刘公岛海洋牧场底层海水溶解氧浓度的变化特征

由于缺乏长期观测资料,前人对山东半岛邻近海域海水溶解氧的时间变化和空间分布特征的研究较少。本文基于威海刘公岛海洋牧场于2016年7月20日至2017年3月14日期间,利用生态环境实时在线观测系统获得的底层海水的温度、盐度、水深、溶解氧数据,分析了该牧场海水溶解氧浓度的时间变化特征及其影响因素,并探讨了低氧灾害发生的可能性。结果表明在观测期间,该牧场海水溶解氧浓度以季节变化为主,冬季最大、夏季最小,其中2月份平均值最高,约为10.86mg/L,8月份平均值最低,约为5.91mg/L。同时海水溶解氧浓度也存在显著的小时变化和日变化,且变化幅度于8月份最大、3月份最小。影响海水溶解氧浓度变化的主要因素是海水温度,溶解氧浓度随着温度的季节性变化而变化。夏季,水体分层会使溶解氧浓度发生大幅度的降低,大风过程对于溶解氧浓度也有一定的影响,通过打破夏季的季节性温跃层使水体发生垂向混合从而为海底提供氧气,但大风过程之后的几天会出现溶解氧浓度降低的现象。本次研究发现刘公岛海洋牧场在观测期间不存在低氧现象。     

热带太平洋海表二氧化碳分压的时空变化特征及其与物理场间的联系

为研究赤道太平洋海表二氧化碳分压(pCO₂^sw)年际变化的机制,基于中科院海洋所宋金明研究团队于2021年发布的中国首套全球海表二氧化碳分压数据产品,使用相关性分析、经验正交函数(empirical orthogonal function, EOF)分析和奇异值分解(singular value decomposition, SVD)等方法,研究了2005～2019年赤道太平洋pCO₂^sw气候态分布及其去趋势后的年际异常的时空演变特征;结合pCO₂^sw与多种参数的相关性和厄尔尼诺-南方涛动(El Ni?o-Southern Oscillation, ENSO)过程探讨了赤道中西太平洋pCO₂^sw年际异常中心形成的原因。研究结果显示,热带太平洋pCO₂^sw季节变化、年际异常及其EOF第一模态特征向量沿赤道均出现两个中心,其中一个在赤道中西太平洋日界线附近,另一个在赤道中东...     

Seasonal variability of dissolved oxygen,percent oxygen saturation,and apparent oxygen utilization in the Atlantic and Pacific Oceans

Using objectively analyzed seasonal fields of dissolved oxygen content, percent oxygen saturation, and apparent oxygen utilization (AOU), we describe the large-scale seasonal variability of oxygen for the Atlantic and Pacific Oceans in the upper 400 m. The winter minus summer basin zonal averages of AOU reveal a two-layer feature in both the Atlantic and the Pacific, for both hemispheres. Biological activity and seasonal stratification in the summer give the upper 50–75 m of the water column in each basin a lower AOU in summer than winter. Greater mixing of upper ocean waters in winter gives the 75–400 m layer lower AOU values in that season. The basin integral seasonal volumes of oxygen for both the North Atlantic and the North Pacific mirror what is occurring in the atmosphere, indicating that there is a seasonal flux of oxygen across the air–sea interface. Winter total O₂ volume in the ocean is above the annual mean; the summer volume is below. Larger seasonal differences in the total O₂ content are observed in the North Atlantic Ocean than the North Pacific Ocean. A seasonal net outgassing (SNO) of 8.3×10¹⁴ moles O₂ is calculated from basin means, which is 25% higher than previous results.     

CERTAIN PROPERTIES AND CAUSES OF VARIATIONS OF THE SOUTH EQUA-TORIAL COUNTERCURRENT IN THE PACIFIC OCEAN

Marine investigations were carried out in the western Central Equatorial Pacific region from 1976 to 1979 by three Chinese research vessels "Xiangyanghong 05", "Xiangyanghong 09" and "Shijian" belonging to the National Bureau of Oceanography. The data of currents, surface wind, drift of the ship, temperature, salinity, and so on, were obtained during the investigations, which provides more reliable basis for further studies on the South Equatorial Countercurrent in the Pacific Ocean. In this paper certain properties and causes of variations of the South Equatorial Countercurrent in the Pacific Ocean are analysed according to the above-mentioned data.     

基于延绳钓观察员数据的热带太平洋中东部食物网拓扑结构分析

热带太平洋是金枪鱼类、旗鱼类等渔业的主要作业海域，但目前针对此海域食物网的研究仍十分缺乏。本文根据2017年6月-11月中国金枪鱼科学观察员在热带太平洋中东部海域（13°09''N -34°27''S, 100°03''-176°17''W）采集的鱼类样品，结合胃含物及其他分析方法以35个物种间的摄食关系为基础对此海域的食物网结构进行了分析。拓扑学指标（节点强度，D；中心性指数，BC和CC；拓扑重要性指数，TI¹和TI³；关键性指数，K、K_t和K_b）和Key-Player算法（KPP-1和KPP-2）用来筛选关键种，并结合体长数据建立了基于关键种的简化食物网。肯德尔相关性分析和聚类分析结果表明，不同拓扑学指标筛选出的关键种是一致的。大多数关键种与太平洋其他海域的研究结果是相同的，如剑鱼（Xiphias gladius）、长鳍金枪鱼（Thunnus alalunga）、小吻四鳍旗鱼（Tetrapturus angustirostris）头足类和鲭属。移除5个关键种后，食物网将被离散为许多互不连接的部分（F=0.632，F^D=0.795，R^D=0.957），表明这些物种在维持食物网结构和稳定性中的必要性。物种体长是本研究构建简化食物网时的决定性因素。研究结果有助于提高对热带太平洋食物网结构的认识，同时为进一步的生态系统动力学研究提供科学依据。     

Oxygen-carbon dioxide-nutrients relationships in the Southeastern Region of the Bering Sea

The vertical distribution of density, salinity, temperature, dissolved oxygen, apparent oxygen utilization, nutrients, preformed phosphate, pH, alkalinity, alkalinity: chlorinity ratio, in situ partial pressure of carbon dioxide, and percent saturation of calcite and aragonite, for the Southeastern Bering Sea, is studied and explained in terms of biological and physical processes. Some hydrological interactions between the Bering Sea and the North Pacific Ocean are explained. The horizontal distribution of dissolved oxygen at 2000 and 2500 m depths, throughout the Bering Sea, indicates that deep water is flowing from the Pacific, through the Kamchatka Strait, and then northward and eastward in the Bering Sea. Based on the dissolved oxygen distribution we estimate roughly that it takes 20 years for the deep waters to move from the Kamchatka Strait to the Southeastern part of the eastern basin. The surface concentration of nutrients is higher in the Bering Sea than in the North Pacific Ocean, probably because of upwelling and intense vertical mixing in the Bering Sea. A multivariable regression analysis of dissolved oxygen as a function of phosphate concentration and potential temperature was applied for the region where the potential temperature-salinity diagram is straight, and the confidence interval of the PO₄ coefficient, at the 95% probability level, was found consistent with theRedfield biochemical oxidation model. The calcium carbonate saturation calculations show that the Bering Sea is supersaturated with aragonite in the upper 100 m, and with calcite in the upper 200 m. Below these depths seawater is undersaturated with respect to these two minerals.     

Characterising the intermediate depth waters of the Pacific Ocean using δ13C and other geochemical tracers

Evidence from geochemical tracers (salinity, oxygen, silicate, nutrients, alkalinity, dissolved inorganic carbon (DIC), carbon isotopes (δ¹³C_DIC) and radiocarbon (Δ¹⁴C)) collected during the Pacific Ocean World Ocean Circulation Experiment (WOCE) voyages (P10, P15, P17 and P19) indicate there are three main water types at intermediate depths in the Pacific Ocean; North Pacific Intermediate Water (NPIW), Antarctic Intermediate Water (AAIW) and Equatorial Pacific Intermediate Waters (EqPIW). We support previous suggestions of EqPIW as a separate equatorial intermediate depth water as it displays a distinct geochemical signature characterised by low salinity, low oxygen, high nutrients and low Δ¹⁴C (older radiocarbon). Using the geochemical properties of the different intermediate depth waters, we have mapped out their distribution in the main Pacific Basin.From the calculated pre-formed δ¹³C_air–sea conservative tracer, it is evident that EqPIW is a combination of AAIW parental waters, while quasi-conservative geochemical tracers, such as radiocarbon, also indicate mixing with old upwelling Pacific Deep Waters (PDW). The EqPIW also displays a latitudinal asymmetry in non-conservative geochemical tracers and can be further split into North (NEqPIW) and South (SEqPIW) separated at ～2°N. The reason for this asymmetry is caused by higher surface diatom production in the north driven by higher silicate concentrations.The δ¹³C signature measured in benthic foraminifera, Cibicidoides spp. (δ¹³C_Cib), from four core tops bathed in AAIW, SEqPIW and NPIW, reflects that of the overlying intermediate depth waters. The δ¹³C_Cib from these cores show similarities and variations down-core that highlight changes in mixing over the last 30,000 yr BP. The reduced offset between the δ¹³C_Cib of AAIW and SEqPIW during the last glacial indicates that AAIW might have had an increased influence in the eastern equatorial Pacific (EEP) region at this time. Additional intermediate depth cores and other paleo-geochemical proxies such as Cd/Ca and radiocarbon are required from the broader Pacific Ocean to further understand changes in intermediate depth water formation, circulation and mixing over glacial/interglacial cycles.     

大西洋热带海域长鳍金枪鱼渔场预报模型的比较

为提高大西洋热带海域长鳍金枪鱼(Thunnus alalunga)渔场预报的准确率,对K最近邻(k nearest neighbor,KNN)、逻辑斯蒂回归(logistic regression,LR)、决策与分类树(classfication and regression tree,CART)、梯度提升决策树(gr...     

Oxygen minimum zones in the eastern tropical Atlantic and Pacific oceans

Within the eastern tropical oceans of the Atlantic and Pacific basin vast oxygen minimum zones (OMZ) exist in the depth range between 100 and 900 m. Minimum oxygen values are reached at 300–500 m depth which in the eastern Pacific become suboxic (dissolved oxygen content <4.5 μmol kg⁻¹) with dissolved oxygen concentration of less than 1 μmol kg⁻¹. The OMZ of the eastern Atlantic is not suboxic and has relatively high oxygen minimum values of about 17 μmol kg⁻¹ in the South Atlantic and more than 40 μmol kg⁻¹ in the North Atlantic. About 20 (40%) of the North Pacific volume is occupied by an OMZ when using 45 μmol kg⁻¹ (or 90 μmol kg⁻¹, respectively) as an upper bound for OMZ oxygen concentration for ocean densities lighter than σ_θ < 27.2 kg m⁻³. The relative volumes reduce to less than half for the South Pacific (7% and 13%, respectively). The abundance of OMZs are considerably smaller (1% and 7%) for the South Atlantic and only 0% and 5% for the North Atlantic. Thermal domes characterized by upward displacements of isotherms located in the northeastern Pacific and Atlantic and in the southeastern Atlantic are co-located with the centres of the OMZs. They seem not to be directly involved in the generation of the OMZs.OMZs are a consequence of a combination of weak ocean ventilation, which supplies oxygen, and respiration, which consumes oxygen. Oxygen consumption can be approximated by the apparent oxygen utilization (AOU). However, AOU scaled with an appropriate consumption rate (aOUR) gives a time, the oxygen age. Here we derive oxygen ages using climatological AOU data and an empirical estimate of aOUR. Averaging oxygen ages for main thermocline isopycnals of the Atlantic and Pacific Ocean exhibit an exponential increase with density without an obvious signature of the OMZs. Oxygen supply originates from a surface outcrop area and can also be approximated by the turn-over time, the ratio of ocean volume to ventilating flux. The turn-over time corresponds well to the average oxygen ages for the well ventilated waters. However, in the density ranges of the suboxic OMZs the turn-over time substantially increases. This indicates that reduced ventilation in the outcrop is directly related to the existence of suboxic OMZs, but they are not obviously related to enhanced consumption indicated by the oxygen ages. The turn-over time suggests that the lower thermocline of the North Atlantic would be suboxic but at present this is compensated by the import of water from the well ventilated South Atlantic. The turn-over time approach itself is independent of details of ocean transport pathways. Instead the geographical location of the OMZ is to first order determined by: (i) the patterns of upwelling, either through Ekman or equatorial divergence, (ii) the regions of general sluggish horizontal transport at the eastern boundaries, and (iii) to a lesser extent to regions with high productivity as indicated through ocean colour data.     

Water masses in the Humboldt Current System: Properties,distribution, and the nitrate deficit as a chemical water mass tracer for Equatorial Subsurface Water off Chile

Three sections are used to analyze the physical and chemical characteristics of the water masses in the eastern South Pacific and their distributions. Oceanographic data were taken from the SCORPIO (May–June 1967), PIQUERO (May–June 1969), and KRILL (June 1974) cruises. Vertical sections of temperature, salinity, σ_θ, dissolved oxygen, nitrate, nitrite, phosphate, and silicate were used to analyze the water column structure. Five water masses were identified in the zone through T–S diagrams: Subantarctic Water, Subtropical Water, Equatorial Subsurface Water, Antarctic Intermediate Water, and Pacific Deep Water. Their proportions in the sea water mixture are calculated using the mixing triangle method. Vertical sections were used to describe the geographical distributions of the water mass cores in the upper 1500 m. Several characteristic oceanographic features in the study area were analyzed: the shallow salinity minimum displacement towards the equator, the equatorial subsurface salinity maximum associated with a dissolved oxygen minimum zone and a high nutrient content displacement towards the south, and the equatorward intermediate Antarctic salinity minimum associated with a dissolved oxygen maximum. The nitrate deficit generated in the denitrification area off Peru and northern Chile is proposed as a conservative chemical tracer for the Equatorial Subsurface Waters off the coast of Chile, south of 25°S.     

Characteristics of the Sôya Warm Current in the Okhotsk Sea

Characteristics of the Sôya Warm Current from Abashiri Bay to the area off the coast of the southern Kuril Islands are clarified by water mass analysis. The water flowing into the Okhotsk Sea as the Sôya Warm Current is divided into two: the Forerunner of the Sôya Warm Water (March to May) and the Sôya Warm Water (June to November). It is shown that in May the Sôya Warm Current flows in the subsurface layer (about 200–400m deep) in Abashiri Bay, and flows northeastward just off the coast of the Kuril Islands as a subsurface current reaching a region northwest of Etorofu Island by the end of May. The dissolved oxygen content is fairly effective in identifying the Forerunner of the Sôya Warm Water in the subsurface layer. The Sôya Warm Current shifts upwards to the surface layer in Abashiri Bay by early July, because the Sôya Warm Water with large thermosteric anomaly _t begins to flow into the Okhotsk Sea in June. It is shown that, in general, the major portion of the Sôya Warm Current flows northeastward just off the coast of the Kuril Islands during the summer season, although a minor branch of the current flows northward in the area off the Shiretoko Peninsula, and another minor branch flows out to the Pacific Ocean through the Nemuro Straits.     

Increase in total carbonate in the western North Pacific water and a hypothesis on the missing sink of anthropogenic carbon

Sea water samples were collected from various depths in the North Pacific (40–21°N) along 165°E in 1991. Their total carbonate (total dissolved carbonate species) contents were determined with random errors less than 0.2% by a coulometric method. The preformed carbonate contents defined by Chen (1982) were calculated from the obtained data and other observed data including potential temperature, salinity, dissolved oxygen and total alkalinity. The same calculation was done for the GEOSECS data obtained in nearly the same region in 1973. The difference between the two data sets reveals that the preformed carbonate has increased by 180±41 gC/m² during the last 18 years. This value is comparable or somewhat larger than 150 gC/m² obtained in the case that the ocean uptakes 3 GtC/yr for 18 years and distributes it equally among the world oceans. Based on the results, a hypothesis on the missing sink for the anthropogenic carbon dioxide is presented, in that the missing sink is the intermediate waters formed in the northern North Pacific and the Southern Ocean besides the deep waters formed in the North Atlantic and the Southern Ocean.     

Distribution and seasonal variation of vitamin B12, thiamine and biotin in the sea

The distributions and seasonal variations of vitamin B₁₂, thiamine and biotin were investigated in waters of the North Pacific Ocean, the East China Sea, and the bays and inlets along the Pacific coast of Japan, by use of microbiological assay methods. A marine diatom Cyclotella nana clone 3H for vitamin B₁₂, and marine yeast Cryptococcus albidus for thiamine, and a marine bacterium Achromobacter sp. strain yH-51 for biotin were used as assay organisms. In the surface water of Sagami Bay, monthly changes in the amounts of the three dissolved vitamins followed closely that of chlorophyll a, being highest in July and lowest during late autumn and winter. The geographical and vertical distributions of thiamine and biotin in the sea generally showed similar patterns to that of chlorophyll a, whereas vitamin B₁₂ did not always follow the trend. Amounts of particulate thiamine and biotin corresponded to about 1 % of that of the dissolved form in the surface water of the North Pacific Ocean. In the coastal waters, however, they were at times found to be 144.0 % and 53.9 % respectively.     

铜藻的分类地位、生物地理分布以及2016年底黄海漂浮铜藻源头的初步分析

通过对我国沿海多次野外实地考察以及文献报道，对铜藻进行了分类地位及生物地理分布特征介绍。结合分子数据，目前由过去单一的狭义铜藻Sargassum horneri和线形马尾藻Sargassum filicinum结合而成广义铜藻。其生物地理分布区系由西北太平洋扩大到东北太平洋的有限区域。根据我国沿海铜藻底栖和漂浮种群的发生季节变化，初步判断我国可能存在2个以上的底栖铜藻种群：春季成熟型、夏季成熟型和/或秋季成熟型。结合铜藻的自然生境、底栖分布区系以及海流等水文资料，本文对2016年底黄海漂浮铜藻种群的源头进行了初步分析，其最可能地域源头为渤海海峡区及其邻近水域，最可能的种群来源为夏季成熟型。     

长江口海域水文环境要素分布及溶解氧垂向输运

本文基于2016年长江口海域(舟山绿华山)的连续观测数据,分析了该海域水文环境要素分布,并估算了溶解氧跨跃层垂向输运。本次观测发现,水体的温度、盐度和溶解氧剖面具有明显的分层结构,三者跃层具有相同的变化趋势且主要受潮流变化影响。通过计算,得到跃层浮性频率的平方(N2)在10–3—10–2/s2之间,剪切的平方(S2)介于10–5—10–2/s2。潮流活动会激发水体剪切不稳定促进水体中溶解氧的垂向交换。最后,采用简化的一维溶解氧垂向输运模型,得到观测周期内跨跃层输运的溶解氧的含量为4.75mmol/(m2·d),佐证层化是长江口海域出现氧亏损现象的主要原因之一。     

东太平洋赤道海域茎柔鱼(Dosidicus gigas)的体型月间变化及环境效应

为了掌握茎柔鱼体型生长变化及其与栖息环境因子的效应关系, 2017年2—4月和6—8月,在东太平洋赤道海域逐月随机采集了3 628尾茎柔鱼样本,进行体质量、胴长的月间变化分析和胴长与海表温、叶绿素a浓度的效应关系研究。结果显示,雌性个体胴长分布范围为163—468mm,体质量分布范围为123—3034g;雄性个体胴长分布范围为171—475mm,体质量分布范围为145—2 681 g。不同月份之间,雌性、雄性个体的胴长和体质量均存在显著性差异,雌雄性个体胴长、体质量均以2月份的最大, 6—8月份的较小。然而,每个月份雌性、雄性个体的胴长分布均为单峰值区间分布。体质量-胴长幂函数关系显示,2—4月份雌雄性个体多倾向于匀速生长、体征较差,6—8月份个体则以负异速生长为主、体征较为良好。雌性、雄性个体胴长与采样海域海表温、采样纬度呈显著的正效应关系,采样海域叶绿素a浓度对雌性胴长产生正效应影响。研究表明,东太平洋赤道海域茎柔鱼体型的月间差异性显著,体型变化与采样海域海表温、采样纬度关系密切,并且雌性体型与海域叶绿素a浓度呈正效应关系。     

太平洋波高成份研究

利用Topex／Poseidon卫星高度计1992年10月到1998年12月连续75个月，230个重复周期的有效波高资料对南北太平洋的波高成份进行了分析，结果显示所有的月份，频数密度峰值对应的波高成份因子为1．4，以赤道太平洋海域最高为1．6，南北太平洋海域为1．2左右。7、8、9、10月份太平洋涌浪成份占频数密度累积率的比例大于95％，其余各月占90%左右，表明太平洋海域波高成份以涌浪为主。     

Vertical and horizontal extension of the oxygen minimum zone in the eastern South Pacific Ocean

Recent hydrographic measurements within the eastern South Pacific (1999–2001) were combined with vertically high-resolution data from the World Ocean Circulation Experiment, high-resolution profiles and bottle casts from the World Ocean Database 2001, and the World Ocean Atlas 2001 in order to evaluate the vertical and horizontal extension of the oxygen minimum zone (<20 μmol kg⁻¹). These new calculations estimate the total area and volume of the oxygen minimum zone to be 9.82±3.60×10⁶ km² and 2.18±0.66×10⁶ km³, respectively. The oxygen minimum zone is thickest (>600 m) off Peru between 5 and 13°S and to about 1000 km offshore. Its upper boundary is shallowest (<150 m) off Peru, shoaling towards the coast and extending well into the euphotic zone in some places. Offshore, the thickness and meridional extent of the oxygen minimum zone decrease until it finally vanishes at 140°W between 2° and 8°S. Moving southward along the coast of South America, the zonal extension of the oxygen minimum zone gradually diminishes from 3000 km (15°S) to 1200 km (20°S) and then to 25 km (30°S); only a thin band is detected at ∼37°S off Concepción, Chile. Simultaneously, the oxygen minimum zone's maximum thickness decreases from 300 m (20°S) to less than 50 m (south of 30°S). The spatial distribution of Ekman suction velocity and oxygen minimum zone thickness correlate well, especially in the core. Off Chile, the eastern South Pacific Intermediate Water mass introduces increased vertical stability into the upper water column, complicating ventilation of the oxygen minimum zone from above. In addition, oxygen-enriched Antarctic Intermediate Water clashes with the oxygen minimum zone at around 30°S, causing a pronounced sub-surface oxygen front. The new estimates of vertical and horizontal oxygen minimum zone distribution in the eastern South Pacific complement the global quantification of naturally hypoxic continental margins by Helly and Levin [2004. Global distribution of naturally occurring marine hypoxia on continental margins. Deep-Sea Research I 51, 1159–1168] and provide new baseline data useful for studies on the role of oxygen in the degradation of organic matter in the water column and the related implications for biogeochemical cycles. Coastal upwelling zones along the eastern Pacific combine with general circulation to provide a mechanism that allows renewal of upper Pacific Deep Water, the most oxygen-poor and oldest water mass of the world oceans.     

柔海胆科(Echinothuriidae)3个属叉棘超微结构的研究

海胆的叉棘是海胆御敌、清除体表异物的重要器官,其形状在海胆的分类上具有重要意义。本文通过扫描电子显微镜对西太平洋海山区柔海胆科软海胆属Araeosoma、兜海胆属Sperosoma和革海胆属Hygrosoma的叉棘形态与结构特征进行研究,并提供了柔海胆科属的检索表。结果表明:柔海胆有三种常见的叉棘形式,三叉叉棘、三叶叉棘和指状叉棘。三叉叉棘和三叶叉棘在3个属中均存在,指状叉棘只在软海胆属中存在,三叶叉棘和指状叉棘的超微结构变化比较细微,三叉叉棘的超微结构特征具有明显的种属间差异。建议将叉棘的种类和结构作为柔海胆科的分类依据。     

利用TOPEX/Poseidon高度计资料提取的太平洋M2内潮能通量分布

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