A general ecosystem model for applications to primary productivity and carbon cycle studies in the global oceans

We have developed a general 1-D multi-component ecosystem model that incorporates a skillful upper ocean mixed layer model based on second moment closure of turbulence. The model is intended for eventual incorporation into coupled 3-D physical–biogeochemical ocean models with potential applications to modeling and studying primary productivity and carbon cycling in the global oceans as well as to promote the use of chlorophyll concentrations, in concert with satellite-sensed ocean color, as a diagnostic tool to delineate circulation features in numerical circulation models. The model is nitrogen-based and the design is deliberately general enough and modular to enable many of the existing ecosystem model formulations to be simulated and hence model-to-model comparisons rendered feasible. In its more general form (GEM10), the model solves for nitrate, ammonium, dissolved nitrogen, bacteria and two size categories of phytoplankton, zooplankton and detritus, in addition to solving for dissolved inorganic carbon and total alkalinity to enable estimation of the carbon dioxide flux at the air–sea interface. Dissolved oxygen is another prognostic variable enabling air–sea exchange of oxygen to be calculated. For potential applications to HNLC regions where productivity is constrained by the availability of a trace constituent such as iron, the model carries the trace constituent as an additional prognostic variable. Here we present 1-D model simulations for the Black Sea, Station PAPA and the BATS site. The Black Sea simulations assimilate seasonal monthly SST, SSS and surface chlorophyll, and the seasonal modulations compare favorably with earlier work. Station PAPA simulations for 1975–1977 with GEM5 assimilating observed SST and a plausible seasonal modulation of surface chlorophyll concentration also compare favorably with earlier work and with the limited observations on nitrate and pCO₂ available. Finally, GEM5 simulations at BATS for 1985–1997 are consistent with the available time series. The simulations suggest that while it is generally desirable to employ a comprehensive ecosystem model with a large number of components when accurate depiction of the entire ecosystem is desirable, as is the prevailing practice, a simpler formulation such as GEM5 (N²PZD model) combined with assimilation of remotely sensed SST and chlorophyll concentrations may suffice for incorporation into 3-D prediction models of primary productivity, upper ocean optical clarity and carbon cycling.     

典型海湾风暴潮增水特征与机理研究

以三门湾为例,基于经验模态分解方法 (EMD)将原始风暴潮增水过程进行分解,并对各个子模态进行能量谱分析,研究每种波动对应的生成机制。结果表明:半封闭海湾内的风暴潮增水较为严重,造成三门湾内强增水的台风为三门湾南侧的西北向登陆台风。EMD分解结果显示三门湾内的风暴潮增水包含6 h,12 h,20 h左右的波动,其中6 h左右的波动来源于海湾共振,共振的频率是由海湾的形状、水深等固有性质所决定的。12 h的波动是由于天文潮与风暴潮耦合作用导致,20 h左右的波动是由于台风移动过程中外海波动的传入。结果表明EMD方法为风暴潮波动增水特征的精细认知提供了一种新的思路和方法,可以加深对海湾内风暴潮波动增水特征的研究。     

Polarography of the bottom sediments in the Sevastopol Bay

By the method of polarographic profiling performed with the help of an Au-Hg glass microelectrode, we obtained the first high-resolution vertical profiles of the distributions of oxygen, sulfides, oxidized and reduced forms of iron, reduced manganese, and iron monosulfide in pore waters of the bottom sediments in the Sevastopol Bay. It is shown that the regional features of the vertical distributions of the main polarographically active compounds are determined by the combination of several factors: the contents of organic carbon and iron and the sizes of particles of the sediments.     

Simulation of wind currents in Sevastopol bays

We the discuss the results of modelling wind currents in the system of Sevastopol bays. Numerical calculations are carried out according to the model of Felzenbaum. It is shown that the decisive role in the formation of distinctive features of circulation of waters and the essentially three-dimenstional character of currents in this part of the sea is played by the bottom topography and the direction of winds. These distinctive features are demonstrated for the cases where the motion is induced by the northeast and northwest winds. In the Sevastopol bays, we discovered the existence of jet longshore currents, vortex character of integral circulation, and intense processes of upwelling and downwelling. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Silicon in waters of the Sevastopol Bay in spring 2008

On the basis of field studies executed in May 2008, we performed the analysis of the distribution of silicon in waters of the Sevastopol Bay under conditions of the formation of a seasonal thermocline. We discuss differences in the distributions of silicon in the surface and bottom layers, including the zone of mixing of river and sea waters. We noticed a significant difference in values of the coefficients of correlation between the concentration of silicon and the salinity for the surface and bottom layers. For bottom layer, we obtain large values of the coefficients of correlation between the concentration of silicon and other hydrochemical characteristics which are explained by the influence of the processes of transformation of organic substance.     

Modelling of the propagation of passive impurities in Sevastopol bays

We discuss the results of numerical experiments modelling the process of propagation of passive impurities from the Karantinnaya Bay caused by steady wind currents and turbulent diffusion. The currents are computed according to the Felzenbaum model for the cases of northeast and north-west winds [1, 2]. We analyse specific features of the space and time distribution of the impurities caused by the three-dimensional character of the currents. Translated by Peter V. Malyshev and Dmitry V. Malyshev     

Methane in the Sevastopol coastal area, Black Sea

Concentrations of dissolved methane in seawater and bottom sediments, as well as of methane emanating from gas seeps were measured at 18 stations including several small bays in the Sevastopol coastal area (Black Sea) during 2007–2008. Methane concentrations in surface waters ranged from 10 to 2,970 nmol l^?1, and correlated well with values recorded for sediments. Methane concentrations in the water column were influenced by water depth, as well as by air and water temperatures. In the spring and summer of 2008, in situ CH₄ saturation relative to air was in the range of 970–71,900%. Maximum saturation was in summer. CH₄ fluxes to the atmosphere from the Sevastopol coastal area were estimated to vary from 190 to 1,550 μmol m^?2 day^?1. Gas bubbles escaping from the seepages contained about 57 vol% methane. Radiocarbon dating of the methane revealed an age not exceeding 150 years, implying a biogenic origin.     

Vertical two-dimensional mechanism of tidal exchange in a bay with a sill-entrance

For a vertical two-dimensional field with a sill at a bay entrance, the tidal exchange mechanism is discussed.The schematic model is proposed as follows. The tidal trapping effect which is detected at the entrance section,i. e., the material transport due to the phase difference between the tidal periodic constituent of material concentration and tidal current at the entrance section, results because the oscillatory tidal flow at the sill entrance induces a gravitational flow along the sill slope inside the entrance. Accordingly, the tidal trapping effect depends largely upon the difference in water density between the bay and open sea and the density stratification in the bay.This model is supported by the observations at Kabira Cove (Okinawa Pref.) and Lake Hamana (Shizuoka Pref.) in 1976 through 1984. In addition, based on this model, in the case of Lake Hamana, the activity of the tidal exchange is inferred to change seasonally.     

海洋浮游细菌在碳循环中的作用

由于海洋浮游细菌(marine bacterioplankton)在全球碳循环中非常重要,浮游细菌的生物学和生态学研究成为当前生物海洋学最活跃的前沿领域之一。浮游细菌主要包括异养细菌(heterotrphic bacteria)和超微型光合原核生物(picoprokaryotes)蓝细菌(Synechococcus,聚球菌属,细胞粒径为0．5-1．5μm)     

Reconstruction of the space and time variability of thermohaline fields in the Sevastopol Bay

The aim of the present work is to reconstruct the space and time variability of the three-dimensional fields of currents, temperature, salinity, and density in the Sevastopol Bay under the influence of the actual external factors in 1999. For this purpose, we use a version of the numerical multilayer model on the σ-coordinates. A vast array of the data of observations accumulated as a result of regular monitoring of the Sevastopol Bay contains, in particular, the data on the sea-surface temperature measured with six-hour intervals (at the hydrometeorological station located near the center of the bay) and almost monthly vertical profiles of temperature and salinity obtained at seven hydrological stations. The comparison of the numerical results with the data of observations enables us to conclude that, in general, the model fairly correctly describes the space structure and rearrangements of the fields of temperature and salinity. Among the most important distinctions, we can mention the fact that the fresh river water penetrating into the bay is mixed with seawater faster than predicted by the model. We also discuss the causes of these distinctions. Translated from Morskoi Gidrofizicheskii Zhurnal, No. 5, pp. 23–39, September–October, 2008.     

河流-河口-近海连续体碳循环研究进展

河流-河口-近海连续体(简称连续体)是连接陆地和大洋的过渡地带,也是目前全球碳收支估算的薄弱环节.这个复杂的海陆交互生态系统不仅可以通过光合作用、溶解作用吸收大气中的CO2,陆地和流域光合作用或化学风化作用固定的碳也可以被横向输送到陆架和大洋中.本文以国际上著名的切萨皮克湾以及长江-长江口-东海等为例,综述了连续体碳循...     

Utilization of carbon sources in a northern Brazilian mangrove ecosystem

Carbon and nitrogen stable isotope ratios (¹³C and ¹⁵N) and trophic level (TL) estimates based on stomach content analysis and published data were used to assess the contribution of autotrophic sources to 55 consumers in an intertidal mangrove creek of the Curuçá estuary, northern Brazil. Primary producers showed δ¹³C signatures ranging between −29.2 and −19.5‰ and δ¹⁵N from 3.0 to 6.3‰. The wide range of the isotopic composition of carbon of consumers (−28.6 to −17.1‰) indicated that different autotrophic sources are important in the intertidal mangrove food webs. Food web segregation structures the ecosystem into three relatively distinct food webs: (i) mangrove food web, where vascular plants contribute directly or indirectly via POM to the most ¹³C-depleted consumers (e.g. Ucides cordatus and zooplanktivorous food chains); (ii) algal food web, where benthic algae are eaten directly by consumers (e.g. Uca maracoani, mullets, polychaetes, several fishes); (iii) mixed food web where the consumers use the carbon from different primary sources (mainly benthivorous fishes). An IsoError mixing model was used to determine the contributions of primary sources to consumers, based on δ¹³C values. Model outputs were very sensitive to the magnitude of trophic isotope fractionation and to the variability in ¹³C data. Nevertheless, the simplification of the system by a priori aggregation of primary producers allowed interpretable results for several taxa, revealing the segregation into different food webs.     

创新循环经济管理机制的思考

文章在分析发展循环经济的管理机制问题及差距的基础上,借鉴国际环境管理体系(EMS)的理念,结合我国国情,从微观层面提出完善循环经济管理机制的具体对策建议:加强循环经济的科学策划规划;积极实施及运行;认真检查与纠正,严格管理评审;坚持持续改进,等。     

Seasonal variations in dissolved organic carbon concentrations and characteristics in a shallow coastal bay

Dissolved organic matter (DOM) composition and dynamics in temperate shallow coastal bays are not well described although these bays may be important as local sources of organic carbon to ocean waters and are often sites of economically-important fisheries and aquaculture. In this study surface water samples were collected on a monthly to bi-monthly basis over two years from a mid-Atlantic coastal bay (Chincoteague Bay, Virginia and Maryland, USA). Dissolved organic carbon (DOC) concentrations and light absorbance characteristics were measured on sterile-filtered water, and high-molecular weight (> 1 kDa) dissolved OM (DOM) was isolated to determine stable isotope composition and molecular-level characteristics. Our time series encompassed both a drought year (2002) and a year of above-average rainfall (2003). During the dry year, one of our sites developed a very intense bloom of the brown tide organism Aureococcus anophagefferens while during the wet year there were brown tide bloom events at both of our sampling sites. During early spring of the wet year, there were higher concentrations of > 1 kDa DOC; this fraction represented a larger proportion of overall DOC and appeared considerably more allochthonous. Based upon colored dissolved organic matter (CDOM) and high-molecular weight DOM analyses, the development of extensive phytoplankton blooms during our sampling period significantly altered the quality of the DOM. Throughout both years Chincoteague Bay had high DOC concentrations relative to values reported for the coastal ocean. This observation, in conjunction with the observed effects of phytoplankton blooms on DOM composition, indicates that Chincoteague Bay may be a significant local source of “recently-fixed” organic carbon to shelf waters. Estimating inputs of DOC from Chincoteague Bay to the Mid-Atlantic Bight suggests that shallow productive bays should be considered in studies of organic carbon on continental shelves.     

广西钦州湾外湾表层沉积硅藻分布特征

本文对钦州湾外湾54个表层沉积物中硅藻进行分析,鉴定出硅藻153种,分属50属。其中Thalassionema nitzschioides是本区域内最为丰富的硅藻种类。对应分析结果表明,钦州湾表层沉积硅藻分布主要受到海水盐度的影响,其中淡水硅藻Achnanthes delicatula、A.hauckiana、A.levanderi和Cocconeis disculus可以作为低盐度海水环境的指示种,半咸水种Cyclotella striata/C.stylorum、Paralia sulcata与海洋中硅藻Thalassionema frauenfeldii、T.nitzschioides则可以很好的指示高盐度环境。钦州湾外湾54个表层沉积站位可划分为3个硅藻分布区,分别对应高低不同的海水盐度,与实际站位地理分布基本一致。     

Atmosphere-ocean general circulation model with the carbon cycle

Results from numerical experiments with an atmosphere-ocean general circulation model coupled to the carbon evolution cycle are analyzed. The model is used to carry out an experiment on the simulation of the climate and carbon cycle change in 1861–2100 under a specified scenario of the carbon dioxide emission from fossil fuel and land use. The spatial distribution of vegetation, soil, and oceanic carbon in the 20th century is generally close to available estimates from observational data. The model adequately reproduces the observed growth of atmospheric CO₂ in the 20th century and the uptake of excess carbon by land ecosystems and by the ocean in the 1980s and 1990s. By 2100, the atmospheric CO₂ concentration is calculated to reach 742 ppmv under emission and land-use scenario A1B. The feedback between climate change and the carbon cycle in the model is positive, with a coefficient close to the mean of all the current models. The ocean and land uptakes of the CO₂ emission by 2100 in the model are 25 and 19%, which are also close to the mean over all models.     

长周期动力形态模型中地形演变方法探讨

PRD-LTMM是一个模拟和描述三角洲地形中、长期演变过程的动力形态模型.在长时间尺度的模拟过程中,必须从模型输入、模型物理系统本身到模型输出等各个角度考虑模拟约减处理.代表性输入条件是实现模型约减的基础,而地形时间的步长延长是提高长周期模型模拟效率的关键.延长技术通常有直接推延、时间中心推延、潮汐延展及泥沙输运率公式线性化等四种方法.通过系列敏感性试验,对PRD-LTMM模型选择潮汐延展技术来进行地形时间步长的延长处理,推延的时间长度为10 a,基于此条件下的PRD-LTMM在长周期模拟中不仅稳定性较好,而且结果也较精确.     

广东流沙湾近岸和离岸育珠海区养殖环境的调查

2011年2月~2012年1月对广东流沙湾近岸和离岸育珠海区6个航次11个指标进行了调查。结果表明,近岸和离岸育珠海区水温、透明度、盐度和pH周年变化范围相似,水温呈现明显季节性变化,透明度、盐度和pH周年比较稳定,揭示目前流沙湾近岸和离岸育珠海区水流交换较好。近岸和离岸育珠海区叶绿素a和浮游植物细胞密度具有类似的周年变化规律,夏秋季高于冬春季。在4~7月份和9~10月份,近岸海区叶绿素a和浮游植物细胞密度呈现显著递增趋势,而10月份之后,显著递减。2~4月份,以及12月份至次年1月份,叶绿素a值和浮游植物细胞密度均较低。5~11月份,离岸海区叶绿素a和浮游植物细胞密度均显著低于近岸海区。近岸和离岸育珠海区COD含量周年变化范围分别为0.2~0.7 mg/L和0.1~0.8 mg/L,均达到国家一类水质标准。近岸海区和离岸海区无机氮(inorganic nitrogen,IN)含量周年变化范围分别为1.9~8.0μmol/L和3.4~8.7μmol/L,均达到国家第二类水质标准。两个海区IN含量的周年变化趋势与叶绿素a值和浮游植物细胞密度的周年变化趋势相反,冬春季高于夏秋季。无机磷(inorganic phosphorus,IP)在流沙湾近岸和离岸海区含量具有相似的周年变化趋势,其季节性变化与无机氮恰好相反,表现为夏、秋季含量高于冬、春季。6~8月份,近岸海区IP超出国家二类水质标准分别达44.67%、96.33%和210%,离岸海区在相同的月份超出国家二类标准分别达75.67%、86%和230.67%。揭示在夏、秋季节应合理控制贝类养殖密度和流沙湾周边环境的污染。     

Oxygen and Sulfides in Bottom Sediments of the Coastal Sevastopol Region of Crimea

Spatial variations in the distribution and fluxes of dissolved oxygen and sulfide in bottom sediments of Omega and Sevastopol bays have been studied. The results of analysis reveal that the distribution of dissolved oxygen and sulfide in pore water depends mostly on seasonal variations in the oxygen concentration in bottom water, grain size, the organic carbon content in bottom sediments, and, additionally for Sevastopol Bay, the iron content. The oxygen flux at the bottom of Sevastopol Bay is 20 times larger in winter–spring compared to that of Omega Bay. Anaerobic conditions in Sevastopol Bay sediments are observed much closer to the surface, with their subsequent development in bottom water.