleoclimate; sediment property https://www.scopus.com/inward/record.uri?eid=2-s2.0-84920896688&doi=10.1016%2fj.palaeo.2014.12.008&partnerID=40&md5=fe3642ee04d5cf20b2ebfe4eedbd7a98 Cited by: 30 Gerald Tamuntuan Satria Bijaksana John King James Russell Umar Fauzi Khoiril Maryunani Nurul Aufa La Ode Safiuddin article Russell20145100 The Indo-Pacific warm pool houses the largest zone of deep atmospheric convection on Earth and plays a critical role in global climate variations. Despite the region's importance, changes in Indo-Pacific hydroclimate on orbital timescales remain poorly constrained. Here we present high-resolution geochemical records of surface runoff and vegetation from sediment cores fromLake Towuti, on the island of Sulawesi in central Indonesia, that continuously span the past 60,000 y.We show that wet conditions and rainforest ecosystems on Sulawesi present during marine isotope stage 3 (MIS3) and the Holocene were interrupted by severe drying between ∼33,000 and 16,000 y B.P. when Northern Hemisphere ice sheets expanded and global temperatures cooled. Our record reveals little direct influence of precessional orbital forcing on regional climate, and the similarity between MIS3 and Holocene climates observed in Lake Towuti suggests that exposure of the Sunda Shelf has a weaker influence on regional hydroclimate and terrestrial ecosystems than suggested previously. We infer that hydrological variability in this part of Indonesia varies strongly in response to high-latitude climate forcing, likely through reorganizations of the monsoons and the position of the intertropical convergence zone. These findings suggest an important role for the tropical western Pacific in amplifying glacial-interglacial climate variability. Article 2014 English 00278424 10.1073/pnas.1402373111 Proceedings of the National Academy of Sciences of the United States of America 111 National Academy of Sciences 5100 – 5105 14 runoff; titanium; article; canopy; climate; climate change; ecosystem; geochemistry; glacial interglacial variability; glacial period; Holocene; hydroclimate; hydrology; ice sheet; Indonesia; interglacial; lake; marine isotope stage 3; Northern Hemisphere; paleoclimate; precipitation; priority journal; sea surface temperature; sediment; stratigraphy; tropical rain forest; vegetation https://www.scopus.com/inward/record.uri?eid=2-s2.0-84898053681&doi=10.1073%2fpnas.1402373111&partnerID=40&md5=15e48141ebdbc687d0dde5a656ca8b9a Cited by: 107; All Open Access, Bronze Open Access, Green Open Access James M. Russell Hendrik Vogel Bronwen L. Konecky Satria Bijaksana Yongsong Huang Nigel Wattrus Kassandra Costa John W. King article Russell201268 The Towuti Drilling Project (TDP) is an international research program, whose goal is to understand long-term environmental and climatic change in the tropical western Pacific, the impacts of geological and environmental changes on the biological evolution of aquatic taxa, and the geomicrobiology and biogeochemistry of metal-rich, ultramafic-hosted lake sediments through the scientific drilling of Lake Towuti, southern Sulawesi, Indonesia. Lake Towuti is a large tectonic lake at the downstream end of the Malili lake system, a chain of five highly biodiverse lakes that are among the oldest lakes in Southeast Asia. In 2015 we carried out a scientific drilling program on Lake Towuti using the International Continental Scientific Drilling Program (ICDP) Deep Lakes Drilling System (DLDS). We recovered a total of ~ 1018m of core from 11 drilling sites with water depths ranging from 156 to 200 m. Recovery averaged 91.7 %, and the maximum drilling depth was 175m below the lake floor, penetrating the entire sedimentary infill of the basin. Initial data from core and borehole logging indicate that these cores record the evolution of a highly dynamic tectonic and limnological system, with clear indications of orbital-scale climate variability during the mid- to late Pleistocene. © Author(s) 2016. Conference paper 2012 English 18163459 10.2204/iodp.sd.14.11.2012 Scientific Drilling 21 Copernicus GmbH 68 – 71 14 Biology; Climate change; Drilling; Microbiology; Tectonics; Biological evolution; Climate variability; Continental scientific drillings; Environmental change; International researches; Limnological system; Scientific drilling; Tropical Western Pacific; Lakes https://www.scopus.com/inward/record.uri?eid=2-s2.0-84867796087&doi=10.2204%2fiodp.sd.14.11.2012&partnerID=40&md5=d2133bb13a3d2340d110012e9a439c50 Cited by: 14; All Open Access, Gold Open Access James Russell Satria Bijaksana article Schippers2010170 Sediments in the Indian Ocean off the coast of the Indonesian island Sumatra were sampled at 25 stations in high resolution near the sediment surface and at three stations up to a maximum depth of 12 meter below seafloor (mbsf) for a quantitative microbial community analysis. Total cell counts were determined applying two different protocols including SYBR Green II as fluorescent staining dye. Total cell counts without detaching cells from sediment particles were 109 cells/ mL sediments at the sediment surface with little variation between all stations. They decreased to 108 cells/ mL at 0.2 to 0.4 mbsf and to 107 cells/ mL below 6 mbsf. The total cell counts after detaching cells from sediment particles were up to one order of magnitude lower above 6 mbsf and showed similar values below. This difference for the two protocols can be explained by a loss of cells during the detachment procedure and/or counting of unspecific signals without detaching cells from sediment particles. Particular phylogenetic and physiological prokaryotic groups were quantified by quantitative, real-time PCR (Q-PCR) targeting 16S rRNA and functional genes. Archaea and Bacteria were found overall in similar 16S rRNA gene copy numbers in the range of the total cell counts at all sediment depths, thus, neither Archaea nor Bacteria could be considered as dominant. The eukaryotic 18S rRNA gene occurred in two orders of magnitude lower numbers than prokaryotic 16S rRNA genes. Fe(III)- and Mn(IV)-reducing bacteria (16S rRNA gene of Geobacteraceae) and sulfate-reducing bacteria (functional gene dsrA) were detected in variable (up to 108 gene copies/ mL sediment) but in always significantly lower numbers than total Bacteria. The proportion of sulfate reducers on the prokaryotic community was between 0.2 and 19%. Calculated aereal sulfate reduction rates were overall low with values between 0.002 and 0.027 mmol m-2a-1, resulting in sulfate reduction rates per cell of 0.0007 and 0.81 fmol cell-1 a-1, similar to published data for other deeply buried marine sediments. Methanogenesis did not seem to play a big role since methane was detected only below 6.5 mbsf, and the functional gene of methanogens and anaerobic methanotrophs mcrA could not be detected in any sample. Article 2010 English 15210529 10.1080/01490450903456798 Geomicrobiology Journal 27 170 – 182 2 Greater Sunda Islands; Indian Ocean; Sumatra; Sunda Isles; Archaea; Bacteria (microorganisms); Eukaryota; Geobacteraceae; Prokaryota; bacterium; marine sediment; methanogenesis; microbial community; polymerase chain reaction; prokaryote; quantitative analysis; seafloor https://www.scopus.com/inward/record.uri?eid=2-s2.0-77949563943&doi=10.1080%2f01490450903456798&partnerID=40&md5=5ee995b15574b48bf60dfa22e93798e5 Cited by: 24 Axel Schippers Gerrit Köweker Carmen Höft Barbara M.A. Teichert article Tierney20091032 Branched glycerol dialkyl glycerol tetraether (GDGT) lipids are abundant and ubiquitous in lake sediments, potentially allowing for a paleolimnological application of the so-called MBT/CBT proxy (methylation index of branched tetraethers/cyclization ratio of branched tetraethers). To investigate the origin and characteristics of these compounds in lacustrine environments, we examined the distributions of GDGTs in soils, river sediments and lake sediments from Lake Towuti on the island of Sulawesi, Indonesia. We found significant differences in the degree of methylation and cyclization (expressed by way of the MBT and CBT indices) between the soil samples and the aquatic samples, suggesting that there may be in situ production of GDGTs in the aquatic environment. Based on these findings, we urge caution in the application of the MBT/CBT paleoproxy to lake sediments and encourage more rigorous study of these compounds in freshwater environments. © 2009 Elsevier Ltd. All rights reserved. Article 2009 English 01466380 10.1016/j.orggeochem.2009.04.014 Organic Geochemistry 40 1032 – 1036 9 Asia; Eurasia; Indonesia; Lake Towuti; Malili Lakes; South Sulawesi; Southeast Asia; Alkylation; Glycerol; Lakes; Methylation; Sedimentology; Soils; Aquatic environments; Degree of methylations; Freshwater environments; In-situ production; Indonesia; Lake sediments; River sediments; Soil sample; Tropical lakes; ether; fluvial deposit; lacustrine deposit; lacustrine environment; lipid; methylation; tropical environment; Sediments https://www.scopus.com/inward/record.uri?eid=2-s2.0-68749095059&doi=10.1016%2fj.orggeochem.2009.04.014&partnerID=40&md5=22404412ed8b1b0683345e032befae4a Cited by: 213 Jessica E. Tierney James M. Russell