Article
Geochemistry & Geophysics
Melissa S. Schwab, Jorg D. Rickli, Robie W. Macdonald, H. Rodger Harvey, Negar Haghipour, Timothy Eglinton
Summary: The interactions between organic matter and its mineral carrier remain strong during sediment transport in the Western Arctic Ocean, indicating the potential for using organic-inorganic tracer measurements to understand sediment sources and physical and geochemical processes. The consistent information obtained from carbon and neodymium isotopic data suggests a new approach for identifying biogeochemical and ecological changes stemming from sea ice loss and increased fluvial inputs of organic carbon in this dynamic high latitude marginal sea.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Oceanography
Ronja Paffrath, Katharina Pahnke, Philipp Boening, Michiel Rutgers van der Loeff, Ole Valk, Sandra Gdaniec, Helene Planquette
Summary: In the central Arctic Ocean, dissolved rare earth element concentrations and the neodymium isotope compositions remain constant in the deep water column, indicating unique seawater-particle interactions. The consistent particulate rare earth element concentrations suggest that particle composition is the primary factor preventing certain elements from being released into the dissolved pool.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Geochemistry & Geophysics
Christina S. Larkin, Alexander M. Piotrowski, Ruth S. Hindshaw, Germain Bayon, Robert G. Hilton, J. Jotautas Baronas, Mathieu Dellinger, Ruixue Wang, Edward T. Tipper
Summary: The study shows that labile iron phases in riverine suspended particulate matter play a significant role in transporting rare earth elements and are derived from sedimentary rock erosion. Environmental changes in the Arctic, such as permafrost thaw, may impact the supply of reactive trace metals in the region.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Frerk Poppelmeier, Marcus Gutjahr, Patrick Blaser, Hartmut Schulz, Finn Suefke, Joerg Lippold
Summary: Research has shown that deep ocean carbon storage increased with limited variations in the past 100,000 years, with northern-sourced water dominating throughout. During Marine Isotope Stage 4, proportions of northern-sourced water even increased by approximately 15% in the Equatorial and Northeast Atlantic, questioning the idea that cold climates promote the expansion of southern-sourced water.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
Jochen Knies
Summary: This work reports on the coupling of dinitrogen fixation and denitrification in oxygen-deficient waters of the Arctic Ocean during the Paleogene. The coupling fertilized marine phytoplankton growth and favored organic carbon burial. The study also indicates a shift in the main source of biologically available nitrogen due to changing nutrient availability and suggests that the Arctic Ocean has been fully ventilated since the early Neogene.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Sophia K. V. Hines, Louise Bolge, Steven L. Goldstein, Christopher D. Charles, Ian R. Hall, Sidney R. Hemming
Summary: The study found that the circulation structure in the far South Atlantic underwent changes throughout the last glacial cycle, contradicting the common conception of the upper circulation cell in the Atlantic being shoaled at the Last Glacial Maximum. Despite little change in mid-depth ocean structure, greater stratification between mid-depth and abyssal sites developed, which may have contributed to glacial carbon storage in the deep ocean.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2021)
Article
Multidisciplinary Sciences
Joan De Vera, Priyanka Chandan, Paulina Pinedo-Gonzalez, Seth G. John, Sarah L. Jackson, Jay T. Cullen, Manuel Colombo, Kristin J. Orians, Bridget A. Bergquist
Summary: The study reveals that anthropogenic lead is widespread and dominant in the western Arctic Ocean, with significant contributions from historic aerosol lead deposited from Europe and Russia during the 20th century. The remobilization of this lead, especially in water layers with higher concentrations, highlights the impact of human activities and environmental changes on the Arctic. Detecting 20th century Eurasian lead in deep water also provides insights into ventilation ages and helps constrain sources of contaminants in Arctic seawater.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Oceanography
Emma J. Bullock, Lauren Kipp, Willard Moore, Kristina Brown, Paul J. Mann, Jorien E. Vonk, Nikita Zimov, Matthew A. Charette
Summary: This study quantifies the river radium inputs into the Arctic Ocean for the first time and improves the estimates for this region. Through lab experiments and data from major rivers around the world, it is found that rivers are an important source of radium to the Arctic Ocean. Understanding river radium inputs is crucial for studying changes in biogeochemically important element fluxes as climate change and Arctic warming continue.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Geography, Physical
Jose N. Perez-Asensio, Kazuyo Tachikawa, Laurence Vidal, Thibault de Garidel-Thoron, Corinne Sonzogni, Abel Guihou, Pierre Deschamps, Stephan J. Jorry, Min-Te Chen
Summary: This study reconstructs the spatial and temporal evolution of glacial carbon-rich deep waters in the southwest Indian Ocean over the past 630 kyr. The analysis of sediment samples reveals that orbital forcing, restricted air-sea exchange, and enhanced ocean stratification fostered higher carbon storage during periods of relatively lower eccentricity and obliquity.
GLOBAL AND PLANETARY CHANGE
(2023)
Article
Geography, Physical
Thomas John Williams, Ellen E. Martin, Elisabeth Sikes, Aidan Starr, Natalie E. Umling, Ryan Glaubke
Summary: The study presents multiproxy data for paleocirculation changes in the deep Indian sector of the Southern Ocean over the past 118,000 years. It reveals a tight coupling between circulation changes, Antarctic climate, and atmospheric CO2 concentrations, even during the initial stages of glacial inception. Cooling periods correspond to reductions in North Atlantic-sourced waters entrainment and slower bottom water flow speeds, linked to Southern hemisphere control on paleocirculation changes.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Oceanography
Bianca T. P. Liguori, Claudia Ehlert, Eva-Maria Noethig, Jan C. van Ooijen, Katharina Pahnke
Summary: In the ice-covered Central Arctic Ocean, diatom production is limited by light availability and nutrient supply, with higher production at the sea ice edge and over partially ice-free shelf areas. The Transpolar Drift transports terrestrial-derived material across the CAO, impacting the Si cycle. Si isotopes help understand the differences in biological production areas and the potential influence of the TPD.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Geochemistry & Geophysics
Paolo Montagna, Christophe Colin, Martin Frank, Tjordis Storling, Toste Tanhua, Micha J. A. Rijkenberg, Marco Taviani, Katrin Schroeder, Jacopo Chiggiato, Guohui Gao, Arnaud Dapoigny, Steven L. Goldstein
Summary: The isotopic composition of neodymium in seawater is an important tracer for investigating water mass provenance and past variations in ocean circulation. However, the available dataset for the Mediterranean Sea is limited, hindering our understanding of neodymium cycling in the basin. This study presents new neodymium isotopic data from 24 depth profiles in the Mediterranean Sea, providing insights into the relationship between dissolved neodymium isotopes and major water masses. The results suggest a zonal and depth gradient in neodymium isotopes, reflecting the basin's large-scale circulation.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Multidisciplinary Sciences
Ronja Paffrath, Georgi Laukert, Dorothea Bauch, Michiel Rutgers van der Loeff, Katharina Pahnke
Summary: By utilizing dissolved neodymium isotopes and rare earth element concentrations, this study identifies the contributions of the Lena and Yenisei/Ob rivers to the Transpolar Drift, as well as their vertical and lateral separation within the current.
SCIENTIFIC REPORTS
(2021)
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
Oceanography
Cecilia Bertosio, Christine Provost, Marylou Athanase, Nathalie Sennechael, Gilles Garric, Jean-Michel Lellouche, Clement Bricaud, Joo-Hong Kim, Kyoung-Ho Cho, Taewook Park
Summary: This study examined the changes in Arctic freshwater distribution and circulation using model simulations and observations. The findings suggest that the Beaufort Gyre serves as the major reservoir of freshwater in the Arctic Ocean, with a northward extension in recent years. Changes in freshwater content were also observed in other regions, which subsequently affected the freshwater export pattern from the Arctic Ocean.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Environmental Sciences
Wangwang Ye, Yuhong Li, Jianwen Wen, Jiexia Zhang, Natalia Shakhova, Jian Liu, Man Wu, Igor Semiletov, Liyang Zhan
Summary: Increasing temperatures in the Arctic Ocean are causing changes in methane cycles, with methane being stored and transported from the Chukchi Sea to the central Arctic. The concentration of methane is increasing in the Upper Halocline, and its distribution is expanding due to intensified Pacific water inflow. Methane is also found in the Polar Mixed Layer and below-ice seawater in the basins, suggesting the influence of sea ice cycles and sediment-origin methane. The Arctic Ocean currently has minor atmospheric methane emissions, but the increasing methane excess and decreasing sea ice cover may lead to future emissions.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Microbiology
Alexander S. Savvichev, Igor I. Rusanov, Vitaly V. Kadnikov, Alexey V. Beletsky, Elena E. Zakcharova, Olga S. Samylina, Pavel A. Sigalevich, Igor P. Semiletov, Nikolai V. Ravin, Nikolay V. Pimenov
Summary: Bottom sediments at methane discharge sites of the Laptev Sea shelf were investigated. The rates of microbial methanogenesis and methane oxidation were measured, and the communities responsible for these processes were analyzed. Methane content in the sediments varied from 0.9 to 37 mu mol CH4 dm(-3). Methane carbon isotopic composition (delta C-13-CH4) varied from -98.9 to -77.6 parts per thousand, indicating its biogenic origin. The rates of hydrogenotrophic methanogenesis were low (0.4-5.0 nmol dm(-3) day(-1)). Methane oxidation rates varied from 0.4 to 1.2 mu mol dm(-3) day(-1) at the seep stations. Four lineages of anaerobic methanotrophic archaea (ANME) (1, 2a-2b, 2c, and 3) were found in the deeper sediments at the seep stations along with sulfate-reducing Desulfobacteriota. The ANME-2a-2b clade was predominant among ANME. Aerobic ammonium-oxidizing Crenarchaeota (family Nitrosopumilaceae) predominated in the upper sediments along with heterotrophic Actinobacteriota and Bacteroidota, and methaneotrophs of the classes Alphaproteobacteria (Methyloceanibacter) and Gammaproteobacteria (families Methylophilaceae and Methylomonadaceae). Members of the genera Sulfurovum and Sulfurimonas occurred in the sediments of the seep stations. Methanotrophs of the classes Alphaproteobacteria (Methyloceanibacter) and Gammaproteobacteria (families Methylophilaceae and Methylomonadaceae) occurred in the sediments of all stations. The microbial community composition was similar to that of methane seep sediments from geographically remote areas of the global ocean.
Article
Engineering, Civil
Irina I. Pipko, Svetlana P. Pugach, Kseniia P. Shcherbakova, Igor P. Semiletov
Summary: Rivers play a crucial role in the carbon cycle in the Arctic. The study investigates the variations in dissolved organic carbon (DOC) concentrations and DOM composition in Siberian rivers and evaluates their relationship with carbonate chemistry. The findings provide valuable information for understanding the impact of climate change on biogeochemical cycles in the Arctic.
JOURNAL OF HYDROLOGY
(2023)
Article
Marine & Freshwater Biology
V. V. Malakhov, N. N. Rimskaya-Korsakova, A. A. Osadchiev, I. P. Semiletov, N. P. Karaseva, M. M. Gantsevich
Summary: This paper describes the discovery of new occurrences of pogonophores Siboglinum sp. and Nereilinum sp. from the St. Anna Trough in the Kara Sea. Previously, pogonophores were reported in the southern part of the Kara Sea. The presence of pogonophores in the St. Anna Trough indicates the presence of a methane flux associated with the inflow of Atlantic water, causing the dissociation of seafloor gas hydrates. The possible role of Arctic warming is apparent in both processes.
RUSSIAN JOURNAL OF MARINE BIOLOGY
(2023)
Review
Chemistry, Analytical
Artem A. Krylov, Roman A. Ananiev, Denis V. Chernykh, Dmitry A. Alekseev, Ermolay I. Balikhin, Nikolay N. Dmitrevsky, Mikhail A. Novikov, Elena A. Radiuk, Anna V. Domaniuk, Sergey A. Kovachev, Georgy K. Timashkevich, Vladimir N. Ivanov, Dmitry A. Ilinsky, Oleg Yu. Ganzha, Alexey Yu. Gunar, Pavel Yu. Pushkarev, Andrey V. Koshurnikov, Leopold I. Lobkovsky, Igor P. Semiletov
Summary: This article discusses the use of marine geophysical equipment in the Russian sector of the Arctic for detecting and studying areas with increased natural gas saturation. The equipment used includes high-frequency echo sounders, sub-bottom profilers, seismographs, and seismoacoustic profiling and electrical exploration equipment. The results obtained in the Laptev Sea show that these geophysical methods are effective in detecting and monitoring underwater gas release and studying the geological causes of gas emission.
Article
Environmental Sciences
Birgit Wild, Nicholas E. Ray, Celine Lett, Amelia Jane Davies, Elena Kirillova, Henry Holmstrand, Elizaveta Klevantceva, Alexander Osadchiev, Ivan Gangnus, Evgeniy Yakushev, Denis Kosmach, Oleg Dudarev, Orjan Gustafsson, Igor Semiletov, Volker Bruchert
Summary: This study focuses on the data-poor Arctic Ocean shelves north of Siberia, which are experiencing rapid warming and increasing nitrogen input due to permafrost thaw. The research finds that nitrogen concentrations in water column and sediments are elevated near large river mouths. N2O concentrations are weakly correlated with dissolved nitrogen and turbidity, indicating the influence of particulate matter from rivers and coastal erosion. The study suggests that N2O dynamics in the region are influenced by water column N2O consumption and production.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Environmental Sciences
Lina Xie, Evgeniy Yakushev, Igor Semiletov, Andrey Grinko, Ivan Gangnus, Anfisa Berezina, Alexander Osadchiev, Igor Zhdanov, Alexander Polukhin, Julia Moiseeva, Darya Purgina, Irina Pipko, Svetlana Pugach, Oleg Dudarev, Zhenming Ge
Summary: Based on data collected from annual transects conducted from 2015-2020, this study explores the impact of River Lena plume dispersion on the hydrophysical and biogeochemical structure of the southeastern Laptev Sea. The results indicate that the spreading patterns of the plume play a crucial role in regulating local processes and show significant variation on both seasonal and interannual scales.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Engineering, Geological
Elena V. Gershelis, Alexey S. Ruban, Denis V. Chernykh, Natalina A. Poltavskaya, Igor P. Semiletov
Summary: Ongoing global warming leads to the accelerated release of organic carbon from permafrost to the Arctic shelf waters, which can be accumulated in sediments and undergo degradation and remineralization, resulting in significant environmental consequences. This study aims to assess the sources and degradation degree of terrigenous organic matter in the surface sediments of the Eastern Arctic seas. The hydrogen index values in modern marine sediments on the Eastern Arctic shelf are associated with the contribution of biolabile terrestrial organic matter, while other Arctic waters show a growing contribution of autochthonous organic matter. Moreover, there are significant deviations from the linear dependence in the d13C and HI/OI correlation, indicating a different geochemical regime in the Eastern Arctic seas.
BULLETIN OF THE TOMSK POLYTECHNIC UNIVERSITY-GEO ASSETS ENGINEERING
(2023)
Article
Geosciences, Multidisciplinary
Sergey Nikiforov, Roman Ananiev, Martin Jakobsson, Evgeny Moroz, Sergey Sokolov, Nikolay Sorokhtin, Nikolay Dmitrevsky, Elena Sukhikh, Igor Chickiryov, Yulia Zarayskaya, Anatoly Razumovskiy, Igor Semiletov
Summary: Based on data acquired during cruises of the RV Akademik Nikolaj Strakhov in 2018-2021, the distribution of submarine glacial landforms in the central part of the Pechora shelf area is revealed. The extent of the ice sheet during the Last Glacial Maximum (LGM) is proposed based on moraines and the distribution of glacial lineations. The mapped glacial landforms indicate the presence of an ice sheet in the area, while the Pechora basin was characterized by a cryogenic subaerial landscape.
Article
Geosciences, Multidisciplinary
Nickolay Sorokhtin, Nikolay Kozlov, Igor Semiletov, Leopold Lobkovsky, Sergey Nikiforov, Dmitry Alekseev, Roman Ananiev
Summary: Studies have shown that the Keivy domain of the Baltic Shield was tectonically overlapped by adjacent microcontinents during regional collision processes in the Late Archean, resulting in the submergence of the continental crust and the formation of a median massif. The Keivy massif entered the cratonization regime and experienced intense denudation processes and sedimentary cover accumulation. These processes occurred during the formation of the first supercontinent and the Early Precambrian glaciation, leading to the accumulation of extensive stratiform deposits of alumina raw materials within the Keivy median massif.
Article
Geosciences, Multidisciplinary
Dmitry A. Alekseev, Andrey V. Koshurnikov, Alexey Yu. Gunar, Ermolay I. Balikhin, Igor P. Semiletov, Natalia E. Shakhova, Nikolay A. Palshin, Leopold I. Lobkovsky
Summary: By using 1D numerical modeling and field data, the capabilities of the time-domain electromagnetic method (TDEM) for subsea permafrost mapping are analyzed. The effect of the background resistivity structure on the accuracy of inversion models is studied for settings typical for the East Siberian Arctic Shelf. Synthetic response analysis and regularized inversion are used to assess sensitivity and uncertainties in the geometry and resistivity of the reconstructed permafrost layer, confirming the efficacy of TDEM technology for subsea permafrost imaging.
Article
Geosciences, Multidisciplinary
Leopold I. Lobkovsky, Alexey A. Baranov, Igor A. Garagash, Mukamay M. Ramazanov, Irina S. Vladimirova, Yurii V. Gabsatarov, Dmitry A. Alekseev, Igor P. Semiletov
Summary: A correlation exists between changes in seismic activity and atmospheric methane concentration over the past 40 years. Deformation waves generated by large earthquakes near polar regions result in methane emission and glacier collapse. These waves can travel distances of 3000-4000 km and impact the Arctic and Antarctica several decades after the earthquakes occur.
Article
Multidisciplinary Sciences
Antao Xu, Ed Hathorne, Georgi Laukert, Martin Frank
Summary: The isotopic signatures of Nd and Hf in the Amazon River estuary are influenced by the nearby Para River. The Para River supplies dissolved trace metals to the estuary and ocean. It is found that the changes in Nd and Hf concentrations across the estuary are due to the admixture of high-concentration Nd and Hf from the Para River.
NATURE COMMUNICATIONS
(2023)
Article
Environmental Sciences
Irina Pipko, Svetlana Pugach, Igor Semiletov, Oleg Konstantinov
Summary: This study assesses the dynamics of the seawater carbonate system, air-sea CO2 fluxes, and the corrosive waters in the East Siberian Sea. The eastern ESS is the main source of corrosive waters into the deep basin. This can potentially impact the ocean water ecosystem.
Article
Geosciences, Multidisciplinary
Denis Chernykh, Natalia Shakhova, Vladimir Yusupov, Elena Gershelis, Boris Morgunov, Igor Semiletov
Summary: This paper presents an improved approach to study seafloor seepages in the Arctic coastal zone using a calibrated echosounder. The study recorded periods of increased activity of rising gas bubbles from the seabed in the East Siberian Arctic Shelf. The quantitative estimates of methane flux at the water column levels suggest that the CH4 transported by rising bubbles can be emitted into the atmosphere through ice features in the water/sea ice interface.
Article
Geochemistry & Geophysics
Xinze Lu, Geoffrey J. Gilleaudeau, Brian Kendall
Summary: The Late Ordovician mass extinction is the first major extinction event in the Phanerozoic, but the reasons for the decline in global biodiversity before the extinction are not well understood.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)
Article
Geochemistry & Geophysics
Junyao Kang, Daniel D. Gregory, Benjamin Gill, Shiqiang Huang, Changxin Lai, Zhaoshan Chang, Huan Cui, Ivan Belousov, Shuhai Xiao
Summary: Sedimentary pyrite is an important geological archive, but it can be altered by diagenetic and hydrothermal processes. This study successfully trained machine learning algorithms to distinguish pyrite origins using trace element data. The approach was validated and applied to identify the origins of pyrite in two sedimentary successions in South China.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)