Sea foam as an object of sea-surface film studies

Sea foam and sea-surface films are pelagic habitats of common origin. This suggests a possible similarity between their microplanktonic assemblages and an a priori possibility to use foam samples in qualitative sea-surface film studies. The composition and abundance of microheterotrophs (nanoflagellates <5 μm and bacteria) in the Dalnezelenetskaya Inlet, Kola Peninsula, Barents Sea, in August 1987, was nearly identical in the foam and sea-surface film samples. In contrast, the enrichment of foam with autotrophs (nano- and microphytoplankton) exceeded by an order of magnitude that of sea-surface films, whereas their taxonomic compositions were virtually identical in both habitats. Elevated growth rates of phytoplankton in sea foam appear to be an ecological mechanism responsible for the enrichment.     

Gonad maturation as an indication of seasonal cycles for several species of small copepods in the Barents Sea

In a remote oceanic area like the Barents Sea, it is often difficult to follow the seasonal development of copepod populations in detail. Information on the gonad maturation stage of older juveniles and adults of a species will reveal the immediate state of reproduction and the expected development of juveniles into reproductively active adults. Winter "resting stages" in juveniles can also be recognised.
Zooplankton were caught during Pro Mare cruises in early March, May, July/August, mid-September and mid-October. Abundance and composition of developmental stages of small copepods were determined for several stations from each cruise. Samples consisting of Stages CIV to CV1 of Pseudocalanus acuspes (Giesbrecht 1881), P. minutus (Kröyer), Microcalanuspusillus (Sars), and M. pygmaeus Sars were stained with carmine and analysed with respect to gonad maturation stage, length, width, and area of the prosome and the area of the gonad and the oil sac. Image analyses were performed from photographs or drawings of copepods using a digitising pad.
With additional information on abundance and stage composition, and by comparing the present data set with information on Pseudocalanus spp. from Balsfjorden, northern Norway, seasonal cycles for the species could be inferred.     

The Corinth-Patras rift as the initial stage of continental fragmentation behind an active island arc (Greece)

Abstract During the migration of the back arc extension from central to western Greece the Corinth and Patras grabens are being formed. Orthogonal opening of these graben zones is accomplished by WNW listric normal faults and NNE transfer faults which produce an along-axis fragmentation. The listric faults show an increase in the dip of the fault plane westwards as well as a decrease in the maximum extension rate from 50% to the east in the Corinth graben, to 10% to the west in the Patras graben. Similarly, towards the west, Plio-Quaternary deposits become thinner whereas Pliocene sediments thin-out indicating a westward rift propagation.
As the back arc extension migrates westwards it is interacting or is being superimposed above another orthogonal fault system consisting of NNW and ENE normal faults. These faults have been formed during general uplift behind the orogenic front which has been migrating from western Greece to the Ionian islands. The ENE-trending Rio graben which belongs to his orthogonal system connects the Patras graben to the Corinth graben and has subsequently been active as a transfer fault between them.
Plio-Quaternary geodynamic processes in central continental Greece are quite similar to those earlier processes observed in the central Aegean region which reflect the initial stage of continental break-up behind a migrating orogenic front.     

Cyanobacteria as a trigger for increased primary productivity during sapropel formation in the Baltic Sea—a study of the Ancylus/Litorina transition

A sediment sequence from the Gotland Basin, representing the Ancylus Lake/Litorina Sea transition, was analysed for pigments, stable isotopes (δ¹³C and δ¹⁵N), diatoms and carbon and nitrogen content. The negative correlation between the cyanobacterial specific pigment zeaxanthin and δ¹⁵N supports the hypothesis that cyanobacteria in the early Litorina Sea indeed were nitrogen fixers. Their incorporation of nitrogen could have acted as a trigger for eutrophication during the Litorina Sea stage of the Baltic Sea. As cyanobacteria normally flourish in eutrophicated waters, the increasing concentrations of zeaxanthin during early Litorina Sea also corroborate that high primary production was an important part of the formation of organic rich (sapropel) sediments in the Baltic Sea. The first occurrence pre-dates the formation of laminated sediments, but the peaks of both zeaxanthin and organic carbon are within laminated sequences. This implies that the oxygen conditions of the bottom water also play a major role in the formation of sapropel sediments.     

利用珊瑚生长率重建西沙海域罗马暖期中期海温变化

珊瑚生长率是记录海水表层温度（SST）的一个重要代用指标。本文以南海中北部西沙永兴岛罗马暖期期间发育的3个澄黄滨珊瑚（Porites lutea）为材料,测量它们的骨骼生长率,并利用珊瑚骨骼生长率与SST的关系式定量重建海温年际变化序列。结果显示：3个滨珊瑚（生长于120-59 BC、46 BC-14 AD和30 BC-28 AD期间）的平均生长率分别为0.88 cm/a（变化于0.53~1.24 cm/a之间）、0.90 cm/a（变化于0.58~1.53 cm/a之间）和1.12 cm/a（变化于0.71~1.46 cm/a之间）。据此重建同时段年平均SST,相应结果分别为26.7℃、26.8℃和27.3℃。2 kaBP前后（120-59 BC,46 BC-28 AD）西沙海域平均SST为26.9±0.4℃,低于现代（1981-2010 AD）约0.7℃。     

港城脱钩的可能性机理与实际估测————以环渤海港口城市为例

在探讨城市发展是否可能与港口运营脱钩的理论探索的基础上,采用Tapio脱钩模型进行估测,构建了包括产业多样化指标的港口及城市评价体系,以2000—2019年环渤海地区12个主要港口城市为样本,实证检验港城脱钩类型。研究发现：尽管大部分港口城市的脱钩状态时常变化,但港城脱钩确实可能成为港口城市的演化路径,其过程是渐进的。港城脱钩的影响因素主要有城市发展阶段、产业多样化等,港口运营与本地经济一直未能深入融合的城市以及经济实力雄厚、发展路径多样的中心城市实现港城脱钩的难度相对较小。在环渤海案例区,丹东和秦皇岛已处于港城脱钩状态,天津和青岛未来出现港城脱钩的潜力较大,大连的港城关系演化尚不稳定,唐山、营口、日照等多数样本的港城关联仍然密切、脱钩可能性较小。     

环渤海地区农村空心化程度与耕地利用集约度的时空变化及其耦合关系

利用环渤海地区分县社会经济数据和土地利用数据, 采用神经网络确定权重的方法, 对该区分县农村空心化程度和耕地利用集约度进行综合测评, 并以山东省为例, 进行两者耦合规律探索。结果表明:① 环渤海地区农村空心化区域差异明显。高度空心化且进入稳定期的地区主要集中在“C”型沿海地区;平原传统农区, 农村空心化正处空心化的成长、兴盛期;农村空心化低值区主要集中落后山区。② 耕地利用集约度时空差异明显。辽中平原粮食主产区、冀中南粮食主产区、鲁西鲁南粮食主产区集约度较高;低集约度主要集中在太行山区、长白山区、沂蒙山区、坝上高原等落后地区。③ 农村空心化与耕地利用集约度变化存在着耦合联动关系。空心化出现、成长期, 农村劳动力向城镇转移, 农村地区隐性失业问题得以解决, 耕地利用集约度不断提升;农村空心化发展至兴盛期, 农村地域发展面临主体弱化, 耕地利用集约度有所下降;至空心化稳定期, 健全的土地流转机制和农业现代化的持续推进, 耕地利用集约度将反弹上升, 最终趋于波动稳定。     

Dynamics of plankton growth in the Barents Sea: model studies

1-D and 3-D models of plankton production in the Barents Sea are described and a few simulations presented. The 1-D model has two compartments for phytoplankton (diatoms and P. pouchelii) , three for limiting nutrients (nitrate, ammonia and silicic acid), and one compartment called "sinking phytoplankton". This model is coupled to a submodel of the important herbivores in the area and calculates the vertical distribution in a water column. Simulations with the 3-D model indicate a total annual primary production of 90-120g C m⁻² yr⁻¹ in Atlantic Water and 20-50g C m⁻² yr⁻¹ in Arctic Water, depending on the persistence of the ice cover during the summer.
The 3-D model takes current velocities, vertical mixing, ice cover, and temperature from a 3-D hydrodynamical model. Input data are atmospheric wind, solar radiation, and sensible as well as latent heat flux for the year 1983. The model produces a dynamic picture of the spatial distribution of phytoplankton throughout the spring and summer. Integrated primary production from March to July indicates that the most productive area is Spitsbcrgenbanken and the western entrance to the Barents Sea. i.e. on the northern slope of Tromsøflaket.     

Formation of turbid ice during autumn freeze-up in the Kara Sea

A one-dimensional (vertical) model is used to estimate the mass of ice-rafted sediment in turbid sea ice on the shallow Kara Sea shelf during autumn freeze-up. Sediment is entrained into the ice through aggregation with frazil ice crystals that are diffused downwards by wind-generated turbulence. Data from local meteorological stations are used to force the model, while water stratification and sediment concentrations from the area are used to initiate the model. Model results indicate a 0.2 m thick layer of slush ice created during 48 h with a mean wind of 6 m/s and an air temperature of −10°C. This ice contains ca. 20 mg/1 of sediment, or in total ca. 2% of the annual sediment discharge by nearby rivers. In shallow areas (<20 m depth) the process is very effective with winds of ca. 12 m/s, and the process can incorporate many years of sediment discharge. In the deeper areas (>20 m depth), the strong salinity stratification implies that winds above 18 m/s are needed for the process to be effective. For the rest of the winter months the same process may lead to additional sediment incorporated in a coastal polynya, but the freeze-up alone has the capacity to incorporate the total summer discharge of sediment into the surface ice. Calculated sediment concentrations in the surface ice cover are in the range 3 mg/1-19 g/1, in good agreement with available field data.     

A coupled multi-category sea ice model and POM for Baffin Bay and the Labrador Sea

An overview of the seasonal variation of sea-ice cover in Baffin Bay and the Labrador Sea is given.A coupled ice-ocean model,CECOM,has been developed to study the seasonal variation and associated ice-ocean processes.The sea-ice component of the model is a multi-category ice model in which mean concentration and thickness are expressed in terms of a thickness distribution function.Ten categories of ice thickness are specified in the model.Sea ice is coupled dynamically and thermo-dynamically to the Princeton Ocean Model.Selected results from the model including the seasonal variation of sea ice in Baffin Bay,the North Water polynya and ice growth and melt over the Labrador Shelf are presented.     

Benthic macroinvertebrates of the northern Caspian Sea during recent rises in water-level

Data on benthic macroinvertebrates of the northern Caspian Sea in 1980–1991 were collected by the Caspian Fishery Research Institute. During the initial period of the water-level rise, the main trends in benthic macroinvertebrates were increases in the biomass of the main groups and decreases in the relative abundance of species of Mediterranean origin. There was no significant alteration in species composition. The increased abundance was due to improved trophic conditions and a decrease in the numbers of benthos-feeding fish. Some decrease in the relative abundance of species of marine origin was related to a decrease in water salinity.     

冰川系统模型及其应用——以金沙江流域为例

全球气候变化带来了一系列的影响,冰川的生存与发展也受到了它的影响.目前,全球变化下冰川的变化是国际冰川学界的研究热点之一.中国是世界上冰川分布最广的中纬度国家,冰川是中国西部干旱地区的重要水资源,冰川的变化对中国环境有重大影响.冰川系统模型是一种基于冰川系统理论的水文学冰川变化预测模型,该模型从系统论的角度对全球变化的背景下冰川融水的变化进行宏观预测,充分利用已有的冰川数据资料对冰川的变化趋势做出总体预测.本文以金沙江流域冰川系统为例,根据流域内的自然环境特征将其分为河源区冰川系统和非河源区冰川系统两个并列的系统,利用冰川系统模型对其在不同的气候变化情景下的响应趋势作了预测,证实了模型的正确性和可行性.这一模型的研究成果对应对全球变化可能产生的影响有积极作用.     

环南海区域发展特征与一体化经济区建设前景

《区域全面经济伙伴关系协定》（RCEP）合作框架正催化全球经济版图格局发生剧烈演变,为应对“百年未有之大变局”,中国需要以“一带一路”倡议为契机,以环南海区域为战略基点,在深入研究区域发展特征的基础上,探讨建设“中国+东南亚”战略性一体化经济区的可能性并付诸实施。本文以环南海区域为重点,结合区域发展重点指标描述了其整体发展特征,利用产业结构相似度指数和贸易结构重合度指数,对环南海区域产业与对外贸易的结构性特征进行了剖析,并刻画了环南海区域核心增长区域的空间网络特征,最后讨论了环南海区域构建多元一体化经济区的前景并提出政策建议。结果表明：① 2000—2017年环南海区域主要发展指标增长态势强劲,发展速度和质量远超全球同期平均水平。② 在全球产业转移周期阶段与空间路径的双重驱动下,环南海区域形成了“澳新港—粤闽台文马—滇桂琼泰印菲越—缅老柬”四大梯级发展格局。③ 环南海区域11个国家间产业结构相似度指数和贸易结构重合度指数均处于较高水平,兼具“横向一体化”和“纵向梯级化”复合特征;产业结构与全球贸易商品结构呈现出“高端化”和“低端化”并举的态势。④ 环南海区域已经形成九大核心增长区域,增长极的极化与扩散效应使得不同区域之间的优势产业和出口商品类型呈现相似性和互补性。⑤ 展望未来,新一轮全球产业转移及其引致的全球价值链重组将构建起深度匹配地区资源禀赋特征的区域一体化生产—消费网络,而城市群、高速交通等空间实体所构建的“点—轴”空间网络和“内—外”开放合作政策平台也将更好保障一体化经济区的构建与发展。     

环渤海城市旅游竞争力差异及整合

以环渤海区域6个滨海城市为例,将评价指标体系分解为旅游现状、旅游基础环境、旅游潜力3类。运用因子分析法,计算各类竞争力得分值,然后加权各类方差贡献率计算各城市旅游竞争力综合评价值。通过比较各滨海城市旅游竞争力差异,建议从旅游资源、旅游产品、旅游市场、旅游空间及旅游管理等方面采取整合措施。