Article
Geosciences, Multidisciplinary
Yeongjin Ryu, Heejun Han, Taehee Na, Guebuem Kim, Ellen R. M. Druffel, Jeomshik Hwang
Summary: The East Sea, connected to the Northwest Pacific, is a miniature ocean with independent deep water circulation. The radiocarbon age of dissolved organic carbon (DOC) in the East Sea is older than its water turnover time, indicating the transportation of aged DOC from the Northwest Pacific. The oldest DOC is found in the subsurface layer and is a mixture of old DOC from the North Pacific and modern DOC produced in the East Sea. These findings provide insights into the global cycling of DOC in the surface ocean.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Federico Baltar, Xose A. Alvarez-Salgado, Javier Aristegui, Ronald Benner, Dennis A. Hansell, Gerhard J. Herndl, Christian Lonborg
Summary: The text discusses the transformation and sequestration of organic carbon produced in the sunlit surface ocean into the ocean's interior, focusing on the refractory dissolved organic carbon (rDOC). It emphasizes the importance of defining rDOC operationally and highlights the various factors influencing its persistence, including intrinsic and extrinsic properties. The text also suggests specific research questions aimed at stimulating further research on the nature, dynamics, and role of rDOC in carbon sequestration under future scenarios of climate change.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Chiara Santinelli, Roberto Iacono, Ernesto Napolitano, Maurizio Ribera d'Alcala
Summary: This study investigates the impact of lateral advection on carbon dynamics in the Western Mediterranean Sea and highlights the crucial role of surface circulation in regulating DOC concentrations and distributions. It also suggests the presence of a compensation mechanism in the Mediterranean Sea that could smooth trophic gradients among regions with different nutrient levels, which may be important in other ocean regions as well.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2021)
Article
Geosciences, Multidisciplinary
Ellen R. M. Druffel, Sheila Griffin, Christian B. Lewis, Megha Rudresh, Noreen G. Garcia, Robert M. Key, Ann P. McNichol, Niels E. Hauksson, Brett D. Walker
Summary: The study found that marine dissolved organic carbon concentrations in the Southern Ocean and eastern Pacific are primarily controlled by the transport of deep waters northward. Low DOC increment C-14 and delta C-13 measurements at specific depths may indicate a source of DOC from nearby hydrothermal ridge systems.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Blanca Ausin, Gina Bossert, Nicola Krake, Sarah Paradis, Negar Haghipour, Xavier Durrieu de Madron, Belen Alonso, Timothy Eglinton
Summary: This study investigates the origin and fate of organic matter in marine sediments in the Western Mediterranean Sea and adjacent Atlantic Ocean sector. The results reveal a southwest to northeast gradient in geographical and sedimentological features. Changes in primary productivity, river discharge, and canyons are identified as factors influencing the spatial distribution of organic carbon. Additionally, the study suggests the influence of lateral transport of allochthonous organic carbon and selective degradation of labile organic matter, as well as the protection of organic matter through association with mineral surfaces.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Environmental Sciences
Edward Tipping, Jessica L. Elias, Patrick O. Keenan, Rachel C. Helliwell, Nikolai Pedentchouk, Richard J. Cooper, Sarah Buckingham, Egil Gjessing, Philippa Ascough, Charlotte L. Bryant, Mark H. Garnett
Summary: This study investigated the concentrations and properties of dissolved organic carbon (DOC) in rivers in relation to terrestrial source solutions at a global scale. The study found significant differences in DOC concentrations and properties among different terrestrial sources, which were explained by optimizing the simulated riverine variables and combinations of source waters. In rivers draining forests and grass-shrub land cover, most of the DOC comes from topsoil and subsoil, with a small contribution from groundwater. In cropland rivers, subsoil and groundwater are the dominant sources of DOC, while in wetland rivers, most of the DOC is from topsoil.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Chemistry, Multidisciplinary
Heejun Han, Taehee Na, Hyung-Mi Cho, Guebuem Kim, Jeomshik Hwang
Summary: The study found significant additional supplies of DOC in the central Yellow Sea, originating from newly produced DOC and the degradation of organic matter. The flux of this additional DOC produced in the East China Sea continental shelf is comparable to that from the Changjiang discharge, indicating its potential global importance in marine DOC budgets.
Article
Geosciences, Multidisciplinary
Christian B. Lewis, Brett D. Walker, Ellen R. M. Druffel
Summary: Radiocarbon measurements indicate that the deep ocean stores marine dissolved organic carbon (DOC) over millennial timescales, with solid-phase extraction (SPE) being a widely used technique to isolate DOC for analysis. Results show that the refractory DOC (RDOC) abundance is similar in the deep Pacific and Indian Oceans, while varying in the surface ocean based on total DOC concentration. This study fills in sampling gaps for SPE-DOC increment C-14 in the global ocean and provides consistent estimates of RDOC abundance compared to previous observations.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Environmental Sciences
Ling Ding, Sen Shan, Chunle Luo, Xuchen Wang
Summary: This study investigated the concentrations and distribution of dissolved organic carbon (DOC) in the South China Sea and the western North Pacific. Laboratory experiments were conducted to determine the microbiological respiration of DOC. The findings revealed that DOC concentrations in the South China Sea varied greatly and were influenced by multiple factors. Physical mixing played a significant role in the distribution of mesopelagic DOC in the northern South China Sea basin.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Environmental Sciences
Margot E. White, Tran B. Nguyen, Irina Koester, Mary C. Lardie Gaylord, J. Michael Beman, Kenneth L. Smith, Ann P. McNichol, Steven R. Beaupre, Lihini I. Aluwihare
Summary: The age of oceanic dissolved organic carbon (DOC), which represents a significant part of the marine carbon cycle, has remained a mystery. Previous models suggested that the old, radiocarbon-depleted DOC forms a uniform reservoir throughout the water column. However, this study found that the radiocarbon age of refractory DOC varies vertically and between oceans, suggesting the addition of pre-aged DOC to the upper ocean. These findings challenge current paradigms and have important implications for our understanding of carbon exchange in the global carbon cycle.
GLOBAL BIOGEOCHEMICAL CYCLES
(2023)
Article
Geochemistry & Geophysics
Ziming Fang, Weifeng Yang, Aron Stubbins, Min Chen, Junjie Li, Renming Jia, Qi Li, Jing Zhu, Bo Wang
Summary: In the Arctic region, the fate and removal process of dissolved black carbon released from river water into the ocean remains unclear. Research findings show that river discharge dominates the spatial distribution of dissolved black carbon in ice-free regions, while sea-ice meltwater dilutes dissolved organic carbon. The removal of riverine dissolved black carbon mainly occurs in shelf regions, playing a crucial role in modulating the delivery of black carbon to the open Arctic Ocean.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Engineering, Environmental
Yuanbi Yi, Jun Zhong, Hongyan Bao, Khan M. G. Mostofa, Sheng Xu, Hua-Yun Xiao, Si-Liang Li
Summary: This study investigated the impact of reservoirs on organic carbon cycling in karst rivers using multiple tracer methods. Results showed that phytoplankton-derived OC gradually increased in dissolved organic carbon in the reservoir area, while terrestrial OC in particulate organic carbon was largely replaced. Higher primary production was observed in the transition area compared to the reservoir area, possibly due to nutrient release from suspended particles.
Article
Geosciences, Multidisciplinary
Ellen R. M. Druffel, Christian B. Lewis, Sheila Griffin, Alessandra Flaherty, Megha Rudresh, Niels E. Hauksson, Robert M. Key, Ann P. Mcnichol, Jeomshik Hwang, Brett D. Walker
Summary: In the West Indian Ocean, the aging of deep DOC differs from that of dissolved inorganic carbon, indicating that transport of deep water northward is not the main control of C-14 in DOC. This suggests that the dissolution of surface-derived organic carbon is a source of modern carbon to deep DOC in the West Indian Ocean.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Katsumi Matsumoto, Tatsuro Tanioka, Maya Gilchrist
Summary: Using a data-constrained circulation model, we efficiently computed the steady state distribution of deep ocean dissolved organic carbon (DOC) at a 1 degree horizontal resolution. Our model simulated the total DOC as a sum of two pools and successfully reproduced the large-scale features of deep ocean DOC. The sensitivity of deep ocean DOC to preformed DOC concentrations and other factors were also investigated.
GLOBAL BIOGEOCHEMICAL CYCLES
(2022)
Article
Environmental Sciences
Ismail Akcay, Mustafa Yucel
Summary: Phosphorus (P) is a crucial element for all life and its cycling in sediment can vary depending on the redox conditions of the water above. This study investigated the biogeochemical cycling of sedimentary P in the Black Sea, Marmara Sea, and Northeastern Mediterranean Sea. The results showed significant variability in porewater and sediment biogeochemistry, with the highest concentrations of P and other nutrients found in hypoxic and anoxic areas. The study predicts that deoxygenation and eutrophication will lead to the release of P in these interconnected marine basins, affecting nutrient stocks and N/P control in marine ecosystems.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Limnology
Benjamin N. Granzow, Oscar A. Sosa, Margherita Gonnelli, Chiara Santinelli, David M. Karl, Daniel J. Repeta
Summary: In oligotrophic oceans, microorganisms supplement their nutrient requirements by extracting phosphorus from dissolved organic matter. While most phosphorus is in the form of phosphate esters hydrolyzed to P-i, a portion exists as phosphonates that require an additional step for cleavage.
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2021)
Article
Oceanography
Chiara Santinelli, Roberto Iacono, Ernesto Napolitano, Maurizio Ribera d'Alcala
Summary: This study investigates the impact of lateral advection on carbon dynamics in the Western Mediterranean Sea and highlights the crucial role of surface circulation in regulating DOC concentrations and distributions. It also suggests the presence of a compensation mechanism in the Mediterranean Sea that could smooth trophic gradients among regions with different nutrient levels, which may be important in other ocean regions as well.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2021)
Article
Chemistry, Multidisciplinary
Jasmin Padan, Sasa Marcinek, Ana-Marija Cindric, Chiara Santinelli, Simona Retelletti Brogi, Olivier Radakovitch, Cedric Garnier, Dario Omanovic
Summary: An improved method for organic copper speciation using anodic stripping voltammetry was developed by adding a nonionic surfactant to eliminate interference from surface-active substances, resulting in more accurate measurements. Two classes of ligands were identified in samples from the Arno River estuary, with varying concentrations between seasons, indicating seasonal changes in the source of organic ligands.
FRONTIERS IN CHEMISTRY
(2021)
Article
Engineering, Marine
Simona Retelletti Brogi, Raffaella Casotti, Benjamin Misson, Cecilia Balestra, Margherita Gonnelli, Stefano Vestri, Chiara Santinelli
Summary: This study investigated biological DOM removal in a small estuary and found that despite differences in initial conditions, the rates of DOC removal were surprisingly similar in two contrasting seasons. The concentration and quality of DOM in the estuary showed marked differences between spring and autumn, with different trends in fluorescent DOM components observed during incubation.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Marc Garel, Christos Panagiotopoulos, Mehdi Boutrif, Daniel Repeta, Richard Sempere, Chiara Santinelli, Bruno Charriere, David Nerini, Jean-Christophe Poggiale, Christian Tamburini
Summary: The study found that deep-sea prokaryotic assemblages have different degradation rates of HMW-DOC under different hydrological conditions, with the hydrological conditions of the water column playing an important role in the remineralization rates of DOC.
Article
Environmental Sciences
Christian Tamburini, Marc Garel, Aude Barani, Dominique Boeuf, Patricia Bonin, Nagib Bhairy, Sophie Guasco, Stephanie Jacquet, Frederic A. C. Le Moigne, Christos Panagiotopoulos, Virginie Riou, Sandrine Veloso, Chiara Santinelli, Fabrice Armougom
Summary: The study used a particle sinking simulator system (PASS) to track the sinking process of laboratory-grown Emiliania huxleyi aggregates in the North Atlantic Ocean, finding that pressure affects prokaryotic degradation and respiration rate, while increasing hydrostatic pressure reduces prokaryotic diversity and species richness.
Article
Environmental Sciences
S. Retelletti Brogi, G. Cossarini, G. Bachi, C. Balestra, E. Camatti, R. Casotti, G. Checcucci, S. Colella, V. Evangelista, F. Falcini, F. Francocci, T. Giorgino, F. Margiotta, M. Ribera d'Alcala, M. Sprovieri, S. Vestri, C. Santinelli
Summary: The rapid spread of the SARS-CoV-2 virus in Italy led to a 3-month lockdown of the entire country, resulting in a marked decrease in dissolved organic carbon concentration in the Arno River and coastal areas affected by its input. Additionally, the optical properties of DOM showed a shift towards smaller and less aromatic molecules during the lockdown period.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Oceanography
Grazia Marina Quero, Simona Retelletti Brogi, Chiara Santinelli, Gian Marco Luna
Summary: This study reveals the composition and diversity patterns of microbial communities in the deep Mediterranean Sea, as well as their relationship with dissolved organic matter. The results show that changes in the quality of dissolved organic matter can influence the composition of microbial communities, further enhancing our understanding of the deep-sea ecosystem in the Mediterranean.
DEEP-SEA RESEARCH PART I-OCEANOGRAPHIC RESEARCH PAPERS
(2023)
Article
Limnology
Giancarlo Bachi, Elisabetta Morelli, Margherita Gonnelli, Cecilia Balestra, Raffaella Casotti, Valtere Evangelista, Daniel J. Repeta, Chiara Santinelli
Summary: This study investigates the link between the biological lability and the molecular weight, fluorescence, and polarity of phytoplankton dissolved organic matter (DOM) by incubating exudates from the diatom Phaeodactylum tricornutum with a natural community of marine heterotrophic prokaryotes. The results show that freshly produced phytoplankton DOM exhibits a dynamic pattern of degradation that is likely related to changes in DOM quality. Protein-like DOM is likely a labile component of phytoplankton exudates, while humic-like substances are resistant to bacterial degradation.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Environmental Sciences
Dario Omanovic, Sasa Marcinek, Chiara Santinelli
Summary: Fluorescence excitation-emission matrices (EEMs) are a useful tool for studying organic matter in water systems. However, the interpretation of EEMs requires appropriate software. TreatEEM is a non-commercial software that provides comprehensive treatment and analysis of EEMs with a user-friendly interface.
Article
Engineering, Marine
Elisabeth Navarro, Chiara Santinelli, Simona Retelletti Brogi, Gael Durrieu, Olivier Radakovitch, Cedric Garnier, Benjamin Misson
Summary: In the marine coastal environment, freshwater and seawater coalescing communities face complex abiotic and biotic influences. This study aimed to evaluate the respective influences of blending and prokaryotic dynamics on community structure. The results showed that salinity was the predominant constraint on community structure, and the distribution of most taxa reflected their blending.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Environmental Sciences
Thorsten Dittmar, Sinikka T. Lennartz, Hagen Buck-Wiese, Dennis A. Hansel, Chiara Santinelli, Chiara Vanni, Bernd Blasius, Jan-Hendrik Hehemann
Summary: This perspective discusses the long-term persistence of marine dissolved organic matter, comparing and contrasting two concepts, and proposing a new research strategy that integrates intrinsic and emergent recalcitrance concepts.
NATURE REVIEWS EARTH & ENVIRONMENT
(2021)
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.