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
Environmental Sciences
Chengji Shen, Yu Fan, Xibin Wang, Wenjing Song, Ling Li, Chunhui Lu
Summary: Submarine groundwater discharge is a crucial pathway for land-derived chemicals to enter the oceans. This study investigates the effects of land reclamation on flow and mixing processes in a nearshore subterranean estuary through laboratory experiments and numerical simulations. The study finds that reclamation soil alters the tide-driven upper saline plume and affects the freshwater discharge zone and saltwater wedge.
WATER RESOURCES RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Donald A. Beebe, Mary Brandon Huettemann, Bret M. Webb, William T. Jackson
Summary: By studying anomalies in coastal aquifer hydraulic head time-series, we found that atmospheric forcing has a greater impact on groundwater exchange and residence time, especially during winter. Winter atmospheric groundwater forcing is associated with winter storm passage, occurring approximately every 7 days. In summer, atmospheric groundwater forcing is limited to weak diurnal atmospheric convection and infrequent tropical cyclone activity.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Xiayang Yu, Pei Xin, Chengji Shen, Ling Li
Summary: This article examined the variation of submarine groundwater discharge and salinity distributions in coastal unconfined aquifers with fixed-head inland boundaries at different distances from the shoreline through numerical simulations. The results showed that as the inland aquifer extent decreased, the fluctuation intensity of freshwater input increased, and interactions among different tidal constituents were enhanced. The influence of antecedent tidal conditions on inland freshwater input and salinity distributions was found to depend on the inland aquifer extent.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2021)
Article
Environmental Sciences
Alison E. O'Connor, Elizabeth A. Canuel, Aaron J. Beck
Summary: The subterranean estuary (STE) is characterized by the mixing of saline and fresh water as well as redox gradients. This study focused on the redox chemistry of the STE and found that microbial respiration and availability of organic matter play important roles in metal transport. Interactions between metals and sulfide, as well as microbial activity, influenced the behavior of redox-sensitive metals in the STE.
FRONTIERS IN ENVIRONMENTAL SCIENCE
(2022)
Article
Biochemistry & Molecular Biology
Clara Ruiz-Gonzalez, Lara Rodriguez-Pie, Olena Maister, Valenti Rodellas, Aaron Alorda-Keinglass, Marc Diego-Feliu, Albert Folch, Jordi Garcia-Orellana, Josep M. Gasol
Summary: This study provides the first spatially-resolved characterization of bacterial assemblages in a coastal aquifer in the NW Mediterranean. The researchers found large variations in prokaryotic abundances, activity, and diversity along the salinity gradient, reflecting the pronounced physicochemical gradients. The study also revealed highly heterogeneous prokaryotic communities in subterranean estuaries, indicating spatial variability in their role in nutrient transformation within these land-sea transition zones.
Article
Water Resources
Laszlo Palcsu, Alena Gessert, Marianna Turi, Attila Kovacs, Istvan Futo, Judit Orsovszki, Anita Puskas-Preszner, Marjan Temovski, Gabriella Koltai
Summary: Our study focuses on three karst regions in Hungary and Slovakia, examining the response of discharging karst waters to recharge using environmental tracers. The results demonstrate the importance of sampling frequency in detecting short residence times and highlight the significance of long-term time series for better estimation of age distribution in karst water systems. The study findings suggest that shallow springs have short residence times, with H-3/He-3 and SF6 apparent ages confirming this to be between 0 and 10 years.
JOURNAL OF HYDROLOGY-REGIONAL STUDIES
(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, Environmental
Zhijia Ci, Yongguang Yin, Wenjie Shen, Baowei Chen
Summary: Coastal ecosystems are important storage zones and hotspots for the production and accumulation of neurotoxic methylmercury. This study explores the dynamics and biogeochemical transformation of mercury in two distinct subterranean estuaries (STE) in northern China. The results show non-conservative mixing behaviors of mercury in the groundwater flow paths of the STEs and highlight the significance of the hydrological shifts and biogeochemical processes in driving the transport and transformation of mercury. These findings have implications for accurately calculating mercury fluxes to coastal waters and understanding the impacts of human activities and climate change on the mercury biogeochemical cycle in coastal aquifers.
Article
Environmental Sciences
Jiapeng Wu, Yiguo Hong, Stephanie J. Wilson, Bongkeun Song
Summary: This study investigated the activities, abundances, and diversity of N loss communities in a subterranean estuary using various techniques. The results showed the presence of denitrifiers and anammox bacteria in the aerobic-anaerobic transition zone, playing equal roles in nitrogen loss.
MARINE POLLUTION BULLETIN
(2021)
Review
Geosciences, Multidisciplinary
Willard S. Moore, Samantha B. Joye
Summary: Saltwater intrusion into freshwater coastal aquifers is a global issue caused by over-pumping of freshwater and sea level rise. This intrusion impacts drinking water, agriculture, industry, and alters the biogeochemistry of subterranean estuaries, resulting in the release of nutrient-rich groundwater into the ocean. Climate change exacerbates sea level variations, potentially increasing saltwater intrusion and promoting biological productivity, but also posing risks to the environment and local ecology.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geochemistry & Geophysics
Larissa Costa, Nicolai Mirlean, Karen H. Johannesson
Summary: The study investigated the content and distribution of rare earth elements (REE) in sediment cores collected from the Patos Lagoon estuary in southern Brazil. The research found that sediments from both relatively unimpacted and polluted areas show enrichment in light REEs (LREE) over heavy REEs (HREE), providing clues to contamination possibly originating from the local fertilizer manufacturing industry.
APPLIED GEOCHEMISTRY
(2021)
Article
Marine & Freshwater Biology
Xijie Yin, Yunpeng Lin, Yunhai Li, Liang Wang, Zhilei Sun, Guogang Li
Summary: The study examined the cycling of inorganic sulfide species and the control mechanisms in sediments of the Pearl River Estuary (PRE). The formation of iron sulfides (AVS and pyrite) was mainly influenced by the reactive iron content in the sediments, with variations in different sediment depths. The delta S-34 values of AVS and SO42- increased synchronously with depth, while the delta S-34 value of pyrite increased slowly due to the burial time. The burial and formation of pyrite differed in different sub-regions of the PRE.
ESTUARINE COASTAL AND SHELF SCIENCE
(2023)
Article
Environmental Sciences
Stephanie J. Wilson, Iris C. Anderson, Bongkeun Song, Craig R. Tobias
Summary: Subterranean estuaries (STEs) are formed at the land-sea boundary where groundwater and seawater mix, influencing groundwater-borne nutrient concentrations and speciation. A study was conducted to assess nutrient fluxes in a STE located in the York River Estuary (YRE). The results showed significant variations in salinity, dissolved oxygen, dissolved inorganic nitrogen (DIN), and dissolved inorganic phosphorus (DIP) with depth and season. Nitrogen removal rates mediated by denitrification were relatively low. The findings suggest the importance of biogeochemical transformations in STEs for nutrient dynamics and coastal eutrophication.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Celine Charbonnier, Pierre Anschutz, Joseph Tamborski, Pieter van Beek
Summary: Benthic fluxes of biogenic compounds are important in shallow aquatic environments. This study quantified diagenetic processes and associated benthic fluxes in a lagoon, showing that molecular diffusion dominates in fine-grained sediments while advection dominates in sandy sediments. The intensity of organic matter mineralization processes is the same in both sediment types, but phosphorus retention is greater in fine sediments.
Article
Ecology
Michelle N. Simone, Joanne M. Oakes, Kai G. Schulz, Bradley D. Eyre
Summary: The impact of future climate change on benthic nitrogen recycling and assimilation was assessed in this study. The results showed that combinations of warming and ocean acidification significantly affected the fluxes of dissolved inorganic nitrogen (DIN), highlighting the importance of considering combined stressor treatments when studying ecosystem responses to future climates.
MARINE ECOLOGY PROGRESS SERIES
(2022)
Article
Multidisciplinary Sciences
Liza K. McDonough, Martin S. Andersen, Megan Behnke, Helen Rutlidge, Phetdala Oudone, Karina Meredith, Denis M. O'Carroll, Isaac R. Santos, Christopher E. Marjo, Robert G. M. Spencer, Amy M. McKenna, Andy Baker
Summary: Groundwater contains a diverse mix of dissolved organic matter (DOM) molecules, which undergo different degradation pathways compared to those in marine, river, and lake systems. The degradation of groundwater DOM has significant implications for the global carbon cycle.
NATURE COMMUNICATIONS
(2022)
Article
Environmental Sciences
Peisheng Huang, Eduardo R. De Sousa, Naomi S. Wells, Bradley D. Eyre, Badin Gibbes, Matthew R. Hipsey
Summary: Estuaries play a significant role in the global greenhouse gas budget, but there are uncertainties in modeling predictions of CO2 and CH4 emissions. This study presents a modeling framework to assess the sensitivity and uncertainty of CO2 and CH4 concentrations and emissions, applied to the Brisbane River in Australia. The findings demonstrate that riverine inputs are the main factor influencing estuarine CO2 concentrations, while sediment production and pelagic oxidation are the main factors influencing estuarine CH4 concentrations.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Limnology
Stefano Bonaglia, Tobias Rutting, Mikhail Kononets, Anders Stigebrandt, Isaac R. Santos, Per O. J. Hall
Summary: Oceanic methane budgets lack data from high-latitude fjords, which often exhibit intermittent anoxic conditions and potentially high methane emissions. A study conducted in a Scandinavian fjord between 2009 and 2021 found that benthic fluxes were highest at the deepest anoxic site, supporting bottom water methane concentrations exceeding 5000 nM. Mixing events displaced methane-rich bottom waters, increasing upper water concentrations and driving high sea-air flux. The study suggests that fjords globally emit 1.0 +/- 0.8 Tg CH4 per year and that ongoing deoxygenation and global change will enhance methane emissions from fjords.
LIMNOLOGY AND OCEANOGRAPHY LETTERS
(2022)
Article
Environmental Sciences
Anita K. Perkins, Isaac R. Santos, Andrew L. Rose, Kai G. Schulz, Hans-Peter Grossart, Bradley D. Eyre, Brendan P. Kelaher, Joanne M. Oakes
Summary: Marine macroalgae, as a primary producer in coastal ecosystems, play a crucial role in blue carbon sequestration. This study focused on the fate of carbon from macroalgal detritus deposition on beaches. The results showed that a significant amount of carbon was released as dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC), while a small portion was emitted as CO2. Carbonate alkalinity formed during degradation could contribute to coastal carbon cycling and marine carbon sequestration.
Article
Geosciences, Multidisciplinary
Bochao Xu, M. Bayani Cardenas, Isaac R. Santos, William C. Burnett, Matthew A. Charette, Valenti Rodellas, Sanzhong Li, Ergang Lian, Zhigang Yu
Summary: Radium isotopes are important tools in oceanography and hydrology research. Current radium mass balance models often overlook the impact of particle scavenging on dissolved radium removal. We built a global ocean Ra-226 mass balance model and reevaluated the importance of particle scavenging. Our study found that particle scavenging is the major pathway for Ra-226 removal in the upper ocean.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Environmental Sciences
Shijie Gu, Siyue Li, Isaac R. Santos
Summary: This study investigates the CO2 emissions from monsoonal rivers in the Han River drainage to the Yangtze in China and reveals the significant impact of anthropogenic land use on riverine CO2 emissions. The findings indicate that agricultural and urban land activities contribute to increased CO2 emissions, while forest cover is negatively correlated with CO2 emissions. The study highlights the importance of considering land use in estimating riverine CO2 emissions and suggests reforestation as a strategy to improve the carbon balance of rivers.
JOURNAL OF ENVIRONMENTAL SCIENCES
(2022)
Article
Limnology
Yvonne Y. Y. Yau, Pei Xin, Xiaogang Chen, Lucheng Zhan, Mitchell Call, Stephen R. Conrad, Christian J. Sanders, Linwei Li, Jinzhou Du, Isaac R. Santos
Summary: Saltmarshes are important blue carbon ecosystems that accumulate a large amount of organic carbon in sediments. This study found that the export of alkalinity into the ocean from saltmarshes can be comparable to organic carbon burial, contributing to the ocean buffering capacity and long-term carbon storage.
LIMNOLOGY AND OCEANOGRAPHY
(2022)
Article
Environmental Sciences
Tiago Passos, Dan Penny, Roberto Barcellos, S. Bijoy Nandan, D. S. Suresh Babu, Isaac R. Santos, Christian J. Sanders
Summary: This study uses sediment profiles from an impacted tropical estuary in India to examine the long-term consequences of mangrove deforestation. The results show that deforestation leads to increased carbon and nutrient accumulation rates, as well as the enrichment of trace metals. The study highlights the critical role of mangrove ecosystems in attenuating anthropogenically-derived pollutants.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Environmental Sciences
Jian-Jhih Chen, Naomi S. Wells, Dirk Erler, Bradley D. Eyre
Summary: Land-use changes in catchments have an impact on benthic N2O cycling in estuaries, with benthic habitats acting as either a sink or source of N2O. Benthic N2O fluxes are significantly correlated with benthic NO3- fluxes, indicating the importance of NO3- availability in controlling benthic N2O fluxes.
JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES
(2022)
Article
Environmental Sciences
Judith A. Rosentreter, Goulven G. Laruelle, Hermann W. Bange, Thomas S. Bianchi, Julius J. M. Busecke, Wei-Jun Cai, Bradley D. Eyre, Inke Forbrich, Eun Young Kwon, Taylor Maavara, Nils Moosdorf, Raymond G. Najjar, V. V. S. S. Sarma, Bryce Van Dam, Pierre Regnier
Summary: This article analyzes data from 738 observation sites and finds that coastal ecosystems have a certain absorption effect on greenhouse gases in the atmosphere, but methane and nitrous oxide emissions counteract the absorption of carbon dioxide. Southeast Asia, North America, and Africa are identified as hotspots for coastal greenhouse gas absorption.
NATURE CLIMATE CHANGE
(2023)
Article
Environmental Sciences
Bradley D. Eyre, Nicola Camillini, Ronnie N. Glud, Judith A. Rosentreter
Summary: Blue carbon refers to carbon stored in vegetated coastal ecosystems for a long time, which is an important sink for atmospheric CO2. However, the production and release of methane and nitrous oxide during organic matter decomposition can affect the climate benefit of blue carbon. A meta-analysis of seagrass methane and nitrous oxide fluxes and organic carbon burial rates was conducted, and the reduced climate benefit of seagrass blue carbon was estimated using three upscaling approaches. The study found that methane and nitrous oxide release from seagrass ecosystems offset around 7% to 33% of the global climate benefits of CO2 drawdown by seagrasses. This highlights the importance of considering methane and nitrous oxide fluxes and using long-term organic carbon burial rates in future assessments of seagrass blue carbon.
COMMUNICATIONS EARTH & ENVIRONMENT
(2023)
Correction
Environmental Sciences
Kay L. Davis, Andrew P. Colefax, James P. Tucker, Brendan P. Kelaher, Isaac R. Santos
COMMUNICATIONS EARTH & ENVIRONMENT
(2022)
Letter
Environmental Sciences
Kay L. Davis, Andrew P. Colefax, James P. Tucker, Brendan P. Kelaher, Isaac R. Santos
COMMUNICATIONS EARTH & 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.