Article
Multidisciplinary Sciences
Sara Berglund, Kristofer Doos, Sjoerd Groeskamp, Trevor J. McDougall
Summary: The Atlantic Meridional Overturning Circulation (AMOC) is crucial for regulating Earth's climate, and a new feature related to the northward flowing component of AMOC within the North Atlantic Subtropical Gyre has been identified. It has been found that 70% of the northward flowing water in AMOC circulates within the Gyre before continuing its northward path. This circulation is important for increasing density and depth, which in turn affect the strength and variability of AMOC and heat transport towards the north.
NATURE COMMUNICATIONS
(2022)
Article
Multidisciplinary Sciences
Alan Condron, Jenna C. Hill
Summary: High-resolution seafloor mapping reveals evidence of massive icebergs drifting south along the eastern United States, with sediment core analysis and numerical modeling providing insights into iceberg transport mechanisms and past climate changes.
NATURE COMMUNICATIONS
(2021)
Article
Geosciences, Multidisciplinary
F. E. Leonelli, M. Bellacicco, J. Pitarch, E. Organelli, B. Buongiorno Nardelli, V de Toma, C. Cammarota, S. Marullo, R. Santoleri
Summary: The North Atlantic Subtropical Gyre (NASTG) has experienced the fastest expansion of oligotrophic waters worldwide in response to ocean warming. The study demonstrates that ultra-oligotrophic waters are spatially expanding and increasing in frequency in the NASTG, shifting it to a dominant quasi-permanent ultra-oligotrophic condition, confirming the ongoing ocean desertification.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geology
J. L. Bernal-Wormull, A. Moreno, C. Perez-Mejias, M. Bartolome, A. Aranburu, M. Arriolabengoa, E. Iriarte, I. Cacho, C. Spoetl, R. L. Edwards, H. Cheng
Summary: The study indicates that major disruptions in the North Atlantic circulation during the last deglaciation triggered climate feedbacks that influenced the course of Termination I. By analyzing the stalagmite record from Ostolo cave in the northern Iberian Peninsula, researchers gained important insights into the structure of the last deglaciation in the Northern Hemisphere.
Article
Multidisciplinary Sciences
Bolan Gan, Jingjie Yu, Lixin Wu, Gokhan Danabasoglu, R. Justin Small, Allison H. Baker, Fan Jia, Zhao Jing, Xiaohui Ma, Haiyuan Yang, Zhaohui Chen
Summary: The formation of subtropical mode water in the North Atlantic is determined by frontal-scale ocean-to-atmosphere feedback. Suppressing this feedback reduces STMW formation by almost half, as it enlarges STMW outcropping by deepening the mixed layer due to excessive latent heat loss and increases air-sea humidity contrast. These findings highlight the importance of resolving FOA feedback to improve the representation of STMWs and their associated heat and carbon uptakes in earth system models.
NATIONAL SCIENCE REVIEW
(2023)
Article
Multidisciplinary Sciences
F. Li, M. S. Lozier, S. Bacon, A. S. Bower, S. A. Cunningham, M. F. de Jong, B. DeYoung, N. Fraser, N. Fried, G. Han, N. P. Holliday, J. Holte, L. Houpert, M. E. Inall, W. E. Johns, S. Jones, C. Johnson, J. Karstensen, I. A. Le Bras, P. Lherminier, X. Lin, H. Mercier, M. Oltmanns, A. Pacini, T. Petit, R. S. Pickart, D. Rayner, F. Straneo, V Thierry, M. Visbeck, I Yashayaev, C. Zhou
Summary: The study using trans-basin observation data found that deep water formation in the subpolar North Atlantic has minimal impact on the overturning circulation, contrary to previous modeling studies. The authors revealed that changes in western boundary currents do not significantly influence the variability of the subpolar overturning circulation over observational time scales.
NATURE COMMUNICATIONS
(2021)
Article
Geochemistry & Geophysics
R. Shuttleworth, H. C. Bostock, T. B. Chalk, E. Calvo, S. L. Jaccard, C. Pelejero, A. Martinez-Garcia, G. L. Foster
Summary: Research indicates that there were two transient intervals of pronounced atmospheric CO2 rise during the last deglaciation, possibly due to deep ocean carbon release from the Southern Ocean and a decline in global efficiency of the biological carbon pump. The Sub-Antarctic region experienced upwelling of carbon-rich water during Heinrich Stadial 1, contributing to the initial increase in atmospheric CO2, but there was no significant outgassing of deep ocean carbon from this region during other periods.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Limnology
Zhongwei Yuan, Eric P. Achterberg, Anja Engel, Zuozhu Wen, Linbin Zhou, Xunchi Zhu, Minhan Dai, Thomas J. Browning
Summary: Atmospheric aerosol deposition is an important nutrient source for primary production in the low latitude oligotrophic ocean. However, the response of phytoplankton to aerosol deposition events, in terms of magnitude and community composition, is not well understood. In this study, we investigated this using field and satellite observations in the subtropical North Atlantic. We found that wet deposition events led to a doubling of chlorophyll a and a shift in dominance from Synechococcus to Prochlorococcus, suggesting the importance of aerosol-derived nitrogen in alleviating nutrient limitation and driving rapid phytoplankton response.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Review
Multidisciplinary Sciences
Harry L. Bryden
Summary: Continuous observations of ocean circulation at 26 degrees N in the subtropical Atlantic Ocean since April 2004 revealed the complexity of the Atlantic Meridional overturning circulation (AMOC) with contributions from wind-driven and buoyancy-driven components. In 2009, there was a sharp reduction in the southward flow of deep waters below 1100 m depth, indicating variability in the buoyancy-driven circulation. Over the 14-year observational period from 2004 to 2018, the AMOC declined by 2.4 Sv.
PROCEEDINGS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Chengfeng Le, Yihui Chen, John C. Lehrter, Chuanmin Hu, Heather Bouman, Wei-Jun Cai, Lin Qi
Summary: By analyzing multi-decadal atmospheric and oceanic data over the North Atlantic Ocean, the researchers found that winter Greenland blocking events are connected to variability in the subtropical spring blooms. The blocking leads to a shift of the jet stream, higher surface westerly winds, and deeper vertical mixing in the subtropical North Atlantic, ultimately promoting larger spring blooms.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Oceanography
Tiago Carrilho Bilo, William E. Johns, Jian Zhao
Summary: This study investigates the dynamics of the deep recirculation offshore of the deep western boundary current in the upper North Atlantic Deep Water layer using two different eddy-resolving numerical simulations. The analysis reveals that despite some differences in recirculation cells, both simulations predict the DWBC flowing southward along the continental slope, while other cells recirculate waters northward in the interior along the DWBC path. Eddies responsible for forcing the recirculation have dominant time scales between 100 and 300 days, which correspond to the primary observed variability scales of the DWBC transport at 26.5 degrees N.
JOURNAL OF PHYSICAL OCEANOGRAPHY
(2021)
Article
Multidisciplinary Sciences
Junjie Wu, Gesine Mollenhauer, Ruediger Stein, Peter Kohler, Jens Hefter, Kirsten Fahl, Hendrik Grotheer, Bingbing Wei, Seung-Il Nam
Summary: This study provides evidence for substantial remobilization of ancient terrestrial carbon in the Canadian Arctic during the deglaciation. Physical erosion of bedrock during glacier retreat has mobilized petrogenic carbon, while coastal erosion during meltwater pulses has remobilized pre-aged carbon from permafrost. These processes have contributed 12 ppm to the rise of CO2 during deglaciation, suggesting a positive climate feedback of ice-sheet retreat and underscoring the impact of cryospheric change on the carbon cycle.
NATURE COMMUNICATIONS
(2022)
Article
Meteorology & Atmospheric Sciences
Hyo-Jeong Kim, Soon-Il An, Jae-Heung Park, Mi-Kyung Sung, Daehyun Kim, Yeonju Choi, Jin-Soo Kim
Summary: Accurate representation of the Atlantic Meridional Overturning Circulation (AMOC) in global climate models is crucial for reliable future climate predictions and projections. In this study, the researchers analyzed low-frequency variability of the AMOC driven by the North Atlantic Oscillation (NAO) using 42 coupled atmosphere-ocean global climate models. The results showed that the influence of the simulated NAO on the AMOC differs significantly between the models due to the diverse oceanic mean state, especially over the subpolar North Atlantic (SPNA), where deep water formation of the AMOC occurs.
NPJ CLIMATE AND ATMOSPHERIC SCIENCE
(2023)
Article
Environmental Sciences
Imants G. Priede, Frank E. Muller-Karger, Tomasz Niedzielski, Andrey V. Gebruk, Daniel O. B. Jones, Ana Colaco
Summary: This study examines the main drivers that may increase biomass and biodiversity of non-chemosynthetic benthic megafauna in the lower bathyal of the Mid-Atlantic Ridge. The findings suggest that primary production in surface waters is not significantly different between the MAR and abyssal regions, but the quantity of organic matter reaching the sea floor is higher on the MAR due to shorter vertical transport distance. Depth variation, substrate heterogeneity, and the presence of a biogeographic overlap zone also contribute to increased biodiversity. However, more intensive biological sampling is urgently needed in the proposed mining areas south of the Azores.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Oceanography
Siren Ruhs, Eric C. J. Oliver, Arne Biastoch, Claus W. Boning, Michael Dowd, Klaus Getzlaff, Torge Martin, Paul G. Myers
Summary: The study evaluates a recent event and the temporal evolution of spatial deep convection patterns in the subpolar North Atlantic since the mid-twentieth century, revealing large interannual variability in the contributions of different regions to total deep convection volume. Particularly, in 2015-2018, deep convection occurred with an unprecedented large relative contribution from the eastern subpolar gyre.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Geochemistry & Geophysics
David J. Janssen, Delphine Gilliard, Joerg Rickli, Philipp Nasemann, Andrea Koschinsky, Christel S. Hassler, Andrew R. Bowie, Michael J. Ellwood, Charlotte Kleint, Samuel L. Jaccard
Summary: Research has focused on the cycling of chromium in the ocean, specifically the influence of deep waters and sediment on the distribution of chromium. The study also examines the potential impact of hydrothermal vents on chromium cycling. The findings suggest that changes in other factors, such as widespread anoxia, may contribute to variations in chromium isotope composition in the paleorecord.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Environmental Sciences
F. Fripiat, D. M. Sigman, A. Martinez-Garcia, D. Marconi, X. E. Ai, A. Auderset, S. E. Fawcett, S. Moretti, A. S. Studer, G. H. Haug
Summary: This study demonstrates that in addition to the input/output budget of fixed nitrogen, the isotopic discrimination of nitrate assimilation in the Southern Ocean plays a role in setting the d(15)N of deep ocean nitrate and global mean ocean nitrate. The impact of the Southern Ocean on deep and mean ocean nitrate d(15)N depends on the degree of nitrate consumption in the surface waters and the proportion of water that enters the pycnocline from the Southern Ocean surface. This research has important implications for paleoceanographic N isotope records.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Multidisciplinary Sciences
Jesse R. Farmer, Tamara Pico, Ona M. Underwood, Rebecca Cleveland Stout, Julie Granger, Thomas M. Cronin, Francois Fripiat, Alfredo Martinez-Garcia, Gerald H. Haug, Daniel M. Sigman
Summary: The growth and decay of continental ice sheets can be reconstructed through the history of global sea level. By reconstructing the flooding history of the Bering Strait, it is found that sea level estimates before the Last Glacial Maximum (LGM) vary greatly. This finding suggests that the relationship between global ice volume and climate during the last ice age was not linearly coupled.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Multidisciplinary Sciences
Robin van der Ploeg, Margot J. Cramwinckel, Ilja J. Kocken, Thomas J. Leutert, Steven M. Bohaty, Chris D. Fokkema, Pincelli M. Hull, A. Nele Meckler, Jack J. Middelburg, Inigo A. Muller, Donald E. Penman, Francien Peterse, Gert-Jan Reichart, Philip F. Sexton, Maximilian Vahlenkamp, David De Vleeschouwer, Paul A. Wilson, Martin Ziegler, Appy Sluijs
Summary: The Middle Eocene Climatic Optimum (MECO) experienced a transient warming of 3 degrees Celsius, leading to increased salinity in the North Atlantic subtropical gyre and potentially a poleward expansion of its northern boundary.
Article
Multidisciplinary Sciences
Jingyu Liu, Yipeng Wang, Samuel L. Jaccard, Nan Wang, Xun Gong, Nianqiao Fang, Rui Bao
Summary: The poorly ventilated conditions in the North Atlantic were linked to enhanced pre-aged organic carbon input. The old organic carbon came mainly from terrigenous sources and was exported to the North Atlantic by ice-rafting. Ocean ventilation plays a crucial role in regulating carbon sequestration and release, which has significant implications for climate evolution.
NATURE COMMUNICATIONS
(2023)
Article
Oceanography
Tanya A. Marshall, Daniel M. Sigman, Lisa M. Beal, Alan Foreman, Alfredo Martinez-Garcia, Stephane Blain, Ethan Campbell, Francois Fripiat, Robyn Granger, Eesaa Harris, Gerald H. Haug, Dario Marconi, Sergey Oleynik, Patrick A. Rafter, Raymond Roman, Kolisa Sinyanya, Sandi M. Smart, Sarah E. Fawcett
Summary: This study used nitrate isotopes to trace water mass circulation and nitrogen cycling in the Agulhas Current and adjacent waters, revealing the processes occurring remotely and the biogeochemical differences between different water sources. It estimated the local N2 fixation rate and carbon export rate using a one-box model.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Environmental Sciences
Jens Zinke, Neal E. Cantin, Kristine L. DeLong, Kylie Palmer, Arnoud Boom, Irka Hajdas, Nicolas Duprey, Alfredo Martinez-Garcia, Neil L. Rose, Sarah L. Roberts, Handong Yang, Lucy R. Roberts, Andrew B. Cundy, Pawel Gaca, James Andy Milton, Grace Frank, Adam Cox, Sue Sampson, Genevieve Tyrrell, Molly Agg, Simon D. Turner
Summary: This study proposes corals as a unique natural archive for marking the Anthropocene epoch and suggests North Flinders Reef in the Coral Sea as a suitable candidate site. By analyzing the geochemical records of corals, the study identifies clear evidence of human impacts.
ANTHROPOCENE REVIEW
(2023)
Article
Environmental Sciences
Kristine L. DeLong, Kylie Palmer, Amy J. Wagner, Mudith M. Weerabaddana, Niall Slowey, Achim D. Herrmann, Nicolas Duprey, Alfredo Martinez-Garcia, Jonathan Jung, Irka Hajdas, Neil L. Rose, Sarah L. Roberts, Lucy R. Roberts, Andrew B. Cundy, Pawel Gaca, J. Andrew Milton, Handong Yang, Simon D. Turner, Chun-Yuan Huang, Chuan-Chou Shen, Jens Zinke
Summary: The West Flower Garden Bank in the Gulf of Mexico is a potential candidate site for studying the Anthropocene epoch. Coral samples taken from this location show clear markers of human impacts, such as increases in atmospheric nuclear bomb testing by-products and declines in coral delta C-13 due to the burning of fossil fuels.
ANTHROPOCENE REVIEW
(2023)
Article
Biology
Jennifer N. Leichliter, Tina Luedecke, Alan D. Foreman, Nicolas Bourgon, Nicolas N. Duprey, Hubert Vonhof, Viengkeo Souksavatdy, Anne-Marie Bacon, Daniel M. Sigman, Thomas Tuetken, Alfredo Martinez-Garcia
Summary: The nitrogen isotope composition of organic matter preserved in mammalian tooth enamel can provide valuable information about diet and trophic level, even in fossil specimens. This method can be used to reconstruct major dietary transitions in ancient vertebrate lineages.
COMMUNICATIONS BIOLOGY
(2023)
Article
Multidisciplinary Sciences
Anya V. Hess, Alexandra Auderset, Yair Rosenthal, Kenneth G. Miller, Xiaoli Zhou, Daniel M. Sigman, Alfredo Martinez-Garcia
Summary: The oxygen content of the oceans has declined due to climate change, especially in oxygen-deficient zones. Climate warming simulations predict the expansion of these zones until at least 2100. The response of ocean oxygenation on longer timescales remains uncertain.
Article
Geosciences, Multidisciplinary
Mengli Cao, Jens Hefter, Ralf Tiedemann, Lester Lembke-Jene, Vera D. Meyer, Gesine Mollenhauer
Summary: Arctic warming and sea level change can lead to permafrost thaw and mobilization. This study uses sedimentary records from the Amur and Yukon rivers to analyze changes in vegetation associated with permafrost mobilization. The results show that vegetation change and wetland expansion started earlier in the Yukon basin compared to the Okhotsk Sea. The permafrost in the Amur basin began to remobilize during the Pre-Boreal period. The study also finds that lignin and lipid biomarkers are transported to the ocean through the same pathway under conditions of rapid sea level rise and shelf flooding.
CLIMATE OF THE PAST
(2023)