Articles | Volume 17, issue 2
https://doi.org/10.5194/cp-17-603-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/cp-17-603-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Mar 2021
Research article |
| 09 Mar 2021
| 09 Mar 2021
Nutrient utilization and diatom productivity changes in the low-latitude south-eastern Atlantic over the past 70 ka: response to Southern Ocean leakage
Katharine Hendry
CORRESPONDING AUTHOR
University of Bristol, School of Earth Sciences, Bristol BS8 1RJ, UK
Oscar Romero
MARUM – Center for Marine Environmental Sciences, University of Bremen, 28359 Bremen, Germany
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 27568 Bremerhaven, Germany
Vanessa Pashley
Geochronology and Tracers Facility, British Geological Survey, Keyworth NG12 5GG, UK
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Alan Marron, Lucie Cassarino, Jade Hatton, Paul Curnow, and Katharine R. Hendry
Biogeosciences, 16, 4805–4813, https://doi.org/10.5194/bg-16-4805-2019, https://doi.org/10.5194/bg-16-4805-2019, 2019
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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.
Anna Mikis, Katharine R. Hendry, Jennifer Pike, Daniela N. Schmidt, Kirsty M. Edgar, Victoria Peck, Frank J. C. Peeters, Melanie J. Leng, Michael P. Meredith, Chloe L. C. Jones, Sharon Stammerjohn, and Hugh Ducklow
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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.
Lucie Cassarino, Christopher D. Coath, Joana R. Xavier, and Katharine R. Hendry
Biogeosciences, 15, 6959–6977, https://doi.org/10.5194/bg-15-6959-2018, https://doi.org/10.5194/bg-15-6959-2018, 2018
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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.
Qiang Zhang, George Edward Alexander Swann, Vanessa Pashley, and Matthew S. A. Horstwood
EGUsphere, https://doi.org/10.5194/egusphere-2024-3686, https://doi.org/10.5194/egusphere-2024-3686, 2024
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We presents the first coupled record of radiolarian silicon isotopes (δ30Sirad) from paired water column and surface sediment samples in the South China Sea. No significant discrepancies in δ30Sirad values were observed between plankton and sediment samples, implying a minimal impact of dissolution on δ30Sirad during deposition of radiolarian shells. This demonstrates the faithful preservation of the δ30Sirad signature and its potential for studying past changes in the marine silicon cycle.
Gerard J. M. Versteegh, Karin A. F. Zonneveld, Jens Hefter, Oscar E. Romero, Gerhard Fischer, and Gesine Mollenhauer
Biogeosciences, 19, 1587–1610, https://doi.org/10.5194/bg-19-1587-2022, https://doi.org/10.5194/bg-19-1587-2022, 2022
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A 5-year record of long-chain mid-chain diol export flux and composition is presented with a 1- to 3-week resolution sediment trap CBeu (in the NW African upwelling). All environmental parameters as well as the diol composition are dominated by the seasonal cycle, albeit with different phase relations for temperature and upwelling. Most diol-based proxies are dominated by upwelling. The long-chain diol index reflects temperatures of the oligotrophic summer sea surface.
Gerhard Fischer, Oscar E. Romero, Johannes Karstensen, Karl-Heinz Baumann, Nasrollah Moradi, Morten Iversen, Götz Ruhland, Marco Klann, and Arne Körtzinger
Biogeosciences, 18, 6479–6500, https://doi.org/10.5194/bg-18-6479-2021, https://doi.org/10.5194/bg-18-6479-2021, 2021
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Low-oxygen eddies in the eastern subtropical North Atlantic can form an oasis for phytoplankton growth. Here we report on particle flux dynamics at the oligotrophic Cape Verde Ocean Observatory. We observed consistent flux patterns during the passages of low-oxygen eddies. We found distinct flux peaks in late winter, clearly exceeding background fluxes. Our findings suggest that the low-oxygen eddies sequester higher organic carbon than expected for oligotrophic settings.
Oscar E. Romero, Simon Ramondenc, and Gerhard Fischer
Biogeosciences, 18, 1873–1891, https://doi.org/10.5194/bg-18-1873-2021, https://doi.org/10.5194/bg-18-1873-2021, 2021
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Upwelling intensity along NW Africa varies on the interannual to decadal timescale. Understanding its changes is key for the prediction of future changes of CO2 sequestration in the northeastern Atlantic. Based on a multiyear (1988–2009) sediment trap experiment at the site CBmeso, fluxes and the species composition of the diatom assemblage are presented. Our data help in establishing the scientific basis for forecasting and modeling future states of this ecosystem and its decadal changes.
Oscar E. Romero, Karl-Heinz Baumann, Karin A. F. Zonneveld, Barbara Donner, Jens Hefter, Bambaye Hamady, Vera Pospelova, and Gerhard Fischer
Biogeosciences, 17, 187–214, https://doi.org/10.5194/bg-17-187-2020, https://doi.org/10.5194/bg-17-187-2020, 2020
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Monitoring of the multiannual evolution of populations representing different trophic levels allows for obtaining insights into the impact of climate variability in marine coastal upwelling ecosystems. By using a multiyear, continuous (1,900 d) sediment trap record, we assess the dynamics and fluxes of calcareous, organic and siliceous microorganisms off Mauritania (NW Africa). The experiment allowed for the recognition of a general sequence of seasonal variations of the main populations.
Alan Marron, Lucie Cassarino, Jade Hatton, Paul Curnow, and Katharine R. Hendry
Biogeosciences, 16, 4805–4813, https://doi.org/10.5194/bg-16-4805-2019, https://doi.org/10.5194/bg-16-4805-2019, 2019
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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.
Anna Mikis, Katharine R. Hendry, Jennifer Pike, Daniela N. Schmidt, Kirsty M. Edgar, Victoria Peck, Frank J. C. Peeters, Melanie J. Leng, Michael P. Meredith, Chloe L. C. Jones, Sharon Stammerjohn, and Hugh Ducklow
Biogeosciences, 16, 3267–3282, https://doi.org/10.5194/bg-16-3267-2019, https://doi.org/10.5194/bg-16-3267-2019, 2019
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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.
Lucie Cassarino, Christopher D. Coath, Joana R. Xavier, and Katharine R. Hendry
Biogeosciences, 15, 6959–6977, https://doi.org/10.5194/bg-15-6959-2018, https://doi.org/10.5194/bg-15-6959-2018, 2018
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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.
Manuel Bringué, Robert C. Thunell, Vera Pospelova, James L. Pinckney, Oscar E. Romero, and Eric J. Tappa
Biogeosciences, 15, 2325–2348, https://doi.org/10.5194/bg-15-2325-2018, https://doi.org/10.5194/bg-15-2325-2018, 2018
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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.
Fatima Abrantes, Pedro Cermeno, Cristina Lopes, Oscar Romero, Lélia Matos, Jolanda Van Iperen, Marta Rufino, and Vitor Magalhães
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Diatoms are the dominant primary producers of the most productive and best fishing areas of the modern ocean, the coastal upwelling systems. This turns them into important contributors to the biological pump and climate change. To help untangle their response to warming climate, we compare the worldwide diatom sedimentary abundance (SDA) to environmental variables and find that the capacity of diatoms to take up silicic acid sets an upper limit on global export production in these ocean regions.
Gerhard Fischer, Johannes Karstensen, Oscar Romero, Karl-Heinz Baumann, Barbara Donner, Jens Hefter, Gesine Mollenhauer, Morten Iversen, Björn Fiedler, Ivanice Monteiro, and Arne Körtzinger
Biogeosciences, 13, 3203–3223, https://doi.org/10.5194/bg-13-3203-2016, https://doi.org/10.5194/bg-13-3203-2016, 2016
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Particle fluxes at the Cape Verde Ocean Observatory in the eastern tropical North Atlantic for the period December 2009 until May 2011 are discussed based on deep sediment trap time-series data collected at 1290 and 3439 m water depths. The typically open-ocean flux pattern with weak seasonality is modified by the appearance of a highly productive and low oxygen eddy in winter 2010. The eddy passage was accompanied by high biogenic and lithogenic fluxes, lasting from December 2009 to May 2010.
Gerhard Fischer, Oscar Romero, Ute Merkel, Barbara Donner, Morten Iversen, Nico Nowald, Volker Ratmeyer, Götz Ruhland, Marco Klann, and Gerold Wefer
Biogeosciences, 13, 3071–3090, https://doi.org/10.5194/bg-13-3071-2016, https://doi.org/10.5194/bg-13-3071-2016, 2016
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The studies were initiated to investigate potential changes in the important coastal upwelling system off NW Africa and to evaluate the role of mineral dust for carbon sequestration into the deep ocean. For this purpose, we deployed time series sediment traps in the deep water column off Cape Blanc, Mauritania. A more than two-decadal sediment trap record from this coastal upwelling system is now presented with respect to deep ocean mass fluxes, flux components and their longer term variability.
V. N. Panizzo, G. E. A. Swann, A. W. Mackay, E. Vologina, M. Sturm, V. Pashley, and M. S. A. Horstwood
Biogeosciences, 13, 147–157, https://doi.org/10.5194/bg-13-147-2016, https://doi.org/10.5194/bg-13-147-2016, 2016
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Lake Baikal, Siberia, is the world's most voluminous lake. Diatoms are the most dominant primary producers in the lake and form the basis of the food chain. This paper investigated the productivity of these organisms over the course of a year with a view to understanding their preservation in sediments and their value for reconstructing past productivity in the lake. This is important when recent climate change and the pressures of pollution are having demonstrable impacts in the region.
C. L. McKay, J. Groeneveld, H. L. Filipsson, D. Gallego-Torres, M. J. Whitehouse, T. Toyofuku, and O.E. Romero
Biogeosciences, 12, 5415–5428, https://doi.org/10.5194/bg-12-5415-2015, https://doi.org/10.5194/bg-12-5415-2015, 2015
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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.
O. Cartapanis, K. Tachikawa, O. E. Romero, and E. Bard
Clim. Past, 10, 405–418, https://doi.org/10.5194/cp-10-405-2014, https://doi.org/10.5194/cp-10-405-2014, 2014
Related subject area
Subject: Carbon Cycle | Archive: Marine Archives | Timescale: Pleistocene
No detectable influence of the carbonate ion effect on changes in stable carbon isotope ratios (δ13C) of shallow dwelling planktic foraminifera over the past 160 kyr
Deglacial export of pre-aged terrigenous carbon to the Bay of Biscay
Atmospheric CO2 estimates for the Miocene to Pleistocene based on foraminiferal δ11B at Ocean Drilling Program Sites 806 and 807 in the Western Equatorial Pacific
Coccolithophore productivity at the western Iberian Margin during the Middle Pleistocene (310–455 ka) – evidence from coccolith Sr∕Ca data
Carbon burial in deep-sea sediment and implications for oceanic inventories of carbon and alkalinity over the last glacial cycle
Peter Köhler and Stefan Mulitza
Clim. Past, 20, 991–1015, https://doi.org/10.5194/cp-20-991-2024, https://doi.org/10.5194/cp-20-991-2024, 2024
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We constructed 160 kyr long mono-specific stacks of δ13C and of δ18O from the wider tropics from the planktic foraminifera G. ruber and/or T. sacculifer and compared them with carbon cycle simulations using the BICYCLE-SE model. In our stacks and our model-based interpretation, we cannot detect a species-specific isotopic fractionation during hard-shell formation as a function of carbonate chemistry in the surrounding seawater, something which is called a carbonate ion effect.
Eduardo Queiroz Alves, Wanyee Wong, Jens Hefter, Hendrik Grotheer, Tommaso Tesi, Torben Gentz, Karin Zonneveld, and Gesine Mollenhauer
Clim. Past, 20, 121–136, https://doi.org/10.5194/cp-20-121-2024, https://doi.org/10.5194/cp-20-121-2024, 2024
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Our study reveals a previously unknown peat source for the massive influx of terrestrial organic matter that was exported from the European continent to the ocean during the last deglaciation. Our findings shed light on ancient terrestrial organic carbon mobilization, providing insights that are crucial for refining climate models.
Maxence Guillermic, Sambuddha Misra, Robert Eagle, and Aradhna Tripati
Clim. Past, 18, 183–207, https://doi.org/10.5194/cp-18-183-2022, https://doi.org/10.5194/cp-18-183-2022, 2022
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Here we reconstruct atmospheric CO2 values across major climate transitions over the past 16 million years (Myr) from two sites in the West Pacific Warm Pool using a pH proxy on surface-dwelling foraminifera. We are able to reproduce pCO2 data from ice cores; therefore we apply the same framework to older samples to create a long-term pH and pCO2 reconstruction. We give quantitative constraints on pH and pCO2 changes over the main climate transitions of the last 16 Myr.
Catarina Cavaleiro, Antje H. L. Voelker, Heather Stoll, Karl-Heinz Baumann, and Michal Kucera
Clim. Past, 16, 2017–2037, https://doi.org/10.5194/cp-16-2017-2020, https://doi.org/10.5194/cp-16-2017-2020, 2020
Olivier Cartapanis, Eric D. Galbraith, Daniele Bianchi, and Samuel L. Jaccard
Clim. Past, 14, 1819–1850, https://doi.org/10.5194/cp-14-1819-2018, https://doi.org/10.5194/cp-14-1819-2018, 2018
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A data-based reconstruction of carbon-bearing deep-sea sediment shows significant changes in the global burial rate over the last glacial cycle. We calculate the impact of these deep-sea changes, as well as hypothetical changes in continental shelf burial and volcanic outgassing. Our results imply that these geological fluxes had a significant impact on ocean chemistry and the global carbon isotopic ratio, and that the natural carbon cycle was not in steady state during the Holocene.
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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.
Productive eastern boundary upwelling systems (EBUs) are characterized by abundant siliceous...
