Articles | Volume 13, issue 23
https://doi.org/10.5194/bg-13-6385-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/bg-13-6385-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
30 Nov 2016
Research article |
| 30 Nov 2016
Stable carbon isotope gradients in benthic foraminifera as proxy for organic carbon fluxes in the Mediterranean Sea
Marc Theodor
CORRESPONDING AUTHOR
Center for Earth System Research and Sustainability, Institute of
Geology, University of Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
Gerhard Schmiedl
Center for Earth System Research and Sustainability, Institute of
Geology, University of Hamburg, Bundesstrasse 55, 20146 Hamburg, Germany
Frans Jorissen
CNRS, UMR 6112, LPG–BIAF, Recent and Fossil Bio-Indicators,
Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX, France
Andreas Mackensen
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine
Research, Am Alten Hafen 26, 27568 Bremerhaven, Germany
Related authors
No articles found.
Werner Ehrmann, Paul A. Wilson, Helge W. Arz, and Gerhard Schmiedl
Clim. Past, 21, 1025–1041, https://doi.org/10.5194/cp-21-1025-2025, https://doi.org/10.5194/cp-21-1025-2025, 2025
Short summary
Short summary
We report palaeoclimate and sediment provenance records for the last 220 kyr from a sediment core from the northern Red Sea. They comprise high-resolution grain size, clay mineral, and geochemical data, together with Nd and Sr isotope data. The data sets document a strong temporal variability in dust influx on glacial–interglacial timescales and several shorter-term strong fluvial episodes. A key finding is that the Nile delta became a major dust source during glacioeustatic sea-level lowstands.
Anjaly Govindankutty Menon, Aaron L. Bieler, Hanna Firrincieli, Rachel Alcorn, Niko Lahajnar, Catherine V. Davis, Ralf Schiebel, Dirk Nürnberg, Gerhard Schmiedl, and Nicolaas Glock
EGUsphere, https://doi.org/10.5194/egusphere-2025-1182, https://doi.org/10.5194/egusphere-2025-1182, 2025
This preprint is open for discussion and under review for Climate of the Past (CP).
Short summary
Short summary
The pore density (number of pores per unit area) of unicellular eukaryotes is used to reconstruct past bottom-water nitrate at the Sea of Okhotsk, the Gulf of California, the Mexican Margin and the Gulf of Guayaquil. The reconstructed bottom-water nitrate at the Sea of Okhotsk, the Gulf of California and the Gulf of Guayaquil are influenced by the intermediate water masses, while the nitrate at the Mexican Margin is related to the deglacial NO3− variability in the Pacific Deep Water.
Jan Maier, Nicole Burdanowitz, Gerhard Schmiedl, and Birgit Gaye
Clim. Past, 21, 279–297, https://doi.org/10.5194/cp-21-279-2025, https://doi.org/10.5194/cp-21-279-2025, 2025
Short summary
Short summary
We reconstruct sea surface temperatures (SSTs) of the past 43 kyr in the Gulf of Oman. We find SST variations of up to 7 °C with lower SSTs during Heinrich events (HEs), especially HE4, and higher SSTs during Dansgaard–Oeschger events. Our record shows no profound cooling during the Last Glacial Maximum but abrupt variations during the Holocene. We surmise that SST variations are influenced by the southwest (northeast) monsoon during warmer (colder) periods.
Katharina D. Six, Uwe Mikolajewicz, and Gerhard Schmiedl
Clim. Past, 20, 1785–1816, https://doi.org/10.5194/cp-20-1785-2024, https://doi.org/10.5194/cp-20-1785-2024, 2024
Short summary
Short summary
We use a physical and biogeochemical ocean model of the Mediterranean Sea to obtain a picture of the Last Glacial Maximum. The shallowing of the Strait of Gibraltar leads to a shallower pycnocline and more efficient nutrient export. Consistent with the sediment data, an increase in organic matter deposition is simulated, although this is based on lower biological production. This unexpected but plausible result resolves the apparent contradiction between planktonic and benthic proxy data.
Nicole Burdanowitz, Gerhard Schmiedl, Birgit Gaye, Philipp M. Munz, and Hartmut Schulz
Biogeosciences, 21, 1477–1499, https://doi.org/10.5194/bg-21-1477-2024, https://doi.org/10.5194/bg-21-1477-2024, 2024
Short summary
Short summary
We analyse benthic foraminifera, nitrogen isotopes and lipids in a sediment core from the Gulf of Oman to investigate how the oxygen minimum zone (OMZ) and bottom water (BW) oxygenation have reacted to climatic changes since 43 ka. The OMZ and BW deoxygenation was strong during the Holocene, but the OMZ was well ventilated during the LGM period. We found an unstable mode of oscillating oxygenation states, from moderately oxygenated in cold stadials to deoxygenated in warm interstadials in MIS 3.
Raphaël Hubert-Huard, Nils Andersen, Helge W. Arz, Werner Ehrmann, and Gerhard Schmiedl
Clim. Past, 20, 267–280, https://doi.org/10.5194/cp-20-267-2024, https://doi.org/10.5194/cp-20-267-2024, 2024
Short summary
Short summary
We have studied the geochemistry of benthic foraminifera (micro-fossils) from a sediment core from the Red Sea. Our data show that the circulation and carbon cycling of the Red Sea during the last glacial period responded to high-latitude millennial-scale climate variability and to the orbital influence of the African–Indian monsoon system. This implies a sensitive response of the Red Sea to climate changes.
Werner Ehrmann, Paul A. Wilson, Helge W. Arz, Hartmut Schulz, and Gerhard Schmiedl
Clim. Past, 20, 37–52, https://doi.org/10.5194/cp-20-37-2024, https://doi.org/10.5194/cp-20-37-2024, 2024
Short summary
Short summary
Climatic and associated hydrological changes controlled the aeolian versus fluvial transport processes and the composition of the sediments in the central Red Sea through the last ca. 200 kyr. We identify source areas of the mineral dust and pulses of fluvial discharge based on high-resolution grain size, clay mineral, and geochemical data, together with Nd and Sr isotope data. We provide a detailed reconstruction of changes in aridity/humidity.
Julien Richirt, Magali Schweizer, Aurélia Mouret, Sophie Quinchard, Salha A. Saad, Vincent M. P. Bouchet, Christopher M. Wade, and Frans J. Jorissen
J. Micropalaeontol., 40, 61–74, https://doi.org/10.5194/jm-40-61-2021, https://doi.org/10.5194/jm-40-61-2021, 2021
Short summary
Short summary
The study presents (1) a validation of a method which was previously published allowing us to recognize different Ammonia phylotypes (T1, T2 and T6) based only on their morphology and (2) a refined biogeographical distribution presented here supporting the putatively invasive character of phylotype T6. Results suggest that phylotype T6 is currently spreading out and supplanting autochthonous phylotypes T1 and T2 along the coastlines of the British Isles and northern France.
Julien Richirt, Bettina Riedel, Aurélia Mouret, Magali Schweizer, Dewi Langlet, Dorina Seitaj, Filip J. R. Meysman, Caroline P. Slomp, and Frans J. Jorissen
Biogeosciences, 17, 1415–1435, https://doi.org/10.5194/bg-17-1415-2020, https://doi.org/10.5194/bg-17-1415-2020, 2020
Short summary
Short summary
The paper presents the response of benthic foraminiferal communities to seasonal absence of oxygen coupled with the presence of hydrogen sulfide, considered very harmful for several living organisms.
Our results suggest that the foraminiferal community mainly responds as a function of the duration of the adverse conditions.
This knowledge is especially useful to better understand the ecology of benthic foraminifera but also in the context of palaeoceanographic interpretations.
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, https://doi.org/10.5194/cp-15-539-2019, https://doi.org/10.5194/cp-15-539-2019, 2019
Short summary
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.
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, https://doi.org/10.5194/bg-15-6315-2018, https://doi.org/10.5194/bg-15-6315-2018, 2018
Short summary
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.
Jassin Petersen, Christine Barras, Antoine Bézos, Carole La, Lennart J. de Nooijer, Filip J. R. Meysman, Aurélia Mouret, Caroline P. Slomp, and Frans J. Jorissen
Biogeosciences, 15, 331–348, https://doi.org/10.5194/bg-15-331-2018, https://doi.org/10.5194/bg-15-331-2018, 2018
Short summary
Short summary
In Lake Grevelingen, a coastal ecosystem, foraminifera experience important temporal variations in oxygen concentration and in pore water manganese. The high resolution of LA-ICP-MS allows us to analyse the chambers of foraminiferal shells separately and to obtain signals from a series of calcification events. We estimate the variability in Mn/Ca observed within single shells due to biomineralization and show that a substantial part of the signal is related to environmental variability.
Sabine Prader, Ulrich Kotthoff, Francine M.G. McCarthy, Gerhard Schmiedl, Timme H. Donders, and David R. Greenwood
Biogeosciences Discuss., https://doi.org/10.5194/bg-2017-511, https://doi.org/10.5194/bg-2017-511, 2018
Manuscript not accepted for further review
Short summary
Short summary
The observed palaeovegetation movement signals probably correspond to several glacial phases of the middle Oligocene and Early Miocene and might be best reflected within peaks of the conifer forests. Glacial phases exposed shallow shelf areas and allowed the spreading of substrate-depending forest formations. Temperature estimates revealing relative stable humid warm temperate conditions. A Sporadic occurred extinct taxon widens the understanding of its distribution pattern during the Cenozoic.
Dorothea Bunzel, Gerhard Schmiedl, Sebastian Lindhorst, Andreas Mackensen, Jesús Reolid, Sarah Romahn, and Christian Betzler
Clim. Past, 13, 1791–1813, https://doi.org/10.5194/cp-13-1791-2017, https://doi.org/10.5194/cp-13-1791-2017, 2017
Short summary
Short summary
We investigated a sediment core from the Maldives to unravel the interaction between equatorial climate and ocean variability of the past 200 000 years. The sedimentological, geochemical and foraminiferal data records reveal enhanced dust, which was transported by intensified winter monsoon winds during glacial conditions. Precessional fluctuations of bottom water oxygen suggests an expansion of the Arabian Sea OMZ and a varying inflow of Antarctic Intermediate Water.
Valerie Menke, Werner Ehrmann, Yvonne Milker, Swaantje Brzelinski, Jürgen Möbius, Uwe Mikolajewicz, Bernd Zolitschka, Karin Zonneveld, Kay Christian Emeis, and Gerhard Schmiedl
Clim. Past Discuss., https://doi.org/10.5194/cp-2017-139, https://doi.org/10.5194/cp-2017-139, 2017
Preprint withdrawn
Short summary
Short summary
This study examines changes in the marine ecosystem during the past 1300 years in the Gulf of Taranto (Italy) to unravel natural and anthropogenic forcing. Our data suggest, that processes at the sea floor are linked to the North Atlantic Oscillation (NAO) and the Atlantic Multidecadal Oscillation. During the past 200 years, the effects of rising northern hemisphere temperature and increasing anthropogenic activity enhanced nutrient and organic matter fluxes leading to more eutrophic conditions.
Thierry Jauffrais, Bruno Jesus, Edouard Metzger, Jean-Luc Mouget, Frans Jorissen, and Emmanuelle Geslin
Biogeosciences, 13, 2715–2726, https://doi.org/10.5194/bg-13-2715-2016, https://doi.org/10.5194/bg-13-2715-2016, 2016
Short summary
Short summary
Some benthic foraminifera can incorporate chloroplasts from microalgae. We investigated chloroplast functionality of two benthic foraminifera (Haynesina germanica & Ammonia tepida) exposed to different light levels. Only H. germanica was capable of using the kleptoplasts, showing net oxygen production. Chloroplast functionality time was longer in darkness (2 weeks) than at high light (1 week). Kleptoplasts are unlikely to be completely functional, thus requiring continuous chloroplast resupply.
Werner Ehrmann, Gerhard Schmiedl, Martin Seidel, Stefan Krüger, and Hartmut Schulz
Clim. Past, 12, 713–727, https://doi.org/10.5194/cp-12-713-2016, https://doi.org/10.5194/cp-12-713-2016, 2016
A. Thibault de Chanvalon, E. Metzger, A. Mouret, F. Cesbron, J. Knoery, E. Rozuel, P. Launeau, M. P. Nardelli, F. J. Jorissen, and E. Geslin
Biogeosciences, 12, 6219–6234, https://doi.org/10.5194/bg-12-6219-2015, https://doi.org/10.5194/bg-12-6219-2015, 2015
Short summary
Short summary
We present a new rapid and accurate protocol to simultaneously sample, in two dimensions, benthic living foraminifera at the centimetre scale and dissolved iron and phosphorus at the submillimetre scale. It was applied to a highly bioturbated site in a mudflat of the Loire estuary and showed that, in the suboxic zone, foraminifera are less affected by active burrows (i.e. reoxygenated) than by iron reactive hotspots. This unexpected result calls for a generalization of this new protocol.
C. Caulle, M. Mojtahid, A. J. Gooday, F. J. Jorissen, and H. Kitazato
Biogeosciences, 12, 5005–5019, https://doi.org/10.5194/bg-12-5005-2015, https://doi.org/10.5194/bg-12-5005-2015, 2015
M. P. Nardelli, C. Barras, E. Metzger, A. Mouret, H. L. Filipsson, F. Jorissen, and E. Geslin
Biogeosciences, 11, 4029–4038, https://doi.org/10.5194/bg-11-4029-2014, https://doi.org/10.5194/bg-11-4029-2014, 2014
E. Metzger, D. Langlet, E. Viollier, N. Koron, B. Riedel, M. Stachowitsch, J. Faganeli, M. Tharaud, E. Geslin, and F. Jorissen
Biogeosciences, 11, 2211–2224, https://doi.org/10.5194/bg-11-2211-2014, https://doi.org/10.5194/bg-11-2211-2014, 2014
D. Langlet, C. Baal, E. Geslin, E. Metzger, M. Zuschin, B. Riedel, N. Risgaard-Petersen, M. Stachowitsch, and F. J. Jorissen
Biogeosciences, 11, 1775–1797, https://doi.org/10.5194/bg-11-1775-2014, https://doi.org/10.5194/bg-11-1775-2014, 2014
L. Max, L. Lembke-Jene, J.-R. Riethdorf, R. Tiedemann, D. Nürnberg, H. Kühn, and A. Mackensen
Clim. Past, 10, 591–605, https://doi.org/10.5194/cp-10-591-2014, https://doi.org/10.5194/cp-10-591-2014, 2014
C. Caulle, K. A. Koho, M. Mojtahid, G. J. Reichart, and F. J. Jorissen
Biogeosciences, 11, 1155–1175, https://doi.org/10.5194/bg-11-1155-2014, https://doi.org/10.5194/bg-11-1155-2014, 2014
S. Romahn, A. Mackensen, J. Groeneveld, and J. Pätzold
Clim. Past, 10, 293–303, https://doi.org/10.5194/cp-10-293-2014, https://doi.org/10.5194/cp-10-293-2014, 2014
Y. Milker, M. Wilken, J. Schumann, D. Sakuna, P. Feldens, K. Schwarzer, and G. Schmiedl
Nat. Hazards Earth Syst. Sci., 13, 3113–3128, https://doi.org/10.5194/nhess-13-3113-2013, https://doi.org/10.5194/nhess-13-3113-2013, 2013
D. Langlet, E. Geslin, C. Baal, E. Metzger, F. Lejzerowicz, B. Riedel, M. Zuschin, J. Pawlowski, M. Stachowitsch, and F. J. Jorissen
Biogeosciences, 10, 7463–7480, https://doi.org/10.5194/bg-10-7463-2013, https://doi.org/10.5194/bg-10-7463-2013, 2013
B. Rabe, P. A. Dodd, E. Hansen, E. Falck, U. Schauer, A. Mackensen, A. Beszczynska-Möller, G. Kattner, E. J. Rohling, and K. Cox
Ocean Sci., 9, 91–109, https://doi.org/10.5194/os-9-91-2013, https://doi.org/10.5194/os-9-91-2013, 2013
Related subject area
Biogeochemistry: Stable Isotopes & Other Tracers
Sea ice and mixed layer depth influence on nitrate depletion and associated isotopic effects in the Drake Passage–Weddell Sea region, Southern Ocean
Stable iron isotope signals indicate a “pseudo-abiotic” process driving deep iron release in methanic sediments
Triple oxygen isotope evidence for the pathway of nitrous oxide production in a forested soil with increased emission on rainy days
Previous integrated or organic farming affects productivity and ecosystem N balance rather than fertilizer 15N allocation to plants and soil, leaching, or gaseous emissions (NH3, N2O, and N2)
How long does carbon stay in a near-pristine central Amazon forest? An empirical estimate with radiocarbon
No increase is detected and modeled for the seasonal cycle amplitude of δ13C of atmospheric carbon dioxide
Fungi present distinguishable isotopic signals when grown on glycolytic versus tricarboxylic acid cycle intermediates
Bias in calculating gross nitrification rates in forested catchments using the triple oxygen isotopic composition (Δ17O) of stream nitrate
Position-specific kinetic isotope effects for nitrous oxide: a new expansion of the Rayleigh model
Technical note: A Bayesian mixing model to unravel isotopic data and quantify trace gas production and consumption pathways for time series data – Time-resolved FRactionation And Mixing Evaluation (TimeFRAME)
Separating above-canopy CO2 and O2 measurements into their atmospheric and biospheric signatures
Climatic controls on leaf wax hydrogen isotope ratios in terrestrial and marine sediments along a hyperarid-to-humid gradient
Fractionation of stable carbon isotopes during microbial propionate consumption in anoxic rice paddy soils
Sources and sinks of carbonyl sulfide inferred from tower and mobile atmospheric observations in the Netherlands
Downpour dynamics: outsized impacts of storm events on unprocessed atmospheric nitrate export in an urban watershed
The hidden role of dissolved organic carbon in the biogeochemical cycle of carbon in modern redox-stratified lakes
Biogeochemical processes captured by carbon isotopes in redox-stratified water columns: a comparative study of four modern stratified lakes along an alkalinity gradient
Partitioning of carbon export in the euphotic zone of the oligotrophic South China Sea
Determination of respiration and photosynthesis fractionation factors for atmospheric dioxygen inferred from a vegetation–soil–atmosphere analogue of the terrestrial biosphere in closed chambers
Permafrost degradation and nitrogen cycling in Arctic rivers: insights from stable nitrogen isotope studies
Neodymium budget in the Mediterranean Sea: evaluating the role of atmospheric dusts using a high-resolution dynamical-biogeochemical model
Nitrate isotope investigations reveal future impacts of climate change on nitrogen inputs and cycling in Arctic fjords: Kongsfjorden and Rijpfjorden (Svalbard)
Mineralization of autochthonous particulate organic carbon is a fast channel of organic matter turnover in Germany's largest drinking water reservoir
Carbon isotopic ratios of modern C3 and C4 vegetation on the Indian peninsula and changes along the plant–soil–river continuum – implications for vegetation reconstructions
Controls on nitrite oxidation in the upper Southern Ocean: insights from winter kinetics experiments in the Indian sector
Tracing the source of nitrate in a forested stream showing elevated concentrations during storm events
Intra-skeletal variability in phosphate oxygen isotope composition reveals regional heterothermies in marine vertebrates
Isotopic differences in soil–plant–atmosphere continuum composition and control factors of different vegetation zones on the northern slope of the Qilian Mountains
An analysis of the variability in δ13C in macroalgae from the Gulf of California: indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation
Summertime productivity and carbon export potential in the Weddell Sea, with a focus on the waters adjacent to Larsen C Ice Shelf
Particulate biogenic barium tracer of mesopelagic carbon remineralization in the Mediterranean Sea (PEACETIME project)
Hydrogen and carbon isotope fractionation factors of aerobic methane oxidation in deep-sea water
Host-influenced geochemical signature in the parasitic foraminifera Hyrrokkin sarcophaga
Comparing modified substrate-induced respiration with selective inhibition (SIRIN) and N2O isotope approaches to estimate fungal contribution to denitrification in three arable soils under anoxic conditions
How are oxygen budgets influenced by dissolved iron and growth of oxygenic phototrophs in an iron-rich spring system? Initial results from the Espan Spring in Fürth, Germany
Stable isotope ratios in seawater nitrate reflect the influence of Pacific water along the northwest Atlantic margin
High-resolution 14C bomb peak dating and climate response analyses of subseasonal stable isotope signals in wood of the African baobab – a case study from Oman
Geographic variability in freshwater methane hydrogen isotope ratios and its implications for global isotopic source signatures
Seasonality of nitrogen sources, cycling, and loading in a New England river discerned from nitrate isotope ratios
Evaluating the response of δ13C in Haloxylon ammodendron, a dominant C4 species in Asian desert ecosystems, to water and nitrogen addition as well as the availability of its δ13C as an indicator of water use efficiency
Modern silicon dynamics of a small high-latitude subarctic lake
Radium-228-derived ocean mixing and trace element inputs in the South Atlantic
Nitrogen isotopic fractionations during nitric oxide production in an agricultural soil
Silicon uptake and isotope fractionation dynamics by crop species
Barium stable isotopes as a fingerprint of biological cycling in the Amazon River basin
Bottomland hardwood forest growth and stress response to hydroclimatic variation: evidence from dendrochronology and tree ring Δ13C values
N2O isotope approaches for source partitioning of N2O production and estimation of N2O reduction – validation with the 15N gas-flux method in laboratory and field studies
Technical note: Single-shell δ11B analysis of Cibicidoides wuellerstorfi using femtosecond laser ablation MC-ICPMS and secondary ion mass spectrometry
Biogeochemical evidence of anaerobic methane oxidation and anaerobic ammonium oxidation in a stratified lake using stable isotopes
Effects of 238U variability and physical transport on water column 234Th downward fluxes in the coastal upwelling system off Peru
Aymeric P. M. Servettaz, Yuta Isaji, Chisato Yoshikawa, Yanghee Jang, Boo-Keun Khim, Yeongjun Ryu, Daniel M. Sigman, Nanako O. Ogawa, Francisco J. Jiménez-Espejo, and Naohiko Ohkouchi
Biogeosciences, 22, 2239–2260, https://doi.org/10.5194/bg-22-2239-2025, https://doi.org/10.5194/bg-22-2239-2025, 2025
Short summary
Short summary
Phytoplankton blooms occur after sea ice retreats in the Southern Ocean. In this study we investigate the influence of seasonal cycle of sea ice concentration on nitrate depletion, testing the hypothesis that meltwater release stabilizes the water column and favors nutrient utilization. We find that, at a regional scale, nitrate depletion and vertical mixing are weakly correlated with sea ice cycle. Nitrate depletion is rather linked to other oceanographic processes controlling mixing depth.
Susann Henkel, Bo Liu, Michael Staubwasser, Simone A. Kasemann, Anette Meixner, David A. Aromokeye, Michael W. Friedrich, and Sabine Kasten
Biogeosciences, 22, 1673–1696, https://doi.org/10.5194/bg-22-1673-2025, https://doi.org/10.5194/bg-22-1673-2025, 2025
Short summary
Short summary
We intend to unravel iron (Fe) reduction pathways in high-deposition methanic sediments because pools of Fe minerals could stimulate methane oxidation and also generation. Our data from the North Sea show that Fe release takes place mechanistically differently to Fe reduction in shallow sediments, which typically fractionates Fe isotopes. We conclude that fermentation of organic matter involving interspecies electron transfer, partly through conductive Fe oxides, could play an important role.
Weitian Ding, Urumu Tsunogai, Tianzheng Huang, Takashi Sambuichi, Wenhua Ruan, Masanori Ito, Hao Xu, Yongwon Kim, and Fumiko Nakagawa
EGUsphere, https://doi.org/10.21203/rs.3.rs-4264720/v2, https://doi.org/10.21203/rs.3.rs-4264720/v2, 2025
Short summary
Short summary
Identifying the pathways of N2O produced through nitrification and denitrification in soil is crucial for effective mitigation. Thus, we monitored a new natural isotopic signature (Δ17O) of N2O in forested soil for identifying the pathways, which is almost stable during various biogeochemical processes. Our results suggest Δ17O is a promising signature for identifying pathways of N2O production, revealing that increased denitrification drives the high emission of N2O in soil on rainy days.
Fawad Khan, Samuel Franco Luesma, Frederik Hartmann, Michael Dannenmann, Rainer Gasche, Clemens Scheer, Andreas Gattinger, Wiebke Niether, Elizabeth Gachibu Wangari, Ricky Mwangada Mwanake, Ralf Kiese, and Benjamin Wolf
EGUsphere, https://doi.org/10.5194/egusphere-2025-292, https://doi.org/10.5194/egusphere-2025-292, 2025
Short summary
Short summary
Crop rotations with legumes and use of organic and mineral fertilizers show potential to reduce agricultural N losses. This study examined N losses, including direct N2 flux, on two adjacent sites with different management history: organic farming (OF) with legume cultivation and integrated farming (IF) using synthetic and organic N inputs. IF increased soil organic carbon and nitrogen content, 15N recovery and showed a balanced N budget, i.e., more efficient N cycling compared to OF.
Ingrid Chanca, Ingeborg Levin, Susan Trumbore, Kita Macario, Jost Lavric, Carlos Alberto Quesada, Alessandro Carioca de Araújo, Cléo Quaresma Dias Júnior, Hella van Asperen, Samuel Hammer, and Carlos A. Sierra
Biogeosciences, 22, 455–472, https://doi.org/10.5194/bg-22-455-2025, https://doi.org/10.5194/bg-22-455-2025, 2025
Short summary
Short summary
Assessing the net carbon (C) budget of the Amazon entails considering the magnitude and timing of C absorption and losses through respiration (transit time of C). Radiocarbon-based estimates of the transit time of C in the Amazon Tall Tower Observatory (ATTO) suggest a change in the transit time from 6 ± 2 years and 18 ± 4 years within 2 years (October 2019 and December 2021, respectively). This variability indicates that only a fraction of newly fixed C can be stored for decades or longer.
Fortunat Joos, Sebastian Lienert, and Sönke Zaehle
Biogeosciences, 22, 19–39, https://doi.org/10.5194/bg-22-19-2025, https://doi.org/10.5194/bg-22-19-2025, 2025
Short summary
Short summary
How plants regulate their exchange of CO2 and water with the atmosphere under global warming is critical for their carbon uptake and their cooling influence. We analyze the isotope ratio of atmospheric CO2 and detect no significant decadal trends in the seasonal cycle amplitude. The data are consistent with the regulation towards leaf CO2 and intrinsic water use efficiency growing proportionally to atmospheric CO2, in contrast to recent suggestions of downregulation of CO2 and water fluxes.
Stanislav Jabinski, Vítězslav Kučera, Marek Kopáček, Jan Jansa, and Travis B. Meador
EGUsphere, https://doi.org/10.5194/egusphere-2024-3153, https://doi.org/10.5194/egusphere-2024-3153, 2024
Short summary
Short summary
Microbial production is a key parameter in estimations of organic matter cycling in environmental systems, and fungi play a major role as decomposers. In order to investigate fungal production and turnover times in soils, we incubated fungal pure cultures with isotopically labelled water and bicarbonate to investigate growth signals encoded into lipid biomarkers, which can be applied to improve flux estimates in environmental studies.
Weitian Ding, Urumu Tsunogai, and Fumiko Nakagawa
Biogeosciences, 21, 4717–4722, https://doi.org/10.5194/bg-21-4717-2024, https://doi.org/10.5194/bg-21-4717-2024, 2024
Short summary
Short summary
Past studies have used the Δ17O of stream nitrate to estimate the gross nitrification rates (GNRs) in each forested catchment by approximating the Δ17O value of soil nitrate to be equal to that of stream nitrate. Based on inference and calculation of measured data, we found that this approximation resulted in an overestimated GNR. Therefore, it is essential to clarify and verify the Δ17O NO3− values in forested soils and streams before applying the Δ17O values of stream NO3− to GNR estimation.
Elise D. Rivett, Wenjuan Ma, Nathaniel E. Ostrom, and Eric L. Hegg
Biogeosciences, 21, 4549–4567, https://doi.org/10.5194/bg-21-4549-2024, https://doi.org/10.5194/bg-21-4549-2024, 2024
Short summary
Short summary
Many different processes produce nitrous oxide (N2O), a potent greenhouse gas. Measuring the ratio of heavy and light nitrogen isotopes (15N/14N) for the non-exchangeable central and outer N atoms of N2O helps to distinguish sources of N2O. To accurately calculate the position-specific isotopic preference, we developed an expansion of the widely used Rayleigh model. Application of our new model to simulated and experimental data demonstrates its improved accuracy for analyzing N2O synthesis.
Eliza Harris, Philipp Fischer, Maciej P. Lewicki, Dominika Lewicka-Szczebak, Stephen J. Harris, and Fernando Perez-Cruz
Biogeosciences, 21, 3641–3663, https://doi.org/10.5194/bg-21-3641-2024, https://doi.org/10.5194/bg-21-3641-2024, 2024
Short summary
Short summary
Greenhouse gases are produced and consumed via a number of pathways. Quantifying these pathways helps reduce the climate and environmental footprint of anthropogenic activities. The contribution of the pathways can be estimated from the isotopic composition, which acts as a fingerprint for these pathways. We have developed the Time-resolved FRactionation And Mixing Evaluation (TimeFRAME) model to simplify interpretation and estimate the contribution of different pathways and their uncertainty.
Kim A. P. Faassen, Jordi Vilà-Guerau de Arellano, Raquel González-Armas, Bert G. Heusinkveld, Ivan Mammarella, Wouter Peters, and Ingrid T. Luijkx
Biogeosciences, 21, 3015–3039, https://doi.org/10.5194/bg-21-3015-2024, https://doi.org/10.5194/bg-21-3015-2024, 2024
Short summary
Short summary
The ratio between atmospheric O2 and CO2 can be used to characterize the carbon balance at the surface. By combining a model and observations from the Hyytiälä forest (Finland), we show that using atmospheric O2 and CO2 measurements from a single height provides a weak constraint on the surface CO2 exchange because large-scale processes such as entrainment confound this signal. We therefore recommend always using multiple heights of O2 and CO2 measurements to study surface CO2 exchange.
Nestor Gaviria-Lugo, Charlotte Läuchli, Hella Wittmann, Anne Bernhardt, Patrick Frings, Mahyar Mohtadi, Oliver Rach, and Dirk Sachse
Biogeosciences, 20, 4433–4453, https://doi.org/10.5194/bg-20-4433-2023, https://doi.org/10.5194/bg-20-4433-2023, 2023
Short summary
Short summary
We analyzed how leaf wax hydrogen isotopes in continental and marine sediments respond to climate along one of the strongest aridity gradients in the world, from hyperarid to humid, along Chile. We found that under extreme aridity, the relationship between hydrogen isotopes in waxes and climate is non-linear, suggesting that we should be careful when reconstructing past hydrological changes using leaf wax hydrogen isotopes so as to avoid overestimating how much the climate has changed.
Ralf Conrad and Peter Claus
Biogeosciences, 20, 3625–3635, https://doi.org/10.5194/bg-20-3625-2023, https://doi.org/10.5194/bg-20-3625-2023, 2023
Short summary
Short summary
Knowledge of carbon isotope fractionation is important for the assessment of the pathways involved in the degradation of organic matter. Propionate is an important intermediate. In the presence of sulfate, it was degraded by Syntrophobacter species via acetate to CO2. In the absence of sulfate, it was mainly consumed by Smithella and methanogenic archaeal species via butyrate and acetate to CH4. However, stable carbon isotope fractionation during the degradation process was quite small.
Alessandro Zanchetta, Linda M. J. Kooijmans, Steven van Heuven, Andrea Scifo, Hubertus A. Scheeren, Ivan Mammarella, Ute Karstens, Jin Ma, Maarten Krol, and Huilin Chen
Biogeosciences, 20, 3539–3553, https://doi.org/10.5194/bg-20-3539-2023, https://doi.org/10.5194/bg-20-3539-2023, 2023
Short summary
Short summary
Carbonyl sulfide (COS) has been suggested as a tool to estimate carbon dioxide (CO2) uptake by plants during photosynthesis. However, understanding its sources and sinks is critical to preventing biases in this estimate. Combining observations and models, this study proves that regional sources occasionally influence the measurements at the 60 m tall Lutjewad tower (1 m a.s.l.; 53°24′ N, 6°21′ E) in the Netherlands. Moreover, it estimates nighttime COS fluxes to be −3.0 ± 2.6 pmol m−2 s−1.
Joel T. Bostic, David M. Nelson, and Keith N. Eshleman
Biogeosciences, 20, 2485–2498, https://doi.org/10.5194/bg-20-2485-2023, https://doi.org/10.5194/bg-20-2485-2023, 2023
Short summary
Short summary
Land-use changes can affect water quality. We used tracers of pollution sources and water flow paths to show that an urban watershed exports variable sources during storm events relative to a less developed watershed. Our results imply that changing precipitation patterns combined with increasing urbanization may alter sources of pollution in the future.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2405–2424, https://doi.org/10.5194/bg-20-2405-2023, https://doi.org/10.5194/bg-20-2405-2023, 2023
Short summary
Short summary
Dissolved organic carbon (DOC) is a reservoir of prime importance in the C cycle of both continental and marine systems. It has also been suggested to influence the past Earth climate but is still poorly characterized in ancient-Earth-like environments. In this paper we show how DOC analyses from modern redox-stratified lakes can evidence specific metabolic reactions and environmental factors and how these can help us to interpret the C cycle of specific periods in the Earth's past.
Robin Havas, Christophe Thomazo, Miguel Iniesto, Didier Jézéquel, David Moreira, Rosaluz Tavera, Jeanne Caumartin, Elodie Muller, Purificación López-García, and Karim Benzerara
Biogeosciences, 20, 2347–2367, https://doi.org/10.5194/bg-20-2347-2023, https://doi.org/10.5194/bg-20-2347-2023, 2023
Short summary
Short summary
We describe the C cycle of four modern stratified water bodies from Mexico, a necessary step to better understand the C cycle of primitive-Earth-like environments, which were dominated by these kinds of conditions. We highlight the importance of local external factors on the C cycle of these systems. Notably, they influence the sensitivity of the carbonate record to environmental changes. We also show the strong C-cycle variability among these lakes and their organic C sediment record.
Yifan Ma, Kuanbo Zhou, Weifang Chen, Junhui Chen, Jin-Yu Terence Yang, and Minhan Dai
Biogeosciences, 20, 2013–2030, https://doi.org/10.5194/bg-20-2013-2023, https://doi.org/10.5194/bg-20-2013-2023, 2023
Short summary
Short summary
We distinguished particulate organic carbon (POC) export fluxes out of the nutrient-depleted layer (NDL) and the euphotic zone. The amount of POC export flux at the NDL base suggests that the NDL could be a hotspot of particle export. The substantial POC export flux at the NDL base challenges traditional concepts that the NDL was limited in terms of POC export. The dominant nutrient source for POC export fluxes should be subsurface nutrients, which was determined by 15N isotopic mass balance.
Clémence Paul, Clément Piel, Joana Sauze, Nicolas Pasquier, Frédéric Prié, Sébastien Devidal, Roxanne Jacob, Arnaud Dapoigny, Olivier Jossoud, Alexandru Milcu, and Amaëlle Landais
Biogeosciences, 20, 1047–1062, https://doi.org/10.5194/bg-20-1047-2023, https://doi.org/10.5194/bg-20-1047-2023, 2023
Short summary
Short summary
To improve the interpretation of the δ18Oatm and Δ17O of O2 in air bubbles in ice cores, we need to better quantify the oxygen fractionation coefficients associated with biological processes. We performed a simplified analogue of the terrestrial biosphere in a closed chamber. We found a respiration fractionation in agreement with the previous estimates at the microorganism scale, and a terrestrial photosynthetic fractionation was found. This has an impact on the estimation of the Dole effect.
Adam Francis, Raja S. Ganeshram, Robyn E. Tuerena, Robert G. M. Spencer, Robert M. Holmes, Jennifer A. Rogers, and Claire Mahaffey
Biogeosciences, 20, 365–382, https://doi.org/10.5194/bg-20-365-2023, https://doi.org/10.5194/bg-20-365-2023, 2023
Short summary
Short summary
Climate change is causing extensive permafrost degradation and nutrient releases into rivers with great ecological impacts on the Arctic Ocean. We focused on nitrogen (N) release from this degradation and associated cycling using N isotopes, an understudied area. Many N species are released at degradation sites with exchanges between species. N inputs from permafrost degradation and seasonal river N trends were identified using isotopes, helping to predict climate change impacts.
Mohamed Ayache, Jean-Claude Dutay, Kazuyo Tachikawa, Thomas Arsouze, and Catherine Jeandel
Biogeosciences, 20, 205–227, https://doi.org/10.5194/bg-20-205-2023, https://doi.org/10.5194/bg-20-205-2023, 2023
Short summary
Short summary
The neodymium (Nd) is one of the most useful tracers to fingerprint water mass provenance. However, the use of Nd is hampered by the lack of adequate quantification of the external sources. Here, we present the first simulation of dissolved Nd concentration and Nd isotopic composition in the Mediterranean Sea using a high-resolution model. We aim to better understand how the various external sources affect the Nd cycle and particularly assess how it is impacted by atmospheric inputs.
Marta Santos-Garcia, Raja S. Ganeshram, Robyn E. Tuerena, Margot C. F. Debyser, Katrine Husum, Philipp Assmy, and Haakon Hop
Biogeosciences, 19, 5973–6002, https://doi.org/10.5194/bg-19-5973-2022, https://doi.org/10.5194/bg-19-5973-2022, 2022
Short summary
Short summary
Terrestrial sources of nitrate are important contributors to the nutrient pool in the fjords of Kongsfjorden and Rijpfjorden in Svalbard during the summer, and they sustain most of the fjord primary productivity. Ongoing tidewater glacier retreat is postulated to favour light limitation and less dynamic circulation in fjords. This is suggested to encourage the export of nutrients to the middle and outer part of the fjord system, which may enhance primary production within and in offshore areas.
Marlene Dordoni, Michael Seewald, Karsten Rinke, Kurt Friese, Robert van Geldern, Jakob Schmidmeier, and Johannes A. C. Barth
Biogeosciences, 19, 5343–5355, https://doi.org/10.5194/bg-19-5343-2022, https://doi.org/10.5194/bg-19-5343-2022, 2022
Short summary
Short summary
Organic matter (OM) turnover into dissolved inorganic carbon (DIC) was investigated by means of carbon isotope mass balances in Germany's largest water reservoir. This includes a metalimnetic oxygen minimum (MOM). Autochthonous particulate organic carbon (POC) was the main contributor to DIC, with rates that were highest for the MOM. Generally low turnover rates outline the environmental fragility of this water body in the case that OM loads increase due to storm events or land use changes.
Frédérique M. S. A. Kirkels, Hugo J. de Boer, Paulina Concha Hernández, Chris R. T. Martes, Marcel T. J. van der Meer, Sayak Basu, Muhammed O. Usman, and Francien Peterse
Biogeosciences, 19, 4107–4127, https://doi.org/10.5194/bg-19-4107-2022, https://doi.org/10.5194/bg-19-4107-2022, 2022
Short summary
Short summary
The distinct carbon isotopic values of C3 and C4 plants are widely used to reconstruct past hydroclimate, where more C3 plants reflect wetter and C4 plants drier conditions. Here we examine the impact of regional hydroclimatic conditions on plant isotopic values in the Godavari River basin, India. We find that it is crucial to identify regional plant isotopic values and consider drought stress, which introduces a bias in C3 / C4 plant estimates and associated hydroclimate reconstructions.
Mhlangabezi Mdutyana, Tanya Marshall, Xin Sun, Jessica M. Burger, Sandy J. Thomalla, Bess B. Ward, and Sarah E. Fawcett
Biogeosciences, 19, 3425–3444, https://doi.org/10.5194/bg-19-3425-2022, https://doi.org/10.5194/bg-19-3425-2022, 2022
Short summary
Short summary
Nitrite-oxidizing bacteria in the winter Southern Ocean show a high affinity for nitrite but require a minimum (i.e., "threshold") concentration before they increase their rates of nitrite oxidation significantly. The classic Michaelis–Menten model thus cannot be used to derive the kinetic parameters, so a modified equation was employed that also yields the threshold nitrite concentration. Dissolved iron availability may play an important role in limiting nitrite oxidation.
Weitian Ding, Urumu Tsunogai, Fumiko Nakagawa, Takashi Sambuichi, Hiroyuki Sase, Masayuki Morohashi, and Hiroki Yotsuyanagi
Biogeosciences, 19, 3247–3261, https://doi.org/10.5194/bg-19-3247-2022, https://doi.org/10.5194/bg-19-3247-2022, 2022
Short summary
Short summary
Excessive leaching of nitrate from forested catchments during storm events degrades water quality and causes eutrophication in downstream areas. Thus, tracing the source of nitrate increase during storm events in forested streams is important for sustainable forest management. Based on the isotopic compositions of stream nitrate, including Δ17O, this study clarifies that the source of stream nitrate increase during storm events was soil nitrate in the riparian zone.
Nicolas Séon, Romain Amiot, Guillaume Suan, Christophe Lécuyer, François Fourel, Fabien Demaret, Arnauld Vinçon-Laugier, Sylvain Charbonnier, and Peggy Vincent
Biogeosciences, 19, 2671–2681, https://doi.org/10.5194/bg-19-2671-2022, https://doi.org/10.5194/bg-19-2671-2022, 2022
Short summary
Short summary
We analysed the oxygen isotope composition of bones and teeth of four marine species possessing regional heterothermies. We observed a consistent link between oxygen isotope composition and temperature heterogeneities recorded by classical methods. This opens up new perspectives on the determination of the thermoregulatory strategies of extant marine vertebrates where conventional methods are difficult to apply, but also allows us to investigate thermophysiologies of extinct vertebrates.
Yuwei Liu, Guofeng Zhu, Zhuanxia Zhang, Zhigang Sun, Leilei Yong, Liyuan Sang, Lei Wang, and Kailiang Zhao
Biogeosciences, 19, 877–889, https://doi.org/10.5194/bg-19-877-2022, https://doi.org/10.5194/bg-19-877-2022, 2022
Short summary
Short summary
We took the water cycle process of soil–plant–atmospheric precipitation as the research objective. In the water cycle of soil–plant–atmospheric precipitation, precipitation plays the main controlling role. The main source of replenishment for alpine meadow plants is precipitation and alpine meltwater; the main source of replenishment for forest plants is soil water; and the plants in the arid foothills mainly use groundwater.
Roberto Velázquez-Ochoa, María Julia Ochoa-Izaguirre, and Martín Federico Soto-Jiménez
Biogeosciences, 19, 1–27, https://doi.org/10.5194/bg-19-1-2022, https://doi.org/10.5194/bg-19-1-2022, 2022
Short summary
Short summary
Our research is the first approximation to understand the δ13C macroalgal variability in one of the most diverse marine ecosystems in the world, the Gulf of California. The life-form is the principal cause of δ13C macroalgal variability, mainly taxonomy. However, changes in habitat characteristics and environmental conditions also influence the δ13C macroalgal variability. The δ13C macroalgae is indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation.
Raquel F. Flynn, Thomas G. Bornman, Jessica M. Burger, Shantelle Smith, Kurt A. M. Spence, and Sarah E. Fawcett
Biogeosciences, 18, 6031–6059, https://doi.org/10.5194/bg-18-6031-2021, https://doi.org/10.5194/bg-18-6031-2021, 2021
Short summary
Short summary
Biological activity in the shallow Weddell Sea affects the biogeochemistry of recently formed deep waters. To investigate the drivers of carbon and nutrient export, we measured rates of primary production and nitrogen uptake, characterized the phytoplankton community, and estimated nutrient depletion ratios across the under-sampled western Weddell Sea in mid-summer. Carbon export was highest at the ice shelves and was determined by a combination of physical, chemical, and biological factors.
Stéphanie H. M. Jacquet, Christian Tamburini, Marc Garel, Aurélie Dufour, France Van Vambeke, Frédéric A. C. Le Moigne, Nagib Bhairy, and Sophie Guasco
Biogeosciences, 18, 5891–5902, https://doi.org/10.5194/bg-18-5891-2021, https://doi.org/10.5194/bg-18-5891-2021, 2021
Short summary
Short summary
We compared carbon remineralization rates (MRs) in the western and central Mediterranean Sea in late spring during the PEACETIME cruise, as assessed using the barium tracer. We reported higher and deeper (up to 1000 m depth) MRs in the western basin, potentially sustained by an additional particle export event driven by deep convection. The central basin is the site of a mosaic of blooming and non-blooming water masses and showed lower MRs that were restricted to the upper mesopelagic layer.
Shinsuke Kawagucci, Yohei Matsui, Akiko Makabe, Tatsuhiro Fukuba, Yuji Onishi, Takuro Nunoura, and Taichi Yokokawa
Biogeosciences, 18, 5351–5362, https://doi.org/10.5194/bg-18-5351-2021, https://doi.org/10.5194/bg-18-5351-2021, 2021
Short summary
Short summary
Hydrogen and carbon isotope ratios of methane as well as the relevant biogeochemical parameters and microbial community compositions in hydrothermal plumes in the Okinawa Trough were observed. We succeeded in simultaneously determining hydrogen and carbon isotope fractionation factors associated with aerobic oxidation of methane in seawater (εH = 49.4 ± 5.0 ‰, εC = 5.2 ± 0.4 ‰) – the former being the first of its kind ever reported.
Nicolai Schleinkofer, David Evans, Max Wisshak, Janina Vanessa Büscher, Jens Fiebig, André Freiwald, Sven Härter, Horst R. Marschall, Silke Voigt, and Jacek Raddatz
Biogeosciences, 18, 4733–4753, https://doi.org/10.5194/bg-18-4733-2021, https://doi.org/10.5194/bg-18-4733-2021, 2021
Short summary
Short summary
We have measured the chemical composition of the carbonate shells of the parasitic foraminifera Hyrrokkin sarcophaga in order to test if it is influenced by the host organism (bivalve or coral). We find that both the chemical and isotopic composition is influenced by the host organism. For example strontium is enriched in foraminifera that grew on corals, whose skeleton is built from aragonite, which is naturally enriched in strontium compared to the bivalves' calcite shell.
Lena Rohe, Traute-Heidi Anderson, Heinz Flessa, Anette Goeske, Dominika Lewicka-Szczebak, Nicole Wrage-Mönnig, and Reinhard Well
Biogeosciences, 18, 4629–4650, https://doi.org/10.5194/bg-18-4629-2021, https://doi.org/10.5194/bg-18-4629-2021, 2021
Short summary
Short summary
This is the first experimental setup combining a complex set of methods (microbial inhibitors and isotopic approaches) to differentiate between N2O produced by fungi or bacteria during denitrification in three soils. Quantifying the fungal fraction with inhibitors was not successful due to large amounts of uninhibited N2O production. All successful methods suggested a small or missing fungal contribution. Artefacts occurring with microbial inhibition to determine N2O fluxes are discussed.
Inga Köhler, Raul E. Martinez, David Piatka, Achim J. Herrmann, Arianna Gallo, Michelle M. Gehringer, and Johannes A. C. Barth
Biogeosciences, 18, 4535–4548, https://doi.org/10.5194/bg-18-4535-2021, https://doi.org/10.5194/bg-18-4535-2021, 2021
Short summary
Short summary
We investigated how high Fe(II) levels influence the O2 budget of a circum-neutral Fe(II)-rich spring and if a combined study of dissolved O (DO) and its isotopic composition can help assess this effect. We showed that dissolved Fe(II) can exert strong effects on the δ18ODO even though a constant supply of atmospheric O2 occurs. In the presence of photosynthesis, direct effects of Fe oxidation become masked. Critical Fe(II) concentrations indirectly control the DO by enhancing photosynthesis.
Owen A. Sherwood, Samuel H. Davin, Nadine Lehmann, Carolyn Buchwald, Evan N. Edinger, Moritz F. Lehmann, and Markus Kienast
Biogeosciences, 18, 4491–4510, https://doi.org/10.5194/bg-18-4491-2021, https://doi.org/10.5194/bg-18-4491-2021, 2021
Short summary
Short summary
Pacific water flowing eastward through the Canadian Arctic plays an important role in redistributing nutrients to the northwest Atlantic Ocean. Using samples collected from northern Baffin Bay to the southern Labrador Shelf, we show that stable isotopic ratios in seawater nitrate reflect the fraction of Pacific to Atlantic water. These results provide a new framework for interpreting patterns of nitrogen isotopic variability recorded in modern and archival organic materials in the region.
Franziska Slotta, Lukas Wacker, Frank Riedel, Karl-Uwe Heußner, Kai Hartmann, and Gerhard Helle
Biogeosciences, 18, 3539–3564, https://doi.org/10.5194/bg-18-3539-2021, https://doi.org/10.5194/bg-18-3539-2021, 2021
Short summary
Short summary
The African baobab is a challenging climate and environmental archive for its semi-arid habitat due to dating uncertainties and parenchyma-rich wood anatomy. Annually resolved F14C data of tree-ring cellulose (1941–2005) from a tree in Oman show the annual character of the baobab’s growth rings but were up to 8.8 % lower than expected for 1964–1967. Subseasonal δ13C and δ18O patterns reveal years with low average monsoon rain as well as heavy rainfall events from pre-monsoonal cyclones.
Peter M. J. Douglas, Emerald Stratigopoulos, Sanga Park, and Dawson Phan
Biogeosciences, 18, 3505–3527, https://doi.org/10.5194/bg-18-3505-2021, https://doi.org/10.5194/bg-18-3505-2021, 2021
Short summary
Short summary
Hydrogen isotopes could be a useful tool to help resolve the geographic distribution of methane emissions from freshwater environments. We analyzed an expanded global dataset of freshwater methane hydrogen isotope ratios and found significant geographic variation linked to water isotopic composition. This geographic variability could be used to resolve changing methane fluxes from freshwater environments and provide more accurate estimates of the relative balance of global methane sources.
Veronica R. Rollinson, Julie Granger, Sydney C. Clark, Mackenzie L. Blanusa, Claudia P. Koerting, Jamie M. P. Vaudrey, Lija A. Treibergs, Holly C. Westbrook, Catherine M. Matassa, Meredith G. Hastings, and Craig R. Tobias
Biogeosciences, 18, 3421–3444, https://doi.org/10.5194/bg-18-3421-2021, https://doi.org/10.5194/bg-18-3421-2021, 2021
Short summary
Short summary
We measured nutrients and the naturally occurring nitrogen (N) and oxygen (O) stable isotope ratios of nitrate discharged from a New England river over an annual cycle, to monitor N loading and identify dominant sources from the watershed. We uncovered a seasonality to loading and sources of N from the watershed. Seasonality in the nitrate isotope ratios also informed on N cycling, conforming to theoretical expectations of riverine nutrient cycling.
Zixun Chen, Xuejun Liu, Xiaoqing Cui, Yaowen Han, Guoan Wang, and Jiazhu Li
Biogeosciences, 18, 2859–2870, https://doi.org/10.5194/bg-18-2859-2021, https://doi.org/10.5194/bg-18-2859-2021, 2021
Short summary
Short summary
δ13C in plants is a sensitive long-term indicator of physiological acclimatization. The present study suggests that precipitation change and increasing atmospheric N deposition have little impact on δ13C of H. ammodendron, a dominant plant in central Asian deserts, but affect its gas exchange. In addition, this study shows that δ13C of H. ammodendron could not indicate its water use efficiency (WUE), suggesting that whether δ13C of C4 plants indicates WUE is species-specific.
Petra Zahajská, Carolina Olid, Johanna Stadmark, Sherilyn C. Fritz, Sophie Opfergelt, and Daniel J. Conley
Biogeosciences, 18, 2325–2345, https://doi.org/10.5194/bg-18-2325-2021, https://doi.org/10.5194/bg-18-2325-2021, 2021
Short summary
Short summary
The drivers of high accumulation of single-cell siliceous algae (diatoms) in a high-latitude lake have not been fully characterized before. We studied silicon cycling of the lake through water, radon, silicon, and stable silicon isotope balances. Results showed that groundwater brings 3 times more water and dissolved silica than the stream inlet. We demonstrate that groundwater discharge and low sediment deposition have driven the high diatom accumulation in the studied lake in the past century.
Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, and Gideon M. Henderson
Biogeosciences, 18, 1645–1671, https://doi.org/10.5194/bg-18-1645-2021, https://doi.org/10.5194/bg-18-1645-2021, 2021
Short summary
Short summary
The South Atlantic near 40° S is one of the high-productivity and most dynamic nutrient regions in the oceans, but the sources and fluxes of trace elements (TEs) to this region remain unclear. This study investigates seawater Ra-228 and provides important constraints on ocean mixing and dissolved TE fluxes to this region. Vertical mixing is a more important source than aeolian or shelf inputs in this region, but particulate or winter deep-mixing inputs may be required to balance the TE budgets.
Zhongjie Yu and Emily M. Elliott
Biogeosciences, 18, 805–829, https://doi.org/10.5194/bg-18-805-2021, https://doi.org/10.5194/bg-18-805-2021, 2021
Short summary
Short summary
In this study, we demonstrated distinct nitrogen isotope effects for nitric oxide (NO) production from major microbial and chemical NO sources in an agricultural soil. These results highlight characteristic bond-forming and breaking mechanisms associated with microbial and chemical NO production and implicate that simultaneous isotopic analyses of NO and nitrous oxide (N2O) can lead to unprecedented insights into the sources and processes controlling NO and N2O emissions from agricultural soils.
Daniel A. Frick, Rainer Remus, Michael Sommer, Jürgen Augustin, Danuta Kaczorek, and Friedhelm von Blanckenburg
Biogeosciences, 17, 6475–6490, https://doi.org/10.5194/bg-17-6475-2020, https://doi.org/10.5194/bg-17-6475-2020, 2020
Short summary
Short summary
Silicon is taken up by some plants to increase structural stability and to develop stress resistance and is rejected by others. To explore the underlying mechanisms, we used the stable isotopes of silicon that shift in their relative abundance depending on the biochemical transformation involved. On species with a rejective (tomato, mustard) and active (wheat) uptake mechanism, grown in hydroculture, we found that the transport of silicic acid is controlled by the precipitation of biogenic opal.
Quentin Charbonnier, Julien Bouchez, Jérôme Gaillardet, and Éric Gayer
Biogeosciences, 17, 5989–6015, https://doi.org/10.5194/bg-17-5989-2020, https://doi.org/10.5194/bg-17-5989-2020, 2020
Short summary
Short summary
The abundance and isotope composition of the trace metal barium (Ba) allows us to track and quantify nutrient cycling throughout the Amazon Basin. In particular, we show that the Ba biological fingerprint evolves from that of a strong net nutrient uptake in the mountainous area of the Andes towards efficient nutrient recycling on the plains of the Lower Amazon. Our study highlights the fact that the geochemical signature of rock-derived nutrients transported by the Amazon is scarred by life.
Ajinkya G. Deshpande, Thomas W. Boutton, Ayumi Hyodo, Charles W. Lafon, and Georgianne W. Moore
Biogeosciences, 17, 5639–5653, https://doi.org/10.5194/bg-17-5639-2020, https://doi.org/10.5194/bg-17-5639-2020, 2020
Short summary
Short summary
Wetland forests in the southern USA are threatened by changing climate and human-induced pressures. We used tree ring widths and C isotopes as indicators of forest growth and physiological stress, respectively, and compared these to past climate data. We observed that vegetation growing in the drier patches is susceptible to stress, while vegetation growth and physiology in wetter patches is less sensitive to unfavorable environmental conditions, highlighting the importance of optimal wetness.
Dominika Lewicka-Szczebak, Maciej Piotr Lewicki, and Reinhard Well
Biogeosciences, 17, 5513–5537, https://doi.org/10.5194/bg-17-5513-2020, https://doi.org/10.5194/bg-17-5513-2020, 2020
Short summary
Short summary
We present the first validation of N2O isotopic approaches for estimating N2O source pathways and N2O reduction. These approaches are widely used for tracing soil nitrogen cycling, but the results of these estimations are very uncertain. Here we report the results from parallel treatments allowing for precise validation of these approaches, and we propose the best strategies for results interpretation, including the new idea of an isotope model integrating three isotopic signatures of N2O.
Markus Raitzsch, Claire Rollion-Bard, Ingo Horn, Grit Steinhoefel, Albert Benthien, Klaus-Uwe Richter, Matthieu Buisson, Pascale Louvat, and Jelle Bijma
Biogeosciences, 17, 5365–5375, https://doi.org/10.5194/bg-17-5365-2020, https://doi.org/10.5194/bg-17-5365-2020, 2020
Short summary
Short summary
The isotopic composition of boron in carbonate shells of marine unicellular organisms is a popular tool to estimate seawater pH. Usually, many shells need to be dissolved and measured for boron isotopes, but the information on their spatial distribution is lost. Here, we investigate two techniques that allow for measuring boron isotopes within single shells and show that they yield robust mean values but provide additional information on the heterogeneity within and between single shells.
Florian Einsiedl, Anja Wunderlich, Mathieu Sebilo, Ömer K. Coskun, William D. Orsi, and Bernhard Mayer
Biogeosciences, 17, 5149–5161, https://doi.org/10.5194/bg-17-5149-2020, https://doi.org/10.5194/bg-17-5149-2020, 2020
Short summary
Short summary
Nitrate pollution of freshwaters and methane emissions into the atmosphere are crucial factors in deteriorating the quality of drinking water and in contributing to global climate change. Here, we report vertical concentration and stable isotope profiles of CH4, NO3-, NO2-, and NH4+ in the water column of Fohnsee (southern Bavaria, Germany) that may indicate linkages between nitrate-dependent anaerobic methane oxidation and the anaerobic oxidation of ammonium.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
Short summary
Short summary
Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Cited articles
Adkins, J. F., McIntyre, K., and Schrag, D. P.: The Salinity, Temperature, and δ18O of the Glacial Deep Ocean, Science, 298, 1769–1773, https://doi.org/10.1126/science.1076252, 2002.
Aksu, A. E., Abrajano, T., Mudie, P. J., and Yasar, D.: Organic geochemical and palynological evidence for terrigenous origin of the organic matter in Aegean sapropel S1, Mar. Geol., 153, 303–318, https://doi.org/10.1016/S0025-3227(98)00077-2, 1999.
Androulidakis, Y. S., Kourafalou, V. H., Kresenitis, Y. N., and Zervakis, V.: Variability of deep water mass characteristics in the North Aegean Sea: The role of lateral inputs and atmospheric conditions, Deep-Sea Res. Pt. I, 67, 55–72, https://doi.org/10.1016/j.dsr.2012.05.004, 2012.
Antia, A. N., Koeve,W., Fischer, G., Blanz, T., Schulz–Bull, D., Scholten, J., Neuer, S., Kremling, K., Kuss, J., Peinert, R., Hebbeln, D., Bathmann, U., Conte, M., Fehner, U., and Zeitzschel, B.: Basin-wide particulate carbon flux in the Atlantic Ocean: regional export patterns and potential for atmospheric CO2 sequestration, Global Biogeochem. Cy., 15, 845–862, https://doi.org/10.1029/2000GB001376, 2001.
Antoine, D. and Morel, A.: Oceanic primary production: 1. Adaptation of a spectral light-photosynthesis model in view of application to satellite chlorophyll observations, Global Biogeochem. Cy., 10, 43–55, https://doi.org/10.1029/95GB02831, 1996.
Bemis, B. E., Spero, H. J., Bijma, J., and Lea, D. W.: Reevaluation of the oxygen isotopic composition of planktonic foraminifera: Experimental results and revised paleotemperature equations, Paleoceanography, 13, 150–160, https://doi.org/10.1029/98PA00070, 1998.
Bernhard, J. M.: Distinguishing Live from Dead Foraminifera: Methods Review and Proper Applications, Micropaleontology, 46, 38–46, 2000.
Betzer, P. R., Showers, W. J., Laws, E. A., Winn, C. D., DiTullio, G. R., and Kroopnick, P. M.: Primary productivity and particle fluxes on a transect of the equator at 153° W in the Pacific Ocean, Deep-Sea Res., 31, 1–11, https://doi.org/10.1016/0198-0149(84)90068-2, 1984.
Bishop, J. K. B.: Autonomous observations of the ocean biological carbon pump, Oceanography, 22, 182–193, https://doi.org/10.5670/oceanog.2009.48, 2009.
Bosc, E., Bricaud, A., and Antoine, D.: Seasonal and interannual variability in algal biomass and primary production in the Mediterranean Sea, as derived from 4 years of SeaWiFS observations, Global Biogeochem. Cy., 18, GB1005, https://doi.org/10.1029/2003GB002034, 2004
Boyd, P. W. and Trull, T. W.: Understanding the export of biogenic particles in oceanic waters: Is there consensus?, Prog. Oceanogr., 72, 276–312, https://doi.org/10.1016/j.pocean.2006.10.007, 2007.
Brückner, S. and Mackensen, A.: Organic matter rain rates, oxygen availability, and vital effects from benthic foraminiferal δ13C in the historic Skagerrak, North Sea, Mar. Micropaleontol., 66, 192–207, https://doi.org/10.1016/j.marmicro.2007.09.002, 2008.
Canals, M., Company, J.B., Martín, D., Sànchez–Vidal, A., and Ramírez-Llodrà, E.: Integrated study of Mediterranean deep canyons: Novel results and future challenges, Prog. Oceanogr. 118, 1–27, https://doi.org/10.1016/j.pocean.2013.09.004, 2013.
Corliss, B. H.: Microhabitats of benthic foraminifera within deep-sea sediments, Nature, 314, 435–438, https://doi.org/10.1038/314435a0, 1985.
Corliss, B. H., McCorkle, D. C., and Higdon, D. M.: A time series study of the carbon isotopic composition of deep-sea benthic foraminifera, Paleoceanography, 17, 1036, https://doi.org/10.1029/2001PA000664, 2002.
Curry, W. B. and Lohmann, G. P.: Carbon Isotopic Changes in Benthic Foraminifera from the Western South Atlantic: Reconstruction of Glacial Abyssal Circulation Patterns, Quaternary Res., 18, 218–235, https://doi.org/10.1016/0033-5894(82)90071-0, 1982.
Danovaro, R., Dinet, A., Duineveld, G., and Tselepides, A.: Benthic response to particulate fluxes in different trophic environments: a comparison between the Gulf of Lions–Catalan Sea (western-Mediterranean) and the Cretan Sea (eastern-Mediterranean), Prog. Oceanogr., 44, 287–312, https://doi.org/10.1016/S0079-6611(99)00030-0, 1999.
Dunbar, R. B. and Wefer, G.: Stable isotope fractionation in benthic foraminifera from the Peruvian continental margin, Mar. Geol., 59, 215–225, https://doi.org/10.1016/0025-3227(84)90094-X, 1984.
Edgar, K. M., Pälike, H., and Wilson, P. A.: Testing the impact of diagenesis on the δ18O and δ13C of benthic foraminiferal calcite from a sediment burial depth transect in the equatorial Pacific, Paleoceanography, 28, 468–480, https://doi.org/10.1002/palo.20045, 2013.
Felix, M.: A comparison of equations commonly used to calculate organic carbon content and marine palaeoproductivity from sediment data, Mar. Geol., 347, 1–11, https://doi.org/10.1016/j.margeo.2013.10.006, 2014.
Fontanier, C., Mackensen, A., Jorissen, F. J., Anschutz, P., Licari, L., and Griveau, C.: Stable oxygen and carbon isotopes of live benthic foraminifera from the Bay of Biscay: Microhabitat impact and seasonal variability, Mar. Micropaleontol., 58, 159–183, https://doi.org/10.1016/j.marmicro.2005.09.004, 2006.
Franco-Fraguas, P., Badaraco Costa, K., and de Lima Toledo, F. A.: Stable Isotope/Test size relationship in Cibicidoides wuellerstorfi, Braz. J. Oceanogr., 59, 287–291, https://doi.org/10.1590/S1679-87592011000300010, 2011.
Giresse, P., Buscail, R., and Charrière, B.: Late Holocene multisource material input into the Aegean Sea: depositional and post-depositional processes, Oceanol. Ac., 26, 657–672, https://doi.org/10.1016/j.oceact.2003.09.001, 2003.
Gogou, A., Sanchez–Vidal, A., Durrieu de Madron, X., Stavrakakis, S., Calafat, A. M., Stabholz, M., Psarra, S., Canals, M., Heussner, S., Stavrakaki, I., and Papathanassiou, E.: Carbon flux to the deep in three open sites of the Southern European Seas (SES), J. Mar. Syst., 129, 224–233, https://doi.org/10.1016/j.jmarsys.2013.05.013, 2014.
Grossman, E. L.: Carbon isotopic fractionation in live benthic foraminifera – comparison with inorganic precipitate studies, Geochim. Cosmochim. Ac., 48, 1505–1512, https://doi.org/10.1016/0016-7037(84)90406-X, 1984a.
Grossman, E. L.: Stable isotope fractionation in live benthic Foraminifera from the Southern California Borderland, Palaeogeogr. Palaeoclimatol., 47, 301–327, https://doi.org/10.1016/0031-0182(84)90100-7, 1984b.
Hemleben, C., Becker, T., Bellas, S., Benningsen, G., Casford, J., Cagatay, N., Emeis, K.-C., Engelen, B., Ertan, T., Fontanier, C., Friedrich, O., Frydas, D., Giunta, S., Hoffelner, H., Jorissen, F., Kahl, G., Kaszemeik, K., Lykousis, V., Meier, S., Nickel, G., Overman, J., Pross, J., Reichel, T., Robert, C., Rohling, E., Ruschmeier, W., Sakinc, M., Schiebel, R., Schmiedl, G., Schubert, K., Schulz, H., Tischnak, J., and Truscheit, T.: Ostatlantik–Mittelmeer–Schwarzes Meer, Part 3, Cruise No.51, Leg 3, 14 November–10 December 2001, Valetta–Istanbul, METEOR-Berichte, Universität Hamburg, 03-1, 57 pp., 2003.
Hernández-Almeida, I. Bárcena, M.A., Flores, J. A., Sierro, F. J., Sanchez-Vidal, A., and Calafat, A.: Microplankton response to environmental conditions in the Alboran Sea (Western Mediterranean): One year sediment trap record, Mar. Micropaleontol., 78, 14–24, https://doi.org/10.1016/j.marmicro.2010.09.005, 2011.
Heussner, S., Durrieu de Madron, X., Calafat, A., Canals, M., Carbonne, J., Delsaut, N., and Saragoni, G.: Spatial and temporal variability of downward particle fluxes on a continental slope: Lessons from an 8-yr experiment in the Gulf of Lions (NW Mediterranean), Mar. Geol., 234, 63–92, https://doi.org/10.1016/j.margeo.2006.09.003, 2006.
Hieke, W., Hemleben, C., Linke, P., Türkay, M., and Weikert, H.: Mittelmeer 1998/99, Cruise No. 40, 28 October 1997–10 February 1998, METEOR-Berichte, Universität Hamburg, 99-2, 286 pp., 1999.
Holsten, J., Stott, L., and Berelson, W.: Reconstructing benthic carbon oxidation rates using δ13C of benthic foraminifera, Mar. Micropaleontol., 53, 117–132, https://doi.org/10.1016/j.marmicro.2004.05.006, 2004.
Hoogakker, B. A. A., Elderfield, H., Schmiedl, G., McCave, I. N., and Rickaby, R. E. M.: Glacial-interglacial changes in bottom-water oxygen content on the Portuguese margin, Nat. Geosci., 8, 40–43, https://doi.org/10.1038/NGEO2317, 2015.
Hübscher, C., Betzler, C., Grevemeyer, I.: Sedimentology, rift-processes and neotectonic in the western Mediterranean, Cruise No. 69, 8 August–20 September 2006, Las Palmas (Spain)–Cartagena (Spain)–La Valletta (Malta), METEOR-Berichte, Universität Hamburg, 99-2, 86 pp., 2010.
Huertas, I. E., Rios, A. F., Garcia-Lafuente, J., Navarro, G., Makaoui, A., Sanchez-Roman, A., Rodriguez-Galvez, S., Orbi, A., Ruiz, J., and Perez, F. F.: Atlantic forcing of the Mediterranean oligotrophy, Global Biogeochem. Cy., 26, Gb2022, https://doi.org/10.1029/2011gb004167, 2012.
Jorissen, F. J., de Stigter, H. C., and Widmark, J. G. V.: A conceptual model explaining benthic foraminiferal microhabitats, Mar. Micropaleontol., 26, 3–15, https://doi.org/10.1016/0377-8398(95)00047-X, 1995.
Keeling, C. D.: The Suess effect: 13Carbon-14Carbon interrelations, Environ. Int., 2, 229–300, https://doi.org/10.1016/0160-4120(79)90005-9, 1979.
Kitazato, H.: Foraminiferal microhabitats in four marine environments around Japan, Mar. Micropaleontol., 24, 29–41, https://doi.org/10.1016/0377-8398(94)90009-4, 1994.
Koho, K. A. and Piña-Ochoa, E.: Benthic Foraminifera: Inhabitants of low-oxygen environments, in: Anoxia: Evidence for Eukaryote Survival and Paleontological Strategies, Cellular Origin, Life in Extreme Habitats and Astrobiology, edited by: Altenbach, A. V., Bernhard, J. M., and Seckbach, J., 21, 249–285, https://doi.org/10.1007/978-94-007-1896-8_14, 2012.
Koho, K. A., García, R., de Stigter, H. C., Epping, E., Koning, E., Kouwenhoven, T. J., and van der Zwaan, G. J.: Sedimentary labile organic carbon and pore water redox control on species distribution of benthic foraminifera: A case study from Lisbon–Setúbal Canyon (southern Portugal), Prog. Oceanogr., 79, 55–82, https://doi.org/10.1016/j.pocean.2008.07.004, 2008.
Kuhnt, T., Schmiedl, G., Ehrmann, W., Hamann, Y., and Andersen, N.: Stable isotope composition of Holocene benthic foraminifers from the Eastern Mediterranean Sea: Past changes in productivity and deep water oxygenation, Palaeogeogr. Palaeoclimatol., 268, 106–115, https://doi.org/10.1016/j.palaeo.2008.07.010, 2008.
Lascaratos, A., Roether, W., Nittis, K., and Klein, B.: Recent changes in the Eastern Mediterranean Deep Waters: a review, Prog. Oceanogr., 44, 5–36, https://doi.org/10.1016/S0079-6611(99)00019-1, 1999.
Licari, L. and Mackensen, A.: Benthic foraminifera off West Africa (1° N to 32° S): Do live assemblages from the topmost sediment reliably record environmental variability?, Mar. Micropaleontol., 55, 205–233, https://doi.org/10.1016/j.marmicro.2005.03.001, 2005.
Linke, P. and Lutze, G. F.: Microhabitat preferences of benthic foraminifera a static concept or a dynamic adaptation to optimize food acquisition?, Mar. Micropaleontol., 20, 215–234, https://doi.org/10.1016/0377-8398(93)90034-U, 1993.
López–Sandoval, D. C., Fernández, A., and Marañón, E.: Dissolved and particulate primary production along a longitudinal gradient in the Mediterranean Sea, Biogeosciences, 8, 815–825, https://doi.org/10.5194/bg-8-815-2011, 2011.
Lutze, G. F. and Thiel, H.: Epibenthic foraminifera from elevated microhabitats: Cibicidoides wuellerstorfi and Planulina ariminensis, J. Foramin. Res., 19, 153–158, https://doi.org/10.2113/gsjfr.19.2.153, 1989.
Lykousis, V., Chronis, G., Tselepides, A., Price, B., Theocharis, A., Siokou-Frangou, I., Van Wambeke, F., Danovaro, R., Stavrakakis, S., Duineveld, G., Georgopoulos, D., Ignatiades, L., Souvermezoglou, E., and Voutsinou-Taliadouri, F.: Major outputs of the recent multidisciplinary biogeochemical researches undertaken in the Aegean Sea, J. Mar. Syst., 33/34, 313–334, https://doi.org/10.1016/S0924-7963(02)00064-7, 2002.
Lyle, M.: The brown-green color transition in marine sediments: A marker of the Fe(III)-Fe(II) redox boundary, Limnol. Oceanogr., 28, 1026–1033, https://doi.org/10.4319/lo.1983.28.5.1026, 1983.
Mackensen, A.: On the use of benthic foraminiferal δ13C in palaeoceanography: constraints from primary proxy relationships, in: Biogeochemical Controls on Palaeoceanographic Environmental Proxies, edited by: Austin, W. E. N. and James, R. H., Geological Society, London, Special Publications 303, 121–133, https://doi.org/10.1144/SP303.9, 2008.
Mackensen, A. and Bickert, T.: Stable carbon isotopes in benthic foraminifera: Proxies for deep and bottom water circulation and new production, in: Use of proxies in paleoceanography: Examples from the South Atlantic, edited by: Fischer, G. and Wefer, G., Springer, Berlin, Heidelberg, 229–254, https://doi.org/10.1007/978-3-642-58646-0_9, 1999.
Mackensen, A. and Douglas, R. G.: Down-core distribution of live and dead deep-water benthic foraminifera in box cores from the Weddell Sea and the California continental borderland, Deep-Sea Res., 36, 879–900, https://doi.org/10.1016/0198-0149(89)90034-4, 1989.
Mackensen, A. and Licari, L.: Carbon isotopes of live benthic foraminifera from the eastern South Atlantic Ocean: Sensitivity to organic matter rain rates and bottom water carbonate saturation state, in: The South Atlantic in the Late Quaternary – Reconstruction of material budget and current systems, edited by: Wefer, G., Mulitza, S., and Rathmeyer, V., Springer-Verlag, Berlin, 623–644, https://doi.org/10.1007/978-3-642-18917-3_27, 2004.
Mackensen, A., Schumacher, S., Radke, J., and Schmidt, D. N.: Microhabitat preferences and stable carbon isotopes of endobenthic foraminifera: clue to quantitative reconstruction of oceanic new production?, Mar. Micropaleontol., 40, 233–258, https://doi.org/10.1016/S0377-8398(00)00040-2, 2000.
Marchitto, T. M., Curry, W. B., Lynch-Stieglitz, J., Bryan, S. P., Cobb, K. M., and Lund, D. C.: Improved oxygen isotope temperature calibrations for cosmopolitan benthic foraminifera, Geochim. Cosmochim. Ac., 130, 1–11, https://doi.org/10.1016/j.gca.2013.12.034, 2014.
Martin, J. H., Knauer, G. A., Karl, D. M., and Broenkow, W. W.: VERTEX: carbon cycling in the northeast Pacific, Deep-Sea Res., 34, 267–285, https://doi.org/10.1016/0198-0149(87)90086-0, 1987.
McCave, I. N., Hall, I. R., Antia, A. N., Chou, L., Dehairs, F., Lampitt, R. S., Thomsen, L., van Weering, T. C. E., and Wollast, R.: Distribution, composition and flux of particulate material over the European margin at 47°–50° N, Deep-Sea Res. Pt. II, 48, 3107–3139, https://doi.org/10.1016/S0967-0645(01)00034-0, 2001.
McConnaughey, T.: 13C and 18O isotopic disequilibrium in biological carbonates: I. Patterns, Geochim. Cosmochim. Ac., 53, 151–162, https://doi.org/10.1016/0016-7037(89)90282-2, 1989a.
McConnaughey, T.: 13C and 18O isotopic disequilibrium in biological carbonates: II. in vitro simulation of kinetic isotope effects, Geochim. Cosmochim. Ac., 53, 163–171, https://doi.org/10.1016/0016-7037(89)90283-4, 1989b.
McCorkle, D. C. and Emerson, S. R.: The relationship between pore water carbon isotopic composition and bottom water oxygen concentration, Geochim. Cosmochim. Ac., 52, 1169–1178, https://doi.org/10.1016/0016-7037(88)90270-0, 1988.
McCorkle, D. C., Bernhard, J. M., Hintz, C. J., Blanks, J. K., Chandler, G. T., and Shaw, T. J.: The carbon and oxygen stable isotopic composition of cultured benthic foraminifera, in: Biogeochemical Controls on Palaeoceanographic Environmental Proxies, edited by: Austin, W. E. N. and James, R. H., Geological Society, London, Special Publications 303, 135–154, https://doi.org/10.1144/SP303.10, 2008.
McCorkle, D. C., Corliss, B. H., and Farnham, C. A.: Vertical distributions and stable isotopic compositions of live (stained) benthic foraminifera from the North Carolina and California continental margins, Deep-Sea Res. Pt. I, 44, 983–1024, https://doi.org/10.1016/S0967-0637(97)00004-6, 1997.
McCorkle, D. C., Emerson, S. R., and Quay, P. D.: Stable carbon isotopes in marine porewaters, Earth Planet. Sc. Lett., 74, 13–26, https://doi.org/10.1016/0012-821X(85)90162-1, 1985.
McCorkle, D. C., Keigwin, L. D., Corliss, B. H., and Emerson, S. R.: The influence of microhabitats on the carbon isotopic composition of deep-sea benthic foraminifera, Paleoceanography, 5, 161–185, https://doi.org/10.1029/PA005i003p00295, 1990.
MedAtlas: Mediterranean Hydrographic Atlas (Mast Supporting Initiative; MAS2-CT93-0074), CD-ROM, 1997.
Möbius, J., Lahajnar, N., and Emeis, K.-C.: Diagenetic control of nitrogen isotope ratios in Holocene sapropels and recent sediments from the Eastern Mediterranean Sea, Biogeosciences, 7, 3901–3914, https://doi.org/10.5194/bg-7-3901-2010, 2010a.
Möbius, J Lahajnar, N., and Emeis, K.-C.: Chemical composition of surface sediment samples from the Eastern Mediterranean Sea, https://doi.org/10.1594/PANGAEA.754732, 2010b.
Moutin, T. and Raimbault, P.: Primary production, carbon export and nutrients availability in western and eastern Mediterranean Sea in early summer 1996 (MINOS cruise), J. Marine Syst., 33/34, 273–288, https://doi.org/10.1016/S0924-7963(02)00062-3, 2002.
Ohga, T. and Kitazato, H.: Seasonal changes in bathyal foraminiferal populations in response to the flux of organic matter (Sagami Bay, Japan), Terra Nova, 9, 33–37, https://doi.org/10.1046/j.1365-3121.1997.d01-6.x, 1997.
Packard, T. T. and Gómez, M.: Modeling vertical carbon flux from zooplankton respiration, Prog. Oceanogr., 110, 59–68, https://doi.org/10.1016/j.pocean.2013.01.003, 2013.
Pahnke, K. and Zahn, R.: Southern hemisphere water mass conversion with North Atlantic climate variability, Science, 307, 1741–1746, https://doi.org/10.1126/science.1102163, 2005.
Pasqual, C., Sanchez–Vidal, A., Zúñiga, D., Calafat, A., Canals, M., Durrieu de Madron, X., Puig, P., Heussner, S., Palanques, A., and Delsaut, N.: Flux and composition of settling particles across the continental margin of the Gulf of Lion: the role of dense shelf water cascading, Biogeosciences, 7, 217–231, https://doi.org/10.5194/bg-7-217-2010, 2010.
Pierre, C.: The oxygen and carbon isotope distribution in the Mediterranean water masses, Mar. Geol., 153, 41–55, https://doi.org/10.1016/S0025-3227(98)00090-5, 1999.
Pinardi, N. and Masetti, E.: Variability of the large scale general circulation of the Mediterranean Sea from observations and modelling: a review, Palaeogeogr. Palaeoclimatol., 158, 153–173, https://doi.org/10.1016/S0031-0182(00)00048-1, 2000.
Pinardi, N., Zavatarelli, M., Adani, M., Coppini, G., Fratianni, C., Oddo, P., Simoncelli, S., Tonani, M, Lyubartsev, V., Dobricic, S., and Bonaduce, A.: Mediterranean Sea large-scale low-frequency ocean variability and water mass formation rates from 1987 to 2007: A retrospective analysis, Prog. Oceanogr. 132, 318–332, https://doi.org/10.1016/j.pocean.2013.11.003, 2015.
Poulos, S. E.: Origin and distribution of the terrigenous component of the unconsolidated surface sediment of the Aegean floor: A synthesis, Cont. Shelf Res., 29, 2045–2060, https://doi.org/10.1016/j.csr.2008.11.010, 2009.
Puig, P. and Palanques, A.: Temporal variability and composition of settling particle fluxes on the Barcelona continental margin (Northwestern Mediterranean), J. Mar. Res., 56, 639–654, https://doi.org/10.1357/002224098765213612, 1998.
Pujo-Pay, M., Conan, P., Oriol, L., Cornet-Barthaux, V., Falco, C., Ghiglione, J.-F., Goyet, C., Moutin, T., and Prieur, L.: Integrated survey of elemental stoichiometry (C, N, P) from the western to eastern Mediterranean Sea, Biogeosciences, 8, 883–899, https://doi.org/10.5194/bg-8-883-2011, 2011.
Pusceddu, A., Bianchelli, S., Canals, M., Sanchez–Vidal, A., Durrieu de Madron, X., Heussner, S., Lykousis, V., de Stigter, H., Trincardi, F., and Danovaro, R.: Organic matter in sediments of canyons and open slopes of the Portuguese, Catalan, Southern Adriatic and Cretan Sea margins, Deep-Sea Res. Pt. I, 57, 441–457, https://doi.org/10.1016/j.dsr.2009.11.008, 2010a.
Quay, P. D., Tilbrook, B., and Wong, C. S.: Oceanic Uptake of Fossil Fuel CO2: Carbon-13 Evidence, Science, 256, 74–79, https://doi.org/10.1126/science.256.5053.74, 1992.
Rathburn, A. E. and Corliss, B. H.: The ecology of living (stained) deep-sea benthic foraminifera from the Sulu Sea, Paleoceanography, 9, 87–150, https://doi.org/10.1029/93PA02327, 1994.
Rathburn, A. E., Corliss, B. H., Tappa, K. D., and Lohmann, K. C.: Comparisons of the ecology and stable isotopic compositions of living (stained) benthic foraminifera from the Sulu and South China Seas, Deep-Sea Res. Pt. I, 43, 1617–1646, https://doi.org/10.1016/S0967-0637(96)00071-4, 1996.
Rhein, M., Send, U., Klein, B., and Krahmann, G.: Interbasin deep water exchange in the western Mediterranean, J. Geophys. Res., 104, 23495–23508, https://doi.org/10.1029/1999JC900162, 1999.
Roether, W., Manca, B. B., Klein, B., Bregant, D., Georgopoulos, D., Beitzel, V., Kovacevic, V., and Luchetta, A.: Recent changes in eastern Mediterranean deep waters, Science, 271, 333–335, https://doi.org/10.1126/science.271.5247.333, 1996.
Roether, W., Klein, B., Manca, B. B., Theocharis, A., and Kioroglou, S.: Transient Eastern Mediterranean deep waters in response to the massive dense-water output of the Aegean Sea in the 1990s, Prog. Oceanogr., 74, 540–571, https://doi.org/10.1016/j.pocean.2007.03.001, 2007.
Rutgers van der Loeff, M. M.: Oxygen in pore waters of deep-sea sediments, Philos. Trans. R. Soc. Lond. A, 331, 69–84, https://doi.org/10.1098/rsta.1990.0057, 1990.
Sanchez-Vidal, A., Calafat, A., Canals, M., and Fabres, J.: Particle fluxes in the Almeria-Oran Front: control by coastal upwelling and sea surface circulation, J. Mar. Syst., 52, 89–106, https://doi.org/10.1016/j.jmarsys.2004.01.010, 2004.
Sanchez-Vidal, A., Calafat, A., Canals, M., Frigola, J., and Fabres, J.: Particle fluxes and organic carbon balance across the Eastern Alboran Sea (SW Mediterranean Sea), Cont. Shelf Res., 25, 609–628, https://doi.org/10.1016/j.csr.2004.11.004, 2005.
Schilman, B., Almogi-Labin, A., Bar-Matthews, M., and Luz, B.: Late Holocene productivity and hydrographic variability in the eastern Mediterranean inferred from benthic foraminiferal stable isotopes, Paleoceanography, 18, 1064, https://doi.org/10.1029/2002PA000813, 2003.
Schmiedl, G. and Mackensen, A.: Multispecies stable isotopes of benthic foraminifers reveal past changes of organic matter decomposition and deepwater oxygenation in the Arabian Sea, Paleoceanography, 21, PA4213, https://doi.org/10.1029/2006PA001284, 2006.
Schmiedl, G., de Bovée, F., Buscail, R., Charrière, B., Hemleben, C., Medernach, L., and Picon, P.: Trophic control of benthic foraminiferal abundance and microhabitat in the bathyal Gulf of Lions, western Mediterranean Sea, Mar. Micropaleontol., 40, 167–188, https://doi.org/10.1016/S0377-8398(00)00038-4, 2000.
Schmiedl, G., Pfeilsticker, M., Hemleben, C., and Mackensen, A.: Environmental and biological effects on the stable isotope composition of recent deep-sea benthic foraminifera from the western Mediterranean Sea, Mar. Micropaleontol., 51, 129–152, https://doi.org/10.1016/j.marmicro.2003.10.001, 2004.
Schroeder, K., Gasparini, G. P., Tangherlini, M., and Astraldi, M.: Deep and intermediate water in the Western Mediterranean under the influence of the Eastern Mediterranean Transient, Geophys. Res. Lett., 33, L21607, https://doi.org/10.1029/2006GL027121, 2006.
Schroeder, K., Ribotti, A., Borghini, M., Sorgente, R., Perilli, A., and Gasparini, G. P.: An extensive western Mediterranean deep water renewal between 2004 and 2006, Geophys. Res. Lett., 35, L18605, https://doi.org/10.1029/2008GL035146, 2008.
Schumacher, S., Jorissen, F. J., Mackensen, A., Gooday, A. J., and Pays, O.: Ontogenetic effects on stable carbon and oxygen isotopes in tests of live (Rose Bengal stained) benthic foraminifera from the Pakistan continental margin, Mar. Micropaleontol., 76, 92–103, https://doi.org/10.1016/j.marmicro.2010.06.002, 2010.
Send, U., Font, J., Krahmann, G., Millot, C., Rhein, M., and Tintore, J.: Recent advances in observing the physical oceanography of the western Mediterranean Sea, Prog. Oceanogr., 44, 37–64, https://doi.org/10.1016/S0079-6611(99)00020-8, 1999.
Shackleton, N. J. and Opdyke, N. D.: Oxygen Isotope and Palaeomagnetic Stratigraphy of Equatorial Pacific Core V28-238: Oxygen Isotope Temperatures and Ice Volumes on a 105 Year and 106 Year Scale, Quaternary Res., 3, 39–55, https://doi.org/10.1016/0033-5894(73)90052-5, 1973.
Siokou-Frangou, I., Bianchi, M., Christaki, U., Christou, E. D., Giannakourou, A., Gotsis, O., Ignatiades, L., Pagou, K., Pitta, P., Psarra, S., Souvermezoglou, E., Van Wambeke, F., and Zervakis, V.: Carbon flow in the planktonic food web along a gradient of oligotrophy in the Aegean Sea (Mediterranean Sea), J. Mar. Syst., 33/34, 335–353, https://doi.org/10.1016/S0924-7963(02)00065-9, 2002.
Skliris, N., Mantziafou, A., Sofianos, S., and Gkanaos, A.: Satellite-derived variability of the Aegean Sea ecohydrodynamics, Cont. Shelf Res. 30, 403–418, https://doi.org/10.1016/j.csr.2009.12.012, 2010.
Stabholz, M., Durrieu de Madron, X., Canals, M., Khripounoff, A., Taupier-Letage, I., Testor, P., Heussner, S., Kerhervé, P., Delsaut, N.,. Houpert, L, Lastras, G., and Dennielou, B.: Impact of open-ocean convection on particle fluxes and sediment dynamics in the deep margin of the Gulf of Lions, Biogeosciences, 10, 1097–1116, https://doi.org/10.5194/bg-10-1097-2013, 2013.
Stott, L. D., Berelson, W., Douglas, R., and Gorsline, D.: Increased dissolved oxygen in Pacific intermediate waters due to lower rates of carbon oxidation in sediments, Nature, 407, 367–370, https://doi.org/10.1038/35030084, 2000.
Suess, E.: Particulate organic carbon flux in the oceans – surface productivity and oxygen utilization, Nature, 288, 260–263, https://doi.org/10.1038/288260a0, 1980.
Tanhua, T., Hainbucher, D., Schroeder, K., Cardin, V., Álvarez, M., and Civitarese, G.: The Mediterranean Sea system: a review and an introduction to the special issue, Ocean Sci., 9, 789–803, https://doi.org/10.5194/os-9-789-2013, 2013.
Tesi, T., Puig, P., Palanques, A., and Goñi, M.A.: Lateral advection of organic matter in cascading-dominated submarine canyons, Prog. Oceanogr., 84, 185–203, https://doi.org/10.1016/j.pocean.2009.10.004, 2010.
Theodor, M., Schmiedl, G., and Mackensen, A.: Stable isotope composition of deep-sea benthic foraminifera under contrasting trophic conditions in the western Mediterranean Sea, Mar. Micropaleontol., 124, 16–28, https://doi.org/10.1016/j.marmicro.2016.02.001, 2016.
Tsiaras, K. P., Kourafalou, V. H., Raitsos, D. E., Triantafyllou, G., Petihakis, G., and Korres, G.: Inter-annual productivity variability in the North Aegean Sea: Influence of thermohaline circulation during the Eastern Mediterranean Transient, J. Mar. Syst., 96/97, 72–81, https://doi.org/10.1016/j.jmarsys.2012.02.003, 2012.
Uitz, J., Huot, Y., Bruyant, F., Babin, M., and Claustre, H.: Relating phytoplankton photophysiological properties to community structure on large scales, Limnol. Oceanogr., 53, 614–630, https://doi.org/10.4319/ lo.2008.53.2.0614, 2008.
Velaoras, D. and Lascaratos, A.: Deep water mass characteristics and interannual variability in the North and Central Aegean Sea, J. Mar. Syst., 53, 59–85, https://doi.org/10.1016/j.jmarsys.2004.05.027, 2005.
Walton, W. R.: Techniques for recognition of living foraminifera, Contributions from the Cushman Foundation for Foraminiferal Research, 3, 56–60, 1952.
Wüst, G.: On the vertical circulation of the Mediterranean Sea, J. Geophys. Res. 66, 3261–3271, https://doi.org/10.1029/JZ066i010p03261, 1961.
Zahn, R., Winn, K., and Sarnthein, M.: Benthic Foraminiferal δ13C and accumulation rates of organic Carbon: Uvigerina peregrina group and Cibicidoides wuellerstorfi, Paleoceanography, 1, 27–42, https://doi.org/10.1029/PA001i001p00027, 1986.
Zervakis, V., Krasakopoulou, E., Georgopoulos, D., and Souvermezoglou, E.: Vertical diffusion and oxygen consumption during stagnation periods in the deep North Aegean, Deep-Sea Res. Pt. I, 50, 53–71, https://doi.org/10.1016/S0967-0637(02)00144-9, 2003.
Zúñiga, D., Calafat, A., Sanchez-Vidal, A., Canals, M., Price, B., Heussner, S., and Miserocchi, S.: Particulate organic carbon budget in the open Algero-Balearic Basin (Western Mediterranean): Assessment from a one-year sediment trap experiment, Deep-Sea Res. Pt. I, 54, 1530–1548, https://doi.org/10.1016/j.dsr.2007.06.001, 2007.
Zúñiga, D., Calafat, A., Heussner, S., Miserocchi, S., Sanchez-Vidal, A., Garcia-Orellana, J., Canals, M., Sánchez-Cabeza, J.A., Carbonne, J., Delsaut, N., and Saragoni, G.: Compositional and temporal evolution of particle fluxes in the open Algero–Balearic basin (Western Mediterranean), J. Mar. Syst., 70, 196–214, https://doi.org/10.1016/j.jmarsys.2007.05.007, 2008.
Altmetrics
Final-revised paper
Preprint