Article
Engineering, Marine
Rachel Presley, Jane M. Caffrey
Summary: Seagrass beds are important coastal habitats that have the ability to fix nitrogen for plant nutrition. This study found that nitrogen fixation rates are higher in sediments colonized by seagrass, with different seagrass species and seasons affecting the rates.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Marine & Freshwater Biology
Olaf Dellwig, Anne Koehler, Florian Kurzweil, Mischa Schoenke, Antje Wegwerth, Siegfried Krueger, Robert Mars, Sascha Plewe, Ingo Schuffenhauer, Ruifeng Zhang, Helena C. Frazao, Joanna J. Waniek, Helge W. Arz
Summary: W tungsten is a promising proxy tool for reconstructing redox conditions, but its behavior in brackish/marine environments is not well studied. This study presents a dataset of W and Mo concentrations in water column and sediment samples from the northern South China Sea, providing insights into the behavior of W in modern aquatic ecosystems.
ESTUARINE COASTAL AND SHELF SCIENCE
(2023)
Article
Environmental Sciences
T. Howson, P. J. Chapman, N. Shah, R. Anderson, J. Holden
Summary: Afforestation is a significant cause of global peatland degradation, affecting water table depth and porewater chemistry in wetlands. Differences in solute concentrations and water table depth were observed between afforested and intact sites, highlighting the impact of forest clear-felling on wetland ecosystems.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Oceanography
Liqin Duan, Jinming Song, Xuegang Li, Huamao Yuan
Summary: This study evaluates the migration and removal of redox sensitive elements (RSEs) at the sediment-water interface (SWI) off the Changjiang Estuary by examining the porewater and solid RSEs. The concentrations of porewater and solid RSEs decrease with depth, and the removal of Mo is mediated by Fe-S phase while the removal of U is microbial-mediated reduction. The peaks of dissolved nitrate, Fe2+ and acid volatile sulfur (AVS) correspond to the downward removal of V, U and Mo, and the upward shift of RSE peaks in porewater reflects the occurrence of hypoxia in summer.
CONTINENTAL SHELF RESEARCH
(2023)
Article
Environmental Sciences
Jelmer van Doorn, Esther C. H. E. T. Lucassen, Sarah Faye Harpenslager, Lennart Santbergen, Jan G. M. Roelofs, Alfons J. P. Smolders
Summary: This study investigated the impact of sudden disappearance of isoetids on biogeochemical carbon and nutrient cycling in organic rich sediments through a greenhouse experiment. The findings revealed that the removal of isoetids led to a decrease in sediment redox potential, resulting in anaerobic breakdown of organic matter and increased concentrations of ammonium, iron, inorganic carbon and methane in porewater.
Article
Environmental Sciences
Xiaozhu Liu, Tao Ma, Qunqun Liu, Yanqing Sheng
Summary: This study investigated the release of arsenic (As) in coastal sediments and its relationship with redox conditions, nitrogen, and phosphate in the overlying water. Under anaerobic conditions, As release showed a release-dynamic equilibrium pattern, mainly due to the reduction of As(V) to As(III). Under aerobic conditions, a release-remove-release pattern was observed. Nitrogen concentration affected anaerobic metabolism of microorganisms and the reduction of Fe(III) oxides, while phosphate had limited effect on As release.
ENVIRONMENTAL EARTH SCIENCES
(2022)
Article
Green & Sustainable Science & Technology
Xin Lv, Songhe Zhang, Lisha Zhang, Shaozhuang Guo, Yu Ma, Tiantian Zhou
Summary: This study investigated nutrient transfer and microbial community shift during the decomposition of submerged macrophyte Hydrillaverticillata in flowing water and static water environments. The results showed that water flow stimulated cellulase activity and influenced nutrient transfer. Turnover affected microbial diversity, and water flow improved microbial community stability and altered the microbial food web.
JOURNAL OF CLEANER PRODUCTION
(2023)
Article
Environmental Sciences
Clara Turetta, Elena Barbaro, Mark L. Skidmore, Andrea Gambaro, Alexander B. Michaud, Andrew C. Mitchell, Trista J. Vick-Majors, John C. Priscu, Carlo Barbante
Summary: This study reports the geochemical characteristics of Whillans Subglacial Lake (SLW) in West Antarctica using direct sampling technology. The results show clear changes in rare earth element concentrations and redox sensitive trace element concentrations in sediment porewaters, indicating the existence of a complex and dynamic geochemical system beneath the West Antarctic Ice Sheet. The study also highlights the importance of subglacial lakes as unique environments for microbial life and natural biogeochemical cycles, as well as their impact on basal hydrology and ice flow variations.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Geochemistry & Geophysics
J. T. Middleton, A. Paytan, M. Auro, M. A. Saito, T. J. Horner
Summary: The isotope composition of barium (Ba) in barite (BaSO4) is a powerful tool for tracing the cycles of pelagic Ba, carbon, and sulfur. This study analyzed the Ba isotope composition of porewaters and co-located BaSO4 in sediments from the Equatorial Pacific, and conducted laboratory experiments to assess the rates of Ba isotope alteration. The results suggest that ion exchange occurs in Equatorial Pacific sediments, and this process drives the observed Ba isotope offsets between pelagic BaSO4 and porewaters.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Marine & Freshwater Biology
Hongtian Luo, Xiaojuan Dai, Yufeng Yang, Songguang Xie
Summary: The decomposition of Gracilaria seaweed has a significant impact on water quality by releasing carbon, nitrogen, and phosphorus into the surrounding environment. Proper management and removal of decaying seaweed are crucial to prevent adverse effects on water quality.
ESTUARINE COASTAL AND SHELF SCIENCE
(2022)
Article
Ecology
Ove H. Meisel, Joshua F. Dean, Jorien E. Vonk, Lukas Wacker, Gert-Jan Reichart, Han Dolman
Summary: Thermokarst lakes play a crucial role in permafrost environments, creating perennially thawed zones that enhance degradation and greenhouse gas emissions. Organic carbon content in lake sediment is higher than in underlying permafrost soil, but both layers exhibit high concentrations of dissolved organic carbon. Stable carbon isotope analysis suggests increased fractionation due to ongoing processes in the lake sediment, indicating greater degradation of organic carbon compared to the underlying soil.
Article
Limnology
Toshimi Nakajima, Ryo Sugimoto, Takahiro Kusunoki, Katsuhide Yokoyama, Makoto Taniguchi
Summary: The study found that oceanic water is the main source of nutrients for coastal ecosystems along the Sanriku Bay, but land-derived nutrients can also accelerate coastal primary production during certain seasons.
LIMNOLOGY AND OCEANOGRAPHY
(2021)
Article
Agronomy
Yupeng Lu, Zhu Gao, Jipeng Mao, Mengfei Lin, Xuchen Gong, Xiaoling Wang
Summary: This study aimed to investigate the decomposition differences of kiwifruit litters with different qualities and confirm the Initial Litter Quality Hypothesis. The results showed that the litter quality affected the decomposition rate, which in turn affected the dynamic processes of nutrient release and soil enzyme activity.
Article
Biochemistry & Molecular Biology
Peng Yin, Bjorn Thrandur Bjornsson, Per Gunnar Fjelldal, Takaya Saito, Sofie Charlotte Remo, Rolf Brudvik Edvardsen, Tom Hansen, Sandeep Sharma, Rolf Erik Olsen, Kristin Hamre
Summary: Accumulating evidence suggests a close relationship between oxidative stress and growth rate in fish, but the underlying mechanisms are not clear. This study investigated the combined effect of dietary antioxidants and growth hormone (GH) on the redox status of liver and muscle in Atlantic salmon. The results show that GH implantation decreases vitamin C and E levels, increases oxidative stress in the liver, and affects the expression of genes and pathways related to antioxidant enzymes and redox balance. Dietary antioxidants do lower oxidative stress but have no effect on the growth rate.
Article
Engineering, Civil
Fan Feng, Yonghai Jiang, Yongfeng Jia, Changjian Shang, Xinying Lian, Yongge Zang, Meng Zhao
Summary: The study evaluated the potential risk of multiple contaminants mobilization from sediment during groundwater recharge induced by reactive organic matter (OM) infiltration. Significant release of NH4-N, PO4, As, Fe, and Mn was observed initially, followed by a decline, reaching low and stable levels. Re-oxidization with SO42- stimulated the release of Fe and Mn, but had no effect on As, NH4-N, and PO4. NH4-N and PO4 were mobilized passively due to the dissolution of Fe/Mn oxides. Cation exchange played a significant role in NH4+ release, while desorption affected PO43-. Microorganisms responded to the infiltration of reactive OM and influenced the mobilization of contaminants. The precipitation of secondary Fe/Mn minerals and their co-precipitation and/or re-absorption lowered the aqueous concentrations. However, the risk of aqueous contamination was hidden in solid reactive secondary minerals, which were disturbed by oxidizers like SO42-. This highlights the importance of considering the perennial release of nutrients and trace elements in areas with reactive OM infiltration and redox/groundwater chemistry fluctuations, such as the hyporheic zone of rivers/lakes and managed aquifer recharge zones.
JOURNAL OF HYDROLOGY
(2023)