Marine Chemistry最新文献

{"title":"Distribution and chemical composition of atmospheric aerosols over the Gulf of Thailand during the southwest monsoon","authors":"Jariya Kayee ,&nbsp;Penjai Sompongchaiyakul ,&nbsp;Reshmi Das ,&nbsp;Xianfeng Wang ,&nbsp;Narainrit Chinfak ,&nbsp;Sukchai Arnupapboon ,&nbsp;Sujaree Bureekul","doi":"10.1016/j.marchem.2026.104645","DOIUrl":"10.1016/j.marchem.2026.104645","url":null,"abstract":"<div><div>Marine aerosols were collected over the Gulf of Thailand (GOT) during the 2018 southwest monsoon on board the M.V. SEAFDEC2 while sailing. Water-soluble inorganic ions (i.e., Na⁺, NH₄⁺, K⁺, Mg²⁺, Ca²⁺, Cl⁻, NO₃⁻, and SO₄²⁻) and elemental concentrations (i.e., Al, As, Ba, Ca, Cd, Cu, Cr, Fe, Mg, Mn, Na, Ni, Pb, Sr, V, and Zn) were determined to investigate their distribution patterns in order to evaluate the influence of particle sources on the chemical properties of atmospheric aerosols. During the southwest monsoon, the wind predominantly blows over the Indian Ocean to the GOT. Correspondingly, our results indicated that coarse particles are dominated by sea salts. Cl⁻ and Na⁺ are the major ions, accounting for ∼64.8% (range: 51.2–84.3%) of total ions in the coarse mode particles. The strong correlation between Cl⁻ and Na⁺ (<em>r</em> = 0.999) along with the Cl/Na ratio (1.5, range: 0.66–2.00) suggest sea salt origin. Enrichment factor (EF) values indicate that elements are originated from oceanic, crustal, and anthropogenic sources. The oceanic source (Sr, Ca, Mg and Na) explains 95% (range: 81–99%) of total elements in the aerosols. Elements such as Al, Fe, Mn and Ba explain 4.6% of the total elements. These elements associate with the crustal source. Only a minimal amount (0.63%, range: 0.02–4.5%) of the total elements is originated from anthropogenic activities over or nearby the GOT as shown by loading of As, Cd, Cu, Cr, Ni, Pb, V and Zn.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"276 ","pages":"Article 104645"},"PeriodicalIF":2.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioaccumulation of rare earth elements (REEs) and trace metals in corals of the South China Sea","authors":"Yao-Wen Qiu ,&nbsp;Han-Lin Qiu","doi":"10.1016/j.marchem.2026.104644","DOIUrl":"10.1016/j.marchem.2026.104644","url":null,"abstract":"<div><div>Global coral coverage has declined significantly, and environmental pollution is a factor that cannot be ignored. This study presents a comprehensive investigation into the bioaccumulation of rare earth elements (REEs) and other trace elements in corals from two distinct coral reef areas in the South China Sea (SCS). Results revealed that the concentrations of trace elements in coastal corals (tissues + skeleton) from Sanya were generally higher than those in offshore Xisha corals, with median REEs values of 1.35 μg g⁻¹ dw and 0.22 μg g⁻¹ dw, respectively. The predominant trace elements in corals from both regions were B, Ni, Zn, and Cu, while the dominant REEs plus yttrium (REY) were Ce, La, Y, and Nd. Trace metal (including REY) concentrations were significantly higher in massive, densely structured <em>Porites</em> than in branching <em>Pocillopora</em> and <em>Acropora</em>. The standardized coral REY patterns showed the depletion of heavy REEs and enrichment of light REEs bioaccumulation, as well as positive anomalies of La and Eu, weak negative anomaly of Ce and high Y/Ho ratio (&gt;50). The results demonstrated that REY accumulated more easily from seawater than from sediment. This study indicates that the geochemical characteristics of REY in corals can serve as a reliable alternative proxy to assess the environmental quality of local seawater and sediment, and may provide new insights into the coral bioaccumulation patterns of trace metals, including REEs.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"276 ","pages":"Article 104644"},"PeriodicalIF":2.5,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147797891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Distributions of particulate Al and Fe in the Bay of Bengal and south Indian subtropical gyre","authors":"Pamela M. Barrett ,&nbsp;Joseph A. Resing ,&nbsp;Maxime M. Grand ,&nbsp;Christopher I. Measures ,&nbsp;William M. Landing","doi":"10.1016/j.marchem.2026.104611","DOIUrl":"10.1016/j.marchem.2026.104611","url":null,"abstract":"<div><div>The trace element composition (Al, Si, P, Ca, and Fe) of suspended particulate matter is presented for the upper 1000 m of the water column along U.S. CLIVAR/CO₂ Repeat Hydrography zonal section I05 (2009) in the South Indian subtropical gyre and meridional section I09N/I08S (2007) in the eastern Indian Ocean from the Bay of Bengal to the subtropical front. Along I09N, high particulate Al and Fe concentrations are found throughout the Bay of Bengal and the northern Indian Ocean indicating significant lithogenic particle loads from river-borne sediment transport and smaller contributions from continental dust flux than current model estimates. Particles have elevated Fe:Al ratios compared to the composition of local shelf sediments, indicating that suspended particulate matter becomes enriched from scavenging of dissolved Fe that accumulates in the oxygen minimum zone in the Bay of Bengal. Along I05, retroflection of the Agulhas Return Current transports African shelf-derived lithogenic particles into the western South Indian basin, resulting in the elevated subsurface concentrations of particulate Al and Fe nearly 3000 km into the interior of the subtropical gyre. Another region of elevated dissolved Fe concentrations and Fe-enriched particulate matter was also observed along I05 in intermediate waters (&gt;600 m) in the subtropical gyre at 32°S between 70 and 74°E, suggesting inputs from a shallow sedimentary or possibly volcanic Fe source to these stations. Comparison of data from the crossover between the I05 and I09N/I08S sections and from the 2007 and 2016 occupations of I09N allows investigation of the temporal variability of basin-scale distributions of particle-associated trace metals with relatively short residence times in the upper water column. The most pronounced differences in trace metal distributions are associated with interannual variability in productive near-coastal and upwelling regions where mixed-layer pFe concentrations vary by a factor of 2–7, whereas Fe and Al in deeper waters and dust-impacted surface waters in oligotrophic regions show significantly less variability.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104611"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399977","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to “Surface macro- and micro-nutrients within the Copper River plume region respond to along-shore winds” [Marine Chemistry volume 270 (2025) Number 104508]","authors":"E.L.S. Ortega,&nbsp;I. Reister,&nbsp;S.L. Danielson,&nbsp;A.M. Aguilar-Islas","doi":"10.1016/j.marchem.2026.104621","DOIUrl":"10.1016/j.marchem.2026.104621","url":null,"abstract":"","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104621"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399979","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The distribution of chlorophyll-a degradation derivatives in the Holocene Black Sea and their marine ecological significance","authors":"Wenshuo Zhao ,&nbsp;Junpeng Fu ,&nbsp;Olawale O. Alo,&nbsp;Xiao-Lei Liu","doi":"10.1016/j.marchem.2026.104606","DOIUrl":"10.1016/j.marchem.2026.104606","url":null,"abstract":"<div><div>Chlorophyll-<em>a</em> degradation derivatives (Chl-<em>a</em>-DDs) provide valuable insights into past phytoplankton dynamics. Using a new LC-QToF-MS method, we identified eleven steryl chlorin esters (SCEs), eight oxidative chlorophyll transformation products (OxCs), four reductive chlorophyll transformation products (ReCs), and two cyclopheophorbide derivatives (CPBs) in the Holocene Black Sea sapropel. Total Chl-<em>a</em>-DDs reveal two productivity peaks: post-stratification (∼7.5 ka) and after surface freshening (∼3 ka). ReCs track progressive redox changes, and a peak in the 3¹-meso-pyropheophytin-<em>a</em>/pyropheophytin-<em>a</em> ratio in upper Unit II implies intensified euxinia between ∼5 and 3 ka B.P. Elevated OxCs in Units II and I suggest intracellular oxidation as the dominant chlorophyll transformation pathway. SCEs dominance in Unit III indicates fecal pellet as the primary organic carbon delivery mechanism preceding stratification, while their decline in Units II and I reflects reduced grazing under euxinia. Increase in CPBs under euxinia likely reflects protists' physiological responses to oxidative stress associated with light stress.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104606"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seasonal variations in mercury species and selenium in plankton from Kagoshima Bay, southern Kyushu, Japan: Impact of active submarine volcanoes on ecosystems","authors":"Takashi Tomiyasu ,&nbsp;Hayato Uwashitomi ,&nbsp;Taijyu Wakimaru ,&nbsp;Hitoshi Kodamatani ,&nbsp;Ryo Kanzaki ,&nbsp;Toru Kobari","doi":"10.1016/j.marchem.2026.104610","DOIUrl":"10.1016/j.marchem.2026.104610","url":null,"abstract":"<div><div>Seawater and plankton sampling were conducted every two months from 2019 to 2022 in the inner and central parts of Kagoshima Bay, where submarine volcanic activity continues at a bottom of 200 m depth in the inner part. Plankton samples were collected using a plankton net, with vertical hauls at depths of 0–140 m and 140–200 m just above the submarine volcano, and at 0–200 m in the central part of the bay. The collected samples were separated into phytoplankton (&lt; 100 mm) and zooplankton (&gt; 100 mm) for analysis of organic mercury, inorganic mercury and total selenium. The inorganic mercury concentrations in phytoplankton and zooplankton collected at the 140–200 m depth just above the submarine volcano were 1.80 ± 0.61 mg kg⁻¹ and 0.47 ± 0.34 mg kg⁻¹, respectively, while organic mercury concentrations were 0.15 ± 0.11 mg kg⁻¹ and 0.16 ± 0.09 mg kg⁻¹, respectively. These values were an order of magnitude higher than those found in plankton samples from the central part of the bay. In the inner part of the bay, the concentrations of these substances increased in summer and decreased in winter, mirroring fluctuations in seawater mercury concentrations, which are influenced by volcanic activity. The selenium concentrations in phytoplankton and zooplankton at 140–200 m above the submarine volcano were 1.64 ± 0.80 mg kg⁻¹ and 1.82 ± 0.86 mg kg⁻¹, respectively, while in the central part, they were 1.17 ± 0.58 mg kg⁻¹ and 1.84 ± 0.67 mg kg⁻¹, respectively. The organic mercury and selenium concentrations were higher in zooplankton than in phytoplankton at the locations of central part and 0–140 m above the fumaroles, which may suggest migration of organic mercury and selenium to higher trophic levels. Conversely, at the location just above the submarine volcano, no significant differences were observed between phytoplankton and zooplankton, and a significant negative correlation (<em>r</em> = −0.72, <em>p</em> &lt; 0.05) was observed between selenium and organic mercury concentrations in zooplankton with high mercury levels. This negative correlation may indicate an antagonistic effect of selenium on the accumulation of organic mercury in zooplankton.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104610"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining the utility of barium isotopes as a tracer of large-scale seafloor methane venting","authors":"Ethan Petrou ,&nbsp;Luke Bridgestock ,&nbsp;Germain Bayon ,&nbsp;Nolwenn Lemaitre ,&nbsp;Ya-Zhen Wu ,&nbsp;Gideon M. Henderson ,&nbsp;Yu-Te Hsieh","doi":"10.1016/j.marchem.2026.104608","DOIUrl":"10.1016/j.marchem.2026.104608","url":null,"abstract":"<div><div>Periods of increased sedimentary barium (Ba) burial rates have been interpreted as evidence for climate-driven release of methane (CH₄) from sediments in the geological past, yet such interpretations remain ambiguous. Here, we present the first Ba isotope measurements from an active methane seep to directly evaluate whether Ba isotopes in seawater or authigenic carbonates can record Ba release associated with seafloor methane venting. Dissolved Ba concentration ([Ba]) and isotope composition (δ^138/134Ba) were measured in seawater profiles (1 m to 60 m above the seafloor) and in authigenic carbonates collected across the Regab pockmark on the Congo Margin. Seawater over the active methane venting site shows an increase of around 8% in dissolved [Ba] compared to ambient seawater at the Reference Site, indicating detectable benthic Ba release during methane venting. However, the δ^138/134Ba values of these samples (+0.23‰ to +0.42‰) are indistinguishable from ambient seawater, demonstrating that Ba released during methane venting does not impart a resolvable isotopic shift to the water column. An additional isotopically light Ba input may arise from the dissolution of Fe<img>Mn oxyhydroxide phases at the sediment water interface, but this interpretation is based on a single data point and requires further investigation. Authigenic carbonates at sites of high methane flux exhibit markedly lower δ^138/134Ba values (−0.30‰ to +0.20‰) that are markedly lower than seawater, coral carbonates, and published porewater values, indicating a potential Ba isotope fractionation linked to cold-seep carbonate formation. Overall, these findings suggest that Ba isotopes are unlikely to be a reliable tracer of Ba mobilisation associated with methane venting and challenges the interpretation of sedimentary Ba isotope records as indicators of past large-scale methane release.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104608"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146048954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Non-ignorable effect of in situ atmospheric CH4 mole fraction on calculation of diffusive CH4 emission","authors":"Kunpeng Zang ,&nbsp;Dongxia Zhao ,&nbsp;Zengyi Yang ,&nbsp;Xuemei Xu","doi":"10.1016/j.marchem.2026.104620","DOIUrl":"10.1016/j.marchem.2026.104620","url":null,"abstract":"<div><div>CH₄ mole fraction in the marine boundary layer (MBL) is one of important parameters for estimating sea-to-air CH₄ flux, while its influence was lack of quantification. In this work, the impacts of three different atmospheric CH₄ data on the calculated sea-to-air CH₄ flux were evaluated. Results showed that, compared to data observed at the Tae-ahn Peninsula station and the simulated MBL-CH₄ references, in situ observed CH₄ mole fraction in the MBL was 132 and 140 nmol/mol higher in July 2013, and 98 and 132 nmol/mol higher in February 2017 in the Bohai Sea, respectively. Different atmospheric CH₄ mole fraction induced mean deviations of 1.5 μmol/m²/day in July 2013 and 1.0 μmol/m²/day in February 2017, respectively. In addition, effects of three different atmospheric CH₄ mole fractions on sea-to-air CH₄ flux in summer in coastal shallow waters were greater than those in winter in deep open oceans. Thus, to narrow the uncertainty of carbon emission, it was essential to calculate sea-to-air CH₄ flux by using the field observed atmospheric CH₄ mole fraction, especially in coastal shallow seas.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104620"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399974","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparing methods for measuring 210Po in seawater: Fe(OH)3 can extract less 210Po than Co-APDC and thus overestimate POC export fluxes","authors":"Harold Carrasco ,&nbsp;J. Kirk Cochran ,&nbsp;Beat Gasser ,&nbsp;Inés Sanz-Alvarez ,&nbsp;Montserrat Roca-Martí ,&nbsp;Christina Heilbrun ,&nbsp;Nicholas S. Fisher ,&nbsp;Jana Friedrich ,&nbsp;Pere Masqué","doi":"10.1016/j.marchem.2026.104618","DOIUrl":"10.1016/j.marchem.2026.104618","url":null,"abstract":"<div><div>Over six decades of research, two methods have been used to extract the natural radionuclides ²¹⁰Pb and ²¹⁰Po from seawater- the precipitation of iron hydroxide (Fe(OH)₃) and coagulation of cobalt ammonium pyrrolidine dithiocarbamate (Co-APDC). Although the two methods had been intercompared for ²¹⁰Pb and shown to agree, they were never intercompared for ²¹⁰Po until <span><span>Roca-Martí et al. (2021)</span></span>, in which only unfiltered samples were used. Here we document that Fe(OH)₃ may be less effective in extracting ²¹⁰Po from a seawater sample than Co-APDC. We hypothesize that cycling of ²¹⁰Po through the marine food web can produce a fraction of dissolved ²¹⁰Po complexed with organic ligands and not efficiently precipitated by Fe(OH)₃. We compare the Fe(OH)₃ and Co-APDC methods through field sampling at the DYFAMED site in the Mediterranean Sea and complementary laboratory incubation experiments using phytoplankton. Lower dissolved ²¹⁰Po activities are extracted with Fe(OH)₃ relative to Co-APDC immediately after sampling at times of high primary productivity. No difference between the methods is found for ²¹⁰Pb. Time-series experiments with stored filtered, acidified samples show that Fe(OH)₃ can yield higher activities of ²¹⁰Po after extended storage (∼2 months), approaching values obtained with Co-APDC immediately after sample collection. In laboratory incubation experiments with diatoms and coccolithophores, exudates produced by diatoms show higher ²¹⁰Po activities using the Co-APDC method; no difference between the methods is apparent for coccolithophores. Direct comparison of the methods during a time of high productivity at the DYFAMED site suggests that POC export fluxes based on the Fe(OH)₃ method can be overestimated by ∼50% in the primary productivity zone and by much larger extents in the mesopelagic. Additional field study results from the Northeast Atlantic and Pacific Oceans support these observations. We recommend the Co-APDC method be used for marine studies involving ²¹⁰Po, especially in biologically active waters and if samples are processed soon after collection.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104618"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399976","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Molecular composition determines the nitrogen isotopic signatures of dissolved organic matter","authors":"Zhenwei Yan ,&nbsp;Yu Xin ,&nbsp;Yuanbi Yi ,&nbsp;Penghui Li ,&nbsp;Wenqi Xu ,&nbsp;Wanqing Xu ,&nbsp;Youping Zhou ,&nbsp;Chuanlun Zhang ,&nbsp;Ding He","doi":"10.1016/j.marchem.2026.104619","DOIUrl":"10.1016/j.marchem.2026.104619","url":null,"abstract":"<div><div>Marine dissolved organic matter (DOM) represents the largest reduced carbon pool in global carbon cycles. Nitrogen within marine DOM plays a crucial role in linking carbon and nitrogen cycles by serving as both a major nitrogen reservoir and a dynamic source for microbial utilization. Stable nitrogen isotopes (δ¹⁵N) of DOM could provide information about its sources and transformation in marine environments. However, the difficulties and complexities of its measurement leading to a lack of data on DOM's δ¹⁵N, limiting our understandings of marine nitrogen and carbon cycles. In this study, we developed a quick and effective machine learning method for linking δ¹⁵N of solid phase extracted DOM and its molecular composition. 325 samples with molecular composition and δ¹⁵N from China coastal environment are used for modeling, achieving a mean absolute error of 0.32‰. We found that all formulas, even those without nitrogen atoms, have direct or indirect connections with DOM's δ¹⁵N. The developed model not only performs well in China coastal environments, but also show great generalization in other estuaries. Furthermore, our model establishes a connection between δ¹⁵N and molecular composition of marine DOM in coastal ocean, revealing that higher δ¹⁵N values are associated with more saturated and marine-derived DOM, whereas lower δ¹⁵N values tend to be more unsaturated and exhibit terrestrial characteristics. This work elucidates the intrinsic coupling between DOM molecular characteristics and nitrogen isotopic composition, advancing our understanding of nitrogen cycling and organic matter dynamics in marine coastal environments.</div></div>","PeriodicalId":18219,"journal":{"name":"Marine Chemistry","volume":"275 ","pages":"Article 104619"},"PeriodicalIF":2.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}