Article
Environmental Sciences
Hannelore Waska, Heike Simon, Soeren Ahmerkamp, Janek Greskowiak, Janis Ahrens, Stephan L. Seibert, Kai Schwalfenberg, Oliver Zielinski, Thorsten Dittmar
Summary: The research revealed that the high-energy beach Subterranean Estuary (STE) has a high diversity and heterogeneity of dissolved organic matter (DOM), possibly due to uneven distribution of buried peat lenses. Along the coast, there is an increasing degradation of soluble DOM and a continuous decline in oxygen concentrations, indicating a consistent degradation trend even in dynamic environments.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Janis Ahrens, Melanie Beck, Philipp Boening, Julius Degenhardt, Katharina Pahnke, Bernhard Schnetger, Hans-Juergen Brumsack
Summary: Pore water data on thallium (Tl) in marine environments are limited. The study found that Tl enrichment in pore waters is associated with aerobic organic matter degradation, while Tl removal is linked to the presence of trace amounts of dissolved sulfide. Fast reaction kinetics result in Tl being removed faster and more completely compared to other trace metals like Mo, U, and Re.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Engineering, Marine
Tracey Schafer, Nicole Dix, Shannon Dunnigan, K. Ramesh Reddy, Todd Z. Osborne
Summary: Hurricanes have the ability to export large amounts of nutrients from terrestrial systems into aquatic networks, affecting ecosystem metabolism. A study in the blackwater river of Florida found that hurricanes, especially after wet summer conditions, significantly increased the export of dissolved organic carbon. However, lower-category hurricanes may not have a significant impact on organic matter export.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Environmental Sciences
Andrea J. Pain, Jonathan B. Martin, Caitlin R. Young
Summary: Submarine groundwater discharge to coastal zones can contribute to harmful algal blooms through the input of terrestrial freshwater and nutrients. The magnitude of nutrient exports via SGD depends on the chemical composition of groundwater and biogeochemical processes within subterranean estuaries. Variability in nutrient concentrations and transformations within subterranean estuaries can lead to heterogeneous nutrient contributions via SGD, complicating assessments of regional and global solute cycles.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Engineering, Civil
Yi Liu, Jiu Jimmy Jiao, Wenzhao Liang, Isaac R. Santos, Xingxing Kuang, Clare E. Robinson
Summary: The study investigates the biogeochemistry of inorganic carbon in an intertidal aquifer in Hong Kong and its impact on Tolo Harbor through submarine groundwater discharge (SGD). It found that locally produced total alkalinity (TAlk) and dissolved inorganic carbon (DIC) in the aquifer contribute over 50% of the discharged TAlk and DIC to the ocean. The distributions of TAlk and DIC in different zones (mangrove and bare beach) vary due to hydrogeological and geochemical conditions. Additionally, TAlk and DIC fluxes discharged with SGD were found to be significantly higher during the wet season compared to the dry season.
JOURNAL OF HYDROLOGY
(2021)
Article
Geosciences, Multidisciplinary
Shuzhen Song, Lei Gao, Jianzhong Ge, Wenyun Guo, Daoji Li
Summary: Nutrients and dissolved organic carbon, including carbohydrates, play a crucial role in the carbon cycle in estuarine and coastal ecosystems. Tidal variations in DOC, monosaccharide, and nutrient concentrations were observed in the Changjiang Estuary and East China Sea, with some components showing correlations with tidal phases and cycles, while others did not. The asymmetrical flood-ebb tidal variations in nutrient concentrations were likely influenced by physical and biological characteristics, with tidal forcing playing a significant role in controlling temporal variations in these components.
JOURNAL OF MARINE SYSTEMS
(2022)
Article
Microbiology
Julius Degenhardt, Julian Merder, Benedikt Heyerhoff, Heike Simon, Bert Engelen, Hannelore Waska
Summary: Microbial communities and dissolved organic matter are closely linked in the global carbon cycle. Studying this link on a molecular level is challenging due to the complexity of the systems, but research in intertidal beach sediments has identified four distinct bacterial clusters with specific metabolic functions and distribution patterns, providing insights into their roles in the degradation of organic matter.
Article
Environmental Sciences
Maria Claudia R. Sola, Aldenor G. Santos, Madson M. Nascimento, Gisele Olimpio da Rocha, Jailson Bittencourt de Andrade
Summary: This study investigated the concentrations of polycyclic aromatic compounds in sediment samples from beaches in Salvador, Brazil. The results showed high levels of parent PAHs and nitro-PAHs, with a potent mutagenic compound found in most samples. Calculations of carcinogenic PAHs and risk assessments for benthic species indicated moderate risks in the sediments.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Environmental Sciences
Elisa Calvo-Martin, Xose Anton Alvarez-Salgado, Carlos Rocha, J. Severino Pino Ibanhez
Summary: Subterranean estuaries are zones where continental groundwaters and saltwaters meet, impacting nutrient fluxes to coastal areas. Two STEs in NW Iberian Peninsula were studied for nitrogen biogeochemistry, showing seasonal water circulation variations and contrasting roles as nitrogen sinks or sources. The presence of gravel layers alters the typical structure of STEs, affecting nitrate concentrations and groundwater-borne nitrogen fluxes to the coast.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Qianqian Wang, Pinghe Cai, Shan Jiang, Xuejing Wang, Gang Li, Zhaoxi Liu, Faming Wang, Hailong Li
Summary: The intertidal zone plays a crucial role in the transport of dissolved carbon across the land-ocean interface. By using the 224Ra/228Th disequilibrium method, we found different characteristics of porewater exchange and dissolved carbon export in sandy and muddy sediments. Sandy sediments act as a sink for DOC and have a high export flux of DIC, while muddy sediments have lower export fluxes of both DOC and DIC.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Environmental Sciences
Carlos Rocha, Shan Jiang, J. S. P. Ibanhez, Qiang Yang, Katerina Mazi, Antonis D. Koussis
Summary: The causal links between subterranean estuary dynamics, climatological drivers, and the ecology of coastal ecosystems are important for the integrated management of these systems. This study examines the composition of submarine groundwater discharge (SGD) to a lagoon and its regulation by the annual oscillation of the local subterranean estuary. The study finds that the dynamics of the subterranean estuary and the resulting pH oscillation determine the nutrient composition ratio in SGD and shape primary production dynamics, emphasizing the importance of linked groundwater reservoirs for ecosystem function.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Engineering, Civil
Nele Gruenenbaum, Thomas Guenther, Janek Greskowiak, Thomas Vienken, Mike Mueller-Petke, Gudrun Massmann
Summary: Understanding the interaction between terrestrial freshwater and seawater in subterranean estuaries is crucial for considering nutrient fluxes from land to sea. Recent research suggests the presence of multiple saline recirculation cells in the subterranean estuary, which can influence the land-sea interaction. This study utilizes Electrical Resistivity Tomography (ERT) and Direct Push (DP) techniques to investigate the salinity distribution in a high-energy beach. The experimental results confirm the existence of upper saline recirculation cells and brackish discharge locations, highlighting the significance of the beach system.
JOURNAL OF HYDROLOGY
(2023)
Article
Marine & Freshwater Biology
Cintia Albuquerque, Rodrigo Kerr, Thiago Monteiro, Iole Beatriz Marques Orselli, Mariah de Carvalho-Borges, Andrea da Consolacao de Oliveira Carvalho, Eunice da Costa Machado, Julia Kalid Mansur, Margareth da Silva Copertino, Carlos Rafael Borges Mendes
Summary: An unprecedented investigation was conducted to study the seasonal variability of carbonate system parameters in the Patos Lagoon Estuary. The study found that the estuary had alkaline conditions throughout the year, with surface waters generally being supersaturated with calcium carbonate. However, during winter and spring, undersaturation conditions were observed. The study also revealed that the dominant processes influencing changes in the carbonate system were salt dilution and concentration. Nonthermal effects had a greater impact on seasonal changes in pCO(2) than thermal effects.
ESTUARINE COASTAL AND SHELF SCIENCE
(2022)
Article
Environmental Sciences
Shan Jiang, Jie Jin, Ying Wu, Yixue Zhang, Yongjun Wei, Carlos Rocha, Juan Severino Pino Ibanhez, Jing Zhang
Summary: The study demonstrates that the removal of NO3− in permeable sediments relies mainly on anaerobic conditions at particle surfaces and the dependence on sedimentary organic matter as an electron supplier. When dissolved oxygen reaches sub-oxic conditions, the addition of glucose benefits NO3− reduction.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Oceanography
Dunia Rios-Yunes, Justin C. Tiano, Pieter van Rijswijk, Emil De Borger, Dick van Oevelen, Karline Soetaert
Summary: This study investigates the differences in biogeochemical fluxes between intertidal and subtidal sediments of the Dutch Eastern Scheldt (ES) and assesses the potential impacts of ongoing erosion on the sedimentary ecosystem. The results suggest that intertidal sediments are more reactive and exhibit higher oxygen fluxes compared to subtidal sediments, indicating a strong influence from microphytobenthos. The intertidal areas also display a different nutrient flux pattern, with nutrients being adsorbed into the sediment instead of released into the water column. The predicted habitat loss may have significant consequences for coastal biogeochemistry.
CONTINENTAL SHELF RESEARCH
(2023)
Correction
Environmental Sciences
Weiqiang Zhao, Hongyan Bao, Dekun Huang, Jutta Niggemann, Thorsten Dittmar, Shuh-Ji Kao
Review
Chemistry, Multidisciplinary
N. Mitschke, S. P. B. Vemulapalli, T. Dittmar
Summary: The presence of liquid water is fundamental for life on Earth and water accounts for the largest habitat for life on our planet. Dissolved organic matter (DOM) is released by organisms during their life and death processes, and it travels with water through land and seascapes. DOM in the ocean and freshwater contains more carbon than all living biomass on Earth combined. However, the molecular composition of DOM remains largely unknown. Nuclear magnetic resonance (NMR) spectroscopy is a promising tool to study the molecular-level characterization of complex mixtures like DOM, but has faced challenges in sensitivity and spectral resolution. Recent improvements in technology and methodology, as well as the utilization of statistical analyses and new chemical strategies, show potential in overcoming these limitations. This review provides an overview of the application of NMR spectroscopy in the structural characterization of marine DOM and discusses its current state, technical improvements, and future directions.
ENVIRONMENTAL CHEMISTRY LETTERS
(2023)
Article
Water Resources
Thomas Riedel, Tobias K. D. Weber, Axel Bergmann
Summary: This study tested the impact of climate change on recharge efficiency and found that the positive effects outweighed the negative effects in our study area. Therefore, the region is expected to maintain current rates of groundwater withdrawal, and the agriculture sector may become a "global warming winner."
HYDROLOGICAL PROCESSES
(2023)
Article
Limnology
Daniele De Corte, Marta M. Varela, Angeles M. Louro, Sarah K. Bercovici, Joaquin Valencia-Vila, Eva Sintes, Federico Baltar, Tamara Rodriguez-Ramos, Meinhard Simon, Antonio Bode, Thorsten Dittmar, Jutta Niggemann
Summary: Zooplankton grazing on phytoplankton promotes the release of organic matter into the water column and is consumed by prokaryotes, contributing to its molecular diversification. In a experiment using zooplankton-derived dissolved organic matter (DOM) as substrate, the prokaryotic community demonstrated exponential growth and transformed the DOM over the incubation period. The results suggest that zooplankton-prokaryotic interactions play a significant role in the ocean's carbon cycle.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Engineering, Environmental
Hui Nai, Jun Zhong, Yuanbi Yi, Manting Lai, Ding He, Thorsten Dittmar, Cong-Qiang Liu, Si-Liang Li, Sheng Xu
Summary: A study reveals that the impacts of human activities on the riverine carbon cycle have been underestimated, especially in alpine areas. By analyzing carbon isotopes, fluorescence, and molecular compositions of dissolved organic matter in Bailong River catchment, researchers found that human activities changed the age and composition of dissolved organic carbon (DOC), predominantly through agriculture and urbanization.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Lena Thissen, Janek Greskowiak, Gudrun Massmann
Summary: This study presents a new approach to estimating freshwater lens volumes on islands by using a circularity parameter to analyze island shape. The study models the freshwater lenses of islands with various shapes, both real and idealized, using a numerical steady-state approach and the Ghyben-Herzberg relation. The results are then compared to estimate the potential freshwater lens volumes of islands with different shapes. The findings provide valuable information for estimating freshwater lens volumes on islands without available data and can also offer insights into potential changes in freshwater lens volumes due to climate change.
Article
Biochemical Research Methods
Cajetan Neubauer, Kristyna Kantnerova, Alexis Lamothe, Joel Savarino, Andreas Hilkert, Dieter Juchelka, Kai-Uwe Hinrichs, Marcus Elvert, Verena Heuer, Martin Elsner, Rani Bakkour, Maxime Julien, Merve Oztoprak, Stefan Schouten, Shohei Hattori, Thorsten Dittmar
Summary: Recent studies have shown that electrospray-ionization Orbitraps and other mass spectrometers widely used in life sciences can be used for high-precision isotope ratio analysis. In this article, the authors introduce current topics in stable isotope research and discuss how soft-ionization mass spectrometry coupled with ultrahigh mass resolution can lead to significant progress. They highlight the potential of observing isotopes in intact polar compounds and speculate on future directions of research in the overlapping realms of biology, chemistry, and geology.
JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY
(2023)
Article
Limnology
Yuanbi Yi, Chen He, Katrin Klaproth, Julian Merder, Penghui Li, Yulin Qi, Pingqing Fu, Siliang Li, Thorsten Dittmar, Quan Shi, Ding He
Summary: Fourier ion cyclotron resonance mass spectrometry (FT-ICR MS), an ultrahigh-resolution technique, is widely used in dissolved organic matter (DOM) research. Different data processing and interpretation strategies do not significantly affect the geochemical interpretations based on DOM molecular composition.
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2023)
Article
Limnology
Sahithya Phani Babu Vemulapalli, Christian Griesinger, Thorsten Dittmar
Summary: An in-depth structural characterization of marine dissolved organic matter (DOM) is crucial for a better understanding of its connection to marine and global biogeochemical cycles. High-field nuclear magnetic resonance (NMR) spectroscopy, especially two-dimensional (2D) correlation spectroscopy (COSY), has been demonstrated to be effective in analyzing the molecular level structural information of marine DOM. The application of nonuniform sampling (NUS) in 2D COSY has shown to reduce the measurement time, improve spectral quality, and enhance signal intensity, leading to significant progress in the analysis of poorly characterized marine DOM.
LIMNOLOGY AND OCEANOGRAPHY-METHODS
(2023)
Article
Environmental Sciences
Hongyan Bao, Jing Qiao, Dekun Huang, Jutta Niggemann, Yuanbi Yi, Weiqiang Zhao, Silin Ni, Thorsten Dittmar, Shuh-Ji Kao
Summary: The biolability of rainwater dissolved organic matter (DOM) at the molecular level has been examined for the first time in this study. Results showed that approximately 50% of rainwater DOC and around 90% of formic acid (FA) and acetic acid (AA) were bioconsumed within 28 days. Additionally, our findings revealed the quantitative and qualitative understanding of the bioavailability of rainwater DOM, which is crucial for comprehending their impact on biogeochemical cycles and environmental health in receiving waters.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Tassiana Soares Gonsalves Serafim, Marcelo Gomes de Almeida, Gerard Thouzeau, Emma Michaud, Jutta Niggemann, Thorsten Dittmar, Michael Seidel, Carlos Eduardo de Rezende
Summary: This study investigated the dynamics, concentrations, and isotopic carbon composition of black carbon (BC) and organic matter (OM) in coastal sediments in northeastern South America. The results showed that the composition of OM has changed due to land-use changes, and BC contents varied between different drainage basin vegetation covers. BC distribution exhibited different trends in the coastal zones, and the sources and transformation processes of BC differed in each area. The findings suggest that land cover changes in the Amazon and Atlantic Rainforests may have significant impacts on marine carbon cycling.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Environmental Sciences
Stephan L. Seibert, Janek Greskowiak, Friederike Bungenstock, Holger Freund, Martina Karle, Rena Meyer, Gualbert H. P. Oude Essink, Joeri van Engelen, Gudrun Massmann
Summary: Groundwater abstraction, drainage, sea-level rise, surface elevation changes, and development of drainage networks and groundwater abstraction are the main drivers for salinization of low-lying coastal groundwater systems in Northwestern Germany over the past 9,000 years. The paleo-modeling framework used in this study provides a blueprint for reconstructing salinity distributions and modeling future groundwater systems in a changing climate.
WATER RESOURCES RESEARCH
(2023)
Article
Limnology
Hongyan Bao, Jutta Niggemann, Moge Du, Weiqiang Zhao, Dekun Huang, Yuanbi Yi, Jin-Yu Terence Yang, Thorsten Dittmar, Shuh-Ji Kao
Summary: Dissolved black carbon (DBC) is a major organic carbon pool in the ocean, but its sources and processing in coastal seas are poorly understood. A study in the East China Sea and South Yellow Sea found that mixing processes primarily control the concentration and composition of DBC. Riverine input and offshore water contributed 22% and 63% of DBC, respectively, in the study region. Atmospheric deposition and other unknown sources also contributed at least 15% of DBC.
LIMNOLOGY AND OCEANOGRAPHY
(2023)
Article
Ecology
Philipp Maurischat, Michael Seidel, Thorsten Dittmar, Georg Guggenberger
Summary: The Tibetan Plateau is the world's largest and highest plateau, highly sensitive to climate change and human activities. Carbon cycling on the plateau is influenced by glacier degradation and pasture ecosystem changes. The complexity of dissolved organic matter (DOM) cycling along the hydrological continuum and its response to land use and climate change are still poorly understood.
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.