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

Differences in bloom phenology and seasonal chlorophyll-a variability in the Fram Strait's hydrographic subregions resolved by a machine learning approach 通过机器学习方法解决了弗拉姆海峡水文分区中开花物候和季节性叶绿素-a变异的差异

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-22 DOI: 10.1016/j.dsr2.2026.105603

Vanessa Lampe, Andreas Oschlies, Markus Schartau

The Fram Strait (FS) exhibits pronounced variability in chlorophyll-a (Chl-a) concentration on intra- and inter-annual scales, which is linked to the complex hydrography of the region, marked by two opposing currents separated by a frontal system. Here, we propose a machine learning approach that partitions the FS into three hydrographical subdomains (sectors) based on remotely sensed sea surface temperature, the main property for water mass identification besides salinity. The sectors resolve the cold Arctic, warm Atlantic, and intermediate front-influenced regions. This sectorisation allows for a nuanced analysis of variability, accounting for the dynamic behaviour of the currents and frontal system. Differences revealed in bloom phenology are reflected in remote-sensing Chl-a concentrations within these hydrographical sectors. Blooms (Chl-a > 1 mg m⁻³) tend to occur in May in the Arctic-influenced sector, which is subject to variable sea ice cover. They appear later, in July, in the Atlantic-influenced sector. The absolute magnitude of Chl-a variability increases with its average concentration. However, concentration-normalised, the variability is notably higher in the Arctic-influenced sector, emphasising the impact of environmental differences within the hydrographic regimes on phytoplankton dynamics. Between 2016 and 2021, we could not detect clear trends in the sectors’ average Chl-a concentration or major changes in bloom timing. This study contributes to a broader comprehension of the expected variability ranges of Chl-a in the Fram Strait. Furthermore, it provides a valuable tool for analysing large geospatial data sets, especially when in-situ measurements of the physical seawater properties are limited in spatial and temporal coverage.

弗拉姆海峡（FS）在年际和年际尺度上表现出明显的叶绿素-a （Chl-a）浓度变化，这与该地区复杂的水文地形有关，其特征是由锋面系统分隔的两股相反的洋流。在这里，我们提出了一种机器学习方法，该方法基于遥感海面温度（除了盐度之外的主要水体识别属性）将FS划分为三个水文子域（扇区）。这些扇区包括寒冷的北极、温暖的大西洋和受中间锋影响的区域。这种划分允许对变异性进行细致入微的分析，考虑到洋流和锋面系统的动态行为。开花物候的差异反映在这些水文部门的遥感Chl-a浓度上。藻华（Chl-a > 1 mg m−3）往往发生在受北极影响的地区，该地区受海冰覆盖变化的影响。它们在7月晚些时候出现在受大西洋影响的地区。Chl-a变率的绝对值随其平均浓度的增加而增加。然而，浓度标准化后，北极影响部门的变异性明显更高，强调了水文制度内环境差异对浮游植物动态的影响。在2016年至2021年期间，我们无法检测到行业平均Chl-a浓度的明确趋势或开花时间的重大变化。本研究有助于更广泛地理解海峡Chl-a的预期变率范围。此外，它为分析大型地理空间数据集提供了一个有价值的工具，特别是当对海水物理性质的现场测量在空间和时间覆盖范围有限时。

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引用次数: 0

Decadal spatial trends in the feeding-type composition of Arctic deep-sea nematodes at LTER-HAUSGARTEN: A dual classification approach LTER-HAUSGARTEN北极深海线虫食性组成的年代际变化趋势：双重分类方法

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-16 DOI: 10.1016/j.dsr2.2026.105601

Jannik Schnier , Christiane Hasemann

This study examined functional changes in free-living meiobenthic nematode communities across different water depths and sediment layers over a 20-year period along a bathymetric transect at LTER observatory HAUSGARTEN in the Fram Strait (1200 m, 2500 m, and 4000 m). The focus was on changes in feeding type composition and comparing the performance two different classification systems (Wieser's and Hodda's) to assess whether they yield consistent functional interpretations or highlight differences.

Published datasets were used to analyse nematode communities, with specimens identified morphologically to the lowest possible taxonomic level and assigned to feeding types. The study investigated how the trophic structure of nematode communities varied over time, with depth, and between sediment layers, aiming to reveal long-term spatio-temporal patterns at HAUSGARTEN.

Microbial feeding nematodes were consistently dominant across all stations and years. While feeding type composition changed significantly over time at each respective station and to a similar strength with water depth, sediment layer had a stronger influence than the temporal variation. Interannual variation of feeding types as well as within-group dissimilarity and dispersion were lowest at the shallowest station and increased with water depth. Similarly, feeding-type composition in the uppermost sediment layer remained most stable over the years and was gradually decreasing with sediment depth. Despite a decline in nematode abundances over time, the overall feeding type composition remained unchanged. Both classification systems produced comparable results, indicating that functional interpretations of nematode communities are robust across classification approaches.

本研究考察了20年来Fram海峡（1200米，2500米和4000米）的LTER观测站HAUSGARTEN的水深样带上不同水深和沉积层的自由生活的低底生线虫群落的功能变化。重点是饲料类型组成的变化，并比较两种不同分类系统（Wieser和Hodda）的性能，以评估它们是否产生一致的功能解释或突出差异。已发表的数据集被用于分析线虫群落，标本在形态学上被识别到尽可能低的分类水平，并被分配到摄食类型。研究了线虫群落的营养结构如何随时间、深度和沉积物层之间的变化而变化，旨在揭示HAUSGARTEN的长期时空格局。微生物取食线虫在所有站点和年份中始终处于优势地位。各站点的供料类型组成随时间变化显著，且随水深变化的强度相似，但沉积物层的影响强于时间变化。饵料类型的年际变化以及组内差异和分散度在最浅的站点最低，随水深的增加而增加。同样，最上层沉积物的喂养型组成在多年中保持最稳定，并随着沉积物深度的增加而逐渐减少。尽管线虫丰度随着时间的推移而下降，但总体摄食类型组成保持不变。两种分类系统都产生了可比较的结果，表明线虫群落的功能解释在各种分类方法中都是可靠的。

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引用次数: 0

The Second International Indian Ocean Expedition (IIOE-2): Motivating new exploration in a poorly understood ocean basin (volume 7) 第二次国际印度洋考察（IIOE-2）：在一个知之甚少的海洋盆地激发新的探索（第7卷）

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-16 DOI: 10.1016/j.dsr2.2025.105566

Raleigh R. Hood , Lynnath E. Beckley , V.V.S.S. Sarma , P.N. Vinayachandran

引用次数: 0

Zooplankton trophic processes in the eastern Indian Ocean off northwest Australia 澳大利亚西北部东印度洋浮游动物的营养过程

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-13 DOI: 10.1016/j.dsr2.2026.105592

Moira Décima , Rasmus Swalethorp , Grace F. Cawley , Claudia Traboni , Claire H. Davies , Michael R. Landry

The region off northwestern Australia in the eastern Indian Ocean is an oligotrophic open-ocean ecosystem characterized by low nutrients and high stratification, and is the only known spawning ground for Southern Bluefin Tuna (SBT). We conducted four multi-day Lagrangian experiments (cycles) and transect sampling to investigate plankton trophic flows during the peak SBT spawning season (Jan–Feb 2022). These cycles were carried out after recent storm mixing and subsequent warming and stratification of the water column. We quantified mesozooplankton size-fractionated biomass and grazing, targeting processes that coincide with SBT larval habitat (upper 30 m) and the full euphotic zone (150 m). Higher grazing occurred in the upper 30 m at the start of our study, coinciding with the deeper mixed layer. Euphotic-zone integrated grazing peaked later, coinciding with higher stratification and increased abundance of diatoms at depth. Mesozooplankton grazing impact averaged 0.11 ± 0.01 d^-1 for the region, equivalent to 21.2 % of phytoplankton growth. Combined with microzooplankton grazing removals, phytoplankton growth and total zooplankton grazing losses were approximately in balance for the euphotic zone. While direct consumption of phytoplankton only supported respiratory needs of a portion of the assemblage in two of the four experimental cycles, respiratory and production needs were largely met by including the consumption of microzooplankton production. Thus, the production of mesozooplankton prey required to sustain SBT larvae in this nutrient-poor environment was obtained by both high grazing and efficient trophic coupling. This study highlights the role of metazoan zooplankton in warm oligotrophic waters of the eastern tropical Indian Ocean, and indicates that efficient ecosystem transfer can be achieved even under conditions assumed to severely limit production and biomass accumulation.

东印度洋澳大利亚西北部海域是一个营养不良的开放海洋生态系统，其特点是低营养和高分层，是唯一已知的南蓝鳍金枪鱼（SBT）的产卵场。通过4个多天拉格朗日实验（循环）和样带取样，研究了SBT产卵高峰期（2022年1 - 2月）浮游生物的营养流动。这些循环是在最近的风暴混合和随后的水柱变暖和分层之后进行的。我们量化了中浮游动物的大小-分异生物量和放牧，目标过程与SBT幼虫栖息地（30米以上）和全光带（150米）一致。在我们的研究开始时，较高的放牧发生在30 m以上，与较深的混合层相一致。光带综合放牧的高峰较晚，与较高的分层和深度硅藻丰度增加相一致。该地区中浮游动物的放牧影响平均为0.11±0.01 d-1，相当于浮游植物生长的21.2%。结合微小浮游动物的放牧去除，浮游植物的生长和浮游动物的总放牧损失在真光区大致平衡。虽然在四个实验周期中的两个周期中，浮游植物的直接消耗仅支持部分组合的呼吸需要，但通过包括微型浮游动物生产的消耗，呼吸和生产需要在很大程度上得到满足。因此，在这种营养匮乏的环境中，维持SBT幼虫所需的中浮游动物猎物的生产是通过高放牧和有效的营养耦合来实现的。本研究强调了热带印度洋东部温暖少营养水域的后生动物浮游动物的作用，并表明即使在严重限制生产和生物量积累的条件下，也可以实现有效的生态系统转移。

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引用次数: 0

Seasonal and spatial variability of marine nepheloid layers in the deep South China Sea 南海深海海相网状层的季节和空间变异

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-13 DOI: 10.1016/j.dsr2.2026.105600

Zhuangcai Tian , Xiujun Guo , Jinjian Huang , Chao Xu , Lei Song , Jianhua Yue

Marine nepheloid layers are extensively distributed across the world's oceans and marginal seas, characterized by significantly high turbidity compared to adjacent layers. In this study, we measured four transects located at 6°N, 10°N, 18°N, and 113°E in the South China Sea (SCS), encompassing a total of 75 CTD stations each year, and conducted four sets of repeated measurements over a four-year period. Our findings indicate that the scale and concentration of Bottom Nepheloid Layer (BNL) and Intermediate Nepheloid Layer (INL) vary significantly across different subbasins and seasons. In the southwestern and northwestern subbasin of the SCS, BNL and multiple INLs persist year-round at different water depths. BNL is commonly observed on the continental slope with the INLs extending along the isopycnals, and both BNL and INLs always are stronger in summer. High turbidity has caused marked alterations in the isopycnal and isotherm structures of the water column, particularly near the slope. In the central basin of the SCS, multiple INLs also persist year-round, especially at water depths 400–1000 m. The changes in the water column by high turbidity in the central basin were weaker. The persistent presence of INLs indicates ongoing transport of particulate matter across the slope. Ocean currents and internal waves predominantly affect the slopes of the southwestern and northwestern subbasins, while the deeper central basin is primarily affected by the ocean currents. The interactions between internal waves or ocean currents and submarine topography contribute to the frequent occurrence of BNL and INLs around the seamounts. This paper aimed to provide a comprehensive analysis of the seasonal and spatial variability of BNLs and INLs in the deep SCS, serving as a reference for future research on the dynamic processes of marine ecological environment and associated source-sink systems.

海洋浊体层广泛分布在世界海洋和边缘海，其特点是与邻近层相比浊度明显高。研究中，我们在南海6°N、10°N、18°N和113°E的4个样带上进行了每年75个CTD站点的测量，并在4年的时间里进行了4组重复测量。研究结果表明，不同亚盆地、不同季节，底部和中间云雾层的规模和浓度存在显著差异。在南海西南和西北次海盆，在不同水深，BNL和多个inl全年持续存在。在大陆斜坡上普遍观测到BNL， inl沿等距平线延伸，夏季BNL和inl都较强。高浊度引起了水柱等平线和等温线结构的明显变化，特别是在斜坡附近。在南海的中央盆地，多个inl也全年持续存在，特别是在400-1000米的水深。中部盆地高浊度对水柱的影响较弱。INLs的持续存在表明颗粒物质正在通过斜坡进行输送。洋流和内波主要影响西南和西北次盆地的斜坡，而较深的中央盆地主要受洋流的影响。内波或海流与海底地形的相互作用是海底山附近频繁发生的海底低洼和海底低洼的重要原因。本文旨在全面分析南海深层生物碱和生物碱的季节和空间变异，为进一步研究海洋生态环境的动态过程和相关的源汇系统提供参考。

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引用次数: 0

Selective feeding of southern Bluefin Tuna (Thunnus maccoyii) larvae on appendicularians in their eastern Indian Ocean spawning region 南蓝鳍金枪鱼（Thunnus maccoyii）幼虫在东印度洋产卵区对尾尾鱼的选择性摄食

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-12 DOI: 10.1016/j.dsr2.2026.105591

Rasmus Swalethorp , Estrella Malca , Akihiro Shiroza , Lindsey Kim , Moira Decima , José M. Quintanilla , Ricardo Borrego-Santos , Claire H. Davies , David Die , Lynnath E. Beckley , Claudia Traboni , Grace F. Cawley , Kamran Walsh , Michael R. Landry , Raúl Laiz-Carrión

We investigated ontogenetic variability in feeding and prey selection by Southern Bluefin Tuna larvae (SBT; Thunnus maccoyii) in their only global spawning region, located in the eastern Indian Ocean between northwestern Australia and Indonesia. Zooplankton prey and SBT larvae were sampled during four multi-day Lagrangian experiments conducted in the southern Argo Basin during the peak midsummer spawning season in January–February 2022. The zooplankton were identified, enumerated, sizes measured, and their developmental stages ascertained both in situ and from the stomach contents of the larvae. Larval stomach contents revealed high feeding incidence of 95 % with at least one prey item ingested with an average of 3.9 zooplankton prey per larva. Diet and prey selection transitioned during larval ontogeny from copepod nauplii to calanoid and corycaeid copepodites, and ultimately to cladocerans, as well as fish larvae when these were available. However, for all developmental stages and experiments, appendicularians stood out as the most significant prey taxon, constituting an average of 57 % of prey carbon biomass consumed and up to 79 % for postflexion stages. We observed some indication of increasing selection for appendicularians and fish larvae where they were most abundant, even when other suitable prey items were more readily available. Our study documents unprecedented high feeding incidence and positive selection for appendicularians compared to previous investigations of bluefin species, highlighting a pathway that enhances food web transfer efficiency. Appendicularians are uniquely able to thrive in oligotrophic environments and could be an optimal food source supporting SBT larvae in the future ocean.

我们研究了南蓝鳍金枪鱼（SBT; Thunnus maccoyii）在其唯一的全球产卵区（位于澳大利亚西北部和印度尼西亚之间的东印度洋）的摄食和猎物选择的个体发育变异性。在2022年1 - 2月的盛夏产卵高峰期，在Argo盆地南部进行了4次多日拉格朗日实验，对浮游动物猎物和SBT幼虫进行了采样。对浮游动物进行了鉴定、枚举，测量了它们的大小，并在原位和从幼虫胃内容物中确定了它们的发育阶段。幼虫胃内容物的摄食率高达95%，至少有一种猎物被摄食，平均每只幼虫捕获3.9种浮游动物。在幼体发育过程中，饮食和猎物选择发生了转变，从鹦鹉螺类桡足类和喙类桡足类，到最终的枝海类，以及有条件的鱼类幼体。然而，在所有发育阶段和实验中，尾虫作为最重要的猎物分类群脱颖而出，平均占猎物碳生物量消耗的57%，在屈曲后阶段高达79%。我们观察到一些迹象表明，即使在其他合适的猎物更容易获得的情况下，尾虫和鱼类幼虫在它们最丰富的地方也会被选择。与以往的研究相比，我们的研究记录了蓝鳍金枪鱼前所未有的高摄食率和正选择，突出了提高食物网转移效率的途径。尾虫在低营养环境中茁壮成长的独特能力，可能是未来海洋中支持SBT幼虫的最佳食物来源。

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引用次数: 0

Sinking particle export within and beneath the euphotic zone in the eastern Indian Ocean 东印度洋光带内部和下方的下沉粒子输出

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-12 DOI: 10.1016/j.dsr2.2026.105590

Michael R. Stukel , Tristan Biard , Moira Décima , Christian K. Fender , Opeyemi Kehinde , Thomas B. Kelly , Sven A. Kranz , Manon Laget , Michael R. Landry , Natalia Yingling

The eastern Indian Ocean is substantially under sampled with respect to the biological carbon pump – the suite of processes that transport the carbon fixed by phytoplankton into the deeper ocean. Using sediment traps and other ecosystem measurements, we quantified sinking organic matter flux and investigated the characteristics of sinking particles in waters overlying the Argo Abyssal Plain directly downstream of the Indonesian Throughflow off northwest Australia. Carbon export from the euphotic zone averaged 7.0 mmol C m⁻² d⁻¹, which equated to an average export efficiency (export/net primary production) of 0.19. Sinking particle flux within the euphotic zone (beneath the mixed layer, but above the deep chlorophyll maximum) averaged slightly higher than flux at the base of the euphotic zone, suggesting that the deep euphotic zone was a depth stratum of net particle remineralization. Carbon flux attenuation continued into the twilight zone with a transfer efficiency (export at euphotic depth + 100m/export at euphotic depth) of 0.62 and an average Martin's b-value of 1.1. Within the euphotic zone, fresh phytoplankton (chlorophyll associated with sinking particles, possibly contained within appendicularian houses) were an important component of sinking particles, but beneath the euphotic zone the fecal pellets of herbivorous zooplankton (phaeopigments) were more important. Changes in carbon and nitrogen isotopic composition with depth further reflected remineralization processes occurring as particles sank. We show similarities with biological carbon pump functioning in a similar semi-enclosed oligotrophic marginal sea, the Gulf of Mexico, including net remineralization across the deep chlorophyll maximum.

东印度洋的生物碳泵（将浮游植物固定的碳输送到更深的海洋的一系列过程）的采样量基本上不足。利用沉积物捕集器和其他生态系统测量方法，我们量化了澳大利亚西北部印尼通流（印度尼西亚通流）下游Argo深海平原上的下沉有机质通量，并研究了下沉颗粒的特征。从光带出口的碳平均为7.0 mmol C m−2 d−1，相当于平均出口效率（出口/净初级生产）为0.19。透光区内下沉颗粒通量（低于混合层，但高于深层叶绿素最大值）平均略高于透光区底部的通量，表明深层透光区是一个净颗粒再矿化的深层地层。碳通量衰减继续进入过渡带，转移效率（出口在光深+ 100m/出口在光深）为0.62，平均马丁b值为1.1。在泛光带内，新鲜浮游植物（与下沉颗粒相关的叶绿素，可能包含在附属虫体内）是下沉颗粒的重要组成部分，但在泛光带下，食草浮游动物的粪便颗粒（phaeopigments）更为重要。碳和氮同位素组成随深度的变化进一步反映了颗粒下沉时发生的再矿化过程。我们展示了在类似的半封闭的低营养边缘海，墨西哥湾中生物碳泵的相似之处，包括深叶绿素最大值的净再矿化。

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引用次数: 0

An eastward branch of the east India coastal current off Sri Lanka: Dynamics, formation mechanisms, and impacts on Bay of Bengal salinity variability 斯里兰卡外东印度海岸流的东支：动力、形成机制和对孟加拉湾盐度变化的影响

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2026-01-08 DOI: 10.1016/j.dsr2.2025.105588

W.G. Indunil Tharaka Gunathilaka , JayarathnaW.N.D. Sandaruwan , Wang Tianyu , Yan Du

The East India Coastal Current (EICC) flows equatorward during early boreal winter, transporting low–salinity Bay of Bengal (BOB) waters southward along the Indian eastern coast. Using satellite measurements, in–situ observations, and ocean model data, we identify a recurrent eastward current (EC) that splits from the EICC off the eastern coast of Sri Lanka. While a weaker branch of the EICC continues equatorward along the coast, a section of rest flow diverts northeastward into the BOB as the EC, indicating a gyre structure in the northwest of BOB. Analysis of 28 years of data (1993–2020) reveals eight distinct EC events, occurring primarily during neutral Indian Ocean dipole years. These events are dynamically forced by two types of eddies, a westward–propagating anticyclonic eddy, linked to downwelling Rossby waves, impinging on the south eastern coast of Sri Lanka, while a cyclonic eddy forms to the north. These events are supported by the following coastal–trapped downwelling Kelvin wave, with the current appearing with increasing frequency over time. The EC, lasting about one-two weeks, exhibits a velocity of 0.3–0.5 m/s and transport flow volume ranging from 0.15 to 0.54 Sv. Despite its brief duration, EC plays a critical role in exporting low–salinity waters (<33 PSU) from Sri Lanka's eastern coast and subsequently transporting high–salinity central BOB waters toward the inner bay. By regulating EICC low–salinity water intrusion, the EC produces distinct freshening effects along Sri Lanka's eastern coast during active years, highlighting its important role in controlling western BOB freshwater distribution patterns.

东印度海岸流（EICC）在北纬初冬向赤道流动，将低盐度的孟加拉湾（BOB）水沿印度东海岸向南输送。利用卫星测量、现场观测和海洋模型数据，我们确定了一个从斯里兰卡东海岸的EICC分裂出来的周期性东流（EC）。当EICC的一个较弱分支沿着海岸继续向赤道方向移动时，一部分剩余气流转向东北进入BOB作为EC，表明BOB西北部存在环流结构。对28年（1993-2020）数据的分析揭示了8个不同的EC事件，主要发生在印度洋中性偶极子年。这些事件是由两种类型的涡流动态推动的，一种是向西传播的反气旋涡流，与下行的罗斯比波有关，撞击斯里兰卡的东南海岸，而一种是在北部形成的气旋涡流。这些事件是由以下海岸捕获的下潜开尔文波支持的，随着时间的推移，水流出现的频率越来越高。EC持续约1 - 2周，流速为0.3-0.5 m/s，输送流量为0.15 - 0.54 Sv。尽管持续时间很短，但东印度洋在从斯里兰卡东海岸出口低盐度水域（<33 PSU）以及随后将高盐度的BOB中部水域输送到内湾方面发挥了关键作用。通过调节EICC低盐度水入侵，EC在斯里兰卡东部沿海活跃年产生明显的清新效应，突出了其在控制西部BOB淡水分布模式中的重要作用。

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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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