Article
Environmental Sciences
Yixue Zhang, Ying Wu, Jing Zhang, Yi Xu, Ke Huang, Jie Jin, Jinlong Dai, Qi Ye, Jian Li, Zhenqiu Zhang
Summary: Through in situ observations and incubation experiments in the Central Indian Ocean and Bay of Bengal, the complexity of marine organic matter (OM) pools and the impact of different regulators on carbon storage are revealed in the tropical eastern Indian Ocean.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Kechen Zhu, Eric P. Achterberg, Nicholas R. Bates, Loes J. A. Gerringa, Rob Middag, Mark J. Hopwood, Martha Gledhill
Summary: An insufficient supply of iron limits phytoplankton growth in the ocean. We calculated the solubility of iron at equilibrium under ambient conditions and compared it to measured dissolved iron in the Atlantic and Pacific Oceans. Our results showed that the solubility of iron was higher than the observed dissolved iron at different depths. We found that changes in solubility of iron, driven by changes in ambient pH and temperature, underlie the vertical distributions of dissolved iron.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Geosciences, Multidisciplinary
Cedric G. Fichot, Maria Tzortziou, Antonio Mannino
Summary: Dissolved organic carbon (DOC) is present in aquatic systems worldwide and plays important roles in biogeochemical and ecological processes. Understanding the stocks, fluxes, and transformations of DOC is crucial for comprehending its functions and vulnerability to changes in the environment. Optical techniques and earth observations have made it possible to quantify DOC on a global scale and have contributed to our current understanding of the global DOC cycle. However, there are still limitations and challenges to be addressed, and upcoming sensors are expected to provide new insights.
EARTH-SCIENCE REVIEWS
(2023)
Article
Environmental Sciences
R. M. Wright, C. Le Quere, N. Mayot, A. Olsen, D. C. E. Bakker
Summary: The Southern Ocean is crucial for carbon uptake, transport, and storage by the global oceans. It is the largest CO2 sink but has low storage of anthropogenic carbon due to the unique combination of upwelling of deep waters and northward transport of surface carbon driven by high winds. Through modeling and observations, we isolate the direct effect of increasing anthropogenic CO2 from the indirect effect of climate variability and change on carbon reorganization in the Southern Ocean. Climate variability and change have a significant impact on carbon storage in the Southern Ocean, comparable to the effect of anthropogenic CO2.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Review
Oceanography
Xilin Xiao, Youhei Yamashita, Michael Gonsior, Nianzhi Jiao
Summary: The source and production mechanism of refractory dissolved organic matter (RDOM) in the ocean remains uncertain, but its biological origin has been recognized as the microbial carbon pump (MCP). Developing a proxy to evaluate the efficiency of MCP production of RDOM is desirable, and the linear correlation between marine humic-like fluorescent dissolved organic matter (FDOMH) and apparent oxygen utilization (AOU) shows promise in exploring this relationship. This article discusses the possibility of using the slope of the AOU-FDOMH correlation as an indicator for evaluating MCP efficiency in the dark ocean. It summarizes the general results and factors that may affect this relationship based on a review of peer-reviewed literature, and proposes future studies to make the AOU-FDOMH relationship globally comparable and applicable for better understanding the sources and sinks of FDOMH and its link to heterotrophic microbial respiration, namely the FDOM-based MCP efficiency.
PROGRESS IN OCEANOGRAPHY
(2023)
Article
Oceanography
Quentin Devresse, Kevin W. Becker, Ahmad Fehmi Dilmahamod, Eva Ortega-Retuerta, Anja Engel
Summary: This study investigated the optical properties of dissolved organic matter in two cyclonic eddies in the Eastern Tropical North Atlantic (ETNA). The results revealed suitable indicators for tracing the transport of freshly produced organic matter and remineralized organic matter within offshore eddies.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Multidisciplinary Sciences
Kavi M. Heerah, Heather E. Reader
Summary: This study used Fourier transformed infrared spectroscopy (FTIR) to identify and quantify iron-binding ligands in a boreal river in Canada. The results show that there are two pools of organic ligands with different behaviors towards iron across a salinity gradient. The stronger ligands play a significant role in providing iron to the coastal and marine environment, while the weaker ligands contribute to iron uptake by flocculation at low salinities.
SCIENTIFIC REPORTS
(2022)
Article
Oceanography
Prince Prakash, Satya Prakash, M. Ravichandran, N. Anil Kumar, T. V. S. Udaya Bhaskar
Summary: The Southern Ocean plays a critical role in global ocean productivity and carbon cycling. Bio-Argo floats deployed in the Indian sector of the Southern Ocean have provided new insights into biogeochemical processes. The study reveals significantly higher dissolved oxygen levels in certain floats during specific seasons, with cyclonic eddies and high chlorophyll concentrations identified as contributing factors.
JOURNAL OF OCEANOGRAPHY
(2022)
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
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
Environmental Sciences
Natalia A. Orekhova, Sergey K. Konovalov, Alexander A. Polukhin, Anna M. Seliverstova
Summary: The concentration of carbon dioxide in the atmosphere has been increasing since pre-industrial times, with a significant portion being absorbed by the World Ocean, particularly the Southern Ocean. Changes in climate can affect the concentrations of oxygen and carbon dioxide dissolved in seawater, which in turn impacts the biogeochemical cycles in the ocean.
Article
Geosciences, Multidisciplinary
Sabi Peris Cabre, Luis Valero, Jorge E. Spangenberg, Andreu Vinyoles, Jean Verite, Thierry Adatte, Maxime Tremblin, Stephen Watkins, Nikhil Sharma, Miguel Garces, Cai Puigdefabregas, Sebastien Castelltort
Summary: The early Cenozoic experienced several episodes of abrupt global warming, called hyperthermals, which had significant impacts on marine life and water physicochemistry. Recent studies have shown that these hyperthermals also affected the hydrologic cycle and led to increased erosion and sediment transport. The Middle Eocene Climatic Optimum (MECO) was a gradual warming event, but little is known about its impact on Earth surface systems. In the South Pyrenean foreland basin (SPFB), a deltaic progradation episode has been associated with the MECO, and new data support a possible hydrological response to this period of warming.
CLIMATE OF THE PAST
(2023)
Article
Environmental Sciences
Chelsea N. Lopez, Dennis A. Hansell
Summary: This study reveals two mechanisms that promote deep particle export in the Southern Ocean: deep frontal mixing and melting of sea ice. By examining data collected in 2008 and 2017, the authors conclude that the sources of iron for export differ in years with anomalously low and high ice melt, respectively.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
E. H. Shadwick, O. A. De Meo, S. Schroeter, M. C. Arroyo, D. G. Martinson, H. Ducklow
Summary: The Southern Ocean is a key player in absorbing atmospheric carbon dioxide, with the West Antarctic Peninsula absorbing CO2 in summer and ice cover preventing outgassing in winter. Future projections suggest that decreasing sea ice formation may weaken the region's ability to uptake carbon dioxide in the coming decades.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Oceanography
Elisa Lovecchio, Louis Clement, Claire Evans, Rachel Rayne, Cynthia Dumousseaud, Saeed Roshan, Sarah L. C. Giering, Adrian Martin
Summary: This study provides the first simultaneous comparison of the contributions of particulate organic carbon (POC), dissolved organic carbon (DOC), and active fluxes by migrating organisms to the ocean's biological pump in the region of South Georgia. The results show that in this region, DOC contributes about 6.6% to the total export flux, active flux has no discernible contribution, and sinking POC flux is dominant.
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Pablo Alba-Gonzalez, Xose Anton Alvarez-Salgado, Antonio Cobelo-Garcia, Joeri Kaal, Eva Teira
Summary: The chemical composition of the seawater soluble fraction (WSF) of yellow-legged gulls and harbour seal faeces and their impact on microbial plankton communities from an eutrophic coastal area have been tested. After characterisation of the C:N:P stoichiometry, trace metals content and organic molecular composition of the faeces, significant differences between species have been observed in all parameters. The study found that seagull faeces had higher N content and were more soluble in seawater than seal faeces, leading to a greater impact on phytoplankton populations.
MARINE ENVIRONMENTAL RESEARCH
(2022)
Review
Oceanography
S. Valiente, B. Fernandez-Castro, R. Campanero, A. Marrero-Diaz, A. Rodriguez-Santana, M. D. Gelado-Cabellero, M. Nieto-Cid, A. Delgado-Huertas, J. Aristegui, X. A. Alvarez-Salgado
Summary: The Cape Verde Frontal Zone (CVFZ) is a highly dynamic region with large fluxes of sinking organic matter. The distribution of dissolved and suspended particulate organic matter in this area is influenced by the position of transects and different water masses, indicating the role of biogeochemical processes in shaping water mass properties. However, mineralization of DOM and POM is low, highlighting the importance of sinking fluxes of organic matter for mineralization processes.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Shuaidong Li, Jie Fang, Xinshu Zhu, Robert G. M. Spencer, Xose Anton Alvarez Salgado, Yongcui Deng, Tao Huang, Hao Yang, Changchun Huang
Summary: This study investigates the response of sediment dissolved organic matter (DOM) to eutrophication and its association with bacterial communities in Dianchi Lake, China. The results show that the composition and structure of sediment DOM are regulated by source transformation during eutrophication, and microbial communities play an important role in sediment biogeochemical processes.
ENVIRONMENTAL POLLUTION
(2022)
Review
Engineering, Environmental
Elisa F. Guallart, Noelia M. Fajar, Maribel I. Garcia-Ibanez, Monica Castano-Carrera, Rocio Santiago-Domenech, Abed El Rahman Hassoun, Fiz F. Perez, Regina A. Easley, Marta Alvarez
Summary: This study assesses the differences among five different approaches for carbonate ion determination in seawater and discusses the sources of uncertainty. The results show that the current methods do not meet the climate goal for ocean acidification studies but usually fulfill the weather goal. The inconsistencies observed among approaches compromise the consistency of data sets among regions and through time, highlighting the importance of a validated standard operating procedure for spectrophotometric carbonate ion measurements.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2022)
Review
Oceanography
Markel Gomez-Letona, Javier Aristegui, Nauzet Hernandez-Hernandez, Xose Anton Alvarez-Salgado, Marta Alvarez, Erick Delgadillo, Maria Perez-Lorenzo, Eva Teira, Santiago Hernandez-Leon
Summary: Organic matter influences the composition and metabolism of marine prokaryotes. This study investigates the relationship between fluorescent dissolved organic matter and prokaryotic community composition in the deep ocean. The results show that water mass mixing, oxygen utilization, and productivity proxies are important factors explaining the distribution of different fluorescence components. The diversity and taxonomic composition of prokaryotic communities are found to vary between water masses, suggesting a link between community composition, oxygen utilization, and fluorescent dissolved organic matter.
PROGRESS IN OCEANOGRAPHY
(2022)
Article
Limnology
Markel Gomez-Letona, Javier Aristegui, Nauzet Hernandez-Hernandez, Maria Perez-Lorenzo, Xose Anton Alvarez-Salgado, Eva Teira, Marta Sebastian
Summary: This study investigates the vertical connectivity between surface productivity regimes and deep ocean prokaryotic communities. The results show that higher prokaryotic abundances and viabilities, as well as smaller cell sizes, are observed below highly productive surface waters. However, leucine uptake rates in deep waters do not show a clear relationship with surface productivity.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Cristina Romera-Castillo, Jonathan Heras, Marta Alvarez, X. Anton Alvarez-Salgado, Gadea Mata, Eduardo Saenz-de-Cabezon
Summary: The distribution of non-conservative variables in the deep open ocean is influenced by the circulation and mixing of water masses and ongoing biological and geochemical processes. Estimating the contribution of different water masses is useful for understanding their distribution and separating the physical and biogeochemical components of variable variability. Machine learning models can be used to solve water mass mixing and provide real-time results, expanding knowledge of water mass composition and distribution in the ocean.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Patrizia Stipcich, Pedro Beca-Carretero, Xose Anton Alvarez-Salgado, Eugenia T. Apostolaki, Niki Chartosia, Pavlos Theofilos Efthymiadis, Carlos E. Jimenez, Gabriella La Manna, Arianna Pansini, Elena Principato, Vasilis Resaikos, Dagmar B. Stengel, Giulia Ceccherelli
Summary: The nutritional content of primary producers has an impact on the entire food web. This study investigated the changes in nutritional value of the endemic Mediterranean seagrass Posidonia oceanica associated with temperature rise and the occurrence of marine heat waves. The results showed a decrease in unsaturated fatty acids and C/N ratio, as well as an increase in monounsaturated fatty acids and nitrogen content during marine heat waves. However, the leaf biochemical composition seemed to be adapted to local water temperature, with only a few significant changes observed during marine heat waves. Future increases in temperature and frequency of marine heat waves may lead to changes in the nutritional value and palatability of seagrass leaves.
MARINE ENVIRONMENTAL RESEARCH
(2023)
Article
Microbiology
Maider Justel-Diez, Erick Delgadillo-Nuno, Alberto Gutierrez-Barral, Paula Garcia-Otero, Isaac Alonso-Barciela, Pablo Pereira-Villanueva, Xose Anton Alvarez-Salgado, Alberto Velando, Eva Teira, Emilio Fernandez
Summary: This study investigated the role of seabird guano in marine ecosystem functioning by adding different concentrations of gull guano to microbial communities collected from coastal waters in NW Spain. Results showed that guano stimulated the growth of certain bacteria and diatoms, and increased chlorophyll a concentration. The study also revealed that guano altered the phytoplankton-bacteria interaction from neutral to positive in low-nutrient environments, but from positive to neutral in high-nutrient environments.
ENVIRONMENTAL MICROBIOLOGY
(2023)
Article
Engineering, Environmental
Shuaidong Li, Lize Meng, Chu Zhao, Yu Gu, Robert G. M. Spencer, Xose Anton Alvarez-Salgado, Anne M. Kellerman, Amy M. McKenna, Tao Huang, Hao Yang, Changchun Huang
Summary: This study investigates the composition and transformation of dissolved organic matter (DOM) in the Yangtze River during long-distance transport and seasonal cycle. The results show that the concentration of dissolved organic carbon (DOC) in the Yangtze River is relatively low, indicating a significant contribution from allochthonous sources. The composition of DOM changes with the slowing water flow and changing hydrological conditions. This research provides important insights into the biogeochemical cycling of DOM in a large river.
Article
Oceanography
M. Segura-Noguera, X. A. Alvarez-Salgado, S. Siedlecki, B. R. Hales
Summary: This study found that the concentrations of inorganic nitrogen may increase in coastal waters after the bloom of phytoplankton and the cessation of upwelling favorable winds. Additionally, the loss of nitrogen was found to occur mainly in particle-rich, low oxygen waters, rather than only in seafloor sediments. These findings emphasize the importance of considering the complete nitrogen cycle in water columns, rather than focusing solely on individual nutrients.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2023)
Article
Environmental Sciences
E. Jerusalen-Lleo, M. Nieto-Cid, I. Fuentes-Santos, Thorsten Dittmar, X. A. Alvarez-Salgado
Summary: Our knowledge of the composition of ocean dissolved organic matter (DOM) is limited due to its molecular diversity, low individual compound concentration, and high ionic strength of ocean waters. Solid phase extraction (SPE) using styrene divinyl benzene polymer cartridges (PPL) is the most commonly used method to concentrate DOM. In this study, we investigate the efficiency and selectivity of SPE-PPL in extracting DOM from Arctic, Mediterranean, and Antarctic waters in the Cape Vert Frontal Zone (CVFZ). We found that the extraction efficiencies varied for different DOM pools and displayed significant differences among water masses.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Environmental Sciences
Juan Severino Pino Ibanhez, Xose Anton Alvarez-Salgado, Carlos Rocha
Summary: The study found that the water sources in the Ria de Vigo catchment have high levels of radon (Rn-222), which may have negative effects on health. During the dry season, the radon levels in the water sources are nearly double compared to the wet season, leading to a total effective dose of radiation that exceeds the recommended limit when consuming untreated groundwater. Therefore, it is recommended to implement measures such as radon remediation during the dry season to protect the health of residents.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2023)
Article
Geosciences, Multidisciplinary
Siv K. Lauvset, Nico Lange, Toste Tanhua, Henry C. Bittig, Are Olsen, Alex Kozyr, Simone Alin, Marta Alvarez, Kumiko Azetsu-Scott, Leticia Barbero, Susan Becker, Peter J. Brown, Brendan R. Carter, Leticia Cotrim da Cunha, Richard A. Feely, Mario Hoppema, Matthew P. Humphreys, Masao Ishii, Emil Jeansson, Li-Qing Jiang, Steve D. Jones, Claire Lo Monaco, Akihiko Murata, Jens Daniel Muller, Fiz F. Perez, Benjamin Pfeil, Carsten Schirnick, Reiner Steinfeldt, Toru Suzuki, Bronte Tilbrook, Adam Ulfsbo, Anton Velo, Ryan J. Woosley, Robert M. Key
Summary: The Global Ocean Data Analysis Project (GLODAP) is a synthesis effort that compiles ocean biogeochemical bottle data, with a focus on seawater inorganic carbon chemistry. GLODAPv2.2022 is an update of the previous version, adding data from 96 new cruises and performing secondary quality control on SF6 data. It includes measurements from almost 1.4 million water samples collected on 1085 cruises.
EARTH SYSTEM SCIENCE DATA
(2022)
Article
Oceanography
Pernille Tonnesen, Shane Gero
Summary: Studying the behavior of deep-sea animals is challenging, but animal-borne camera tags may help understand predator-prey interactions. Research showed that camera-associated white light may affect foraging behavior, but has minimal long-term fitness impact on sperm whales. However, this impact should be considered and monitored for longer camera tag deployments.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2024)
Article
Oceanography
Sarah N. de Mendonca, Anna Metaxas
Summary: Ecological processes impact spatial patterns in abundance and distribution of megafauna. This study used spatial statistics to identify significant megafaunal patterns in the Laurentian Channel Marine Protected Area. The patterns varied among taxa and were related to geological factors. The study highlights the importance of considering fine-scale patterns and provides insights for ecological research, monitoring, and conservation in deep-sea ecosystems.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2024)
