Marine Chemistry最新文献_第8页

Comparative study of dissolved copper speciation using DGT and CLE-AdSV in a contaminated urban river estuary and marina DGT法和cl - adsv法在污染城市河口和码头中溶解铜形态的比较研究

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-02-20 DOI: 10.1016/j.marchem.2025.104500

Billie G.B. Benedict , Rebecca Zitoun , Keith A. Hunter , Sylvia G. Sander

A comprehensive study was conducted in a river estuary and marina in Auckland, New Zealand, to examine the in-situ speciation of copper (Cu) complexes across freshwater, estuarine, and marine environments using the diffusive gradient in thin films (DGT) technique. The study employed both open-pore (OP) and restrictive-pore (RP) diffusive gels of varying thicknesses to assess the effectiveness of DGT hydrogels and the role of the apparent diffusive boundary layer (ADBL) in determining the lability of Cu complexes in natural waters. The DGT findings were compared with results from competing ligand exchange–adsorptive stripping voltammetry (CLE-AdSV) and a speciation prediction model (WHAM/Model-VII). The study highlighted the critical importance of accounting for the ADBL, as its exclusion led to an average underestimation of Cu-complex lability by approximately 50 %. Given the minimal difference in outcomes between DGT-OP and DGT-RP, the use of standard DGT-OP is recommended. Further analysis revealed a strong correlation between DGT-labile Cu (CuDGT-lab), the weaker Cu-L₂ complexes detected by CLE-AdSV, and the inorganic Cu species predicted by WHAM/Model-VII, the latter two based on discrete samples. A strong relationship was also noted between Cu_DGT-lab and the inorganic Cu measured by CLE-AdSV. The study provided compelling evidence that the in-situ ligand pool consists of a mixture of terrestrial humic substances and marine-derived organic ligands. These marine ligands form highly stable Cu-L₁ complexes along the salinity gradient, which were mostly DGT-inert. The DGT results indicated that the lability of in-situ Cu complexes decreased with increasing salinity, with over 60 % of Cu in freshwater being DGT-labile. Overall, the study demonstrates that the DGT technique is a robust and straightforward method for environmental monitoring and risk assessment across diverse physico-chemical water conditions.

在新西兰奥克兰的河口和码头进行了一项综合研究，利用薄膜扩散梯度（DGT）技术检查淡水、河口和海洋环境中铜（Cu）配合物的原位形态。该研究采用不同厚度的开孔（OP）和限制孔（RP）扩散凝胶来评估DGT水凝胶的有效性，以及表观扩散边界层（ADBL）在确定天然水体中Cu配合物稳定性中的作用。DGT结果比较了竞争配体交换吸附溶出伏安法（cl - adsv）和物种形成预测模型（WHAM/ model - vii）的结果。该研究强调了考虑ADBL的重要性，因为它的排除导致对cu复合物稳定性的平均低估约50%。鉴于DGT-OP和DGT-RP之间的结果差异很小，建议使用标准DGT-OP。进一步分析表明，dgt -不稳定Cu （CuDGT-lab）、CLE-AdSV检测到的较弱Cu- l2配合物和WHAM/Model-VII预测的无机Cu物种之间存在很强的相关性，后两者基于离散样本。CuDGT-lab与CLE-AdSV测量的无机Cu之间也存在很强的关系。该研究提供了令人信服的证据，表明原位配体池由陆地腐殖质物质和海洋来源的有机配体组成。这些海洋配体沿盐度梯度形成高度稳定的Cu-L1配合物，这些配合物大多是dgt惰性的。DGT结果表明，原位Cu配合物的稳定性随着盐度的增加而降低，淡水中超过60%的Cu是DGT不稳定的。总体而言，该研究表明，DGT技术是一种强大而直接的方法，可用于各种物理化学水条件下的环境监测和风险评估。

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引用次数: 0

Excess alkalinity and its impacts on pCO2 estimation in coastal and estuarine waters of the Yellow Sea 黄海沿岸和河口过量碱度及其对pCO2估算的影响

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-02-11 DOI: 10.1016/j.marchem.2025.104499

Young Ho Ko , Seung-Hee Shin , Seong-Gil Kim , Mi-Ok Park , Min-Woo Seok , Min-Soo Kim , Kitack Lee , Tae-Wook Kim

Excess alkalinity (TA_EX) represents an uncharacterized component of total alkalinity (TA), which can introduce significant uncertainty in the estimation of other carbonate parameters. This effect is particularly pronounced in productive coastal regions, where the use of measured TA as an input parameter may lead to inaccurate assessment. In this study, we evaluated the seasonal variability of TA_EX along the western coast of South Korea by applying an overdetermination method, which allows for the quantification of discrepancies (i.e., TA_EX) between measured TA and values calculated from pH and dissolved inorganic carbon (DIC). Samples with salinity below 20 were excluded due to difficulties in accurately quantifying uncertainties in TA_EX calculations, which increase significantly below this threshold. Elevated TA_EX concentrations were found in waters with salinity below 25, with some instances exhibiting TA_EX values reaching up to 50 μmol kg⁻¹, suggesting riverine influence. Additionally, elevated TA_EX values (> 20 μmol kg⁻¹) were also observed in locations markedly undersaturated with respect to atmospheric CO₂, indicating contributions from in-situ biological production. The high TA_EX values associated with increased water transparency during autumn and winter months suggested that light penetration may significantly enhance biological activity, subsequently increasing TA_EX levels. These findings highlight the importance of riverine inputs and biological processes in shaping the spatial and temporal distribution of TA_EX. In the study area, TA_EX should be accounted for in seawater partial pressure of CO₂ (pCO₂) calculations using the DIC–TA pair, as TA_EX significantly influences these calculations compared to the pH–TA and pH–DIC pair.

过量碱度（TAEX）是总碱度（TA）的一个未表征成分，它会给其他碳酸盐参数的估计带来很大的不确定性。这种影响在沿海生产地区尤其明显，在这些地区，使用测量的热饱和度作为输入参数可能导致不准确的评估。在这项研究中，我们通过应用超测定方法评估了韩国西海岸TAEX的季节性变化，该方法允许量化测量TA与pH和溶解无机碳（DIC）计算值之间的差异（即TAEX）。由于难以准确量化TAEX计算中的不确定度，盐度低于20的样品被排除在外，TAEX计算中的不确定度在此阈值以下显着增加。在盐度低于25的水中发现TAEX浓度升高，某些情况下TAEX值高达50 μmol kg - 1，表明河流的影响。此外，TAEX值升高(>；在相对于大气CO2明显不饱和的位置也观察到20 μmol kg−1)，表明原位生物生产的贡献。高TAEX值与秋冬季节水透明度的增加有关，这表明光的穿透可能显著增强生物活性，从而增加TAEX水平。这些发现强调了河流输入和生物过程在形成TAEX时空分布中的重要性。在研究区，使用DIC-TA对计算海水CO2分压（pCO2）时应考虑TAEX，因为与pH-TA和pH-DIC对相比，TAEX对这些计算有显著影响。

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引用次数: 0

Achieving measurement comparability in mercury speciation analysis in seawater: Key requirements and best practices 实现海水中汞形态分析的测量可比性：关键要求和最佳做法

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-02-04 DOI: 10.1016/j.marchem.2025.104498

Igor Živković , Lars-Eric Heimbürger-Boavida , Mariia V. Petrova , Aurélie Dufour , Ermira Begu , Milena Horvat

The comparability of measurement results is an important issue in contemporary mercury (Hg) speciation in seawater. Sampling campaigns must be properly designed to determine significant differences on spatial and temporal scales, considering two major parameters: the variability of expected data at a given sampling point/transect and variability in the results due to the intrinsic properties of specific analytical methods, particularly the measurement uncertainty. This study assessed the required sample size, considering several aspects of data variability when determining total Hg, dissolved gaseous Hg, and methylated Hg species in seawater. The required sample sizes were calculated using (1) the measurement uncertainty of a single-laboratory measurement of analytical methods used; (2) performance of the laboratories in interlaboratory comparison exercises; and (3) natural variability in Hg species/fractions in a selected case study in the Central Adriatic Sea. It was shown that the measurement uncertainty of a particular method and interlaboratory variability among laboratories have significant influence on data interpretation in case natural variability of Hg fractions is relatively small, such as for example the open seawater depth profiles. In contrary, in areas with large natural variability of Hg contractions, such as coastal and contaminated sites, their influence on data interpretation is negligible. The present paper introduces the importance of proper estimation of measurement uncertainty in international programs, such as GEOTRACES, where data comparability is of fundamental importance to assess temporal and spatial trends of Hg measurements in the marine environment.

测量结果的可比性是当代海水中汞形态形成的一个重要问题。必须适当地设计抽样活动，以确定空间和时间尺度上的显著差异，同时考虑两个主要参数：给定采样点/样条上预期数据的可变性，以及由于特定分析方法的内在特性，特别是测量不确定性而导致的结果的可变性。本研究评估了所需的样本量，在确定海水中总汞、溶解气态汞和甲基化汞的种类时，考虑了数据可变性的几个方面。所需的样本量使用(1)所用分析方法的单实验室测量的测量不确定度计算；(2)实验室在实验室间比较活动中的表现；(3)亚得里亚海中部汞种类/组分的自然变异。结果表明，在自然变异相对较小的情况下，例如开放海水深度剖面，特定方法的测量不确定度和实验室间的变异对数据解释有显著影响。相反，在汞收缩自然变异性较大的地区，如沿海和污染场地，它们对数据解释的影响可以忽略不计。本文介绍了在GEOTRACES等国际项目中正确估计测量不确定性的重要性，这些项目中数据的可比性对于评估海洋环境中汞测量的时空趋势至关重要。

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引用次数: 0

Physical-biological processes regulating summer sea-air CO2 exchanges along the Drake Passage and northern Antarctic Peninsula 调节夏季德雷克海峡和南极半岛北部海气二氧化碳交换的物理-生物过程

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-02-01 DOI: 10.1016/j.marchem.2025.104497

Rodrigo Kerr , Thiago Monteiro , Matheus S. Batista , Brendon Yuri Damini

We determined the sea-air carbon dioxide (CO₂) exchanges and investigated the main physical-biological processes responsible for regulating the sea surface partial pressure of CO₂. This was done through the analysis of continuous and discrete measurements of oceanographic and atmospheric variables measured during the NAUTILUS V cruise (January 2019) crossing the main fronts along the Drake Passage and several distinct biogeochemical provinces along the northern Antarctic Peninsula. The main findings indicated that the Drake Passage acted as a weak net CO₂ outgassing area (∼0.1 mmol m⁻² d⁻¹), although contrasting regions with close sea-air CO₂ fluxes magnitudes of ∼3 mmol m⁻² d⁻¹ were identified north (a net CO₂ sink zone regulated by net photosynthesis) and south (a net CO₂ source zone regulated by net respiration) of the Polar Front. On the other hand, the northern Antarctic Peninsula areas demonstrated a more heterogeneous sea-air CO₂ exchanges behaviour varying from moderate net CO₂ outgassing of ∼1.3 mmol m⁻² d⁻¹ (Bransfield Strait, western Antarctic Peninsula and Weddell Sea continental shelves) to a moderate (∼ −2.4 mmol m⁻² d⁻¹) or weak (∼ −0.1 mmol m⁻² d⁻¹) net CO₂ ingassing in Antarctic Sound surroundings and Gerlache Strait, respectively. It is interesting to note that a huge intensification of the net CO₂ outgassing of ∼5 mmol m⁻² d⁻¹ was identified in the area under the influence of the Antarctic Slope Front bifurcation eddy south of Clarence Island. The CO₂ outgassing is expected in this stationary and anticyclonic feature, but its magnitude was ∼75 % higher than the known estimate, which was associated with strengthen winds and eddy dynamics. Net respiration was the leading biological process occurring in the study area, except north of Polar Front where net photosynthesis prevailed. The patchy distribution of sea-air CO₂ exchanges behaviour along the Drake Passage and northern Antarctic Peninsula reinforced the needs for better understanding and focus on finer resolution of the CO₂ chemistry and processes at regional and local investigations, especially in a region suffering with multiple climate stressors, located in a transition zone of warm and cold environments, and key to connect the Southern Ocean ecosystems in a circumpolar way.

我们测定了海气二氧化碳交换，并研究了调节海面二氧化碳分压的主要物理-生物过程。这是通过分析鹦鹉螺号V号巡航（2019年1月）穿越德雷克海峡主要锋面和南极半岛北部几个不同的生物地球化学省期间测量的连续和离散海洋和大气变量的测量结果来完成的。主要研究结果表明，尽管北极锋北部（净光合作用调节的净CO2汇区）和南部（净呼吸调节的净CO2源区）的海气CO2通量值接近于~ 3 mmol m−2 d−1，但德雷克通道是一个弱的净CO2放出区（~ 0.1 mmol m−2 d−1）。另一方面，南极半岛北部地区表现出更不均匀的海气CO2交换行为，从中度的CO2净排放（~ 1.3 mmol m−2 d−1）（布兰斯菲尔德海峡、南极半岛西部和威德尔海大陆架）到中度（~−2.4 mmol m−2 d−1）或弱（~−0.1 mmol m−2 d−1）的CO2净排放（南极海峡周围和Gerlache海峡）。值得注意的是，在克拉伦斯岛以南的南极坡锋分岔涡的影响下，该地区的净CO2释放量大幅增加了~ 5 mmol m−2 d−1。预计在这一静止和反气旋特征中会出现二氧化碳脱气，但其量级比已知的估计高出约75%，这与加强的风和涡流动力学有关。除极锋以北以净光合作用为主外，净呼吸作用是研究区主要的生物过程。德雷克海峡和南极半岛北部海气二氧化碳交换行为的不均匀分布，加强了在区域和地方调查中更好地理解和关注二氧化碳化学和过程的精细分辨率的需求，特别是在一个遭受多种气候压力的地区，位于温暖和寒冷环境的过渡地带，以及以环极地方式连接南大洋生态系统的关键。

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引用次数: 0

Vertical biochemical composition of particulate organic matter in the Seychelles-Chagos Thermocline Ridge (SCTR), southwestern Indian Ocean 西南印度洋塞舌尔-查戈斯温跃层脊（SCTR）颗粒有机质垂直生化组成

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-19 DOI: 10.1016/j.marchem.2025.104496

Sanghoon Park , Yejin Kim , Jaesoon Kim , Jae Ha Jeon , Inhee Lee , Doshik Hahm , Dong-Jin Kang , Sang Heon Lee

The Seychelles-Chagos Thermocline Ridge (SCTR) in the southwestern Indian Ocean is characterized by upwelling-driven nutrient enrichment and enhanced biological activity compared to adjacent non-SCTR regions. This study investigated the vertical distribution and biochemical composition of particulate organic matter (POM) within these contrasting environments. The SCTR featured a shallower thermocline and cooler sea surface temperatures, indicative of upwelling, which correlated with significantly higher chlorophyll-a concentrations (t-test, p < 0.05). A notable dominance of micro-sized phytoplankton was observed in the SCTR, contributing 13.6 ± 3.0 % of the total phytoplankton biomass, compared to 5.6 ± 1.6 % in the non-SCTR. CHEMTAX analysis revealed distinct phytoplankton communities, with diatoms being approximately four times more abundant in the SCTR (16.5 ± 4.5 %) than in the non-SCTR (4.2 ± 1.2 %). Meanwhile, Prochlorococcus dominated both regions but contributed less in the SCTR (25.2 ± 3.9 %) than non-SCTR (46.8 ± 7.1 %). The biological macromolecular composition of POM showed clear regional differences, with lipid concentrations in the SCTR's photic layer significantly higher (61.3 μg L⁻¹) than in the non-SCTR (23.4 μg L⁻¹). Total biological macromolecule concentrations in the SCTR's photic zone was more than double that of the non-SCTR (96.3 μg L⁻¹ vs. 40.9 μg L⁻¹), reflecting enhanced biological productivity. Elevated macromolecule concentrations were also detected in the aphotic layer of the SCTR. Notably, the less pronounced decline in the protein-to-carbohydrate ratio from photic to aphotic layers in the SCTR suggests that POM sinking to the deep ocean in this region is relatively fresher and less degraded, indicating a more efficient biological carbon pump and enhanced potential for carbon sequestration. These findings highlight the SCTR as a key region of elevated biological productivity and distinct environmental mechanisms driving biogeochemical cycling, providing critical insights into organic matter preservation and carbon export processes in tropical upwelling systems and their role in global marine ecosystems.

与邻近的非塞舌尔-查戈斯温跃层脊区相比，西南印度洋塞舌尔-查戈斯温跃层脊区具有上升流驱动的营养物质富集和生物活性增强的特征。本研究研究了不同环境下颗粒物有机质（POM）的垂直分布和生化组成。SCTR具有较浅的温跃层和较低的海面温度，表明上升流，这与叶绿素-a浓度显著升高相关(t检验，p <；0.05)。微细浮游植物在SCTR中占明显优势，占总浮游植物生物量的13.6±3.0%，而在非SCTR中为5.6±1.6%。CHEMTAX分析揭示了不同的浮游植物群落，硅藻在SCTR中的丰度（16.5±4.5%）大约是非SCTR的4倍（4.2±1.2%）。原绿球藻在两个区域均占主导地位，但在SCTR中所占比例（25.2±3.9%）低于非SCTR（46.8±7.1%）。POM的生物大分子组成存在明显的区域差异，SCTR光化学层的脂质浓度（61.3 μg L−1）显著高于非SCTR光化学层（23.4 μ L−1）。SCTR光区生物大分子总浓度（96.3 μg L−1 vs. 40.9 μg L−1）是非SCTR光区生物大分子浓度的两倍多，反映出生物生产力的增强。在SCTR的凋亡层中也检测到大分子浓度升高。值得注意的是，SCTR中从光层到光层的蛋白质与碳水化合物比率下降不太明显，这表明该地区下沉到深海的POM相对较新鲜，降解程度较低，表明生物碳泵更有效，碳固存潜力增强。这些发现强调了SCTR是生物生产力提高和驱动生物地球化学循环的独特环境机制的关键区域，为热带上升流系统的有机质保存和碳输出过程及其在全球海洋生态系统中的作用提供了重要见解。

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引用次数: 0

Influence of the Mackenzie River plume dispersal on the dissolved barium concentrations in the upper Canada Basin waters 麦肯齐河羽流扩散对加拿大盆地上游水域溶解钡浓度的影响

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-17 DOI: 10.1016/j.marchem.2025.104495

M. Gamrani , S. Zimmermann , W.J. Williams , C. Guéguen

Dissolved barium has been shown to have the potential to track river runoff in marine waters. In this study, the distribution of dissolved barium was determined in the upper 450 m waters of the Canada Basin along the Joint Ocean Ice Study 140°W transect in August/September 2019–2021. In these highly stratified Canada Basin waters, the dBa concentrations increased from 42.51 nmol kg⁻¹ in the Atlantic waters to 128.91 nmol kg⁻¹ in the polar mixed layer. The dispersal of Ba-rich surface waters found over the slope and outer shelves is attributed to the Mackenzie River plume. These waters were either confined nearshore with northwest winds (2019 and 2020) or entrained into the Beaufort Gyre interior under easterly winds (2021). In the subsurface layers, the vertical variation in barium concentration in the Pacific Winter Water and Atlantic Halocline waters showed evidence of mixing. Dissolved Ba dynamics provide a window into the complex interplay between physical, biological, and chemical processes in Arctic waters, making it a valuable tracer for understanding ocean circulation, nutrient transport, and ecosystem functioning in the rapidly changing Arctic region.

溶解的钡已被证明具有追踪海水中河流径流的潜力。本研究于2019年8 / 9月- 2021年9月在加拿大盆地140°W样带上450 m水域测定了溶解钡的分布。在这些高度分层的加拿大盆地水域，dBa浓度从大西洋水域的42.51 nmol kg−1增加到极地混合层的128.91 nmol kg−1。在斜坡和外大陆架上发现的富含ba的地表水的扩散归因于麦肯齐河的羽流。这些水域要么被西北风（2019年和2020年）限制在近岸，要么被东风（2021年）带入波弗特环流内部。在次表层，太平洋冬季水和大西洋盐斜海水钡浓度的垂直变化表现出混合的迹象。溶解Ba动力学为了解北极水域物理、生物和化学过程之间复杂的相互作用提供了一个窗口，使其成为了解快速变化的北极地区海洋环流、营养物质运输和生态系统功能的有价值的示踪剂。

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引用次数: 0

Carbonate and isotope chemistry in the outer Yellow River Estuary and beyond: Effects of flood and cold wave on interannnual variations in coastal stable carbon isotope 黄河口外及以外地区碳酸盐和同位素化学：洪水和寒潮对海岸稳定碳同位素年际变化的影响

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-03 DOI: 10.1016/j.marchem.2025.104486

Zi-chen Liu , Wei-dong Zhai

The stable carbon isotope composition (δ¹³C) of dissolved inorganic carbon (DIC) traces many biogeochemical processes in large river estuaries and adjacent coastal seas. To better understand the dynamics of DIC and its isotope composition (δ¹³C_DIC) responding to floods and cold waves in the outer Yellow River Estuary and adjacent Laizhou Bay and central Bohai Sea, seven field surveys were conducted in summer and autumn of 2021 and 2022. Interannual variations in carbonate chemistry and δ¹³C_DIC were investigated. In the outer Yellow River Estuary, distributions of DIC and δ¹³C_DIC had little difference before and after an artificial flood, although water mixing dominates spatial variations of carbonate chemistry and stable isotopic composition in summer. The excess carbonate relative to a simplified two-endmember water-mixing was likely caused by the release of bicarbonate ions from the sediment and/or coastal wetlands over the Yellow River Estuary. In contrast, metabolic processes significantly affected the changes in DIC and δ¹³C_DIC in the adjacent central Bohai Sea. In 2022, δ¹³C_DIC in Laizhou Bay was lighter than that in 2021, while δ¹³C_DIC in the central Bohai Sea was heavier than that in 2021. This can be attributed to the wintertime super cold waves at the beginning of 2021 that affects the Bohai Sea and an unusual autumnal flood in 2021 that affects the Laizhou Bay. Both events make δ¹³C_DIC lighter (over half a year later) at given salinity with negligible changes in DIC concentrations. Our results also revealed that the lower reach of the Yellow River Estuary was a source of atmospheric CO₂ in summer. Although the quick transport of terrestrial nutrients caused by the artificial water-sediment regulation did not promote net community production soon, likely owing to high turbidity and relatively short residence time before our July cruises, the unusual autumnal flood likely transported much more nutrients into the Estuary and triggered algal blooms and turned it into a sink area of the atmospheric CO₂ in autumn. These findings provide fundamental information and new insights that support better understanding the complexity of the carbonate chemistry and isotope geochemistry dynamics in this ocean margin.

溶解无机碳（DIC）的稳定碳同位素组成δ13C （δ13C）反映了大河口和邻近近海的生物地球化学过程。为了更好地了解黄河口外及邻近莱州湾和渤海中部地区DIC及其同位素组成（δ13CDIC）对洪水和寒潮的响应动态，在2021年和2022年夏、秋进行了7次野外调查。研究了碳酸盐岩化学和δ13CDIC的年际变化。在黄河口外，人工洪水前后DIC和δ13CDIC的分布差异不大，但夏季碳酸盐化学和稳定同位素组成的空间变化主要由水混合主导。相对于简化的二元水混合，过量的碳酸盐可能是由沉积物和/或黄河口沿岸湿地释放的碳酸氢盐离子引起的。与此相反，代谢过程显著影响了邻近渤海中部地区DIC和δ13CDIC的变化。2022年莱州湾δ13CDIC较2021年轻，而渤海中部δ13CDIC较2021年重。这可以归因于2021年初影响渤海的冬季超级寒潮和2021年影响莱州湾的异常秋季洪水。这两个事件都使δ13CDIC在给定盐度下变轻（半年后），而DIC浓度的变化可以忽略不计。黄河口下游是夏季大气CO2的主要来源之一。虽然人工水沙调节引起的陆地营养物质的快速运输并没有很快促进净群落生产，可能是由于高浊度和7月邮轮前相对较短的停留时间，但不寻常的秋季洪水可能将更多的营养物质输送到河口并引发藻华，使其成为秋季大气CO2的汇区。这些发现提供了基本信息和新的见解，有助于更好地理解该海洋边缘碳酸盐化学和同位素地球化学动力学的复杂性。

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引用次数: 0

Redox speciation of copper in the estuarine environment: Towards better understanding of copper water chemistry 河口环境中铜的氧化还原形态：对铜水化学的更好理解

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-01 DOI: 10.1016/j.marchem.2024.104471

Dora Crmarić, Saša Marcinek, Ana-Marija Cindrić, Dario Omanović, Elvira Bura-Nakić

An adapted solid-phase extraction method was used for Cu redox speciation in the dissolved fraction in the stratified Krka River estuary in March and July 2023 at a “clean” and a “polluted” site, while anodic stripping voltammetry in differential pulse mode was used for Cu determination in the Cu(I), Cu(II) and Cu_T fractions. Overall, [Cu(I)]/[Cu_T] was significant in the Krka River estuary and varied between 20.7 and 88.7 %. At the “clean” site E1, the surface maximum of [Cu(I)]/[Cu_T] was observed in March. This was assumed to be related to the biological activity of the freshwater biota, as the temperature rose in March (compared to the previous winter months) and the salinity was low. On the other hand, at E1 in July, the maximum of [Cu(I)]/[Cu_T] was observed at the halocline and corresponded to the highest biological production thus we hypothesised it to be the result of Cu(I) complexation with ligands of biological origin. The minimum of [Cu(I)]/[Cu_T] was observed at the surface at E1 in July where terrestrial humic-like substances were present with higher affinity for Cu(II) than for Cu(I). At the “polluted site” E2 high [Cu(I)]/[Cu_T] values were observed at both the surface and the halocline in March. However, [Cu(I)]/[Cu_T] maximum was observed at the halocline at E2 in July and was associated with the highest biological production, as also observed at E1 in July. Nevertheless, the stabilisation of Cu(I) by chloride should not be disregarded as it maintained relatively high [Cu(I)]/[Cu_T] in the seawater layer at both stations in March and July. The fluctuations in [Cu(I)]/[Cu_T] occurred during the day at the surface at E2 in July, with the minimum of [Cu(I)]/[Cu_T] observed in the early morning, followed by an increase in [Cu(I)]/[Cu_T] during the day, indicating the importance of photochemical reactions in the Cu(I) formation and stabilisation.

2023年3月和7月，分别在“洁净”和“污染”两种情况下，采用固相萃取法测定了克尔卡河口分层沉积物中溶解组分中的Cu氧化还原形态，采用差分脉冲模式阳极溶出伏安法测定了Cu(I)、Cu（II）和CuT组分中的Cu。总体而言，[Cu(I)]/[CuT]在库尔卡河河口显著，变化在20.7% ~ 88.7%之间。在“干净”点E1， [Cu(I)]/[CuT]的表面最大值出现在3月份。这被认为与淡水生物群的生物活性有关，因为3月份气温上升（与前几个冬季相比），盐度较低。另一方面，在7月E1处，[Cu(I)]/[CuT]在盐跃层处达到最大值，对应于最高的生物产量，因此我们假设这是Cu(I)与生物源配体络合的结果。7月E1地表[Cu(I)]/[CuT]最小，陆生腐殖质样物质对Cu（II）的亲和力大于对Cu(I)的亲和力。在“污染点”，3月地表和盐跃层均出现E2高[Cu(I)]/[CuT]值。7月E2盐跃层[Cu(I)]/[CuT]最大，生物产量最高，7月E1盐跃层也是如此。然而，氯化物对Cu(I)的稳定作用不可忽视，在3月和7月两个站点的海水层中都保持了较高的[Cu(I)]/[CuT]。7月E2点地表[Cu(I)]/[CuT]的波动发生在白天，[Cu(I)]/[CuT]在清晨达到最小值，随后白天[Cu(I)]/[CuT]增加，说明光化学反应在Cu(I)的形成和稳定中的重要性。

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引用次数: 0

Advanced deep learning technique for estimating global surface ocean calcium carbonate saturation (Ωcal) 估算全球海洋表面碳酸钙饱和度的先进深度学习技术（Ωcal）

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-01 DOI: 10.1016/j.marchem.2024.104483

Ibrahim Shaik , P.V. Nagamani , Sandesh Yadav , Yash Manmode , G. Srinivasa Rao

The accurate estimation of surface ocean calcium carbonate saturation (Ω_cal) is crucial for understanding the impacts of ocean acidification (OA) on marine ecosystems, particularly for calcifying organisms. This study investigates the estimation of global surface ocean Ω_cal using machine learning (ML) models and satellite-derived data. Three ML models such as feed-forward neural networks (FFNN), random forests (RF), and Tabularnet (TabNet) were employed to estimate Ω_cal, utilizing in-situ and satellite measurements of sea surface temperature (SST), sea surface salinity (SSS), and Chlorophyll-a concentration (Chla). Among these, the TabNet model exhibited superior performance, with a root-mean-square error (RMSE) of 0.39, mean relative error (MRE) of 0.019, mean normalized bias (MNB) of 0.0058 and coefficient of determination (R²) of 0.96. SST showed a strong positive correlation with Ω_cal (r = 0.95), while SSS and Chla exhibited moderate positive (r = 0.49) and weak negative (r = −0.27) correlations, respectively. The study revealed significant spatiotemporal variability in Ω_cal, driven by seasonal changes and ocean circulation patterns. Sensitivity analysis highlighted the robustness of the TabNet model, maintaining high predictive capability despite variations in SST, SSS, and Chla. The TabNet model high accuracy provides a valuable tool for monitoring and forecasting changes in ocean chemistry, informing conservation efforts and policy-making. This study emphasizes the importance of advanced ML models in marine science and their potential for enhancing our understanding of global oceanic processes.

准确估计海洋表面碳酸钙饱和度（Ωcal）对于了解海洋酸化（OA）对海洋生态系统的影响，特别是对钙化生物的影响至关重要。本研究利用机器学习（ML）模型和卫星衍生数据研究了全球表面海洋Ωcal的估计。采用前馈神经网络（FFNN）、随机森林（RF）和Tabularnet (TabNet) 3种ML模型，利用现场和卫星测量的海面温度（SST）、海面盐度（SSS）和叶绿素-a浓度（Chla）估算Ωcal。其中，TabNet模型表现较好，均方根误差（RMSE）为0.39，平均相对误差（MRE）为0.019，平均归一化偏差（MNB）为0.0058，决定系数（R2）为0.96。SST与Ωcal呈强正相关（r = 0.95）， SSS与Chla呈中正相关（r = 0.49），弱负相关（r = - 0.27）。该研究揭示了Ωcal在季节变化和海洋环流模式的驱动下存在显著的时空变异。敏感性分析强调了TabNet模型的稳健性，尽管SST、SSS和Chla存在变化，但TabNet模型仍保持较高的预测能力。高精度的TabNet模型为监测和预测海洋化学变化提供了有价值的工具，为保护工作和决策提供了信息。这项研究强调了先进的ML模型在海洋科学中的重要性，以及它们对增强我们对全球海洋过程的理解的潜力。

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引用次数: 0

QUODcarb: A Bayesian solver for over-determined datasets of seawater carbon dioxide system chemistry 海水二氧化碳系统化学超确定数据集的贝叶斯解算器

IF 3 3区地球科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Marine Chemistry

Pub Date : 2025-01-01 DOI: 10.1016/j.marchem.2024.104470

Marina Fennell, François Primeau

We present QUODcarb, a new solver for the CO₂-system in seawater, designed to handle any combination of system parameter measurements, whether exactly- or over-determined. QUODcarb, which stands for Quantifying Uncertainty in an Over-Determined marine carbonate system, is formulated in terms of a Bayesian estimation problem. By combining prior thermodynamic information on the acid/base chemistry of CO₂ in seawater with measured parameters and their uncertainties, QUODcarb yields a probability distribution for the true CO₂-system state of a water parcel from which estimates of all system parameters with associated uncertainties can be obtained. By providing a single best estimate for the true CO₂-system state, QUODcarb enables a simplified, more accurate internal consistency analysis of the marine CO₂ system.

To demonstrate QUODcarb's utility, we analyze the GOMECC-3 dataset, that includes measurements of five CO₂-system parameters. A key finding is that by analyzing these high-quality, over-determined measurements with QUODcarb, we can achieve the GOA-ON 1 % uncertainty goal for carbonate ion concentration, even when accounting for the propagated uncertainty in the dissociation constants – a level of accuracy unattainable with exactly determined calculations. Using a single internal consistency metric, we rank 26 alternative measurement combinations, finding that (pH,

p {CO}_{2}

) performs worst, while the combination with all five measurements performs best. Furthermore, the internally-consistent thermodynamic state estimates constrained by all five measurements fall within the range expected by the assumed measurement uncertainties for over 98 % of samples, with only minor adjustments to the dissociation constants, all of which remain within the reported uncertainties for their parameterized formulas.

我们提出了QUODcarb，一种新的海水中二氧化碳系统求解器，设计用于处理系统参数测量的任何组合，无论是精确还是过度确定。QUODcarb，即在一个过度确定的海相碳酸盐系统中量化不确定性，是用贝叶斯估计问题来表述的。通过将海水中CO2的酸碱化学的先验热力学信息与测量参数及其不确定性相结合，QUODcarb得出了一个水包中CO2系统真实状态的概率分布，由此可以获得所有系统参数与相关不确定性的估计。通过提供对二氧化碳系统真实状态的单一最佳估计，QUODcarb可以对海洋二氧化碳系统进行简化、更准确的内部一致性分析。为了演示QUODcarb的实用性，我们分析了gomec -3数据集，其中包括五个co2系统参数的测量值。一个关键的发现是，通过用QUODcarb分析这些高质量的、过度确定的测量结果，我们可以实现GOA-ON 1%的碳酸盐离子浓度不确定度目标，即使考虑到解离常数的传播不确定度——精确计算无法达到的精度水平。使用单一的内部一致性度量，我们对26种替代测量组合进行了排名，发现（pH, pCO2）表现最差，而所有五种测量组合表现最佳。此外，所有五种测量约束下的内部一致热力学状态估计都在98%以上样品的假设测量不确定度所期望的范围内，只有对解离常数进行了微小的调整，所有这些都保持在其参数化公式的报告不确定度之内。

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引用次数: 0