Article
Environmental Sciences
Tim Rixen, Niko Lahajnar, Tarron Lamont, Rolf Koppelmann, Bettina Martin, Justus E. E. van Beusekom, Claire Siddiqui, Keshnee Pillay, Luisa Meiritz
Summary: The study shows that a topographically steered nutrient trapping zone develops during the main upwelling season in the southern Benguela Upwelling System, enhancing productivity but potentially decreasing oxygen concentrations. At the end of the upwelling season, the front separating the trapped and open shelf waters weakens or collapses due to upwelling cessation and changing current regimes.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Environmental Sciences
Jennifer M. Jackson, Sophia Johannessen, Justin Del Bel Belluz, Brian P. Hunt, Charles G. Hannah
Summary: A subsurface oxygen minimum layer was identified and characterized in Rivers Inlet, influenced by the cessation of winter storms, remineralization of organic matter, and deep-water renewal. The strength and persistence of the OML vary interannually due to hemispheric-scale winds and primary production, with hypoxic conditions in some years impacting the local marine ecosystem. Changes in downwelling, upwelling, or primary production could affect the OML in the future.
ESTUARIES AND COASTS
(2022)
Article
Geochemistry & Geophysics
Frederik Gaeng, Philipp Boening, Volker Bruchert, Niko Lahajnar, Katharina Pahnke
Summary: This study investigates the source and accumulation mechanisms of trace elements in sediments of the Namibian shelf and continental shelf anoxic zones. The results show that Zr is a sensitive tracer of dust input and/or sediment reworking, and the combination of Zr, organic matter, and P enrichments can differentiate different sediment environments. Uranium is mainly incorporated into apatite under oscillating oxic to sulfidic conditions, and its use as an indicator of suboxic conditions is questionable. The lithogenic fractions of Ba and Ni are found to be elevated, and their authigenic contents can be calculated to obtain more realistic values. Furthermore, the increase in the authigenic Ni/TOC ratio with sediment depth suggests better preservation and retention of Ni, supporting its use as a productivity indicator for upwelling sediments.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Marine & Freshwater Biology
Ryan K. Walter, Stephen A. Huie, Jon Christian P. Abraham, Alexis Pasulka, Kristen A. Davis, Thomas P. Connolly, Piero L. F. Mazzini, Ian Robbins
Summary: Declining dissolved oxygen (DO) in nearshore ecosystems is a growing concern. This study reveals the dynamics and hypoxia risk in this highly variable environment. The study finds that nearshore DO is influenced by low-frequency synoptic variability, with higher variance near the surface and inside the bay. Two nearshore hypoxic regimes are identified, one driven by advection and exchange of low DO waters from the shelf during strong upwelling, and the other driven by localized respiration and stratification inside the bay during weaker upwelling.
ESTUARINE COASTAL AND SHELF SCIENCE
(2022)
Article
Environmental Sciences
G. V. M. Gupta, R. Jyothibabu, Ch Ramu, A. Yudhistir Reddy, K. K. Balachandran, V Sudheesh, Sanjeev Kumar, N. V. H. K. Chari, Kausar F. Bepari, Prachi H. Marathe, B. Bikram Reddy, Anil Kumar Vijayan
Summary: This study reveals for the first time that the world's largest hypoxic-anoxic zone along the west coast of India is formed through a natural process, with the extent and persistence of coastal oxygen deficiency depending on the degree of deoxygenation of source waters for the upwelling, confined to the central shelf region.
ENVIRONMENTAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Praxedes Munoz, Alexis Castillo, Jorge Valdes, Boris Dewitte
Summary: This study investigates the temporal variability of bottom oxygen conditions along the Chilean continental margin in the last 2000 years, revealing a close relationship between the upper part of the OMZ and climatic oscillations. The results show a weakening trend in the upper boundary of the OMZ in recent decades, which is interpreted as a cumulative effect of ventilation processes at different time scales.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Christian Furbo Reeder, Damian L. Arevalo-Martinez, Joan A. Carreres-Calabuig, Tina Sanders, Nicole R. Posth, Carolin Regina Loscher
Summary: This study provides a detailed analysis of diazotrophic diversity in the North BUS OMZ and the Angola tropical zone (ATZ), revealing the presence of various diazotrophs in the OMZ but no active N-2 fixation. The results show regional variations in the role and diversity of diazotrophs in OMZs, which are crucial for understanding the nitrogen cycle in OMZ waters and predicting the future development of OMZ biogeochemistry in a changing ocean.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Anja Engel, Carolina Cisternas-Novoa, Helena Hauss, Rainer Kiko, Frederic A. C. Le Moigne
Summary: This study provides evidence of hypoxia-tolerant zooplankton feeding on sinking particles in the extensive Oxygen Minimum Zone (OMZ) off Peru, and shows significant control of carbon export by these organisms. These findings challenge the assumption of consistently efficient biological carbon pump in OMZs and highlight the importance of considering mesopelagic organisms in studying oceanic carbon sequestration.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Article
Geosciences, Multidisciplinary
Takaaki K. Watanabe, Tsuyoshi Watanabe, Miriam Pfeiffer, Hsun-Ming Hu, Chuan-Chou Shen, Atsuko Yamazaki
Summary: Research shows that the intensity of upwelling in the Arabian Sea has been stable over the past millennium but is currently declining rapidly, indicating that anthropogenic factors may be causing its weakening.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Sara Zaferani, Harald Biester
Summary: Understanding marine mercury biogeochemistry is crucial for human health, as consumption of mercury-enriched ocean fish is a major pathway of mercury uptake. Research on mercury accumulation in ocean sediments is still rare, but findings show that in upwelling areas, mercury accumulation rates are significantly higher, indicating effective atmospheric mercury input through scavenging by organic particles.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Elisa Lovecchio, Stephanie Henson, Filipa Carvalho, Nathan Briggs
Summary: This study investigates the variability and drivers of low-oxygen events in the offshore northern Benguela Upwelling System (BenUS) using high-resolution glider data. The results show that oxygen concentrations are determined by the alternation of low-oxygen Angola-derived water and oxygenated water from the south. Hypoxic events are more persistent at certain depths and more sporadic at shallower depths. The findings emphasize the need for long-term and high-resolution measurements and studies focusing on future changes in both tropical oxygen levels and lateral fluxes in this region.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Microbiology
Aurele Vuillemin
Summary: Productive oxygen minimum zones are regions dominated by heterotrophic denitrification fueled by sinking organic matter, which result in the loss and overall geochemical deficit in inorganic fixed nitrogen in the water column, thereby impacting global climate in terms of nutrient equilibrium and greenhouse gases.
FRONTIERS IN MICROBIOLOGY
(2023)
Article
Marine & Freshwater Biology
Paula M. Ruz-Moreno, Pamela Hidalgo, Marcela Cornejo-D'Ottone, Pamela Fierro-Gonzalez, Javier Babbonney, Kam W. Tang
Summary: Expansion and shallowing of the Oxygen Minimum Zone (OMZ) in coastal upwelling systems can result in dire consequences for ecosystem structure and productivity. A study on the copepod Acartia tonsa collected in northern Chile revealed that hypoxia significantly affected its survival and vital rates.
JOURNAL OF SEA RESEARCH
(2023)
Article
Ecology
Mariana Hill Cruz, Iris Kriest, Yonss Saranga Jose, Rainer Kiko, Helena Hauss, Andreas Oschlies
Summary: The study investigates the potential effects of variability in small pelagic fish populations on lower trophic levels using a coupled physical-biogeochemical model. The results indicate that large zooplankton is the main driver of the community response.
Article
Geosciences, Multidisciplinary
Yuntao Zhou, Hongjing Gong, Feng Zhou
Summary: Global oceanic dissolved oxygen is decreasing and oxygen minimum zones are expanding due to climate change. This research estimates the annual global and regional areas of these zones and finds significant expansions since the late 2000s, particularly in the North Pacific.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Anjali Kumar, Timothy J. Divoll, Priya M. Ganguli, Florencia A. Trama, Carl H. Lamborg
ENVIRONMENTAL POLLUTION
(2018)
Article
Engineering, Environmental
William F. Fitzgerald, Daniel R. Engstrom, Chad R. Hammerschmidt, Carl H. Lamborg, Prentiss H. Balcom, Ana L. Lima-Braun, Michael H. Bothner, Christopher M. Reddy
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2018)
Article
Marine & Freshwater Biology
Carl Lamborg, Tracy Mincer, William Buchanan, Caroline Collins, Gretchen Swarr, Priya Ganguli, Kristen Whalen, Michael Bothner, Ivan Valiela
ESTUARINE COASTAL AND SHELF SCIENCE
(2019)
Article
Environmental Sciences
Laura C. Motta, Joel D. Blum, Marcus W. Johnson, Blaire P. Umhau, Brian N. Popp, Spencer J. Washburn, Jeffrey C. Drazen, Claudia R. Benitez-Nelson, Cecelia C. S. Hannides, Hilary G. Close, Carl H. Lamborg
GLOBAL BIOGEOCHEMICAL CYCLES
(2019)
Article
Chemistry, Multidisciplinary
Alison M. Agather, Katlin L. Bowman, Carl H. Lamborg, Chad R. Hammerschmidt
Article
Biodiversity Conservation
M. E. Gilmour, J. L. Lavers, C. Lamborg, O. Chastel, S. A. Kania, S. A. Shaffer
ECOLOGICAL INDICATORS
(2019)
Article
Environmental Sciences
Yasuhiko Murata, Doreen B. Finkelstein, Carl H. Lamborg, Myra E. Finkelstein
ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY
(2019)
Article
Limnology
Katlin L. Bowman, R. Eric Collins, Alison M. Agather, Carl H. Lamborg, Chad R. Hammerschmidt, Drishti Kaul, Christopher L. Dupont, Geoff A. Christensen, Dwayne A. Elias
LIMNOLOGY AND OCEANOGRAPHY
(2020)
Article
Environmental Sciences
M. E. Gilmour, S. A. Trefry Hudson, C. Lamborg, A. B. Fleishman, H. S. Young, S. A. Shaffer
SCIENCE OF THE TOTAL ENVIRONMENT
(2019)
Article
Environmental Sciences
Katlin L. Bowman, Carl H. Lamborg, Alison M. Agather
SCIENCE OF THE TOTAL ENVIRONMENT
(2020)
Article
Environmental Sciences
Mae Sexauer Gustin, Michael S. Bank, Kevin Bishop, Katlin Bowman, Brian Branfireun, John Chetelat, Chris S. Eckley, Chad R. Hammerschmidt, Carl Lamborg, Seth Lyman, Antonio Martinez-Cortizas, Jonas Sommar, Martin Tsz-Ki Tsui, Tong Zhang
SCIENCE OF THE TOTAL ENVIRONMENT
(2020)
Article
Oceanography
Matthew A. Charette, Lauren E. Kipp, Laramie T. Jensen, Jessica S. Dabrowski, Laura M. Whitmore, Jessica N. Fitzsimmons, Tatiana Williford, Adam Ulfsbo, Elizabeth Jones, Randelle M. Bundy, Sebastian M. Vivancos, Katharina Pahnke, Seth G. John, Yang Xiang, Mariko Hatta, Mariia Petrova, LarsEric Heimburger-Boavida, Dorothea Bauch, Robert Newton, Angelica Pasqualini, Alison M. Agather, Rainer M. W. Amon, Robert F. Anderson, Per S. Andersson, Ronald Benner, Katlin L. Bowman, R. Lawrence Edwards, Sandra Gdaniec, Loes J. A. Gerringa, Aridane G. Gonzalez, Mats Granskog, Brian Haley, Chad R. Hammerschmidt, Dennis A. Hansell, Paul B. Henderson, David C. Kadko, Karl Kaiser, Patrick Laan, Phoebe J. Lam, Carl H. Lamborg, Martin Levier, Xianglei Li, Andrew R. Margolin, Chris Measures, Rob Middag, Frank J. Millero, Willard S. Moore, Ronja Paffrath, Hlne Planquette, Benjamin Rabe, Heather Reader, Robert Rember, Micha J. A. Rijkenberg, Matthieu Roy-Barman, Michiel Rutgers van der Loeff, Mak Saito, Ursula Schauer, Peter Schlosser, Robert M. Sherrell, Alan M. Shiller, Hans Slagter, Jeroen E. Sonke, Colin Stedmon, Ryan J. Woosley, Ole Valk, Jan van Ooijen, Ruifeng Zhang
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2020)
Article
Environmental Sciences
Katlin L. Bowman, Carl H. Lamborg, Alison M. Agather, Chad R. Hammerschmidt
Summary: This study found that plastic debris can alter the biogeochemical cycling of mercury in aquatic ecosystems, as microbial communities on plastic may contain mercury methylating microbes and mer genes.
MARINE POLLUTION BULLETIN
(2021)
Article
Environmental Sciences
Amina T. Schartup, Anne L. Soerensen, Helene Angot, Katlin Bowman, Noelle E. Selin
Summary: This study examines the response of Arctic Ocean mercury (Hg) concentrations to various factors and simulates future environmental changes. The findings suggest that anthropogenic Hg emissions and sea-ice cover changes have a significant impact on Hg concentrations in the Arctic Ocean, while river inputs contribute to increased concentrations. Moreover, the study highlights the importance of taking prompt and ambitious measures to reduce Hg concentrations in the Arctic region.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Chemistry, Multidisciplinary
Morgane Leon, Pieter van Beek, Virginie Sanial, Marc Souhaut, Paul Henderson, Matthew A. Charette
Summary: The analysis of radium and actinium isotopes in seawater requires the collection of large volumes of water and the use of high sensitivity instruments. To concentrate these isotopes, filters impregnated with MnO2 are typically used. However, the extraction efficiency of these filters for the target isotopes needs to be determined.