Articles | Volume 16, issue 16
Research article 30 Aug 2019
Research article | 30 Aug 2019
Temporal variability in foraminiferal morphology and geochemistry at the West Antarctic Peninsula: a sediment trap study
Anna Mikis et al.
No articles found.
Charlotte L. Spencer-Jones, Erin L. McClymont, Nicole J. Bale, Ellen C. Hopmans, Stefan Schouten, Juliane Müller, E. Povl Abrahamsen, Claire Allen, Torsten Bickert, Claus-Dieter Hillenbrand, Elaine Mawbey, Victoria Peck, Aleksandra Svalova, and James A. Smith
Biogeosciences, 18, 3485–3504,Short summary
Long-term ocean temperature records are needed to fully understand the impact of West Antarctic Ice Sheet collapse. Glycerol dialkyl glycerol tetraethers (GDGTs) are powerful tools for reconstructing ocean temperature but can be difficult to apply to the Southern Ocean. Our results show active GDGT synthesis in relatively warm depths of the ocean. This research improves the application of GDGT palaeoceanographic proxies in the Southern Ocean.
Mark A. Stevenson, Suzanne McGowan, Emma J. Pearson, George E. A. Swann, Melanie J. Leng, Vivienne J. Jones, Joseph J. Bailey, Xianyu Huang, and Erika Whiteford
Biogeosciences, 18, 2465–2485,Short summary
We link detailed stable isotope and biomarker analyses from the catchments of three Arctic upland lakes on Disko Island (West Greenland) to a recent dated sediment core to understand how carbon cycling has changed over the past ~500 years. We find that the carbon deposited in sediments in these upland lakes is predominately sourced from in-lake production due to the catchment's limited terrestrial vegetation and elevation and that recent increases in algal production link with climate change.
Katharine Hendry, Oscar Romero, and Vanessa Pashley
Clim. Past, 17, 603–614,Short summary
Productive eastern boundary upwelling systems (EBUs) are characterized by abundant siliceous algae and diatoms, and they play a key role in carbon fixation. Understanding past shifts in diatom production is critical for predicting the impact of future climate change. We combine existing sediment archives from the Benguela EBU with new diatom isotope analyses and modelling to reconstruct late Quaternary silica cycling, which we suggest depends on both upwelling intensity and surface utilization.
Hyewon Heather Kim, Ya-Wei Luo, Hugh W. Ducklow, Oscar M. Schofield, Deborah K. Steinberg, and Scott C. Doney
Geosci. Model Dev. Discuss.,
Revised manuscript under review for GMDShort summary
The West Antarctic Peninsula (WAP) is a rapidly warming region, revealed by multi-decadal observations. Despite the region being data-rich, there is a lack of focus on ecosystem model development. Here, we introduce a data assimilation ecosystem model for the WAP region. Experiments by assimilating data from an example growth season capture key WAP features. This study enables us to glue the snapshots from available data sets together to explain the observations in the WAP.
Tom Dunkley Jones, Yvette L. Eley, William Thomson, Sarah E. Greene, Ilya Mandel, Kirsty Edgar, and James A. Bendle
Clim. Past, 16, 2599–2617,Short summary
We explore the utiliity of the composition of fossil lipid biomarkers, which are commonly preserved in ancient marine sediments, in providing estimates of past ocean temperatures. The group of lipids concerned show compositional changes across the modern oceans that are correlated, to some extent, with local surface ocean temperatures. Here we present new machine learning approaches to improve our understanding of this temperature sensitivity and its application to reconstructing past climates.
Gordon N. Inglis, Fran Bragg, Natalie J. Burls, Margot J. Cramwinckel, David Evans, Gavin L. Foster, Matthew Huber, Daniel J. Lunt, Nicholas Siler, Sebastian Steinig, Jessica E. Tierney, Richard Wilkinson, Eleni Anagnostou, Agatha M. de Boer, Tom Dunkley Jones, Kirsty M. Edgar, Christopher J. Hollis, David K. Hutchinson, and Richard D. Pancost
Clim. Past, 16, 1953–1968,Short summary
This paper presents estimates of global mean surface temperatures and climate sensitivity during the early Paleogene (∼57–48 Ma). We employ a multi-method experimental approach and show that i) global mean surface temperatures range between 27 and 32°C and that ii) estimates of
bulkequilibrium climate sensitivity (∼3 to 4.5°C) fall within the range predicted by the IPCC AR5 Report. This work improves our understanding of two key climate metrics during the early Paleogene.
Lisa Thompson, Madison Smith, Jim Thomson, Sharon Stammerjohn, Steve Ackley, and Brice Loose
The Cryosphere, 14, 3329–3347,Short summary
The offshore winds around Antarctica can reach hurricane strength and produce intense cooling, causing the surface ocean to form a slurry of seawater and ice crystals. For the first time, we observed a buildup of heat and salt in the surface ocean, caused by loose ice crystal formation. We conclude that up to 1 m of ice was formed per day by the intense cooling, suggesting that unconsolidated crystals may be an important part of the total freezing that happens around Antarctica.
Hyewon Heather Kim, Jeff S. Bowman, Ya-Wei Luo, Hugh W. Ducklow, Oscar M. Schofield, Deborah K. Steinberg, and Scott C. Doney
Preprint under review for BG
Kirsty M. Edgar, Steven M. Bohaty, Helen K. Coxall, Paul R. Bown, Sietske J. Batenburg, Caroline H. Lear, and Paul N. Pearson
J. Micropalaeontol., 39, 117–138,Short summary
We identify the first continuous carbonate-bearing sediment record from the tropical ocean that spans the entirety of the global warming event, the Middle Eocene Climatic Optimum, ca. 40 Ma. We determine significant mismatches between middle Eocene calcareous microfossil datums from the tropical Pacific Ocean and established low-latitude zonation schemes. We highlight the potential of ODP Site 865 for future investigations into environmental and biotic changes throughout the early Paleogene.
James M. Russell, Philip Barker, Andrew Cohen, Sarah Ivory, Ishmael Kimirei, Christine Lane, Melanie Leng, Neema Maganza, Michael McGlue, Emma Msaky, Anders Noren, Lisa Park Boush, Walter Salzburger, Christopher Scholz, Ralph Tiedemann, Shaidu Nuru, and the Lake Tanganyika Scientific Drilling Project (TSDP) Consortium
Sci. Dril., 27, 53–60,Short summary
Our planet experienced enormous environmental changes in the last 10 million years. Lake Tanganyika is the oldest lake in Africa and its sediments comprise the most continuous terrestrial environmental record for this time period in the tropics. This workshop report identifies key research objectives in rift processes, evolutionary biology, geomicrobiology, paleoclimatology, paleoecology, paleoanthropology, and geochronology that could be addressed by drilling this globally important site.
Sophie Kendall, Felix Gradstein, Christopher Jones, Oliver T. Lord, and Daniela N. Schmidt
J. Micropalaeontol., 39, 27–39,Short summary
Changes in morphology during development can have profound impacts on an organism but are hard to quantify as we lack preservation in the fossil record. As they grow by adding chambers, planktic foraminifera are an ideal group to study changes in growth in development. We analyse four different species of Jurassic foraminifers using a micro-CT scanner. The low morphological variability suggests that strong constraints, described in the modern ocean, were already acting on Jurassic specimens.
Alan Marron, Lucie Cassarino, Jade Hatton, Paul Curnow, and Katharine R. Hendry
Biogeosciences, 16, 4805–4813,Short summary
Isotopic signatures of silica fossils can be used as archives of past oceanic silicon cycling, which is linked to marine carbon uptake. However, the biochemistry that lies behind such chemical fingerprints remains poorly understood. We present the first measurements of silicon isotopes in a group of protists closely related to animals, choanoflagellates. Our results highlight a taxonomic basis to silica isotope signatures, possibly via a shared transport pathway in choanoflagellates and animals.
Dana Ridha, Ian Boomer, and Kirsty M. Edgar
J. Micropalaeontol., 38, 189–229,Short summary
This paper records the spatial and temporal distribution of deep-sea benthic microfossils (Foraminifera, single-celled organisms) from the latest Oligocene to earliest Pliocene (about 28 to 4 million years ago) from Ocean Drilling Program cores in the southern Indian Ocean. Key taxa are illustrated and their stratigraphic distribution is presented as they respond to a period of marked global climatic changes, with a pronounced warm period in the mid-Miocene followed by subsequent cooling.
Elizabeth Atar, Christian März, Andrew C. Aplin, Olaf Dellwig, Liam G. Herringshaw, Violaine Lamoureux-Var, Melanie J. Leng, Bernhard Schnetger, and Thomas Wagner
Clim. Past, 15, 1581–1601,Short summary
We present a geochemical and petrographic study of the Kimmeridge Clay Formation from the Cleveland Basin (Yorkshire, UK). Our results indicate that deposition during this interval was very dynamic and oscillated between three distinct modes of sedimentation. In line with recent modelling results, we propose that these highly dynamic conditions were driven by changes in climate, which affected continental weathering, enhanced primary productivity, and led to organic carbon enrichment.
Christopher J. Hollis, Tom Dunkley Jones, Eleni Anagnostou, Peter K. Bijl, Margot J. Cramwinckel, Ying Cui, Gerald R. Dickens, Kirsty M. Edgar, Yvette Eley, David Evans, Gavin L. Foster, Joost Frieling, Gordon N. Inglis, Elizabeth M. Kennedy, Reinhard Kozdon, Vittoria Lauretano, Caroline H. Lear, Kate Littler, Lucas Lourens, A. Nele Meckler, B. David A. Naafs, Heiko Pälike, Richard D. Pancost, Paul N. Pearson, Ursula Röhl, Dana L. Royer, Ulrich Salzmann, Brian A. Schubert, Hannu Seebeck, Appy Sluijs, Robert P. Speijer, Peter Stassen, Jessica Tierney, Aradhna Tripati, Bridget Wade, Thomas Westerhold, Caitlyn Witkowski, James C. Zachos, Yi Ge Zhang, Matthew Huber, and Daniel J. Lunt
Geosci. Model Dev., 12, 3149–3206,Short summary
The Deep-Time Model Intercomparison Project (DeepMIP) is a model–data intercomparison of the early Eocene (around 55 million years ago), the last time that Earth's atmospheric CO2 concentrations exceeded 1000 ppm. Previously, we outlined the experimental design for climate model simulations. Here, we outline the methods used for compilation and analysis of climate proxy data. The resulting climate
atlaswill provide insights into the mechanisms that control past warm climate states.
Maria Grigoratou, Fanny M. Monteiro, Daniela N. Schmidt, Jamie D. Wilson, Ben A. Ward, and Andy Ridgwell
Biogeosciences, 16, 1469–1492,Short summary
The paper presents a novel study based on the traits of shell size, calcification and feeding behaviour of two planktonic foraminifera life stages using modelling simulations. With the model, we tested the cost and benefit of calcification and explored how the interactions of planktonic foraminifera among other plankton groups influence their biomass under different environmental conditions. Our results provide new insights into environmental controls in planktonic foraminifera ecology.
Marcus P. S. Badger, Thomas B. Chalk, Gavin L. Foster, Paul R. Bown, Samantha J. Gibbs, Philip F. Sexton, Daniela N. Schmidt, Heiko Pälike, Andreas Mackensen, and Richard D. Pancost
Clim. Past, 15, 539–554,Short summary
Understanding how atmospheric CO2 has affected the climate of the past is an important way of furthering our understanding of how CO2 may affect our climate in the future. There are several ways of determining CO2 in the past; in this paper, we ground-truth one method (based on preserved organic matter from alga) against the record of CO2 preserved as bubbles in ice cores over a glacial–interglacial cycle. We find that there is a discrepancy between the two.
Hilde Pracht, Brett Metcalfe, and Frank J. C. Peeters
Biogeosciences, 16, 643–661,Short summary
In palaeoceanography the shells of single-celled foraminifera are routinely used as proxies to reconstruct the temperature, salinity and circulation of the ocean in the past. Traditionally a number of specimens were pooled for a single stable isotope measurement; however, technical advances now mean that a single shell or chamber of a shell can be measured individually. Three different hypotheses regarding foraminiferal biology and ecology were tested using this approach.
Lucie Cassarino, Christopher D. Coath, Joana R. Xavier, and Katharine R. Hendry
Biogeosciences, 15, 6959–6977,Short summary
Using a simple model, we show that the silicon isotopic composition of sponges can be used to estimate the silicic acid concentration of seawater, a key parameter linked to nutrient and carbon cycling. However, our data illustrate that skeletal type and growth rate also control silicon isotopic composition of sponges. Our study demonstrates the paleoceanographic utility of sponges as an archive for ocean silica content provided that suitable skeleton types are selected.
Dominic A. Hodgson, Kelly Hogan, James M. Smith, James A. Smith, Claus-Dieter Hillenbrand, Alastair G. C. Graham, Peter Fretwell, Claire Allen, Vicky Peck, Jan-Erik Arndt, Boris Dorschel, Christian Hübscher, Andrew M. Smith, and Robert Larter
The Cryosphere, 12, 2383–2399,Short summary
We studied the Coats Land ice margin, Antarctica, providing a multi-disciplinary geophysical assessment of the ice sheet configuration through its last advance and retreat; a description of the physical constraints on the stability of the past and present ice and future margin based on its submarine geomorphology and ice-sheet geometry; and evidence that once detached from the bed, the ice shelves in this region were predisposed to rapid retreat back to coastal grounding lines.
Tom Dunkley Jones, Hayley R. Manners, Murray Hoggett, Sandra Kirtland Turner, Thomas Westerhold, Melanie J. Leng, Richard D. Pancost, Andy Ridgwell, Laia Alegret, Rob Duller, and Stephen T. Grimes
Clim. Past, 14, 1035–1049,Short summary
The Paleocene–Eocene Thermal Maximum (PETM) is a transient global warming event associated with a doubling of atmospheric carbon dioxide concentrations. Here we document a major increase in sediment accumulation rates on a subtropical continental margin during the PETM, likely due to marked changes in hydro-climates and sediment transport. These high sedimentation rates persist through the event and may play a key role in the removal of carbon from the atmosphere by the burial of organic carbon.
Rowan Dejardin, Sev Kender, Claire S. Allen, Melanie J. Leng, George E. A. Swann, and Victoria L. Peck
J. Micropalaeontol., 37, 25–71,
Bernd Wagner, Thomas Wilke, Alexander Francke, Christian Albrecht, Henrike Baumgarten, Adele Bertini, Nathalie Combourieu-Nebout, Aleksandra Cvetkoska, Michele D'Addabbo, Timme H. Donders, Kirstin Föller, Biagio Giaccio, Andon Grazhdani, Torsten Hauffe, Jens Holtvoeth, Sebastien Joannin, Elena Jovanovska, Janna Just, Katerina Kouli, Andreas Koutsodendris, Sebastian Krastel, Jack H. Lacey, Niklas Leicher, Melanie J. Leng, Zlatko Levkov, Katja Lindhorst, Alessia Masi, Anna M. Mercuri, Sebastien Nomade, Norbert Nowaczyk, Konstantinos Panagiotopoulos, Odile Peyron, Jane M. Reed, Eleonora Regattieri, Laura Sadori, Leonardo Sagnotti, Björn Stelbrink, Roberto Sulpizio, Slavica Tofilovska, Paola Torri, Hendrik Vogel, Thomas Wagner, Friederike Wagner-Cremer, George A. Wolff, Thomas Wonik, Giovanni Zanchetta, and Xiaosen S. Zhang
Biogeosciences, 14, 2033–2054,Short summary
Lake Ohrid is considered to be the oldest existing lake in Europe. Moreover, it has a very high degree of endemic biodiversity. During a drilling campaign at Lake Ohrid in 2013, a 569 m long sediment sequence was recovered from Lake Ohrid. The ongoing studies of this record provide first important information on the environmental and evolutionary history of the lake and the reasons for its high endimic biodiversity.
Jack H. Lacey, Melanie J. Leng, Alexander Francke, Hilary J. Sloane, Antoni Milodowski, Hendrik Vogel, Henrike Baumgarten, Giovanni Zanchetta, and Bernd Wagner
Biogeosciences, 13, 1801–1820,Short summary
We use stable isotope data from carbonates to provide a palaeoenvironmental reconstruction covering the last 637 kyr at Lake Ohrid (FYROM/Albania). Our results indicate a relatively stable climate until 450 ka, wetter climate conditions at 400–250 ka, and a transition to a drier climate after 250 ka. This work emphasises the importance of Lake Ohrid as a valuable archive of climate change in the northern Mediterranean region.
M. Wall, F. Ragazzola, L. C. Foster, A. Form, and D. N. Schmidt
Biogeosciences, 12, 6869–6880,Short summary
We investigated the ability of cold-water corals to deal with changes in ocean pH. We uniquely combined morphological assessment with boron isotope analysis to determine if changes in growth are related to changes in control of calcification pH. We found that the cold-water coral Lophelia pertusa can maintain the skeletal morphology, growth patterns as well as internal calcification pH. This has important implications for their future occurrence and explains their cosmopolitan distribution.
C. Hauri, S. C. Doney, T. Takahashi, M. Erickson, G. Jiang, and H. W. Ducklow
Biogeosciences, 12, 6761–6779,Short summary
Evaluation of a unique 20-year-long time series of inorganic carbon and nutrient observations from the West Antarctic Peninsula region shows that summertime biological productivity and meltwater input drive a large range of surface aragonite saturation states from values < 1 (undersaturated) up to 3.9. Even though we did not detect any statistically significant long-term trends, ongoing ocean acidification and freshwater input may soon induce more unfavorable conditions than seen today.
L. A. Melbourne, J. Griffin, D. N. Schmidt, and E. J. Rayfield
Biogeosciences, 12, 5871–5883,Short summary
Using Finite element modelling (FEM) we show that a simplified geometric FE model can predict the structural strength of the coralline algal skeleton. We compared a series of 3D geometric FE-models with increasing complexity to a biologically accurate model derived from computed tomography (CT) scan data. Using geometric models provides the basis for a better understanding of the potential effect of climate change on the structural integrity of these organisms.
B. Metcalfe, W. Feldmeijer, M. de Vringer-Picon, G.-J. A. Brummer, F. J. C. Peeters, and G. M. Ganssen
Biogeosciences, 12, 4781–4807,Short summary
Iron biogeochemical budgets during the natural ocean fertilisation experiment KEOPS-2 showed that complex circulation and transport pathways were responsible for differences in the mode and strength of iron supply, with vertical supply dominant on the plateau and lateral supply dominant in the plume. The exchange of iron between dissolved, biogenic and lithogenic pools was highly dynamic, resulting in a decoupling of iron supply and carbon export and controlling the efficiency of fertilisation.
A. M. Snelling, G. E. A. Swann, J. Pike, and M. J. Leng
Clim. Past, 10, 1837–1842,
C. V. Davis, M. P. S. Badger, P. R. Bown, and D. N. Schmidt
Biogeosciences, 10, 6131–6139,
A. G. M. Caromel, D. N. Schmidt, and J. C. Phillips
Revised manuscript not accepted
Daniela N. Schmidt, Jeremy R. Young, Shirley Van Heck, and Jackie Lees
J. Micropalaeontol., 28, 91–93,
Related subject area
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Martin Tetard, Laetitia Licari, Ekaterina Ovsepyan, Kazuyo Tachikawa, and Luc Beaufort
Biogeosciences, 18, 2827–2841,Short summary
Oxygen minimum zones are oceanic regions almost devoid of dissolved oxygen and are currently expanding due to global warming. Investigation of their past behaviour will allow better understanding of these areas and better prediction of their future evolution. A new method to estimate past [O2] was developed based on morphometric measurements of benthic foraminifera. This method and two other approaches based on foraminifera assemblages and porosity were calibrated using 45 core tops worldwide.
Maximiliano Rodríguez and Christelle Not
Biogeosciences, 18, 1987–2001,Short summary
Mg/Ca in calcium carbonate shells of marine organisms such as foraminifera and ostracods has been used as a proxy to reconstruct water temperature. Here we provide new Mg/Ca–temperature calibrations for two shallow marine species of ostracods. We show that the water temperature in spring produces the best calibrations, which suggests the potential use of ostracod shells to reconstruct this parameter at a seasonal scale.
Hongrui Zhang, Chuanlian Liu, Luz María Mejía, and Heather Stoll
Biogeosciences, 18, 1909–1916,
Revised manuscript accepted for BGShort summary
This paper presents the first results of laboratory-produced charcoal morphological features of various fuel types originating from Siberia. It explores the influence of temperatures on charcoal production and improves the attribution of charcoal particles to fuel types and fire characteristics. It also provides recommendations for the applicability of such results to refine the reconstruction of wildfire histories.
Delphine Dissard, Gert Jan Reichart, Christophe Menkes, Morgan Mangeas, Stephan Frickenhaus, and Jelle Bijma
Biogeosciences, 18, 423–439,Short summary
Results from a data set acquired from living foraminifera T. sacculifer collected from surface waters are presented, allowing us to establish a new Mg/Ca–Sr/Ca–temperature equation improving temperature reconstructions. When combining equations, δ18Ow can be reconstructed with a precision of ± 0.5 ‰, while successive reconstructions involving Mg/Ca and δ18Oc preclude salinity reconstruction with a precision better than ± 1.69. A new direct linear fit to reconstruct salinity could be established.
Feng Wang, Dominique Arseneault, Étienne Boucher, Shulong Yu, Steeven Ouellet, Gwenaëlle Chaillou, Ann Delwaide, and Lily Wang
Biogeosciences, 17, 4559–4570,Short summary
Wood stain is challenging the use of the blue intensity technique for dendroclimatic reconstructions. Using stained subfossil trees from eastern Canadian lakes, we compared chemical destaining approaches with the
delta bluemathematical correction of blue intensity data. Although no chemical treatment was completely efficient, the delta blue method is unaffected by the staining problem and thus is promising for climate reconstructions based on lake subfossil material.
Dulcinea V. Groff, David G. Williams, and Jacquelyn L. Gill
Biogeosciences, 17, 4545–4557,Short summary
Tussock grasses that grow along coastlines of the Falkland Islands are slow to decay and build up thick peat layers over thousands of years. Grass fragments found in ancient peat can be used to reconstruct past climate because grasses can preserve a record of growing conditions in their leaves. We found that modern living tussock grasses in the Falkland Islands reliably record temperature and humidity in their leaves, and the peat they form can be used to understand past climate change.
Maxence Guillermic, Sambuddha Misra, Robert Eagle, Alexandra Villa, Fengming Chang, and Aradhna Tripati
Biogeosciences, 17, 3487–3510,Short summary
Boron isotope ratios (δ11B) of foraminifera are a promising proxy for seawater pH and can be used to constrain pCO2. In this study, we derived calibrations for new foraminiferal taxa which extend the application of the boron isotope proxy. We discuss the origin of different δ11B signatures in species and also discuss the potential of using multispecies δ11B analyses to constrain vertical pH and pCO2 gradients in ancient water columns to shed light on biogeochemical carbon cycling in the past.
Zeynep Erdem, Joachim Schönfeld, Anthony E. Rathburn, Maria-Elena Pérez, Jorge Cardich, and Nicolaas Glock
Biogeosciences, 17, 3165–3182,Short summary
Recent observations from today’s oceans revealed that oxygen concentrations are decreasing, and oxygen minimum zones are expanding together with current climate change. With the aim of understanding past climatic events and their relationship with oxygen content, we looked at the fossils, called benthic foraminifera, preserved in the sediment archives from the Peruvian margin and quantified the bottom-water oxygen content for the last 22 000 years.
Hannah K. Donald, Gavin L. Foster, Nico Fröhberg, George E. A. Swann, Alex J. Poulton, C. Mark Moore, and Matthew P. Humphreys
Biogeosciences, 17, 2825–2837,Short summary
The boron isotope pH proxy is increasingly being used to reconstruct ocean pH in the past. Here we detail a novel analytical methodology for measuring the boron isotopic composition (δ11B) of diatom opal and apply this to the study of the diatom Thalassiosira weissflogii grown in culture over a range of pH. To our knowledge this is the first study of its kind and provides unique insights into the way in which diatoms incorporate boron and their potential as archives of palaeoclimate records.
Eleonora Fossile, Maria Pia Nardelli, Arbia Jouini, Bruno Lansard, Antonio Pusceddu, Davide Moccia, Elisabeth Michel, Olivier Péron, Hélène Howa, and Meryem Mojtahid
Biogeosciences, 17, 1933–1953,Short summary
This study focuses on benthic foraminiferal distribution in an Arctic fjord characterised by continuous sea ice production during winter and the consequent cascading of salty and corrosive waters (brine) to the seabed. The inner fjord is dominated by calcareous species (C). In the central deep basins, where brines are persistent, calcareous foraminifera are dissolved and agglutinated (A) dominate. The high A/C ratio is suggested as a proxy for brine persistence and sea ice production.
Johannes Hepp, Imke Kathrin Schäfer, Verena Lanny, Jörg Franke, Marcel Bliedtner, Kazimierz Rozanski, Bruno Glaser, Michael Zech, Timothy Ian Eglinton, and Roland Zech
Biogeosciences, 17, 741–756,
Julian Struck, Marcel Bliedtner, Paul Strobel, Jens Schumacher, Enkhtuya Bazarradnaa, and Roland Zech
Biogeosciences, 17, 567–580,Short summary
We present leaf wax n-alkanes and their compound-specific (CS) δ13C isotopes from semi-arid and/or arid Mongolia to test their potential for paleoenvironmental reconstructions. Plants and topsoils were analysed and checked for climatic control. Chain-length variations are distinct between grasses and Caragana, which are not biased by climate. However CS δ13C is strongly correlated to climate, so n-alkanes and their CS δ13C show great potential for paleoenvironmental reconstruction in Mongolia.
Elena Lo Giudice Cappelli, Jessica Louise Clarke, Craig Smeaton, Keith Davidson, and William Edward Newns Austin
Biogeosciences, 16, 4183–4199,Short summary
Fjords are known sinks of organic carbon (OC); however, little is known about the long-term fate of the OC stored in these sediments. The reason for this knowledge gap is the post-depositional degradation of OC. This study uses benthic foraminifera (microorganisms with calcite shells) to discriminate between post-depositional OC degradation and actual OC burial and accumulation in fjordic sediments, as foraminifera would only preserve the latter information in their assemblage composition.
Sara K. E. Goulden, Naohiko Ohkouchi, Katherine H. Freeman, Yoshito Chikaraishi, Nanako O. Ogawa, Hisami Suga, Oliver Chadwick, and Benjamin Z. Houlton
Biogeosciences, 16, 3869–3882,Short summary
We investigate whether soil organic compounds preserve information about nitrogen availability to plants. We isolate chlorophyll degradation products in leaves, litter, and soil and explore possible species and climate effects on preservation and interpretation. We find that compound-specific nitrogen isotope measurements in soil have potential as a new tool to reconstruct changes in nitrogen cycling on a landscape over time, avoiding issues that have limited other proxies.
Nicolai Schleinkofer, Jacek Raddatz, André Freiwald, David Evans, Lydia Beuck, Andres Rüggeberg, and Volker Liebetrau
Biogeosciences, 16, 3565–3582,Short summary
In this study we tried to correlate Na / Ca ratios from cold-water corals with environmental parameters such as salinity, temperature and pH. We do not observe a correlation between Na / Ca ratios and seawater salinity, but we do observe a strong correlation with temperature. Na / Ca data from warm-water corals (Porites spp.) and bivalves (Mytilus edulis) support this correlation, indicating that similar controls on the incorporation of sodium exist in these aragonitic organisms.
Mattia Greco, Lukas Jonkers, Kerstin Kretschmer, Jelle Bijma, and Michal Kucera
Biogeosciences, 16, 3425–3437,Short summary
To be able to interpret the paleoecological signal contained in N. pachyderma's shells, its habitat depth must be known. Our investigation on 104 density profiles of this species from the Arctic and North Atlantic shows that specimens reside closer to the surface when sea-ice and/or surface chlorophyll concentrations are high. This is in contrast with previous investigations that pointed at the position of the deep chlorophyll maximum as the main driver of N. pachyderma vertical distribution.
Eunmi Park, Jens Hefter, Gerhard Fischer, Morten Hvitfeldt Iversen, Simon Ramondenc, Eva-Maria Nöthig, and Gesine Mollenhauer
Biogeosciences, 16, 2247–2268,Short summary
We analyzed GDGT-based proxy temperatures in the polar oceans. In the eastern Fram Strait (79° N), the nutrient distribution may determine the depth habit of Thaumarchaeota and thus the proxy temperature. In the Antarctic Polar Front (50° S), the contribution of Euryarchaeota or the nonlinear correlation between the proxy values and temperatures may cause the warm biases of the proxy temperatures relative to SSTs.
Marijke W. de Bar, Jenny E. Ullgren, Robert C. Thunnell, Stuart G. Wakeham, Geert-Jan A. Brummer, Jan-Berend W. Stuut, Jaap S. Sinninghe Damsté, and Stefan Schouten
Biogeosciences, 16, 1705–1727,Short summary
We analyzed sediment traps from the Cariaco Basin, the tropical Atlantic and the Mozambique Channel to evaluate seasonal imprints in the concentrations and fluxes of long-chain diols (LDIs), in addition to the long-chain diol index proxy (sea surface temperature proxy) and the diol index (upwelling indicator). Despite significant degradation, LDI-derived temperatures were very similar for the sediment traps and seafloor sediments, and corresponded to annual mean sea surface temperatures.
Jens Zinke, Juan P. D'Olivo, Christoph J. Gey, Malcolm T. McCulloch, J. Henrich Bruggemann, Janice M. Lough, and Mireille M. M. Guillaume
Biogeosciences, 16, 695–712,Short summary
Here we report seasonally resolved sea surface temperature (SST) reconstructions for the southern Mozambique Channel in the SW Indian Ocean, a region located along the thermohaline ocean surface circulation route, based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores for the past 42 years. Particularly, we show the suitability of both separate and combined Sr / Ca and Li / Mg proxies for improved multielement SST reconstructions.
Hilde Pracht, Brett Metcalfe, and Frank J. C. Peeters
Biogeosciences, 16, 643–661,Short summary
In palaeoceanography the shells of single-celled foraminifera are routinely used as proxies to reconstruct the temperature, salinity and circulation of the ocean in the past. Traditionally a number of specimens were pooled for a single stable isotope measurement; however, technical advances now mean that a single shell or chamber of a shell can be measured individually. Three different hypotheses regarding foraminiferal biology and ecology were tested using this approach.
Anna Jentzen, Dirk Nürnberg, Ed C. Hathorne, and Joachim Schönfeld
Biogeosciences, 15, 7077–7095,
Shauna Ní Fhlaithearta, Christophe Fontanier, Frans Jorissen, Aurélia Mouret, Adriana Dueñas-Bohórquez, Pierre Anschutz, Mattias B. Fricker, Detlef Günther, Gert J. de Lange, and Gert-Jan Reichart
Biogeosciences, 15, 6315–6328,Short summary
This study looks at how foraminifera interact with their geochemical environment in the seabed. We focus on the incorporation of the trace metal manganese (Mn), with the aim of developing a tool to reconstruct past pore water profiles. Manganese concentrations in foraminifera are investigated relative to their ecological preferences and geochemical environment. This study demonstrates that Mn in foraminiferal tests is a promising tool to reconstruct oxygen conditions in the seabed.
Siobhan Williams, Walter Adey, Jochen Halfar, Andreas Kronz, Patrick Gagnon, David Bélanger, and Merinda Nash
Biogeosciences, 15, 5745–5759,
Robert Frei, Cora Paulukat, Sylvie Bruggmann, and Robert M. Klaebe
Biogeosciences, 15, 4905–4922,Short summary
The reconstruction of paleo-redox conditions of seawater has the potential to link to climatic changes on land and therefore to contribute to our understanding of past climate change. The redox-sensitive chromium isotope system is applied to marine calcifiers in order to characterize isotope offsets that result from vital processes during calcification processes and which can be eventually used in fossil equivalents to reconstruct past seawater compositions.
Thomas M. DeCarlo, Michael Holcomb, and Malcolm T. McCulloch
Biogeosciences, 15, 2819–2834,Short summary
Understanding the mechanisms of coral calcification is limited by the isolation of the calcifying environment. The boron systematics (B / Ca and δ11B) of aragonite have recently been developed as a proxy for the carbonate chemistry of the calcifying fluid, but a variety of approaches have been utilized. We assess the available experimental B / Ca partitioning data and present a computer code for deriving calcifying fluid carbonate chemistry from the boron systematics of coral skeletons.
Manuel Bringué, Robert C. Thunell, Vera Pospelova, James L. Pinckney, Oscar E. Romero, and Eric J. Tappa
Biogeosciences, 15, 2325–2348,Short summary
We document 2.5 yr of dinoflagellate cyst production in the Cariaco Basin using a sediment trap record. Each species' production pattern is interpreted in the context of the physico-chemical (e.g., temperature, nutrients) and biological (other planktonic groups) environment. Most species respond positively to upwelling, but seem to be negatively impacted by an El Niño event with a 1-year lag. This work helps understanding dinoflagellate ecology and interpreting fossil assemblages in sediments.
Gabriella M. Weiss, Eva Y. Pfannerstill, Stefan Schouten, Jaap S. Sinninghe Damsté, and Marcel T. J. van der Meer
Biogeosciences, 14, 5693–5704,Short summary
Algal-derived compounds allow us to make assumptions about environmental conditions in the past. In order to better understand how organisms record environmental conditions, we grew microscopic marine algae at different light intensities, salinities, and alkalinities in a temperature-controlled environment. We determined how these environmental parameters affected specific algal-derived compounds, especially their relative deuterium content, which seems to be mainly affected by salinity.
S. Nemiah Ladd, Nathalie Dubois, and Carsten J. Schubert
Biogeosciences, 14, 3979–3994,Short summary
Hydrogen isotopes of lipids provide valuable information about microbial activity, climate, and environmental stress. We show that heavy hydrogen in fatty acids declines from spring to summer in a nutrient-rich and a nutrient-poor lake and that the effect is nearly 3 times as big in the former. This effect is likely a combination of increased biomass from algae, warmer temperatures, and higher algal growth rates.
Karoliina A. Koho, Lennart J. de Nooijer, Christophe Fontanier, Takashi Toyofuku, Kazumasa Oguri, Hiroshi Kitazato, and Gert-Jan Reichart
Biogeosciences, 14, 3067–3082,Short summary
Here we report Mn / Ca ratios in living benthic foraminifera from the NE Japan margin. The results show that the Mn incorporation directly reflects the environment where the foraminifera calcify. Foraminifera that live deeper in sediment, under greater redox stress, generally incorporate more Mn into their carbonate skeletons. As such, foraminifera living close to the Mn reduction zone in sediment appear promising tools for paleoceanographic reconstructions of sedimentary redox conditions.
Stefania Milano, Gernot Nehrke, Alan D. Wanamaker Jr., Irene Ballesta-Artero, Thomas Brey, and Bernd R. Schöne
Biogeosciences, 14, 1577–1591,
Diana Zúñiga, Celia Santos, María Froján, Emilia Salgueiro, Marta M. Rufino, Francisco De la Granda, Francisco G. Figueiras, Carmen G. Castro, and Fátima Abrantes
Biogeosciences, 14, 1165–1179,Short summary
Diatoms are one of the most important primary producers in highly productive coastal regions. Their silicified valves are susceptible to escape from the upper water column and be preserved in the sediment record, and thus are frequently used to reconstruct environmental conditions in the past from sediment cores. Here, we assess how water column diatom’s community in the NW Iberian coastal upwelling system is seasonally transferred from the surface to the seafloor sediments.
Andreia Rebotim, Antje H. L. Voelker, Lukas Jonkers, Joanna J. Waniek, Helge Meggers, Ralf Schiebel, Igaratza Fraile, Michael Schulz, and Michal Kucera
Biogeosciences, 14, 827–859,Short summary
Planktonic foraminifera species depth habitat remains poorly constrained and the existing conceptual models are not sufficiently tested by observational data. Here we present a synthesis of living planktonic foraminifera abundance data in the subtropical eastern North Atlantic from vertical plankton tows. We also test potential environmental factors influencing the species depth habitat and investigate yearly or lunar migration cycles. These findings may impact paleoceanographic studies.
Clemens Vinzenz Ullmann and Philip A. E. Pogge von Strandmann
Biogeosciences, 14, 89–97,Short summary
This study documents how much control growth rate has on the chemical composition of fossil shell material. Using a series of chemical analyses of the fossil hard part of a belemnite, an extinct marine predator, a clear connection between the rate of calcite formation and its magnesium and strontium contents was found. These findings provide further insight into biomineralization processes and help better understand chemical signatures of fossils as proxies for palaeoenvironmental conditions.
Justine Kimball, Robert Eagle, and Robert Dunbar
Biogeosciences, 13, 6487–6505,Short summary
Deep-sea corals are a potentially valuable archive of temperature and ocean chemistry. We analyzed clumped isotope signatures (Δ47) in live-collected aragonitic scleractinian and high-Mg calcitic gorgonian deep-sea corals and compared results to published data and found offsets between taxa. The observed patterns in deep-sea corals may record distinct mineral equilibrium signatures due to very slow growth rates, kinetic isotope effects, and/or variable acid digestion fractionation factors.
Lisa Warden, Jung-Hyun Kim, Claudia Zell, Geert-Jan Vis, Henko de Stigter, Jérôme Bonnin, and Jaap S. Sinninghe Damsté
Biogeosciences, 13, 5719–5738,Short summary
Enhanced analytical techniques were applied to characterize fossilized microbial cell membrane lipids from samples in the Tagus River basin spanning the last 6000 years. Using the novel methods and calibration, the pH estimates were improved upon, and this study reveals new factors that should be considered when using this proxy as well as affirms the importance of examining the provenance of these lipids before applying them for paleoclimate reconstructions.
A. Ponnurangam, M. Bau, M. Brenner, and A. Koschinsky
Biogeosciences, 13, 751–760,Short summary
Our study demonstrates that rare earth elements and yttrium (REY) accumulating in mussel shells emerge as potential proxies for environmental changes. Focusing on pH and temperature variation effects on the distribution of REY in seawater, we show that shells incorporate the free REY3+ species and that decreasing pH leads to increased REY concentrations, while rising temperatures impact the REY distribution pattern with minor effects on the absolute REY concentrations in shells.
O. T. Moldovan, S. Constantin, C. Panaiotu, R. D. Roban, P. Frenzel, and L. Miko
Biogeosciences, 13, 483–497,Short summary
The paper presents the results of a fossil invertebrates study in four caves of the Romanian Carpathians, to complement paleoenvironmental data previously reported. Oribatid mites and ostracods are the most common invertebrates in the studied cave sediments. By corroborating the fossil invertebrates' record with the information given by magnetic properties and sediment structures, complementary data on past vegetation, temperatures, and hydraulic regimes could be gathered.
C. Häggi, C. M. Chiessi, and E. Schefuß
Biogeosciences, 12, 7239–7249,
J. M. Bernhard, W. G. Phalen, A. McIntyre-Wressnig, F. Mezzo, J. C. Wit, M. Jeglinski, and H. L. Filipsson
Biogeosciences, 12, 5515–5522,Short summary
We present an innovative method using osmotic pumps and the fluorescent marker calcein to help identify where and when calcareous bottom-dwelling organisms mineralize in sediments. These organisms, and their geochemical signatures in their carbonate, are the ocean’s storytellers helping us understand past marine conditions. For many species, the timing and location of their calcite growth is not known. Knowing this will enable us to reconstruct past marine environments with greater accuracy.
C. L. McKay, J. Groeneveld, H. L. Filipsson, D. Gallego-Torres, M. J. Whitehouse, T. Toyofuku, and O.E. Romero
Biogeosciences, 12, 5415–5428,Short summary
We highlight the proxy potential of foraminiferal Mn/Ca determined by secondary ion mass spectrometry and flow-through inductively coupled plasma optical emission spectroscopy for recording changes in bottom-water oxygen conditions. Comparisons with Mn sediment bulk measurements from the same sediment core largely agree with the results. High foraminiferal Mn/Ca occurs in samples from times of high productivity export and corresponds with the benthic foraminiferal faunal composition.
J. Schilder, C. Tellenbach, M. Möst, P. Spaak, M. van Hardenbroek, M. J. Wooller, and O. Heiri
Biogeosciences, 12, 3819–3830,Short summary
We show that the stable (C, N, O) isotopic composition of the water flea Daphnia pulicaria is strongly related to that of its diet (C, N) and the water they live in (O). We also show that the stable isotopic composition of the sheaths of Daphnia resting eggs (ephippia) is indicative of the isotopic composition of Daphnia that produced them. This implies that stable isotope ratios of fossil Daphnia ephippia can provide information on past ecological and climatic developments in and around lakes.
W. Clymans, L. Barão, N. Van der Putten, S. Wastegård, G. Gísladóttir, S. Björck, B. Moine, E. Struyf, and D. J. Conley
Biogeosciences, 12, 3789–3804,Short summary
Biogenic silica (BSi) is used as a proxy by soil scientists to identify biological effects on the Si cycle and by palaeoecologists to study environmental changes. We show the presence of tephra constituents can make measurements erroneous at low BSi concentrations, with repercussions for soil and palaeoecological studies. However, we also show that glass shards do not produce an identical dissolution signal to that of BSi, meaning they can be distinguished with appropriate experimental setups.
T. Bauersachs, J. Rochelmeier, and L. Schwark
Biogeosciences, 12, 3741–3751,
K. R. Hendry, G. E. A. Swann, M. J. Leng, H. J. Sloane, C. Goodwin, J. Berman, and M. Maldonado
Biogeosciences, 12, 3489–3498,Short summary
The stable isotope composition of benthic sponge silica skeletons (spicules) has been shown to be a source of useful palaeoceanographic information about past deep seawater chemistry. Here, we investigate the biological vital effects on silica stable isotope composition in a Southern Ocean carnivorous sponge, Asbestopluma sp. We find significant variations in isotopic composition within the specimen – in both silicon and oxygen isotopes – that appear to be related to unusual spicule growth.
Y.-W. Liu, S. M. Aciego, and A. D. Wanamaker Jr.
Biogeosciences, 12, 3351–3368,Short summary
We report the first high-resolution strontium (87Sr/86Sr and δ88/86Sr) and boron (δ11B) isotopic values in the aragonite shell of cultured Arctica islandica. These results suggest that well-preserved subfossil specimens may be used to determine the past Sr isotopic composition of seawater. The δ11B in this experiment suggests that the boron uptake of the shell changes at a temperature threshold of 13°C and a species-specific fractionation factor may be required for seawater pH reconstructions.
L. Jonkers and M. Kučera
Biogeosciences, 12, 2207–2226,
K. Kaczmarek, G. Langer, G. Nehrke, I. Horn, S. Misra, M. Janse, and J. Bijma
Biogeosciences, 12, 1753–1763,Short summary
Culture experiments based on a decoupled pH and CO32- chemistry indicate that the δ11B of the test of A. lessonii is related to pH whereas the B/Ca of the foraminiferal shells show a positive correlation with B(OH)4-/HCO3-. The latter observation suggests a competition between B(OH)4- and HCO3- of the culture media for B uptake into the test.
T. Pados, R. F. Spielhagen, D. Bauch, H. Meyer, and M. Segl
Biogeosciences, 12, 1733–1752,Short summary
Fossil planktic foraminifera and their geochemical composition are commonly used proxies in palaeoceanography. Our study with living specimens revealed that in the Fram Strait both Neogloboquadrina pachyderma and Turborotalita quinqueloba from the water column have lower δ18O and δ13C values than inorganically precipitated calcite/fossil tests from the sediment surface. These offsets indicate biological influence during calcification and a change of water column properties in the recent past.
K. H. Salmon, P. Anand, P. F. Sexton, and M. Conte
Biogeosciences, 12, 223–235,Short summary
Planktonic foraminifera are an important component of the marine carbon/carbonate cycle, yet the environmental controls on their abundances are still debated. In our study, we see larger foraminifera fluxes, particularly of heavy species, during winter when nutrients are mixed into the surface waters or during eddy mixing. Climatic factors that control mixing could therefore control the flux of planktonic foraminfera and the carbon/carbonate flux on seasonal and decadal timescales.
Altuna, N. E. B., Pieńkowski, A. J., Eynaud, F., and Thiessen, R.: The morphotypes of Neogloboquadrina pachyderma: Isotopic signature and distribution patterns in the Canadian Arctic Archipelago and adjacent regions, Mar. Micropaleontol., 142, 13–24, 2018. a
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Cape, M. R., Vernet, M., Pettit, E. C., Wellner, J. S., Truffer, M., Akie, G., Domack, E., Leventer, A., Smith, C. R., and Huber, B. A.: Circumpolar Deep Water impacts glacial meltwater export and coastal biogeochemical cycling along the west Antarctic Peninsula, Front. Mar. Sci., 6, 1–23, 2019. a
Coplen, T. B.: Normalization of oxygen and hydrogen isotope data, Chem. Geol., 72, 293–297, 1988. a
Darling, K. F., Kucera, M., Kroon, D., and Wade, C. M.: A resolution for the coiling direction paradox in Neogloboquadrina pachyderma, Paleoceanography, 21, 1–14, 2006. a
Eynaud, F., Cronin, T., Smith, S., Zaragosi, S., Mavel, J., Mary, Y., Mas, V., and Pujol, C.: Morphological variability of the planktonic foraminifer Neogloboquadrina pachyderma from ACEX cores: Implications for Late Pleistocene circulation in the Arctic Ocean, Micropaleontology, 55, 101–116, 2009. a, b
Ezard, T. H., Edgar, K. M., and Hull, P. M.: Environmental and biological controls on size-specific δ13C and δ18O in recent planktonic foraminifera, Paleoceanography, 30, 151–173, 2015. a
Gleiber, M. R., Steinberg, D. K., and Ducklow, H. W.: Time series of vertical flux of zooplankton fecal pellets on the continental shelf of the western Antarctic Peninsula, Mar. Ecol. Prog. Ser., 471, 23–36, 2012. a
Gyldenfeldt, A.-B. v., Carstens, J., and Meincke, J.: Estimation of the catchment area of a sediment trap by means of current meters and foraminiferal tests, Deep-Sea Res. Pt. II, 47, 1701–1717, 2000. a
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Huber, R., Meggers, H., Baumann, K.-H., Raymo, M. E., and Henrich, R.: Shell size variation of the planktonic foraminifer Neogloboquadrina pachyderma sin. in the Norwegian–Greenland Sea during the last 1.3 Myrs: implications for paleoceanographic reconstructions, Palaeogeogr. Palaeocl., 160, 193–212, 2000. a
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Kim, H., Ducklow, H. W., Abele, D., Ruiz Barlett, E. M., Buma, A. G., Meredith, M. P., Rozema, P. D., Schofield, O. M., Venables, H. J., and Schloss, I. R.: Inter-decadal variability of phytoplankton biomass along the coastal West Antarctic Peninsula, Philos. T. R. Soc. A, 376, 20170174, https://doi.org/10.1098/rsta.2017.0174, 2018. a, b
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Kohfeld, K. E., Fairbanks, R. G., Smith, S. L., and Walsh, I. D.: Neogloboquadrina pachyderma (sinistral coiling) as paleoceanographic tracers in polar oceans: Evidence from Northeast Water Polynya plankton tows, sediment traps, and surface sediments, Paleoceanography, 11, 679–699, 1996. a, b, c, d, e, f, g
Kuroyanagi, A., Kawahata, H., and Nishi, H.: Seasonal variation in the oxygen isotopic composition of different-sized planktonic foraminifer Neogloboquadrina pachyderma (sinistral) in the northwestern North Pacific and implications for reconstruction of the paleoenvironment, Paleoceanography, 26, 1–10, 2011. a, b
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Antarctic marine calcifying organisms are threatened by regional climate change and ocean acidification. Future projections of regional carbonate production are challenging due to the lack of historical data combined with complex climate variability. We present a 6-year record of flux, morphology and geochemistry of an Antarctic planktonic foraminifera, which shows that their growth is most sensitive to sea ice dynamics and is linked with the El Niño–Southern Oscillation.
Antarctic marine calcifying organisms are threatened by regional climate change and ocean...