Article
Microbiology
Megan Brauner, Brandon R. Briggs
Summary: Glaciers in Arctic regions are major sources of iron for rivers, but estuaries are considered iron sinks. This study found that there were no significant differences in microbial communities between the river and estuary environments, but genes related to iron transport and storage varied between the two. These differences may be influenced by environmental conditions and physical drivers.
ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Multidisciplinary Sciences
Evan M. F. Shepherdson, Marie A. Elliot
Summary: Streptomyces bacteria have complex life cycles and remarkable metabolic capabilities. Their recently discovered exploration ability allows them to successfully compete with other microbes. Nutrient availability affects exploration rates and metabolic output, with glycerol dramatically increasing exploration rates. Different siderophores play different roles in exploration, and the alternative siderophore foroxymithine is more important than desferrioxamine during coculture.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2022)
Article
Environmental Sciences
N. A. Wiseman, J. K. Moore, B. S. Twining, D. S. Hamilton, N. M. Mahowald
Summary: Dissolved iron (dFe) is crucial for regulating marine productivity. Its availability affects carbon export and nitrogen fixation, and is dependent on phytoplankton iron quotas. Adding dynamic, group-specific, phytoplankton Fe:C ratios to ocean models improves representation of observed trends and helps understand biogeochemical responses to varying iron cycling and atmospheric deposition.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Geosciences, Multidisciplinary
D. Konig, T. M. Conway, D. S. Hamilton, A. Tagliabue
Summary: This study uses a global ocean biogeochemical model with active Fe isotope cycling to investigate the impact of anthropogenic Fe sources on surface ocean dFe and δFe-56(diss). The results show that the response of dFe, δFe-56(diss), and primary productivity is variable and regulated by the biogeochemical regime, rather than following the footprint of atmospheric deposition. The study also finds that while δFe-56(diss) can trace anthropogenic input, its response is attenuated by fractionation during phytoplankton uptake, but amplified by other isotopically-light Fe sources.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Multidisciplinary Sciences
Carolina Silveira de Moraes, Andrea Teixeira Ustra, Alexandre Muselli Barbosa, Rosely Aparecida Liguori Imbernon, Cinthia Midory Uehara Tengan
Summary: Soils and groundwater contamination modify the physical-chemical conditions, altering natural processes and mineral transformations, with iron playing a crucial role. This study investigates the relationship between creosote biodegradation and precipitation of magnetic minerals in contaminated sediments. The magnetic signatures suggest an increase of superparamagnetic grains in the water table fluctuation zone and a lower heterogeneity of magnetic mineral phases in contaminated samples compared to uncontaminated ones.
SCIENTIFIC REPORTS
(2022)
Review
Biotechnology & Applied Microbiology
Mohit Singh Rana, Sanjeev Kumar Prajapati
Summary: Iron is crucial for microalgae growth as it is required for maintaining photosynthetic and metabolic reactions. The limited bioavailability of iron is a significant challenge for algal-biotechnology industries. Different mechanisms of iron uptake by microalgae and cyanobacteria are discussed, along with recent attempts to improve microalgae growth through chelated iron and iron nanoparticle supplementation. The judicious supplementation of iron for commercial applications is also highlighted in the review.
ALGAL RESEARCH-BIOMASS BIOFUELS AND BIOPRODUCTS
(2021)
Review
Biochemistry & Molecular Biology
Elvira Crescenzi, Antonio Leonardi, Francesco Pacifico
Summary: The review focuses on the different roles of NGAL in the tumor microenvironment and in cancer senescence-associated secretory phenotype (SASP), highlighting the most crucial functions that could be eventually targetable in cancer therapy.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2021)
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)
Review
Biochemistry & Molecular Biology
Cassidy Scott, Gaurav Arora, Kayle Dickson, Christian Lehmann
Summary: Iron is essential in biochemical pathways for both humans and pathogens. In local infections, restricting iron availability can reduce reactive oxygen species and bacterial growth. Therapeutic use of iron chelators to induce iron deprivation shows potential in treating infections.
Article
Microbiology
Peter J. Brechting, Chandan Shah, Liva Rakotondraibe, Qian Shen, Chad A. Rappleye
Summary: Peroxisomes are essential for fungal functions such as fatty acid metabolism, reactive oxygen species detoxification, and secondary metabolite biosynthesis. Disruption of peroxisomal protein import and siderophore biosynthesis attenuates the virulence of Histoplasma capsulatum, a fungal pathogen that infects host phagocytes and establishes a replication-permissive niche within the cells. The multiple roles of peroxisomes in H. capsulatum pathogenesis suggest that targeting these organelles could be a potential strategy for developing therapeutics.
Article
Environmental Sciences
D. Konig, T. M. Conway, M. J. Ellwood, W. B. Homoky, A. Tagliabue
Summary: Iron isotopes in the ocean are crucial in studying the iron cycle, but the complexity of various external sources and fractionation processes can complicate the interpretation of observations. By incorporating iron isotopes into a global ocean biogeochemical model, research finds that distinct external source endmembers and isotopic fractionation are essential for explaining the distribution of dissolved iron isotopes, with the water column's δFe-56(diss) distribution influenced by regional imbalance of remineralization and abiotic removal processes.
GLOBAL BIOGEOCHEMICAL CYCLES
(2021)
Article
Ecology
Indah Ardiningsih, Kyyas Seyitmuhammedov, Sylvia G. Sander, Claudine H. Stirling, Gert-Jan Reichart, Kevin R. Arrigo, Loes J. A. Gerringa, Rob Middag
Summary: Organic ligands play a crucial role in determining the availability of dissolved iron in the Southern Ocean. The study found that organic ligands in the region are sourced from ice-algal exudates, melting sea ice, resuspended sediment, and phytoplankton blooms. Overall, organic ligand concentrations are always higher than dissolved iron concentrations, with excess ligand concentrations being able to stabilize additional iron inputs in dissolved form.
Article
Biochemistry & Molecular Biology
Wei-Liang Kong, Tong-Yue Wen, Ya-Hui Wang, Xiao-Qin Wu
Summary: The study found that siderophores produced by plant growth-promoting rhizobacteria can effectively increase iron content and improve iron nutrition in plants by activating the glutathione synthesis pathway and enhancing ferric-chelate reductase activity, thereby alleviating chlorosis in plants.
INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES
(2022)
Article
Biochemistry & Molecular Biology
Alasteir Ong, Mark R. O'Brian
Summary: In Bradyrhizobium japonicum, iron uptake involves selective outer membrane proteins and non-selective periplasmic and cytoplasmic membrane components. FsrB is identified as an iron-regulated gene required for growth on catecholate- and hydroxymate-type siderophores. The activity of FsrB occurs in the periplasm and is involved in the reduction and dissociation of iron from the siderophore.
MOLECULAR MICROBIOLOGY
(2023)
Article
Multidisciplinary Sciences
Derek C. K. Chan, Inokentijs Josts, Kalinka Koteva, Gerard D. Wright, Henning Tidow, Lori L. Burrows
Summary: The outer membrane of gram-negative bacteria acts as a barrier against antibiotics, limiting their effectiveness. However, certain antimicrobials can exploit iron transporters to cross this barrier. In this study, we found that the transporter protein FoxA in Pseudomonas aeruginosa can transport the xenosiderophore bisucaberin, in addition to the antibiotic thiocillin. By analyzing the crystal structure, we discovered that bisucaberin forms a unique 3:2 siderophore-iron complex. Mutations in a specific extracellular loop of FoxA affected its binding, uptake, and signal transduction abilities for nocardamine, thiocillin, and bisucaberin. These findings highlight the importance of extracellular loops in controlling ligand uptake and have implications for the development of siderophore-antibiotic conjugates.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Biodiversity Conservation
Juliano Palacios-Abrantes, Thomas L. Frolicher, Gabriel Reygondeau, U. Rashid Sumaila, Alessandro Tagliabue, Colette C. C. Wabnitz, William W. L. Cheung
Summary: Climate change is causing shifts in the distribution of shared fish stocks between neighboring countries, affecting international fisheries governance. By 2030, 23% of transboundary stocks will have shifted, and by the end of the century, projections show that 45% of stocks globally will have shifted. Countries highly dependent on fisheries will be hotspots for these shifts.
GLOBAL CHANGE BIOLOGY
(2022)
Article
Environmental Sciences
Anh Le-Duy Pham, Olivier Aumont, Lavenia Ratnarajah, Alessandro Tagliabue
Summary: Marine free-living bacteria play a crucial role in the cycling of essential biogeochemical elements, and their growth is regulated by nutrient availability, particularly iron. Understanding the factors limiting bacterial growth and their role in the iron cycle is important for understanding biogeochemical cycling.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Limnology
Philip W. Boyd, Scott C. Doney, Sam Eggins, Michael J. Ellwood, Marion Fourquez, Brook L. Nunn, Robert Strzepek, Emma Timmins-Schiffman
Summary: The influence of global change on Southern Ocean productivity is significant, and combining laboratory, field, and modeling approaches helps us better understand methods for future management of polar life.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Oceanography
Alice Della Penna, Joan Llort, Sebastien Moreau, Ramkrushnbhai Patel, Rudy Kloser, Peter Gaube, Peter Strutton, Philip W. Boyd
Summary: Studies have shown that mesoscale eddies in the Southern Ocean affect the distribution of micronekton, which are important prey for megafauna. This study analyzes acoustic observations in a cyclonic eddy and its surrounding waters, revealing that the acoustic backscatter distribution matches the underwater light conditions of the eddy core, periphery, and surrounding waters at scales smaller than 10 km. The results suggest that the eddy maintains its biological characteristics from its source waters, creating a unique habitat compared to its surroundings.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Geosciences, Multidisciplinary
P. N. Sedwick, B. M. Sohst, K. N. Buck, S. Caprara, R. J. Johnson, D. C. Ohnemus, L. E. Sofen, A. Tagliabue, B. S. Twining, T. E. Williams
Summary: Constraining the role of dust deposition in regulating the concentration of iron in surface ocean waters requires understanding the flux of seawater-soluble iron in aerosols and the replacement time of dissolved iron in the euphotic zone. This study estimates these quantities using DFe data from the Bermuda Atlantic Time-series Study region and measurements of iron in aerosols and rain from Bermuda in 2019. The results suggest a seasonal variation in surface DFe concentrations and a mean euphotic-zone residence time of 0.8-1.9 years for DFe with respect to aeolian input.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Multidisciplinary Sciences
Thomas J. Ryan-Keogh, Sandy J. Thomalla, Pedro M. S. Monteiro, Alessandro Tagliabue
Summary: Southern Ocean primary productivity is affected by light and iron limitation, but the factors determining iron availability, accessibility, and demand are uncertain. In this study, we analyzed long-term data collected by Biogeochemical Argo floats and ship-based platforms to examine the effects of iron stress on phytoplankton photophysiology. We observed a significant multidecadal trend of increasing iron stress and declining regional net primary production. This trend is attributed to changes in the Southern Ocean mixed-layer physics and complex biological and chemical feedback, highlighting important ongoing changes in the Southern Ocean carbon cycle.
Article
Multidisciplinary Sciences
Leo Lacour, Joan Llort, Nathan Briggs, Peter G. G. Strutton, Philip W. W. Boyd
Summary: At high latitudes, the gravitational sinking of particulate organic carbon has been considered as the sole particle export pathway of the biological carbon pump. However, recent studies suggest that particle injection pumps, such as the mixed layer and eddy subduction pumps, also contribute significantly to the downward flux of particulate organic carbon. In this study, we used year-round robotic observations and bio-optical signal analysis to concurrently investigate the functioning of these particle injection pumps and the gravitational pump in the Southern Ocean. Our results reveal the distinct seasonality and importance of different export pathways, providing insights into carbon sequestration efficiency over the annual cycle.
NATURE COMMUNICATIONS
(2023)
Letter
Limnology
Clara R. Vives, Christina Schallenberg, Peter G. Strutton, Philip W. Boyd
Summary: In the Southern Ocean, understanding the timing of phytoplankton blooms is crucial for studying ecosystem dynamics and carbon export. Previous studies have yielded inconsistent findings regarding bloom timing. This study compares bloom dynamics based on different diagnostics and highlights the importance of considering phytoplankton physiology when choosing proxies for their growth.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2023)
Article
Limnology
Lennart T. Bach, David T. Ho, Philip W. Boyd, Michael D. Tyka
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2023)
Article
Biology
Ellie R. Paine, Philip W. Boyd, Robert F. Strzepek, Michael Ellwood, Elizabeth A. Brewer, Guillermo Diaz-Pulido, Matthias Schmid, Catriona L. Hurd
Summary: Laboratory experiments show that insufficient iron availability in the open ocean is a major challenge for growing kelp for carbon sequestration. Carbon dioxide removal and emissions reduction are crucial for mitigating climate change. Ocean macroalgal afforestation is a CDR method that involves growing nearshore kelps offshore, but the limitation of dissolved iron supply is overlooked in discussions. The study finds that kelp growth and physiological functions are impaired at oceanic iron concentrations, which are 1000-fold lower than required by the kelp species. Additional iron fertilization may be necessary for successful ocean macroalgal afforestation.
COMMUNICATIONS BIOLOGY
(2023)
Article
Biodiversity Conservation
Alessandro Tagliabue, Benjamin S. Twining, Nicolas Barrier, Olivier Maury, Manon Berger, Laurent Bopp
Summary: Climate change scenarios indicate the need for large-scale carbon dioxide removal to combat global warming, putting the focus back on ocean iron fertilization (OIF). However, our study shows that while OIF can increase carbon sequestration, it may also intensify the decline of tropical ocean productivity and ecosystem biomass, with limited impact on atmospheric CO2. The interaction between OIF and ongoing climate change could lead to reduced animal biomass in tropical regions, particularly in coastal exclusive economic zones (EEZs), which could have implications for fisheries.
GLOBAL CHANGE BIOLOGY
(2023)
Article
Multidisciplinary Sciences
Alessandro Tagliabue, Kristen N. N. Buck, Laura E. E. Sofen, Benjamin S. S. Twining, Olivier Aumont, Philip W. W. Boyd, Salvatore Caprara, William B. B. Homoky, Rod Johnson, Daniela Konig, Daniel C. C. Ohnemus, Bettina Sohst, Peter Sedwick
Summary: Iron is important in regulating the ocean carbon cycle, with organic ligands playing a crucial role in stabilizing dissolved iron concentrations. However, the role of authigenic iron phases and the inconsistencies observed in dissolved iron cycling challenge the primary control of ligands. Through a study in the Bermuda Atlantic Time-series Study (BATS) region, it was found that upper-ocean dissolved iron dynamics are decoupled from ligands, indicating the need for a mechanism that allows dissolved iron to escape ligand stabilization and form a reservoir of settling iron particles. When this mechanism was implemented in a global-scale biogeochemical model, it successfully reproduced seasonal iron-cycle dynamics and global datasets where previous models failed.
Editorial Material
Multidisciplinary Sciences
Lennart T. Bach, Veronica Tamsitt, Jim Gower, Catriona L. Hurd, John A. Raven, Philip W. Boyd
NATURE COMMUNICATIONS
(2023)
Article
Ecology
Garrett Sharpe, Liang Zhao, Meredith G. Meyer, Weida Gong, Shannon M. Burns, Allesandro Tagliabue, Kristen N. Buck, Alyson E. Santoro, Jason R. Graff, Adrian Marchetti, Scott Gifford
Summary: Synechococcus, the most abundant cyanobacteria in high latitude regions, plays a significant role in annual marine net primary productivity. However, the uneven sampling of Synechococcus populations across the ocean, particularly in high-latitude, High Nutrient Low Chlorophyll (HNLC) regions, has limited our understanding of their adaptations to iron limitation and their influence on carbon, nitrogen, and iron cycles. This study focuses on Synechococcus populations in the subarctic North Pacific, a well-characterized HNLC region, and reveals their dependence on ammonium and other forms of recycled nitrogen, leading to reduced iron requirements. The findings have important implications for modeling the contribution of cyanobacteria to primary production and carbon export.
ISME COMMUNICATIONS
(2023)
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.