Deep-sea Research Part Ii-topical Studies in Oceanography最新文献

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IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-01

引用次数: 0

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-01

引用次数: 0

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-01

引用次数: 0

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-01

引用次数: 0

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-01

引用次数: 0

A prior-knowledge-integrated downscaling approach for subsurface thermal structure reconstruction in the tropical Indian Ocean 热带印度洋地下热结构重建的先验知识集成降尺度方法

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-31 DOI: 10.1016/j.dsr2.2025.105589

Zhongkun Feng , Jifeng Qi , Bowen Xie , Yuan Cao , Delei Li , Chuanyu Liu , Baoshu Yin

Accurately obtaining high-resolution ocean subsurface thermal structure (OSTS) is essential for resolving mesoscale dynamics in the tropical Indian Ocean (TIO), yet observations remain sparse and uneven. We present a Transformer-based neural network model, the Downscaling Vision Transformer (DSVIT), which integrates prior knowledge to reconstruct high-resolution OSTS in the TIO. Inputs include sea surface temperature (SST), absolute dynamic topography (ADT), and wind stress curl (WSC), as well as temporal, geographic, and climatological information. DSVIT enhances a standard Vision Transformer (ViT) with a geographic positional prior and a physics-aware loss that emphasizes thermocline and surface variability. On an independent test set, DSVIT achieves a Root Mean Square Error (RMSE) of 0.29 °C and a Coefficient of Determination (R²) of 0.9962 for reconstructed subsurface temperature, outperforming traditional recurrent neural network (RNN) and convolutional neural network (CNN) models. Moreover, a key innovation of this study lies in its novel downscaling strategy, which effectively improves the EN4 subsurface temperature resolution from 1° to 1/4° by altering the input segmentation. Compared with traditional interpolation and assessed against independent high-resolution products, the downscaled outputs exhibit lower RMSE and higher R², indicating enhanced physical consistency and mesoscale representation. SHapley Additive exPlanations (SHAP) analysis further reveals that climatology and SST are the dominant predictors, followed by ADT. This study provides a novel approach for downscaling OSTS and offers valuable insights for advancing oceanic and climatic research.

准确获取高分辨率海洋地下热结构（OSTS）对于解析热带印度洋（TIO）中尺度动力学至关重要，但观测数据仍然稀疏且不均匀。我们提出了一种基于变压器的神经网络模型，即降尺度视觉变压器（DSVIT），它集成了先验知识来重建TIO中的高分辨率OSTS。输入包括海温（SST）、绝对动力地形（ADT）、风应力旋度（WSC）以及时间、地理和气候信息。DSVIT增强了标准视觉变压器（ViT）的地理位置先验和强调温跃层和地表变化的物理感知损失。在独立测试集上，DSVIT重建地下温度的均方根误差（RMSE）为0.29°C，决定系数（R2）为0.9962，优于传统的递归神经网络（RNN）和卷积神经网络（CNN）模型。此外，本研究的一个关键创新在于其新颖的降尺度策略，通过改变输入分割，有效地将EN4地下温度分辨率从1°提高到1/4°。与传统插值方法相比，并通过独立的高分辨率产品进行评估，缩小后的输出显示出更低的RMSE和更高的R2，表明物理一致性和中尺度代表性增强。SHapley加性解释（SHAP）进一步揭示了气候和海温是主要的预测因子，其次是ADT。该研究为降低OSTS的尺度提供了一种新的方法，为推进海洋和气候研究提供了有价值的见解。

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引用次数: 0

Time series of dissolved organic carbon in the Fram Strait (2010–2021): Indications for increased river export of DOC to the East Greenland Current? Fram海峡溶解有机碳的时间序列（2010-2021）：DOC向东格陵兰洋流输出增加的迹象？

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-22 DOI: 10.1016/j.dsr2.2025.105586

Anja Engel , Anabel von Jackowski , Vanessa Lampe , Eva-Maria Nöthig

Climate change impacts the Arctic Ocean more profoundly than other regions, with uncertain consequences for carbon cycling. Additionally, allochthonous and autochthonous sources of organic carbon undergo extreme seasonal variability. Distinguishing climate-induced changes from seasonal variability in carbon cycling thus remains a significant challenge. We investigated interannual changes in dissolved organic carbon (DOC) concentration and lability. i.e., the lifetime of DOC, which we inferred from amino acid composition, in surface waters of the Fram Strait using time series data collected between 2010 and 2021. Sampling was conducted during summer with the RV POLARSTERN at or around the Long-Term Ecological Research observatory HAUSGARTEN. Our results show that the two major water masses in Fram Strait, the Polar Water (PW; T < 0 °C; S < 34.0) predominant in the East Greenland Current and the Atlantic Water (AW; T > 3 °C; S > 34.9) predominant in the West Spitzbergen Current, differ greatly in their DOC concentration and composition. PW carries high amounts of semi-labile DOC (SL-DOC) from the Arctic Ocean southwards, whereas AW contains less but more labile DOC. No clear trend in DOC concentration over the 10-year time series was detected for AW. In contrast, samples collected in PW between 2016 and 2021 showed a 15 % increase in DOC, which was attributable to an increase in SL-DOC. Interannual variability in DOC lability was most pronounced in the eastern Fram Strait, likely driven by differences in the seasonal progression of the pelagic ecosystem. Our data suggest that DOC dynamics in the Fram Strait are influenced by an enhanced riverine input of DOC to the Arctic Ocean, leading to an increased DOC export to the North Atlantic.

气候变化对北冰洋的影响比其他地区更深远，对碳循环的影响不确定。此外，外来和本地有机碳源经历了极端的季节变化。因此，将气候引起的变化与碳循环的季节变化区分开来仍然是一项重大挑战。研究了土壤中溶解有机碳（DOC）浓度和稳定性的年际变化。即，利用2010 - 2021年的时间序列数据，从氨基酸组成推断出海峡表层DOC的寿命。夏季，利用RV POLARSTERN在HAUSGARTEN长期生态研究观测站或其周围进行采样。结果表明，以东格陵兰海流为主的极地水（PW; T < 0°C; S < 34.0）和以西斯皮次卑尔根海流为主的大西洋水（AW; T < 3°C; S > 34.9）两大海峡水团DOC浓度和组成差异较大。PW从北冰洋向南携带大量的半不稳定DOC (SL-DOC)，而AW含有较少但较多的不稳定DOC。在10年时间序列中，没有检测到AW的DOC浓度的明显趋势。相比之下，2016年至2021年期间在PW收集的样本显示DOC增加了15%，这是由于SL-DOC的增加。DOC稳定性的年际变化在海峡东部最为明显，这可能是由远洋生态系统的季节变化所驱动的。我们的数据表明，弗拉姆海峡的DOC动态受到河流向北冰洋输入DOC增强的影响，导致DOC向北大西洋输出增加。

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引用次数: 0

Trophic specialization enhances growth performance in larvae of southern bluefin, albacore, and skipjack tunas from the eastern Indian ocean 营养特化提高了东印度洋南部蓝鳍金枪鱼、长鳍金枪鱼和鲣鱼幼虫的生长性能

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-19 DOI: 10.1016/j.dsr2.2025.105585

Raúl Laiz-Carrión , Ricardo Borrego-Santos , José María Quintanilla , Claudio Quezada- Romegialli , Estrella Malca , Rasmus Swalethorp , Francisco Abascal , María Grazia Pennino , Manuel Vargas-Yáñez , Carolina Johnstone , Miguel Ángel Godoy-Bermúdez , David Die , Michael R. Landry

We examined trophic ecology and its influence on larval growth variability for three scombrids, southern bluefin (Thunnus maccoyii, SBT), albacore (T. alalunga, ALB), and skipjack tunas (Katsuwonus pelamis, SKJ), that share a common spawning ground in the eastern Indian Ocean. We combined otolith-based ageing with bulk nitrogen and carbon stable isotope analysis (SIA) of individual larva. Significant interspecific differences in δ¹⁵N and δ¹³C indicate adaptive resource partitioning that allows these tunas to coexist during early ontogeny. Trophic position and isotopic niche were estimated with both frequentist and Bayesian approaches, enabling the evaluation of ontogenetic isotope shifts, niche overlap, and resource use in relation to growth. ALB grew fastest, had the highest trophic position, and the broadest isotopic niche. Optimally growing tuna larvae occupied the narrowest trophic niche and had lower trophic positions for all three species, supporting the hypothesis that strong trophic specialization supports better growth performance and that feeding on more efficient shorter food chains (e.g., microbial loop via appendicularians) can enhance larval fitness. Using lower C:N ratio as a proxy of larval condition found in optimal growing groups supports the broader hypothesis that growth potential is closely tied to energy allocation strategies during early ontogeny. A detailed understanding of how larval trophodynamics, niche breadth, and resource partitioning interact with growth and survival during these vulnerable stages is essential for ecosystem-based management, particularly in systems where growth rate modulates predation risk and competitive fitness.

我们研究了南蓝鳍金枪鱼（Thunnus maccoyii， SBT）、长鳍金枪鱼（T. alalunga， ALB）和鲣鱼（Katsuwonus pelamis， SKJ）这三种鲭鱼的营养生态学及其对幼虫生长变异的影响，这三种鲭鱼在东印度洋共享一个产卵地。我们将基于耳石的老化与个体幼虫的体积氮碳稳定同位素分析（SIA）相结合。δ15N和δ13C的显著种间差异表明，在个体发育早期，这些金枪鱼的适应性资源分配使其能够共存。利用频率和贝叶斯方法估算了营养位置和同位素生态位，从而评估了与生长相关的个体成因同位素变化、生态位重叠和资源利用。ALB生长最快，营养地位最高，同位素生态位最广。最佳生长的金枪鱼幼虫占据了最窄的营养生态位，并且在所有三个物种中都处于较低的营养位置，这支持了强营养专业化支持更好的生长性能的假设，以及更有效的短食物链（例如通过阑尾虫的微生物环）的摄食可以提高幼虫的适应性。利用较低的碳氮比作为最佳生长群体中幼虫状况的代表，支持了一个更广泛的假设，即生长潜力与个体发育早期的能量分配策略密切相关。在这些脆弱阶段，详细了解幼虫营养动力学、生态位宽度和资源分配如何与生长和生存相互作用，对于基于生态系统的管理至关重要，特别是在生长速度调节捕食风险和竞争适应性的系统中。

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引用次数: 0

Subsurface mixing and ventilation of oxygen minimum zone waters in the southern Bay of Bengal during summer monsoon 夏季风期间孟加拉湾南部氧最小带水域的地下混合和通气

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-15 DOI: 10.1016/j.dsr2.2025.105584

Rajdeep Roy , P.N. Vinayachandran , Jenson George , Amit Sarkar , Chandanlal Parida

During the summer monsoon, the influence of the cyclonic curl of local wind forcing around Sri Lanka causes the formation of a cold dome called the Sri Lanka Dome (SLD), which upwells subsurface water. To the east of SLD, the summer monsoon Current (SMC) flows into the Bay of Bengal (BoB), transporting Arabian Sea high salinity water. We show that SMC, alongside the upwelled waters of SLD, is ventilated episodically during the summer monsoon in the southern BoB, leading to a net exchange of low oxygen subsurface waters with the oxygen-saturated surface mixed layers. We observed the presence of a hypoxic boundary <63 μmol kg⁻¹ very close to the surface. Within the SLD, it shoaled between 35 and 40 m with oxygen concentrations reaching as low as 6 μmol kg⁻¹ at the bottom of the thermocline. Negative fluxes representing the in-gassing rates ranged between (-0.33 to - 9.43 μmol m⁻² sec⁻¹) within SLD and SMC. We emphasize that episodic ventilation observed during this investigation may lead to disequilibrium in the surface mixed layers and can contribute to mid-depth oxygen enrichment. Our present study possibly illustrates a likely mechanism that contributes to preventing denitrification in this region.

在夏季季风期间，斯里兰卡周围的气旋旋度的影响导致了一个被称为斯里兰卡圆顶（SLD）的冷圆顶的形成，该圆顶使地下水上升。在SLD以东，夏季风流（SMC）流入孟加拉湾（BoB），输送阿拉伯海高盐度水。研究表明，在夏季风期间，南太平洋的SMC与SLD上升水一起偶尔通风，导致低氧地下水与含氧饱和的地表混合层的净交换。我们观察到非常接近表面的低氧边界<；63 μmol kg−1的存在。在SLD内，它在35 ~ 40 m之间浅滩，在温跃层底部氧浓度低至6 μmol kg−1。负通量表示SLD和SMC的入气速率在（-0.33 ~ - 9.43 μmol m−2 sec−1）之间。我们强调，在本研究中观察到的间歇性通气可能导致表层混合层的不平衡，并有助于中深度的氧富集。我们目前的研究可能说明了一种可能的机制，有助于防止该地区的反硝化。

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引用次数: 0

Dissolved nitrogen in a tropical river-sea continuum: a seasonal view on the distribution and transformation 热带河海连续体中的溶解氮：分布和转变的季节性观点

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-08 DOI: 10.1016/j.dsr2.2025.105583

Longyun Lai , Moritz Müller , Rahayu Sukmaria Sukri , Changi Wong , Aazani Mujahid , Sumei Liu , Zhaomeng Xu , Tim Rixen , Thorsten Warneke , Justus Notholt , Shan Jiang

The Belait River is a typical blackwater river in Brunei, characterized by deep tea-brown water rich in dissolved organic matter (DOM) derived from surrounding peat swamps and rainforests. This study provides a systematic assessment of the chemical composition, transformation, and transport processes of dissolved nitrogen (N) in the Belait River during alternating wet and dry seasons by integrating nitrate (NO₃⁻) stable isotope techniques with microbial analyses. Results indicate that dissolved organic nitrogen (DON) constitutes the primary component of total dissolved nitrogen (TDN), with its seasonal dynamics significantly controlled by hydrological climate and microbial activity. Along the salinity gradient, DON decreases due to dilution and degradation, while ammonium (NH₄⁺) and NO₃⁻ accumulate significantly in densely populated areas owing to anthropogenic inputs. The extremely low dissolved inorganic phosphorus (DIP) concentrations in the Belait River highlight the crucial role of P limitation in maintaining the system's oligotrophic state. Through the investigation in this representative blackwater system, this study highlights complex N cycling mechanisms in blackwater and provides a critical gauge in land-ocean material fluxes at the Indo-Pacific Convergence Area.

Belait河是文莱典型的黑水河流，其特点是深茶色的水富含来自周围泥炭沼泽和雨林的溶解有机质（DOM）。本研究通过将硝酸盐（NO3−）稳定同位素技术与微生物分析相结合，系统地评估了干湿交替季节Belait河中溶解态氮(N)的化学组成、转化和运输过程。结果表明，溶解有机氮（DON）是总溶解氮（TDN）的主要组成部分，其季节动态受水文气候和微生物活动的显著控制。沿盐度梯度，DON因稀释和降解而减少，而在人口密集地区，铵（NH4+）和NO3−因人为输入而显著积累。Belait河中极低的溶解无机磷（DIP）浓度突出了P限制在维持系统寡营养状态中的关键作用。通过对这一具有代表性的黑水系统的调查，本研究突出了黑水中复杂的N循环机制，并为印太辐合区陆-海物质通量提供了一个关键指标。

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