Hinrichs Lab - News

Publication in Nature Communications

April 2023: Role of Wildfires at the end Permian mass extinction - At the end of the Permian, large-scale volcanic activity was seated at the northeastern of paleocontinent pangaea and lasted for ca 1 million years (Siberian Traps). However, the third largest mass extinction started at the end of this period and occured within about 60,000 years. The exact drivers had not yet been clearly identified. In this study with Ryosuke Saito as first author, we used the ultra-high resolution molecular imaging method (MSI) and elemental mapping to analyze the upper 20 cm of rock sample from the end Permian Meishan section. The results of those ca 8000 years indicate several series of wild fires and other environmental degradations on land affecting the ocean system.

Publication in Nature

November 2022: The high-resolution molecular imaging method (MSI) on intact sediments developed in the ZOOMecular project has refined the temporal resolution of climate reconstructions from sediment archives by orders of magnitude. In this study by Lars Wörmer as first author, the effects of the last global warming, during the transition from the Pleistocene to the Holocene, on temperature fluctuations are described in seasonal resolution. For this purpose, a 60 cm section of the laminated sediments of the Cariaco Basin was analyzed with MSI at a resolution of 100 µm.

 Publication in Nature Geoscience

Sept 2022: The high-resolution molecular imaging method (MSI), developed in the ZOOMecular project, was used to study paleo temperature records in the eastern Mediterranean Sea by Igor Obreht and colleagues. They established a ~4.800-year-long record of sea surface temperature (SST) variability at 1–4-year resolution from a finely laminated sapropel deposited during the Last Interglacial. Results are presented and discussed here.

MARUM press release

 Publication in Science Advances

May 2021: In so-called sulfate-methane transition zones in the seafloor, where sulfate from seawater meets methane from the deeper sediment, specialized microbes (ANME) consume this methane by the anaerobic oxidation of methane (AOM). This process leads to an enrichment of heavier ¹³C in the remaining methane. However, often very light methane is found in those transition zones, indicating to methane production. Gunter Wegener and co-authors from Rehovot and Bremen could clarify this contradiction showing that the isotopes effects in AOM depend on the availability of sulfate.

MARUM press release

 Publication in Science

December 2020: Based on IODP Expedition 370 „T-Limit“, an international team of scientists gained new insights in the temperature limits of life in deep subseafloor sediments of the Nankai Trough subduction zone. Here, Verena Heuer and colleagues present their unique findings of life signals down to deep sediments with temperatures up to 120 °C.

MARUM press release

Election to Leopoldina

May 2019:  Kai-Uwe Hinrichs has been elected member of Leopoldina, the National Academy of Sciences. This membership is considered one of the highest distinctions for scientists in the German speaking area

New publication in Science Advances

June 2018: In this publication an international collaboration team presents the latest results of the deep biosphere drilling investigations in the Nankai Trough. Multidisciplinary analysis about interactions between deep-biosphere and geosphere revealed an unexpected high deposit of methane within mud volcanoes and its microbial origin.

New publication in PNAS

May 2018: Bathyarchaeota have been suggested to play a globally important role in the carbon cycling in marine sediments, but the evidence for their potential metabolic functions has not yet been demonstrated. This study investigated different carbon and energy sources in enrichment cultures and discovered the capability of growing with lignin,which is originating from land plants and know for its poor biodegradability.

New taxa of Archaea in International Journal of Systematic and Evolutionary Microbiology

October 2017: An international team of scientists reports the taxonomic description of four marine ammonia-oxidizing archaea of the phylum Thaumarchaeota within the genus Nitrosopumilus gen.nov.

New Publication in Marine Chemistry

July 2017: Guangchao Zhuang and colleagues analyzed the natural abundunce of methylated sulfides and amines (e.g. DMS, DMS(P) and TMA) in marine sediments from Aarhus Bay with respect to their potential as methanogenic substrates. In this study, the stable carbon isotopic composition of TMA and DMS(P) was reported for the first time.

New Publication in Environmental Microbiology

May 2017: Thaumarchaeota are a major source of archaeal lipids that form the basis of the TEX86 paleothermometer in the geologic record. However, knowledge of thaumarchaeal lipid composition is limited to a small number of studied species and a small set of compounds, likely underestimating lipid diversity. Felix Elling and colleagues show in a new study on ten strains of Thaumarchaeota that their lipid composition is highly complex and dependent on the phylogenetic relationships between strains and the diverse environments (ocean, soil, hydrothermal springs) they inhabit.

Pat­ter­son Award 2017 to Kai-Uwe Hin­richs

March 2017: The Geochemical Society has named Kai-Uwe Hinrichs as Patterson Medalist 2017 for his work on the interactions between microbial life and the carbon cycle on a range of spatial, temporal and molecular scales. The Clair C. Patterson Medal is awarded for an innovative breakthrough of fundamental significance in environmental geochemistry and will be presented at the Goldschmidt Conference in Paris.

International drilling expedition movie

January 2017: IODP expedition 370, exploring the "T-Limit of deep biosphere off Muroto" with participation of Hinrichs Lab is presenting a movie reportage about the cruise on the expedition homepage.

International drilling expedition

September 2016: Verena Heuer (MARUM), Fumio Inagaki and Yuki Morono (JAMSTEC) are leading IODP Expedition 370 "T-Limit of the Deep Biosphere off Muroto" as co-chief scientists. This expedition will investigate the vertical extent of subseafloor microbial life close to its upper limit of temperature by drilling through sediments in the central Nankai Trough with D/V Chikyu.
Presentation to Science

New Publication in Proceedings of the National Academy of Sciences, USA

June 2016: The membrane lipids of planktonic archaea form the basis of the paleothermometer TEX₈₆, which is broadly used by geochemists to reconstruct ocean water temperatures from past to present. In their new study, Sarah Hurley and Felix Elling demonstrated that the lipid composition of planktonic archaea changes in response to the respiration rate and thus, added a new, biological aspect to the application of fossil biomarkers as molecular temperature proxies.

New Publication in Geochimica et Cosmochimica Acta

 June 2016: A team of scientists from Hinrichs Lab, the Aarhus University (Denmark), and JAMSTEC (Japan) presents a new procedure (density gradient centrifugation-based cell separation) for the analysis of microbial biomolecules in environmental samples with complex sample matrices. This approach will facilitate and improve the use of biomolecules as proxies for microbial abundance in environmental samples.

New Publication in The Holocene

 June 2016: Marcus Elvert and colleagues reconstructed methane turnover and environmental conditions for the Holocene from a thermokarst lake in Arctic Alaska by using source-specific lipid biomarkers preserved in a radiocarbon-dated sediment core. Detailed signals of methane oxidation since the last ~12,300 years indicate that recent organic matter decomposition and enhanced methane production thereof probably amplify climate feedback in the future.

New Publication in Applied Environmental Microbiology

 May 2016: Kevin Becker and colleagues investigated the membrane lipid composition of Methanomassilicoccus luminyensis, the only cultured representative of the novel seventh order of methanogens, and found that this archaeon contains butane- and pentanetriol-based tetraethers as major lipids. Butane- and pentanetriol moieties replacing the typical glycerol backbone are highly unconventional building blocks that disagree with known pathways of lipid biosynthesis.

New Laboratory

April 2016: The now officially opened Geobiomolecular Imaging Laboratory is the central platform of the ERC-project ZOOMecular, granted to Kai-Uwe Hinrichs. The lab is equipped with a Laser Desorption Ionization-Fourier Transform-Ion Cyclotron Resonance-Mass Spectrometer (LDI-FTMS) and a µ-XRF Spectrometer. Both scanning techniques will be applied on intact sediment cores to obtain high-resolution spatial distributions of lipid biomarkers and elements in the marine sedimentary matrix.

New Publication in Environmental Microbiology

 October 2015: Felix Elling and colleagues present the comprehensive analysis of the distribution of membrane-bound electron carriers (respiratory quinones) in 25 cultivated archaeal strains and environmental samples. The authors show that respiratory quinones, in particular in combination with membrane lipids, bear significant potential for tracing major archaeal clades and their associated redox processes in the marine environment.

New Publication in Organic Geochemistry

August 2015: So far, several widely used temperature proxies have been determined by separate analytical methods. In this publication, Kevin Becker and colleagues introduce a new analytical protocol based on HPLC-MS that enables the simultaneous acquisition of three paleo sea surface temperature proxies and six additional proxies such as the archaeol/caldarchaeol ecometric and the methane index for the reconstruction of paleosalinity and past methane hydrate dissociation, respectively. This rapid and reliable method facilitates the analysis of multiple proxies, which are required to interpret paleo records.

New Publication in Science

July 2015: Kai-Uwe Hinrichs (MARUM) and Fumio Inagaki (JAMSTEC) had been leading IODP expedition 337, drilling the world's deepest marine sediment core in the Pacific ocean off Shimokita (Japan). This week in Science (24.07.2015), Hinrichs and Inagaki and their team of scientists report on the detection of microbial life signals and intact cells in this sediment core of the deep biosphere down to 2.5 km length. Here the deepest ever recorded microbial communities were found in coal beds between 1.5 and 2.5 km depth, obviously they are driven by methanogenesis and resemble terrestrial communities of forest soils.

New ERC project

July 2015: Kai-Uwe Hinrichs has been awarded the second Advanced Grant by the European Research Council in the 2014 competition, following the just completed DARCLIFE project. The 5-year project "ZOOMecular" will start in November 2015 and analyze lipid biomarkers in sediment cores at unprecedented spatial resolution in order to reconstruct climate processes in Earth's recent history and to interrogate microbial processes in marine sediments.

Highlighted paper in Nature Communications

July 2015: Wetlands are known as one large natural source of atmospheric methane. In this publication, a team of marine scientists from the University of Georgia and Hinrichs Lab elucidated the methane consumption processes in different wetland systems. A great amount of the microbially produced methane was consumed directly within the systems by anaerobic oxidation of methane, showing oxidation rates per day comparable to those in marine environments.
UGA press release

New paper in Science

March 2015: An international research team around Shuhei Ono and David Wang (MIT, Cambridge, USA) presents a novel technology for identifying the sources of natural methane, a climate relevant gas and important energy source. This approach is based on the abundance of the rare clumped isotopologue ¹³CH₃D, which has recently been proposed for estimating the formation temperature of methane. The present study shows that microbial methane results in untypical methane formation temperatures and provides clues about methane sources in various environments.
MIT press release

New paper in The ISME Journal

March 2015: Mofette soils are characterized by elevated CO₂ flow due to volcanic gas upstreams. Felix Beulig in collaboration with colleagues from the Hinrichs Lab studied the influence of extremely high CO₂ concentrations in a mofette soil on microbial communities and carbon flow, e.g. the uptake of CO₂ into biomass, compared to unaffected reference soil.

New paper in Frontiers in Microbiology

January 2015: Marcos Yoshinaga and colleagues present the first attempt to study how archaeon Methanothermobacter thermautotrophicus modulates its membrane lipids in response to environmental growth conditions. The authors designed cultivation experiments to investigate changes in the detailed IPL composition in dependence on limited energy (H₂) and nutrient (potassium, phosphate) supply.

New paper in the Proceedings of the National Academy of Sciences

October 2014: Lars Wörmer and colleagues present an innovative technique for molecular biomarker analysis directly on sediment core surfaces. This technique, that is laser desorption ionization coupled to mass spectrometry, allows us to access rich paleoenvironmental information on the µm-scale.

New paper in Geochimica et Cosmochimica Acta

July 2014: In laboratory experiments with pure cultures of Nitrosopumilus maritimus, Felix Elling and colleagues investigated the intact polar and core GDGT content of these ammonia oxidizing archaea (AOA). Their results will help track active AOA communities and contribute to a better understanding of the formation of paleoenvironmental proxies, e.g. TEX86.

New paper in Geochimica et Cosmochimica Acta

June 2014: Dissolved organic matter (DOM) is a complex mixture of thousands of individual constituents. With ultrahigh-resolution Fourier Transform Ion-Cyclotron Resonance Mass Spectrometry (FT-ICR MS) this mixture can be resolved and the elemental composition of individual DOM molecules can be determined. Using this method and Black Sea sediments, Frauke Schmidt and colleagues have compared the composition of two different DOM pools that potentially serve as carbon and energy source for benthic mircoorganisms: organic matter that is dissolved in sediment pore-waters and organic matter that is released from the sediment’s solid phase by aqueous Soxhlet extraction.

New paper in the Proceedings of the National Academy of Sciences

May 2014: CO₂ fixation is the most important biosynthetic process on Earth, enabling autotrophic organisms to build up their entire biomass from inorganic carbon. Elucidating the biochemistry of the autotrophy cycle in ammonia-oxidizing archaea, Martin Könneke and colleagues from Freiburg, Zurich and Seattle found the most energy-efficient mechanism for autotrophic CO₂ fixation in the presence of oxygen. This discovery offers a biochemical explanation for the remarkable ecological success of the ammonia-oxidizing archaea in extremely nutrient-limited environments typical of most of the open ocean.

New paper in Rapid Communications in Mass Spectrometry

May 2014: Studies of archaeal glycerol dibiphytanyl glycerol tetraethers (GDGTs) in the environment and cultures have exclusively focused on compounds with fully saturated alkyl moieties. Using a new LC/MS protocol, Charlie (Chun) Zhu and colleagues found a number of novel unsaturated GDGTs (uns-GDGTs) whose alkyl chains contain up to six double bonds and zero to two cyclopentyl moieties. They were detected as both core lipids and intact polar lipids. Investigation of samples from various marine environments suggests that uns-GDGTs contribute significantly to the archaeal lipid pool in anoxic methane-rich environments (Black Sea, Cariaco Basin, seep sites) but are barely detectable in oxic or hypersaline settings.

New paper in Science

May 2014: Marshall Bowles and colleagues developed a novel computer model to estimate how much sulfate is turned over by microorganisms in the subseafloor worldwide. Their findings differ highly from previous estimates, because the new model better acounts for sandy areas where the organic carbon content and the sulfate reduction rates are lower than in the intensively studied sediments of highly-productive regions.

New paper in Organic Geochemistry

April 2014: When Sitan Xie and colleagues investigated the distributions of microbial membrane lipids in the oxygen minimum zone of the Eastern Tropical North Pacific Ocean, they found nine groups of glycerol ether core lipids, among other OH-GDDs, OB-GDGTs, SB-GDGTs, IB-GDGTs and H-1020. This is the first report of these “orphan lipids” in the marine water column, suggesting that anaerobic planktonic microbes are their main source.

New paper in Marine Chemistry

March 2014: When microbes degrade organic matter in marine sediments, low-molecular-weight alcohols are produced and released into the pore-waters. So far, only little is known about the biogeochemical behavior of these alcohols due to analytical challenges. In this study, Guangchao Zhuang and colleagues describe methods for the analysis of trace amounts of methanol and ethanol in marine pore waters and present results for sediments of the Black Sea and the Gulf of Mexico.

New paper in Organic Geochemistry

February 2014: A recently described new class of archaean lipid biomarkers, i.e. GDD core lipids with varying glycosidic head group, was analyzed by Travis Meador and colleagues in marine sediments as well as pure culture of the Thaumarchaeon Nitrosopumilus maritimus. The specific cycloalkyl distribution pattern of these lipids indicates to a biosynthetic formation instead of diagenectic degradation of the corresponding GDGTs only.

New paper in Frontiers in Microbiology

January 2014: Concerning archaea, little information exists about the response of membrane lipids to growth conditions in the environment. Travis Meador and colleagues for the first time studied the composition of intact polar lipids in dependence of growth stage and phosphorus supply of the thermophilic archaeon Thermococcus kodakarensis, and provide evidence of a specific IPL biomarker.

New paper in Nature Geoscience

January 2014: Marcos Y. Yoshinaga and colleagues demonstrate how the unusual ¹³C-depletion of methane in subseafloor sulfate–methane transition zones can be caused by low concentrations of sulfate, thus leading to new insights about the metabolic processes of Archaea in the deep biosphere.

New paper in Rapid Communications in Mass Spectrometry

December 2013: Glycerol serves as the principal backbone moiety bound to various acyl/alkyl chains for membrane lipids of Eukarya, Bacteria, and Archaea. In this study, Charlie (Chun) Zhu and colleagues report a suite of unusual tetraether lipids in which one of the two conventional glycerol backbones is substituted by butanetriol or pentanetriol. Of these, isoprenoidal butanetriol dialkyl glycerol tetraethers (iso-BDGTs) were the most abundant. They are likely produced by Archaea. Butanetriol- and pentanetriol-based tetraether lipids occur in modern estuarine and deeply buried subseafloor sediments, suggesting the presence of alternative backbones in archaeal lipids.

New paper in Organic Geochemistry

October 2013: Charlie (Chun) Zhu and colleagues developed a novel chromatographic method for the separation of glycerol ether lipids and their mass spectrometric detection. Thereby it is now possible to simultaneously characterize headgroup and alkyl moiety variability. Widely used paleoenvironmental proxies can thus be determined in both core and intact polar lipids.

New paper in Organic Geochemistry

October 2013: The novel cleanup procedure for sediment extracts developed by Rong Zhu and her colleagues is based on solid phase extraction on a zirconia-coated silica phase. This method specifically targets phospholipids and demonstrates superior selectivity, thus enabling strongly improved detection of these compounds and more accurate lipid-based fingerprinting of microbial communities

New paper in Applied and Environmental Microbiology

August 2013: The uncultured miscellaneous crenarchaeotic group (MCG) archaea comprise one of the most abundant microbial groups in the Earth's subsurface environment. However, very little information is available regarding the lifestyle, physiology, and factors controlling the distribution of members of this group. Using a novel method consisting of both cultivation and molecular techniques, Emma Gagen and colleagues investigated enrichment cultures prepared from estuarine sediment with a variety of carbon substrates and cultivation conditions. They found viable MCG archaea that are amenable to in vitro cultivation and tolerant to initially oxic conditions.

New publication in Organic Geochemistry

June 2013: Kevin Becker and colleagues have introduced an improved method for the separation of core ether lipids involving UHPLC with two HILIC columns in tandem. 

New publication in Organic Geochemistry

June 2013: Sitan Xie and colleagues have identified potential substrates that can be converted microbially to ethane and propane during incubation with marine sediment.

New publication in Organic Geochemistry

June 2013: Lars Wörmer and colleagues extend the methodological toolbox for IPL analysis by introducing new protocols for UPLC, qTOF, and a range of new chromatographic columns.

New paper in Proceedings of the National Academy of Sciences of the United States of America

April 2013: Sitan Xie and colleagues determined the degradation kinetics of intact archaeal glycolipids under subseafloor conditions; the results indicate that substantial fossil contributions limit their use as life markers. Implementation of the kinetic parameters in biogeochemical models provides important clues on growth rates of sedimentary archaea.

MARUM Research Award

December 2012: Matthias Kellermann was rewarded with the „MARUM Research Award for Marine Geosciences 2012“ for his outstanding PhD thesis "Lipid biomolecules reveal patterns of microbial metabolism in extreme environment".

IODP Expedition 337 on marumTV

November 2012: IODP Expedition 337 has drilled 2466 m deep into the seafloor to investigate the deep biosphere associated with coal beds in the continental margin off Japan. The Hinrichs Lab was intensively involved in this expedition with Kai-Uwe Hinrichs being one of two co-chief scientists, and Yushih-Lin, Marshall Bowles and Verena Heuer sailing as members of the shipboard scientific party. Shipboard work can now be watched on marumTV

New paper in the Proccedings of the National Academy of Sciences

November 2012: Matthias Kellermann and colleagues have used dual stable isotope probing to investigate carbon flow in methane-rich, hydrothermally heated sediments of the Guaymas Basin. They find that methane-oxidizing ANME-1 archaea are chemoorganoautotrophs and not methanotrophs.

New paper in Limnology and Oceanography

November 2012: Lars Wörmer and colleagues have investigated the distribution of heterocyst glycolipids in cyanobacteria and the environment. They find that these lipids have biomarker potential for applications in both ecological and paleoenvironmental studies.

BIOMARIS Research Award

October 2012: Marcus Elvert received the BIOMARIS research award 2012. He was awarded because of his outstanding achievements in research and his personal engagement for marine science at MARUM and the University of Bremen.

New paper in Rapid Communications in Mass Spectrometry

October 2012: Xiaolei Liu and colleagues have discovered several novel series of archaeal and putative bacterial lipids in twelve globally distributed marine subsurface sediments that were analyzed by atmospheric pressure chemical ionization mass spectrometry (APCI-MS). Tandem mass (MS/MS) spectra of compounds were obtained with a quadrupole time-of-flight (qTOF) mass spectrometer.

Perspective in Science: Downsizing the Deep Biosphere

October 2012: Kai-Uwe Hinrichs and Fumio Inagaki reflect on a recent study that provides new constraints on the size and distribution of microbial biomass beneath the ocean floor.

New paper in Environmental Ecology

October 2012: Yu-Shih Lin and colleagues performed long-term stable isotope probing experiments to investigate the biosynthesis of archaeal membrane lipids in deep marine sediments. They found that the growth rates of benthic archaea from about 8 m subseafloor depth are very low; the turnover time of the major group of archaeal polar lipids in marine sediments is between 1,700 and 20,500 years.

New paper in Geochimica et Cosmochimica Acta

April 2012: Identification and rigorous structural characterization of hydroxilated GDGTs is presented by Xiao-Lei Liu and colleagues. The wide distribution of these compounds, both as intact and core lipids, points to their potential use as proxies.

New paper in Deep-Sea Research I

February 2012: Stuart Wakeham is a professor at Skidaway Institute of Oceanography (USA), Hanse-Wissenschaftskolleg Fellow and long-term collaborator of the Hinrichs Lab. In this paper, he and his colleagues generated a multidimensional, high resolution data set that shows the existence of a multilayered chemocline with tightly coupled element cycles in the anoxic Cariaco Basin off Venezuela.

New paper in Archaea

February 2012: Marcos Yoshinaga and colleagues analyzed intact polar lipid composition of microbial communities associated with methane seepage in deep sea sediments. Novel, highly diverse archaeal cardiolipin analogues are identified and their potential role as a substantial contributor to membranes of methanotrophic archaea is discussed.

New paper in Geochimica et Cosmochimica Acta

January 2012: Yu-Shih Lin and colleagues have optimized and tested methods for the analysis of H2 concentrations in porewaters of deep subseafloor sediments. In sediments on the continental margin off Namibia they find a relaxation of syntrophic coupling betwen H2-producing and H2-consuming activities.

New paper in Rapid Communications in Mass Spectrometry

November 2011: Marcos Yoshinaga and colleagues achieve rapid and straightforward characterization of intact archaeal membrane lipids in the complex organic matrices of natural environments using HPLC/electrospray ionization (ESI)-ITMSn and the systematic MS2 fragementation patterns of these lipids.

New paper in Organic Geochemistry

November 2011: Xiaolei Liu and colleagues present a series of novel archaeal lipids tentatively identified as isoprenoid glycerol dialkanol diethers (GDDs). These widespread lipids are analogous to GDDTs, but lack one glycerol unit. A common biological source for GDDs and GDGTs is proposed based on common ring indices.

New paper in Organic Geochemistry

October 2011: Aiming to elucidate the symbiosis between mussels and chemosynthetic microorganisms at cold seeps and hot vents, Matthias Kellermann and colleagues have tracked the carbon flow in such systems by qualitative and stable carbon isotope analysis of membrane lipids. They find that the bacterial symbionts have characteristic intact polar lipids which qualify as specific biomarkers and that they serve as the main carbon source for the mussels.

Two new papers in Geochimica et Cosmochimica Acta

May 2011: Interested in the impact of oil on the marine environment, Florence Schubotz and collegues investigated microbial life in asphalt volcanos at the seafloor of the Gulf of Mexico. They find that natural seepage of heavy-oil greatly stimulates the activity of oil-degrading bacteria as well methane-related processes, such as anaerobic oxidation of methane and methanogenesis.

New paper in Environmental Science & Technology

May 2011: Frauke Schmidt and colleagues have characterized the molecular composition of dissolved organic matter in bottom waters and sediment pore waters of the Black Sea. Their FT-ICR-MS data suggest that nitrogen-bearing compounds (e.g. proteins) are more intensively degraded in sediments than in bottom waters.

New paper in Paleoceanography

May 2011: Mea Cook and colleagues have identified multiple episodes of intense methane release from sediments in the Bering Sea during the last glacial period, using stable carbon isotope analysis of carbonates and lipid biomarkers. The release cannot be explained by gas hydrate destabilization but might be related to seismic activity.

New paper in Geobiology

March 2011: Solveig Bühring and colleagues investigated biomarkers and uptake of 13C-labelled carbon in microbial communities of a natural spring with extremely high concentrations of dissolved sulfide and hydrocarbon gases. They find evidence for anoxygenic photosynthesis and photoheterotrophy under conditions that were common on Earth during the late Archean and early-to-mid Proterozoic Age.

New paper in Organic Geochemistry

February 2011: Xiaolei Liu and colleagues have observed a coupling of two pools of biomarkers in sediments, i.e. intact GDGTs which are related to living benthic archaea and core GDGTs which are molecular fossils from past planktonic archaea and related to (paleo) sea surface temperature. Understanding the link between the two pools is important for the interpretation of both proxies.