Mercury (Hg) isotopes provide a useful tool to understand Hg sources and processes in the environment. The Hg isotopic composition of seawater remains poorly constrained due to the lack of an efficient method to process large volumes of low-Hg-concentration seawater samples. Here, we develop a continuous flowdouble purge and trap device for the in situ preconcentration of Hg in seawater. This method yielded a good Hg recovery of 91.7 ± 3.3% ( = 4, 1SD) for spiked seawater samples and gave reasonably similar Hg isotope ratios of NIST 8610, indicating a limited matrix effect and limited Hg isotope fractionation during processing of seawater. NIST 8610 δHg (-0.55 ± 0.09‰, = 4, 1SD) and ΔHg (0.07 ± 0.02‰, = 4, 1SD) were similar to previously published data. The method was successfully applied to seawater collected from the Xiamen Bay and the South China Sea. The seawater samples showed a Hg recovery of 91.6 ± 5.4% ( = 12, 1SD). Seawater ΔHg (-0.04 ± 0.05‰, = 7, 1SD) in the Xiamen Bay was different from seawater ΔHg (0.05 ± 0.07‰, = 5, 1SD) in the South China Sea, which implies distinct Hg sources to coastal and open ocean areas and highlights the robustness of our method in understanding the Hg isotopic composition of seawater.
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Sci Rep
December 2024
School of Environmental Science, The University of Shiga Prefecture, Hassakacho, Hikone, 2500, 522-8533, Japan.
Mangrove forests are increasingly recognized as vital blue carbon ecosystems due to their high carbon sequestration capacity, primarily through the accumulation of soil organic carbon (SOC). Recent research highlights that, in addition to SOC, dissolved inorganic carbon (DIC), particularly in the form of bicarbonate (HCO₃⁻), plays a crucial role in carbon sequestration by being exported from these ecosystems to adjacent coastal waters. This study aims to investigate the previously unexamined mechanisms behind bicarbonate production in mangrove soils.
View Article and Find Full Text PDFNat Commun
December 2024
Department of Marine Science, University of Otago, Dunedin, New Zealand.
What little we know about how microbiomes change over the course of host dispersal has been gleaned from simulations or snapshot sampling of microbiomes of hosts undertaking regular, cyclical migrations. These studies suggest that major changes in both microbiome richness and turnover occur in response to long-distance movements, but we do not yet know how rare or sporadic dispersal events for non-migratory organisms might affect the microbiomes of their hosts. Here we directly examine the microbiomes of rafting seaweed, leveraging host genomic analyses, amplicon sequencing, and oceanographic modelling to study the impacts of ecological dispersal of hosts on their microbiomes.
View Article and Find Full Text PDFChemosphere
December 2024
Department of Earth, Environmental & Space Sciences, Chungnam National University, Daejeon 34134, Republic of Korea. Electronic address:
This study focused on analyzing the spatial and vertical distributions of 28 per- and polyfluoroalkyl substances (PFASs), which comprised five precursors and three alternatives, in the water columns of the regional seas surrounding South Korea, such as the Yellow Sea (YS, Y1-Y10), East China Sea (ECS, EC1-EC6), South Sea (SS, S1-S5), and East Sea (ES, E1-E7). The concentrations of these PFASs detected in 204 seawater samples varied from below the limit of detection (
Mar Pollut Bull
December 2024
Department of Marine Ecology, Faculty of Aquaculture and Marine Fisheries, Arish University, Egypt. Electronic address:
This study examines pollution, ecotoxicological, and health risks of B, F, and S in seawater and sediments along the southern Mediterranean Sea. Strong positive loading on B in sediment, PLI, and NPI suggested that the high B content raises the total amount of contamination and cumulative risks to benthic organisms. Logk for S and F were <3 indicating that they were easily transported to the water column.
View Article and Find Full Text PDFSci Total Environ
December 2024
Ministry of Natural Resources Key Laboratory for Polar Sciences, Polar Research Institute of China, NO.451, Jinqiao Road, Shanghai, 200136, China; Zhejiang University of Water Resources and Electric Power, NO. 508, Second Avenue, Hangzhou, Zhejiang, 310018, China. Electronic address:
We investigate the spatial distribution and potential ecological impact of Currently Used Organophosphorus Pollutants (CUOPPs) in the Arctic Ocean, focusing on the East Siberian Sea, Laptev Sea, and high Arctic regions. Analyzing surface water samples collected during a scientific expedition aboard the "Xuelong 2" in August and September 2021, we detected 38 out of 83 targeted CUOPPs, including Phorate, Paraoxon, and Azinphos-ethyl, with concentrations exhibiting significant geographical variance. The results reveal a pronounced increase in CUOPP concentrations towards the Arctic poles, diverging markedly from the patterns observed in the East China Sea, thereby highlighting distinct regional pollution profiles and environmental interactions.
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