Distribution of Calanus finmarchicus in the northern North Atlantic and Arctic Ocean—Expatriation and potential colonization

The distribution of Calanus finmarchicus was studied on a transect across the central Greenland Sea, and on five transects from the Eurasian shelves across the Atlantic Inflow in the Arctic Ocean. Stage composition was used as an indicator for successful growth; gonad maturity and egg production were taken as indicators for reproductive activity. On the Arctic Ocean transects, these parameters were measured simultaneously from the sibling species Calanus glacialis. Response of egg production rate to different temperatures at optimal food conditions was very similar between both species in the laboratory. C. finmarchicus was present at all stations studied, but young developmental stages were only present close to the regions of submergence of Atlantic water under the Polar water. This together with a decreasing abundance and biomass from west to east along the Atlantic Inflow in the Arctic Ocean and reproductive failure indicates that C. finmarchicus is expatriated in the Arctic Ocean. We hypothesize that the late availability of food in the Arctic Ocean, rather than low temperature per se, limits reproductive success. Better reproductive success in the very low temperature regions of the Return Atlantic Current and the marginal ice zone in the Greenland Sea supports this hypothesis. The possibility for a replacement of C. glacialis by C. finmarchicus and consequences for the ecosystem after increasing warming of the Arctic are discussed.     

三沙市海域海平面变化

使用1993-2011年的台站和卫星高度计资料详细分析了三沙市海域近19 a的海平面变化特征及规律。结果表明:三沙市周边海域海平面存在明显的季节变化,且区域特征明显。海平面变化除了明显的年和半年周期,2~3 a、4~7 a和准9 a的周期也较显著。海平面长期变化呈现明显的波动上升趋势,且空间分布上区域特征显著,西沙群岛南部海域海平面上升趋势最强,西沙群岛北部与中沙群岛西部次之,南沙群岛东部海平面上升速率较快,南沙群岛西部上升趋势最弱。受大气环流等异常气候事件的影响,1998年和2010年海平面的年际变化波动较大,年变化振幅显著偏高。未来三沙市海平面将继续上升,预计2030年、2050年、2070年和2100年海平面将比常年分别升高约11 cm、20 cm、30 cm和45 cm。     

The Northwest Pacific—the UNEP action plan facing the sub-polar Asian seas

The countries surrounding the Northwest Pacific marginal seas have different levels of economic development and different political systems. With the rapid economic development in the region, the marine environment received high pressure, which requires high attention of the governments concerned, and urgent actions.As the Northwest Pacific marginal seas shared by several countries, regional co-operation and co-ordination are the effective means to address the marine environmental problems in the region. The Northwest Pacific Action Plan, the Northeast Asian Regional GOOS are providing the intergovernmental mechanism to facilitate the regional co-operation and co-ordination. Effective implementation of these projects is a critical task facing to all countries in the region.     

Bayesian classification of the ice cover of the Arctic seas

A classification of sea ice in the Arctic by age (multiyear; first-year; and first-year deformed ice, nilas, etc.) is developed based on the Bayesian approach using satellite radar data and taking into account regional peculiarities of these types of ice for different sectors of the Arctic. Estimations of a priori probabilities for each ice type, which are required for the use of the Bayesian classification, are obtained by the analysis of ice charts in the Arctic seas developed at the AARI in 2008–2013 using satellite data. A posterior probabilities are estimated visually by an expert. Types of sea ice distinguished by the expert on satellite images make it possible to create sample values of the radar-scattering cross section (RSCS). Examples of the proposed Bayesian classification of ice in the Laptev Sea according to Envisat satellite data are given.     

Lunar monthly and fortnightly tides in the Russian Arctic seas

Characteristic features of the spatial distribution of monthly and fortnightly tides in the Barents, Kara, Laptev, East Siberian, and Chukchi seas are considered on the basis of a harmonic analysis of multiannual observations of the sea level at 57 stations. The amplitude and phase responses are close to the static values only for the monthly tide in the Barents Sea. In the Kara Sea, the dynamic component of the tide becomes traceable. The tide demonstrates a dynamical behavior throughout the remaining area. The fortnightly tide demonstrates a clearly expressed dynamical behavior with an increasing progressive type of the wave from the west to the east.     

The regional management of the seas around the United Kingdom

The development phases of management of the seas around the United Kingdom are classified in terms of a sequence of control, regulation and management extending from the 15th century to the present. The sectoral pattern of management is considered in terms of two groups of activities, namely private sector industries and public sector activities. Management trends identified include the drive towards integrated coastal management, the evolution of North West European sectorally based regional management, and national boundary delimitation.     

Past glacial and interglacial conditions in the Arctic Ocean and marginal seas – a review

Past changes in the Arctic Ocean and its marginal seas have been profound, even during the last 10,000 years. Understanding these changes, such as those occurring during the transition from glacial to interglacial climates, are important for research on modern processes, because this knowledge provides a framework and unique perspective in which to view the modern physical and biological processes. This paper discusses our current understanding of past environmental change and processes relative to those currently in progress. Special emphasis is placed on the most recent transition from a glacial state to the modern interglacial conditions.     

Current estimates of freshwater flux through Arctic and subarctic seas

As the world warms, the expectation is that the freshwater outflows from the Arctic Ocean to the North Atlantic will strengthen and may act to suppress the rate of the climatically-important Atlantic meridional overturning circulation. Hitherto, however, we have lacked the system of measurements required to estimate the totality of the freshwater flux through subarctic seas. Though observations remain patchy and rudimentary in places, we piece-together the results from recent large-scale observational programmes together with associated modelling, to establish preliminary maps of the rates and pathways of freshwater flux through subarctic seas. These fluxes are calculated according to two reference salinities, S = 34.8 to conform with the majority of estimates reported in the literature, and S = 35.2, the salinity of the inflowing Atlantic water, to calculate the freshwater balance of the ‘Arctic Mediterranean’. We find that 148 mSv of freshwater enters the Nordic Seas across its northern boundary. There it is supplemented by around 54 mSv of freshwater from Baltic runoff, Norwegian runoff, P − E and Greenland ice melt, so that the total freshwater contribution to the Nordic Seas from all sources is 202 mSv. Of this, around 51 mSv of freshwater is estimated to pass south to the deep Atlantic in the dense water overflows leaving an assumed balance of 151 mSv to leave the Nordic Seas in the upper water export through Denmark Strait. The corresponding estimate for the freshwater outflow west of Greenland is 103 mSv relative to 35.2 so that the total freshwater flux reaching the North Atlantic through subarctic seas is around 300 mSv.     

Investigation of a mushroom-like flow in the shelf edge area of northern seas

The dynamics of the evolution of a mushroom-like flow in the shelf edge area of northern seas in April 1989 are analysed using regular satellite data. The use of hydrologic shipboard observations conducted by a research ice-breaker in the area of development of the mushroom-like flow allowed some insights into the mechanism of its generation.Translated by V. Puchkin.     

Satellite monitoring of ice features to ensure safety of offshore operations in the Arctic seas

Methods for processing satellite data on ice features that pose a threat to the safety of offshore operations in the Arctic seas are considered. They are divided into interactive, automated, and automatic methods. The methods are illustrated by examples of archival satellite data on the Russian Arctic sector. Radar and optical data have been used as the satellite information source. It is shown that the successful satellite monitoring of dangerous ice features requires the optimal combination of satellite observations at various stages that provide for a synergistic approach to the data assimilation of different spectral bands obtained using different spacecraft.     

Interannual variability of the primary production and organic carbon fluxes in the Arctic seas of Russia

To estimate the response of the primary production to the climate warning, the trends of the production changes within 1998–2006 were considered in tests areas in the Barents, Kara, and Chukchi seas using satellite and field data. Both positive and negative trends were revealed with a general tendency to an increase in the primary production and in the extent of the organic carbon burial in the bottom sediments.     

Comparative analysis of satellite and shipborne data on ice cover in the Russian Arctic seas

The SSM/I data processed by the NASA Team algorithm are used to compare the total ice concentration obtained from the visual shipborne observations with satellite images. A comparison of the satellite images with the shipborne data shows significant differences with the shipborne data observed onboard ice-breakers during 15 scientific expeditions to the Barents, Kara, Laptev, and East Siberian seas. The most pronounced differences are observed in the ice edge regions. They cause errors in the estimates of the total ice concentration and ice extent, which makes difficult to use them in various practical and scientific tasks. Generally, the methods of remote sensing (RS) underestimate the real sea ice concentration: the average error is on the order of 10% in both winter and in summer. A statistical analysis of the comparison of two sources of information was carried out separately for the total ice concentration for summer and winter data taking into account the new ice and without it. During the summer period in the area of open ice, the SSM/I data over-estimate the total ice concentration by 0.5–1, but in close ice they underestimate it on average by 2 grades. If the new ice is subtracted from the total ice concentration obtained onboard the icebreakers, the total error decreases to ?3.4%. In the winter period in the region of rare ice, the SSM/I data overestimate the total ice concentration by 1–2 grades, but in close ice this difference is as high as 2, like in summer. New ice in winter is determined better by remote sensing methods than in summer; hence, its exclusion from the total ice concentration does not lead to a decrease in the average error.     

Formation of fast ice and its influence on the coastal zone of the Arctic seas

The formation of fast ice in the costal zone of freezing seas (immobile ice) is considered on the basis of a specially developed thermodynamic model that takes into account the energy exchange in the atmospheric boundary layer and the salinification of the water layer under the ice. The conditions at which the wind forced onshore motion of the ice under the influence of the wind stress at the ice’s surface is possible are studied using the example of the Baidaratskaya Guba in the Kara Sea.     

中国近海区域浮游植物生态对气候变化的响应

我国近海区域对气候变化高度敏感,浮游植物生态的变化关系到我国近海生态安全.采用重构的遥感数据等资料,分析并综述我国近海区域浮游植物叶绿素a浓度、初级生产力和浮游植物群落结构对气候变化背景下海水升温、风场等环境因子的响应.结果表明,东(南)中国海叶绿素a浓度略有上升(下降)的趋势,但浮游植物群落结构和生物量有明显的变化;其中,微微型浮游植物和甲藻占比增加,小型浮游植物物种成为海区优势种,暖水性种分布区北扩,而这与气候变化背景下海洋热动力环境的长期变化及其对营养盐供给的影响关系密切.分析还指出了气候变化对我国近海区域海洋生态影响研究迫切需要开展的若干工作.     

中国北方海域扇贝重金属含量的比较与质量评价

于2005年10～11月在大连湾、秦皇岛、莱州湾、烟台、威海、胶州湾、胶南7个海域,进行了海湾扇贝(Argopecten irradians)和栉孔扇贝(Chlamys farreri)As,Hg,Pb,Cu,Zn5种重金属含量的调查。重金属含量的测定采用原子吸收法进行。结果表明:(1)重金属含量存在着组织差异性,贝边的含量高于贝柱;(2)取自同一海域的栉孔扇贝重金属含量高于海湾扇贝;(3)5种重金属的平均含量排序为:Zn>Cu>As>Pb>Hg;(4)胶州湾栉孔扇贝Zn有超标现象,贝柱和贝边中的含量分别是限量标准的1.24倍和1.59倍;Hg,Pb,As和Cu均未超标。     

Sediment dynamics in the Eurasian Arctic Ocean during the last deglaciation — The clay mineral group smectite perspective

This study focuses on sedimentological investigations of sediment cores recovered during the international Arctic′91, expeditions with the German research ice breaker RV “Polarstern” to the European sector of the Arctic Ocean. Here, we deduce the last glacial/interglacial changes in transport mechanism and sedimentation from the clay mineral group smectite. We choose the smectites as an example of how sediment mineralogy can be linked with particular source regions (the Kara and Laptev seas), distinct transport mechanism (sea ice and surface currents) and sedimentation processes. Smectite contents in Arctic sediments discussed for two time slices, including the Last Glacial Maximum (LGM), and the last deglaciation (Termination I), reveal the highest variability subsequent to the retreat of the Eurasian ice sheets. Our results show that smectite anomalies in the Eurasian Basin are associated with distinct meltwater pulses and occurred around 13.5–13.0 ¹⁴C ka B.P. Compelling evidence is provided that these anomalies are deduced from sea-ice entrained sediments from the eastern Kara Sea that entered the Arctic Ocean after ice-sheet break-up and eventually flooding of the Kara Sea. We propose that smectite anomalies in sediments of the eastern Arctic Ocean can be utilized to identify deglacial events and to help decipher configurations of the Eurasian ice sheets. The identification of smectite maxima along the modern sea-ice edge in the Eurasian Basin further indicates biologically enhanced sedimentation from melting sea ice allowing the reconstruction of seasonally open water in the region. Hence, considering the poor preservation conditions of primary paleoceanographic proxies in the Arctic Ocean, the clay mineral contents, particularly the smectite group, may be one alternative tool for paleoclimatic reconstruction in the Eurasian Basin.     

General forecast of the evolution of the coastal zone of the Eurasian Arctic seas in the 21st century

Principal regularities of the evolution of the Arctic coasts of Eurasia in the 21st century related to the climate warming and sea level rise are assessed. It is stated that the most significant changes may be expected in the most ice-covered seas of the Arctic Ocean, where the area of the ice cover may significantly decrease while the duration of the ice-free periods will grow. Thermoabrasive coasts will be the most subjected to the changes; the rate of their recession will increase 1.5–2.5 fold. The further development of accumulative coasts in the Arctic seas will proceed against the background of a transgression; meanwhile, in the 21st century, one can expect no catastrophic changes such as washing away of coastal accumulative features.     

基于CMIP6模式分析北极典型海区浮游植物藻华模拟误差

在海冰覆盖的极地海区,浮游植物季节性藻华变化呈现典型的单峰特征。由于藻华过程受控于海冰、光照、混合层深度和营养盐供给等多个因素,其发生时间和强度在地球系统模式模拟结果中存在较大的不确定性。本研究选取11种CMIP6地球系统模式结果,以多种类型的观测资料和产品作为判断参考值,评估各模式结果能否准确模拟北极典型海区（巴伦支海、楚科奇海及白令海）浮游植物藻华动态的变化规律。通过计算能表征光照和营养盐限制的多个指标,分析表层叶绿素a浓度模拟结果的误差来源。结果表明,依据冰下光照时长、混合层变化速率、表层硝酸盐指标将11种模式分为3组,与参考值指标差异较小组别中的模式在藻华模拟方面明显占优,而其余模式在表层硝酸盐或混合层变化的模拟上存在较大误差,导致表层叶绿素a浓度峰值的发生时间延后且峰值浓度误差大。总体而言,地球系统模式配置中除要考虑光照和营养盐这两种基础限制条件外,也需关注由温盐控制的上混合层深度,从而准确模拟出表层叶绿素a浓度的季节性变化规律,上述研究为地球系统模式中相关参数化方案的改进提供了参考。     

中国近海北部陆架海相地层解体问题的研究

晚更新世以来,中国近海北部陆架近岸地区至少发生了三次海侵并保留三期海相地层.在研究了数千千米的浅地层剖面仪测量资料及大量钻孔资料后,笔者发现最后冰期最盛时期陆架出露,海相地层并非简单地、原封不动地被保留下来.在强大的风力作用下,除进行正常的风成沉积以外,还产生了沉积分异作用,出现风暴沉积及其衍生沉积,裸露的陆架至少部分地改变了原来的沉积结构,形成了新的沉积类型,构成复杂的混杂堆积区和黄土堆积区.这样,原先的海相地层被破坏,或者部分被保留下来,即陆架上海相地层发生了解体.