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

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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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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引用次数: 0

Revisiting daily growth and survival insights of Southern Bluefin Tuna (Thunnus maccoyii) larvae in the eastern Indian Ocean 重访东印度洋南部蓝鳍金枪鱼（Thunnus maccoyii）幼虫的日常生长和生存见解

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-01 DOI: 10.1016/j.dsr2.2025.105572

Ricardo Borrego-Santos , José M. Quintanilla , Raúl Laiz-Carrión , Alberto García , Estrella Malca , Francisco J. Abascal , David Die , Isabel Riveiro , Rasmus Swalethorp , Michael R. Landry

This study analyzed the growth patterns and survival of Southern bluefin tuna (SBT, Thunnus maccoyii) larvae collected during January–February 2022 in their only known spawning area in the eastern Indian Ocean (IO). Otolith microstructure was examined to characterize both population-level and intra-population growth (OPT-optimal and DEF-deficient group), with special emphasis on the flexion process, as well as to provide insights into larval survival. SBT larvae began flexion at sizes and ages comparable to those reported in other bluefin tuna species. At the intra-population level, OPT larvae reached flexion earlier in a better physical condition, with greater length, weight, and body depth, likely increasing their chances of survival at later stages. The observed larval growth rates (0.38 mm d⁻¹) exceeded that from a historical study in 1987 (0.33 mm d⁻¹), likely due to a ∼2 °C increase in sea surface temperature and shifts in prey availability. Larval survival appears to depend on a selective process based on growth, in which only a small proportion of individuals (<2 %) exhibited width increment in otoliths similar to those of surviving larvae, allowing for faster development and earlier access to larger prey. These findings highlight the need for expanded research on the early life stages of SBT, particularly in the context of ongoing ocean warming and climate change.

本研究分析了2022年1 - 2月在东印度洋唯一已知的南蓝鳍金枪鱼产卵区收集的南蓝鳍金枪鱼（SBT, Thunnus maccoyii）幼虫的生长模式和存活率。研究人员检查了耳石微观结构，以表征种群水平和种群内的生长（OPT-optimal和DEF-deficient组），特别强调了弯曲过程，并提供了对幼虫存活的见解。SBT幼虫在大小和年龄上开始弯曲，与其他蓝鳍金枪鱼物种相当。在种群内水平，OPT幼虫较早到达屈曲状态，身体状况较好，体长、体重和体深较大，可能增加其后期的生存机会。观察到的幼虫生长速率（0.38 mm d - 1）超过了1987年的历史研究（0.33 mm d - 1），可能是由于海面温度升高~ 2°C和猎物可得性的变化。幼虫的生存似乎依赖于一个基于生长的选择过程，在这个过程中，只有一小部分个体（2%）的耳石宽度增加与存活的幼虫相似，这使得它们能够更快地发育并更早地获得更大的猎物。这些发现突出表明，有必要扩大对SBT早期生命阶段的研究，特别是在持续的海洋变暖和气候变化的背景下。

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引用次数: 0

Exploring the roles of trophic mode and microbial prey size in grazing pathways of tropical oligotrophic waters of the eastern Indian ocean 探索东印度洋热带少营养水域的营养模式和微生物猎物大小在放牧路径中的作用

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-01 DOI: 10.1016/j.dsr2.2025.105573

Claudia Traboni , Grace F. Cawley , Karen E. Selph , Michael R. Landry , Moira Décima

Prey removal incubations were conducted in the Argo Basin (eastern Indian Ocean) to investigate the trophic ecology of the zooplankton community supporting Southern Bluefin Tuna larvae. Copepod grazing and selectivity were evaluated considering prey trophic mode and size as food quality descriptors and compared with microzooplankton grazing. Copepods ingested between 3.4 and 138 ng carbon (C) ind⁻¹ d⁻¹. Diet was dominated by mixotrophic (5–89 %) and heterotrophic (0–84 %) prey, with autotrophs contributing 2–17 %. Nanoplankton provided the highest C intake to copepods (62–99 %) versus picoplankton (0.8–38 %), despite more picoplankton cells ingested. No measurable reduction in chlorophyll a (Chla) concentration occurred from copepod grazing through food removal, suggesting an indirect trophic pathway, although gut content revealed ingestion of 0.8 μg Chla ind⁻¹ d⁻¹. Calculations from disappearance incubations imply copepod selection on picoplankton (E = 0.3) over nanoplankton, but picoplankton were likely ingested as aggregates or depressed due to a trophic cascade of copepods ingesting nano-microzooplankton. Copepods ingested protistan consumers and/or metazoans fed on ¹⁵N-cyanobacteria with ∼5-fold higher N uptake from 1 to 2 μm ¹⁵N-Synechococcus than from <1 μm ¹⁵N-Prochlorococcus. Microzooplankton grazing on eukaryotes (0.07–2.5 d⁻¹) and prokaryotes (0.3–2.1 d⁻¹) greatly exceeded copepod grazing. Microzooplankton diet consisted mostly of heterotrophs (25–59 %) and mixotrophs (13–41 %) followed by autotrophs (12–33 %), with more nano- (95–98 %) than picophytoplankton (2–5 %). Overall, microzooplankton removed most daily production (111 %) in contrast to 7 % for copepods. Our findings indicate that mixotrophy, intraguild grazing and nutrient channeling support the food web in this oligotrophic region.

为了研究南蓝鳍金枪鱼幼虫的营养生态学，在东印度洋的Argo盆地进行了捕食物去除孵化。以猎物的营养方式和大小作为食物质量描述因子，对桡足类动物的放牧和选择性进行了评价，并与微型浮游动物的放牧进行了比较。桡足类动物摄取的碳(C)在3.4 ~ 138 ng之间。食性以混合营养（5 - 89%）和异养（0 - 84%）猎物为主，自养动物占2 - 17%。纳米浮游生物为桡足类动物提供了最高的碳摄入量（62% - 99%），而微浮游生物（0.8 - 38%），尽管微浮游生物摄入的细胞更多。尽管肠道含量显示摄入了0.8 μg Chla d - 1，但桡足类动物通过食物清除并没有显著降低叶绿素a （Chla）的浓度，这表明了间接的营养途径。根据消失孵育的计算结果表明，桡足类对微浮游生物的选择（E = 0.3）高于纳米浮游生物，但微浮游生物很可能被作为聚集体摄入，或者由于桡足类摄入纳米微浮游动物的营养级联而被抑制。桡足类动物摄取的原细菌和/或后生动物以15n -蓝藻为食，从1 ~ 2 μm 15n -聚藻球菌中摄取的氮量比从1 μm 15n -原绿球藻中摄取的氮量高约5倍。浮游微动物对真核生物（0.07 ~ 2.5 d−1）和原核生物（0.3 ~ 2.1 d−1）的取食远远超过桡足类动物。微浮游动物以异养生物（25 - 59%）和混合生物（13 - 41%）为主，其次是自养生物（12 - 33%），其中纳米浮游动物（95 - 98%）多于浮游植物（2 - 5%）。总的来说，微型浮游动物减少了大部分的日产量（111%），而桡足类动物减少了7%。我们的研究结果表明，混合营养、野生放牧和营养渠道支持了这个营养不良地区的食物网。

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引用次数: 0

Interaction of bay outflow and wind-driven upwelling in chlorophyll patterns in the Gulf of the Farallones 法拉隆湾叶绿素模式中海湾流出流与风驱动上升流的相互作用

IF 3 3区地球科学 Q2 OCEANOGRAPHY

Deep-sea Research Part Ii-topical Studies in Oceanography

Pub Date : 2025-12-01 DOI: 10.1016/j.dsr2.2025.105558

Candice N. Cooper , Christopher A. Edwards , John L. Largier , Piero L.F. Mazzini

A descriptive analysis of remotely-sensed surface chlorophyll-a within the Gulf of the Farallones and nearby coastal waters occupying portions of three NOAA National Marine Sanctuaries along the central California coast is presented. The seasonal cycle from a 25-year chlorophyll-a record reveals elevated levels near the mouth of San Francisco Bay at the Golden Gate, with broad spatial extent climatologically from April through November. A 19-year time series of normalized water-leaving radiance at the 555 nm band (nLw555) was used to estimate the presence of waters representing the San Francisco Bay plume. Although the plume shows its largest spatial extent in winter, decreasing during spring and summer, chlorophyll-a was enhanced within plume waters relative to non-plume waters during all months; however, was not statistically different during upwelling months (April–June). Linear correlations between chlorophyll-a and a 20-year record of wind stress, a 10-year record of surface currents, and a 20-year record of sea surface temperatures reveal consistent, coherent regional spatial patterns. Weighted averages confirm that poleward winds and surface currents result in enhanced chlorophyll-a in nearshore waters north of the Golden Gate and around Point Reyes. Periods of equatorward winds and surface transport exhibit elevated chlorophyll-a and temperature south of the Golden Gate, offshore of Half Moon Bay, and are associated with nearby onshore currents. Correlations of plume concentrations (nLw555

\geq 12

W m⁻²

μ

m⁻¹ sr⁻¹) with wind stress, however, do not show the same coherent patterns as with chlorophyll-a, and turbid plume waters are largely confined to the Gulf of the Farallones. These analyses suggest that surface chlorophyll-a within the inner Gulf of the Farallones close to San Francisco Bay is significantly influenced by outflow from the Bay, but the greater Gulf of Farallones is more strongly influenced by upwelling and relaxation effects.

本文对法拉隆湾和位于加州中部海岸的三个NOAA国家海洋保护区附近的沿海水域的遥感地表叶绿素- A进行了描述性分析。从25年的叶绿素记录的季节周期来看，在金门湾的旧金山湾口附近，从4月到11月，在气候上具有广泛的空间范围，叶绿素水平升高。在555nm波段（nLw555）的19年标准化水离开辐射时间序列被用来估计代表旧金山湾羽流的水的存在。尽管羽流的空间范围在冬季最大，在春夏两季逐渐减小，但在所有月份中，羽流水体内的叶绿素a均比非羽流水体增强；而在上升流月份（4 - 6月），差异无统计学意义。叶绿素-a与20年风应力记录、10年地表洋流记录和20年海面温度记录之间的线性相关揭示了一致的、连贯的区域空间格局。加权平均值证实，在金门以北和雷耶斯角附近的近岸水域，向极地方向的风和表面洋流导致叶绿素-a的增加。在金门以南，半月湾近海，赤道风和地面运输的时期，叶绿素-a和温度升高，并与附近的陆上洋流有关。然而，羽流浓度（nLw555≥12 W m−2 μm−1 sr−1）与风应力的相关性与叶绿素-a的相关性不一致，并且浑浊的羽流水主要局限于Farallones湾。这些分析表明，在靠近旧金山湾的Farallones内湾，表层叶绿素-a受到海湾流出物的显著影响，但Farallones大湾受上升流和松弛效应的影响更为强烈。

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引用次数: 0