Article
Geochemistry & Geophysics
Ruixue Wang, Josephine A. Clegg, Peter M. Scott, Christina S. Larkin, Feifei Deng, Alexander L. Thomas, Xin-Yuan Zheng, Alexander M. Piotrowski
Summary: Despite decades of research, significant gaps in our understanding of the oceanic cycling of neodymium (Nd) and rare earth elements (REEs) remain. Observations show that dissolved Nd concentration typically increases with depth, while Nd isotopes reflect conservative water mass mixing in the intermediate and deep ocean, known as the Nd paradox. This study in the South Atlantic provides detailed insights into the spatial controls on ocean geochemistry and the processes influencing Nd isotopic compositions.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Multidisciplinary Sciences
Nathan T. Lanning, Shuo Jiang, Vinicius J. Amaral, Katherine Mateos, Janelle M. Steffen, Phoebe J. Lam, Edward A. Boyle, Jessica N. Fitzsimmons
Summary: Reversible scavenging is the process by which dissolved metals exchange onto and off sinking particles and are transported to deeper depths. This process deepens the distribution of adsorptive elements and shortens their residence times in the ocean. Understanding which metals undergo reversible scavenging and under what conditions is important.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Environmental Sciences
Wenhao Wang, Heather Goring-Harford, Korinna Kunde, E. Malcolm S. Woodward, Maeve C. Lohan, Douglas P. Connelly, Rachael H. James
Summary: Chromium isotopic composition in ancient marine sediments can be used to infer changes in past seawater oxygenation or biological productivity. The relative contribution of external sources and internal cycling on the distribution of dissolved chromium in the oceans is still debated. In this study, water column profiles were obtained for dissolved chromium concentrations and chromium isotopes in the sub-tropical North Atlantic. The results suggest that benthic inputs and the formation of colloid aggregates of Fe-(oxyhydr)oxides play important roles in shaping the distribution of chromium.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Chemistry, Multidisciplinary
R. Zitoun, E. P. Achterberg, T. J. Browning, L. J. Hoffmann, S. Krisch, S. G. Sander, A. Koschinsky
Summary: The study found that copper speciation in the South-East Atlantic is influenced by a complex interplay between biotic and abiotic processes, with ligand sources including dissolved organic matter from the Congo River and the Benguela upwelling system. Additionally, the spatial features of the ligand pool are influenced by the phylogeography of different microorganisms.
Article
Geochemistry & Geophysics
Yingzhe Wu, Leopoldo D. Pena, Robert F. Anderson, Alison E. Hartman, Louise L. Bolge, Chandranath Basak, Joohee Kim, Micha J. A. Rijkenberg, Hein J. W. De Baar, Steven L. Goldstein
Summary: The global overturning ocean circulation is crucial for global climate and can be traced using neodymium (Nd) isotopes. However, the value of Nd isotopes as a circulation tracer has been questioned due to various processes that can modify seawater Nd isotope ratios. This study investigates the integrity of Nd isotopes as an ocean circulation tracer in the Southwest Atlantic and confirms their potential for reconstructing past ocean circulation changes.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Chemistry, Multidisciplinary
R. Cloete, J. C. Loock, N. R. van Horsten, J-L Menzel Barraqueta, S. Fietz, T. N. Mtshali, H. Planquette, M. I. Garcia-Ibanez, A. N. Roychoudhury
Summary: The first winter measurements of dissolved zinc (dZn) and particulate zinc (pZn) in the Indian Sector of the Southern Ocean showed increased dZn and decreased pZn at higher latitudes, indicating reduced biological uptake and preferential dZn resupply due to deep winter mixing. Additionally, the study revealed potential hydrothermal activity and transport of continental sediment as sources of zinc, and demonstrated a longer remineralisation length scale for zinc compared to phosphorus.
Article
Geochemistry & Geophysics
Wen-Hsuan Liao, Shotaro Takano, Hung-An Tian, Hung-Yu Chen, Yoshiki Sohrin, Tung-Yuan Ho
Summary: The study determined the elemental and isotopic composition of zinc in sinking particles in the deep water of the northern South China Sea (NSCS) to investigate different sources and assess their isotopic signatures. It was found that anthropogenic aerosol Zn accounted for the majority of zinc in sinking particles, with a larger discrepancy between estimated and measured values during the high productivity season. Elevated delta Zn-66 values were observed at 3500 m during autumn due to the influence of authigenic particles.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Environmental Sciences
Arianna Olivelli, Katy Murphy, Luke Bridgestock, David J. Wilson, Micha Rijkenberg, Rob Middag, Dominik J. Weiss, Tina van de Flierdt, Mark Rehkamper
Summary: Anthropogenic emissions have had a significant impact on the marine biogeochemical cycle of lead (Pb). New data from surface seawater in the western South Atlantic in 2011 reveal that the equatorial zone is dominated by previously deposited Pb, while the subtropical zone reflects anthropogenic Pb emissions from South America and the subantarctic zone presents a mixture of South American anthropogenic Pb and natural Pb from Patagonian dust. The average Pb concentration has decreased by 34% since the 1990s, primarily driven by changes in the subtropical zone and an increase in the fraction of natural Pb.
MARINE POLLUTION BULLETIN
(2023)
Article
Environmental Sciences
Ryan Cloete, Jean C. Loock, Natasha R. van Horsten, Susanne Fietz, Thato N. Mtshali, Helene Planquette, Alakendra N. Roychoudhury
Summary: Winter distributions of dissolved cadmium and particulate cadmium were measured for the first time in the Indian sector of the Southern Ocean, revealing the important role of biological uptake in the biogeochemical cycling of cadmium during winter months, although weaker compared to summer. Distinct, biologically driven changes in cadmium cycling were observed across different latitudinal zones, with surface distributions of cadmium influenced by the preferential uptake and regeneration of diatoms with high cadmium content as well as the upwelling of cadmium-enriched water masses in the Antarctic zone.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Lise Artigue, Neil J. Wyatt, Francois Lacan, Claire Mahaffey, Maeve C. Lohan
Summary: New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 show an east to west increase in dAl concentration in the surface waters along 22 degrees N in the subtropical North Atlantic. Results indicate that advection, dust dissolution, and erosion products from the Lesser Antilles contribute to dAl sources, while scavenging, water mass transport, and internal dAl inputs play important roles in dAl removal and distribution in the North Atlantic Ocean. Taking advection into consideration is crucial for understanding the impact of external sources and dissolved-particulate interactions on the Al cycle.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Oceanography
L. J. A. Gerringa, M. J. A. Rijkenberg, H. A. Slagter, P. Laan, R. Paffrath, D. Bauch, M. Rutgers van der Loeff, R. Middag
Summary: During the PS94 expedition in summer 2015, sources and sinks of dissolved metals in the central Arctic Ocean were studied, revealing different concentrations of metals in various regions, highlighting the importance of different water sources in influencing metal distributions.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Environmental Sciences
Igor Zivkovic, Matthew P. Humphreys, Eric P. Achterberg, Cynthia Dumousseaud, E. Malcolm S. Woodward, Natalia Bojanic, Mladen Solic, Arne Bratkic, Joze Kotnik, Mitja Vahcic, Kristina Obu Vazner, Ermira Begu, Vesna Fajon, Yaroslav Shlyapnikov, Milena Horvat
Summary: The speciation of mercury in the South Atlantic Ocean was investigated, and it was found that methylated mercury concentrations were related to seawater temperature, salinity, and fluorescence, while dissolved gaseous mercury concentrations were related to water column depth, macronutrient concentrations, and dissolved inorganic carbon. The linear correlation observed between dissolved gaseous mercury and dissolved inorganic carbon suggests possible production of dissolved gaseous mercury through organic matter remineralization.
MARINE POLLUTION BULLETIN
(2022)
Article
Geochemistry & Geophysics
Wen-Hsuan Liao, Helene Planquette, Brivaela Moriceau, Christophe Lambert, Floriane Desprez de Gesincourt, Emmanuel Laurenceau-Cornec, Geraldine Sarthou, Thomas Gorgues
Summary: Sediments are usually considered to have limited influence on the dissolved iron (dFe) pool in the ocean, but recent observations and experiments suggest that iron released from suspended sediment particles can fertilize large areas of the ocean. In this study, dissolution experiments were conducted to measure the amount of dFe released from two types of resuspended sediments (silicate and calcite-rich) at different temperatures. The results showed that temperature influenced the dissolution of iron, but not manganese. Scavenging of iron and complexation with ligands were found to be important factors in both the release and fractionation of iron isotopes at the sediment-water boundary.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Multidisciplinary Sciences
Saumik Samanta, Ryan Cloete, Subhra Prakash Dey, Jan-Lukas Menzel Barraqueta, Jean C. Loock, Jan-Olaf Meynecke, Jasper de Bie, Marcello Vichi, Alakendra N. Roychoudhury
Summary: Using a spatiotemporal dataset, this study explores the exchange of dissolved lead (dPb) between the Indian and Atlantic Oceans in the subtropical oceans surrounding South Africa. The findings reveal that the high surface dPb concentration in the southeast Cape Basin is primarily delivered from the Indian Ocean via the Agulhas Current. Eddy dynamics, leakage at Agulhas retroflection, and atmospheric Pb emissions from South Africa contribute to the temporal changes in dPb in the Cape Basin.
SCIENTIFIC REPORTS
(2023)
Article
Geosciences, Multidisciplinary
Te Liu, Mark J. Hopwood, Stephan Krisch, Lucia H. Vieira, Eric P. Achterberg
Summary: Wet deposition is identified as an additional source of trace metals (TMs) to the Congo plume, supplementing the TM input from the Congo River. The study shows the significant contribution of wet deposition to the TM fluxes in the Congo plume, including Cd, Cu, Pb, and Zn.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Corey Archer, Derek Vance, Angela Milne, Maeve C. Lohan
EARTH AND PLANETARY SCIENCE LETTERS
(2020)
Article
Environmental Sciences
Qian Wang, Lian Zhou, Susan H. Little, Jinhua Liu, Lanping Feng, Shuoyun Tong
SCIENCE OF THE TOTAL ENVIRONMENT
(2020)
Article
Environmental Sciences
Lise Artigue, Neil J. Wyatt, Francois Lacan, Claire Mahaffey, Maeve C. Lohan
Summary: New dissolved aluminum (dAl) data from the 2017 GEOTRACES process study GApr08 show an east to west increase in dAl concentration in the surface waters along 22 degrees N in the subtropical North Atlantic. Results indicate that advection, dust dissolution, and erosion products from the Lesser Antilles contribute to dAl sources, while scavenging, water mass transport, and internal dAl inputs play important roles in dAl removal and distribution in the North Atlantic Ocean. Taking advection into consideration is crucial for understanding the impact of external sources and dissolved-particulate interactions on the Al cycle.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Geosciences, Multidisciplinary
Lena Chen, Susan H. Little, Katharina Kreissig, Silke Severmann, James McManus
Summary: Cadmium is a trace metal in the ocean that mimics phosphate concentration, but deviations occur in oxygen deficient zones. Organic-rich sediments have light Cd isotope compositions, suggesting a light source of Cd, yet the application of Cd isotopes as a paleoproductivity proxy is complex due to multiple possible sources and processes in the water column.
FRONTIERS IN EARTH SCIENCE
(2021)
Review
Environmental Sciences
T. J. Horner, S. H. Little, T. M. Conway, J. R. Farmer, J. E. Hertzberg, D. J. Janssen, A. J. M. Lough, J. L. McKay, A. Tessin, S. J. G. Galer, S. L. Jaccard, F. Lacan, A. Paytan, K. Wuttig
Summary: Understanding the operation of the biological pump in the past is crucial, and bioactive trace metals and their isotopes can serve as proxies. Among them, cadmium, barium, nickel, and chromium isotopes show the most promise as tracers of ancient productivity, while iron, zinc, copper, and molybdenum are less suitable for this purpose.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Ecology
E. Cerdan-Garcia, A. Baylay, D. Polyviou, E. M. S. Woodward, L. Wrightson, C. Mahaffey, M. C. Lohan, C. M. Moore, T. S. Bibby, J. C. Robidart
Summary: The study demonstrates how Trichodesmium acclimates to resource availability by upregulating iron-stress biomarker genes with decreasing Fe availability and upregulating genes involved in the acquisition of diverse P sources with decreasing P availability. Enhanced N-2 fixation within the Fe and P co-stressed transition region was associated with a distinct metabolic profile, suggesting unique physiological responses to exploit the Fe and P co-limited niche.
Article
Chemistry, Multidisciplinary
Kechen Zhu, Antony J. Birchill, Angela Milne, Simon Ussher, Matthew P. Humphreys, Nealy Carr, Claire Mahaffey, Maeve C. Lohan, Eric P. Achterberg, Martha Gledhill
Summary: Using a combined ion pairing - organic matter speciation model, this study predicted the organic complexation of iron in the Celtic Sea, optimized through comparison with experimental results and simulated titrations. The results suggest that dissolved organic carbon concentrations in marine waters may not significantly impact the heterogeneity or concentrations of Fe binding sites, with implications for understanding the dissolved Fe inventory in the ocean. The study also calculated Fe solubility under ambient conditions in the Celtic Sea, showing that the interaction between Fe solubility and binding by organic matter plays a key role in controlling the dissolved Fe concentrations in marine environments.
Article
Geochemistry & Geophysics
Hollie Packman, Susan H. Little, Alex R. Baker, Luke Bridgestock, Rosie J. Chance, Barry J. Coles, Katharina Kreissig, Mark Rehkaemper, Tina van de Flierdt
Summary: Anthropogenic activities have increased the input of metals into the ocean, affecting marine ecosystems. This study shows that Zn and Cu isotopes can distinguish between natural and anthropogenic atmospheric inputs. Analysis of aerosols collected from the eastern tropical Atlantic Ocean reveals a significant anthropogenic component, indicating the potential of Zn isotopes to track anthropogenic sources of atmospheric Zn to the surface ocean.
Article
Oceanography
Stephen M. Chiswell, Philip W. Boyd, Sylvia G. Sander, Michael J. Ellwood, Angela Milne
Summary: Subtropical and subantarctic waters on both sides of the southern hemisphere Subtropical Front are iron-limited. A study conducted in the subtropical waters east of New Zealand found a significant positive correlation between chlorophyll and dissolved iron. A simple model suggests that iron entrainment from high-iron coastal water into low-iron offshore Subtropical Water supports primary production. Therefore, mesoscale eddy-induced lateral advection of iron may play a significant role in the total primary production within the Subtropical Front.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2022)
Article
Geosciences, Multidisciplinary
Alessandro Tagliabue, Alastair J. M. Lough, Clement Vic, Vassil Roussenov, Jonathan Gula, Maeve C. Lohan, Joseph A. Resing, Richard G. Williams
Summary: The dispersal of dissolved iron from hydrothermal vents in the Trans-Atlantic-Geotraverse system is mainly controlled by physical processes and occurs predominantly in the colloidal phase. Fine-scale mixing near the seafloor and transport through fracture zones play important roles in the dispersal, leading to predominant westward dispersal away from the Mid-Atlantic ridge at a larger scale, while diapycnal mixing drives northward transport within the ridge axial valley. Coarse resolution ocean models often used to assess ocean iron cycling are not able to accurately reproduce the observed dispersal due to the omission of local topography and mixing.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Ecology
Alastair J. M. Lough, Alessandro Tagliabue, Clement Demasy, Joseph A. Resing, Travis Mellett, Neil J. Wyatt, Maeve C. Lohan
Summary: The supply of iron to the surface ocean affects primary productivity, but the extent of iron input from hydrothermal sources in the deep ocean is poorly understood. This study examines the variability in dissolved iron to excess helium ratios at four hydrothermal vent sites along the Mid-Atlantic Ridge. The results show that the ratios differ due to differences in plume age, and the presence of particulates affects the ratio within a certain distance from the vents. The study highlights the need for further research on vent sources and their impact on iron flux in the deep ocean.
Article
Ecology
Neil J. Wyatt, Angela Milne, Eric P. Achterberg, Thomas J. Browning, Heather A. Bouman, E. Malcolm S. Woodward, Maeve C. Lohan
Summary: This study reports the distributions and stoichiometry of dissolved zinc and cobalt in the sub-tropical and sub-Antarctic waters of the south-eastern Atlantic Ocean during the austral spring of 2010 and summer of 2011/2012. It found that higher concentrations of dZn in the subtropical surface waters during early spring were derived from offshore transport, while the sub-Antarctic surface waters displayed consistent dZn and dCo concentrations across seasons. The study also revealed a greater overall removal of dZn relative to dCo in the upper water column of the south-eastern Atlantic.
Article
Ecology
Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, Gideon M. Henderson
Summary: This study investigated the distribution of the naturally occurring radioisotope 228Ra in the water column of the South Atlantic to estimate ocean mixing and trace element supply to the surface ocean at 40 degrees S. Results showed that vertical mixing is an important source of dissolved trace elements in the surface ocean, but additional inputs are needed to balance the element budgets, especially for iron.
Article
Geochemistry & Geophysics
Zhen-Min Ge, Xiao-Long Huang, Wei Xie, Tobias W. Hofig, Fan Yang, Yang Yu, S. Khogenkumar Singh
Summary: The mantle source composition of the nascent oceanic crust in the central part of the Gulf of California has been investigated using basaltic glass samples. These samples show trace element patterns similar to enriched mid-ocean ridge basalts, suggesting that the nascent oceanic crust in the Guaymas Basin might be generated through partial melting of a depleted mantle source metasomatized by subducted slab materials.
Article
Geochemistry & Geophysics
Jean-Michel Brazier, Katja E. Goetschl, Martin Dietzel, Vasileios Mavromatis
Summary: This study estimated the distribution coefficient of Zn2+ between calcite/aragonite and reactive fluids and found that the growth rate strongly influences D-Zn(2+) in both minerals. Additionally, a linear correlation was found between D-Zn(2+) and the saturation degree of the reactive fluid.
Article
Geochemistry & Geophysics
Ming Lei, Michele Lustrino, Jifeng Xu, Zhiqiang Kang, Zhengfu Guo, Jianlin Chen
Summary: This study presents a comprehensive geochronological, mineralogical, and geochemical analysis of olivine leucitites in the Maiga area of southern Tibet, suggesting that these rocks originate from a carbonated peridotite mantle source and highlighting the possibility of carbonates being recycled deep into the mantle during continental subduction.
Article
Geochemistry & Geophysics
Yuntao Ye, Xiaomei Wang, Huajian Wang, Haifeng Fan, Zhigang Chen, Qingjun Guo, Ziteng Wang, Chaodong Wu, Donald E. Canfield, Shuichang Zhang
Summary: Phosphorus is an essential element for life and its cycle in the ocean is closely connected with the carbon and oxygen cycles. The study of phosphate oxygen isotopes can provide insights into various reactions related to phosphorus. By analyzing carbonate fluorapatite samples from the Mesoproterozoic Era in North China, it was found that the oxygen isotope values were lower compared to modern samples, indicating a warmer climate during that time period and a potential reason for the scarcity of phosphorite.
Article
Geochemistry & Geophysics
Vincent Busigny, Oanez Lebeau, Didier Jezeduel, Carine Chaduteau, Sean Crowe, Magali Ader
Summary: This study conducted high-precision Mo isotope research on hydrothermal metal sulfides from a porphyry copper deposit in Southwest China and found that different stages of mineralization have distinct Mo isotope compositions, providing valuable insights into the behavior of Mo isotopes in magmatic-hydrothermal systems.
Article
Geochemistry & Geophysics
Min Ji, Xiao-Ying Gao, Yong-Fei Zheng, Bing Gong
Summary: The study examines the anatectic mechanisms in the Himalayan orogen, finding that pressure and temperature control the reaction, while water content mainly affects the solid-phase composition. Dehydration and hydration melting likely occur at different depths in the crust. This research provides important insights into the melting processes in collisional orogens.