海洋生态系统及海岸工程生态影响预测模型研究进展

对海洋生态系统的研究已形成了以实验观测为基础、建立生态模型的方法。文章对已有的海洋生态模型研究成果进行了归纳总结,认为初级生产力模型是纯生态模型的主要发展方向,综合考虑物理生化作用的生态系统动力学模型将是未来海洋生态研究的必然趋势。同时,由于我国大规模海岸工程建设对近岸海域生态系统造成了较大影响,而相关的生态影响预测模型研究较少,为有效预测评价海岸工程建设对近岸海域生态系统的影响,进一步深入研究海岸工程建设对近岸海洋生态影响预测模型将显得尤为重要。     

Methane release and coastal environment in the East Siberian Arctic shelf

In this paper we present 2 years of data obtained during the late summer period (September 2003 and September 2004) for the East Siberian Arctic shelf (ESAS). According to our data, the surface layer of shelf water was supersaturated up to 2500% relative to the present average atmospheric methane content of 1.85 ppm, pointing to the rivers as a strong source of dissolved methane which comes from watersheds which are underlain with permafrost. Anomalously high concentrations (up to 154 nM or 4400% supersaturation) of dissolved methane in the bottom layer of shelf water at a few sites suggest that the bottom layer is somehow affected by near-bottom sources. The net flux of methane from this area of the East Siberian Arctic shelf can reach up to 13.7 × 10⁴ g CH₄ km^− 2 from plume areas during the period of ice free water, and thus is in the upper range of the estimated global marine methane release. Ongoing environmental change might affect the methane marine cycle since significant changes in the thermal regime of bottom sediments within a few sites were registered. Correlation between calculated methane storage within the water column and both integrated salinity values (r = 0.61) and integrated values of dissolved inorganic carbon (DIC) (r = 0.62) suggest that higher concentrations of dissolved methane were mostly derived from the marine environment, likely due to in-situ production or release from decaying submarine gas hydrates deposits. The calculated late summer potential methane emissions tend to vary from year to year, reflecting most likely the effect of changing hydrological and meteorological conditions (temperature, wind) on the ESAS rather than riverine export of dissolved methane. We point out additional sources of methane in this region such as submarine taliks, ice complex retreat, submarine permafrost itself and decaying gas hydrates deposits.     

《极地规则》与北极俄罗斯沿岸水域的制度安排

由于全球气候变暖,夏秋季节北极部分区域已成为少冰或无冰的可航水域,且持续时间逐年增加,使北极区域船舶航行、海洋工程、科学考察、极区旅游具备了较好的条件,北极区域的新航路逐步成为跨洲际海上贸易便捷、经济、安全的新通道。     

Bacterial production and microbial food web structure in a large arctic river and the coastal Arctic Ocean

Globally significant quantities of organic carbon are stored in northern permafrost soils, but little is known about how this carbon is processed by microbial communities once it enters rivers and is transported to the coastal Arctic Ocean. As part of the Arctic River-Delta Experiment (ARDEX), we measured environmental and microbiological variables along a 300 km transect in the Mackenzie River and coastal Beaufort Sea, in July–August 2004. Surface bacterial concentrations averaged 6.7 × 10⁵ cells mL^− 1 with no significant differences between sampling zones. Picocyanobacteria were abundant in the river, and mostly observed as cell colonies. Their concentrations in the surface waters decreased across the salinity gradient, dropping from 51,000 (river) to 30 (sea) cells mL^− 1. There were accompanying shifts in protist community structure, from diatoms, cryptophytes, heterotrophic protists and chrysophytes in the river, to dinoflagellates, prymnesiophytes, chrysophytes, prasinophytes, diatoms and heterotrophic protists in the Beaufort Sea.Size-fractionated bacterial production, as measured by ³H–leucine uptake, varied from 76 to 416 ng C L^− 1 h^− 1. The contribution of particle-attached bacteria (> 3 µm fraction) to total bacterial production decreased from > 90% at the Mackenzie River stations to < 20% at an offshore marine site, and the relative importance of this particle-based fraction was inversely correlated with salinity and positively correlated with particulate organic carbon concentrations. Glucose enrichment experiments indicated that bacterial metabolism was carbon limited in the Mackenzie River but not in the coastal ocean. Prior exposure of water samples to full sunlight increased the biolability of dissolved organic carbon (DOC) in the Mackenzie River but decreased it in the Beaufort Sea.Estimated depth-integrated bacterial respiration rates in the Mackenzie River were higher than depth-integrated primary production rates, while at the marine stations bacterial respiration rates were near or below the integrated primary production rates. Consistent with these results, P_CO2 measurements showed surface water supersaturation in the river (mean of 146% of air equilibrium values) and subsaturation or near-saturation in the coastal sea. These results show a well-developed microbial food web in the Mackenzie River system that will likely convert tundra carbon to atmospheric CO₂ at increasing rates as the arctic climate continues to warm.     

Winter–spring dynamics in sea-ice carbon cycling in the coastal Arctic Ocean

An understanding of microbial interactions in first-year sea ice on Arctic shelves is essential for identifying potential responses of the Arctic Ocean carbon cycle to changing sea-ice conditions. This study assessed dissolved and particulate organic carbon (DOC, POC), exopolymeric substances (EPS), chlorophyll a, bacteria and protists, in a seasonal (24 February to 20 June 2004) investigation of first-year sea ice and associated surface waters on the Mackenzie Shelf. The dynamics of and relationships between different sea-ice carbon pools were investigated for the periods prior to, during and following the sea-ice-algal bloom, under high and low snow cover. A predominantly heterotrophic sea-ice community was observed prior to the ice-algal bloom under high snow cover only. However, the heterotrophic community persisted throughout the study with bacteria accounting for, on average, 44% of the non-diatom particulate carbon biomass overall the study period. There was an extensive accumulation of sea-ice organic carbon following the onset of the ice-algal bloom, with diatoms driving seasonal and spatial trends in particulate sea-ice biomass. DOC and EPS were also significant sea-ice carbon contributors such that sea-ice DOC concentrations were higher than, or equivalent to, sea-ice-algal carbon concentrations prior to and following the algal bloom, respectively. Sea-ice-algal carbon, DOC and EPS-carbon concentrations were significantly interrelated under high and low snow cover during the algal bloom (r values ≥ 0.74, p < 0.01). These relationships suggest that algae are primarily responsible for the large pools of DOC and EPS-carbon and that similar stressors and/or processes could be involved in regulating their release. This study demonstrates that DOC can play a major role in organic carbon cycling on Arctic shelves.     

用生态动力学模型分析海带养殖对浮游生态系统的影响

以我国近海典型海带养殖区桑沟湾为例,建立了"浮游植物-海带-浮游动物-营养盐-有机碎屑"生态动力学模型,较好地模拟了不同养殖密度下浮游生态系统结构的变化,通过灵敏度分析,研究状态变量对模型初值和参数变化的响应,提出了参数优化的思路.     

Number and phylogenetic affiliation of bacteria assimilating dimethylsulfoniopropionate and leucine in the ice-covered coastal Arctic Ocean

The ability of bacteria to assimilate sulfur from dimethylsulfoniopropionate (DMSP) was examined in the western Arctic Ocean by combining microautoradiography and fluorescence in situ hybridization (FISH). Assimilation of leucine was also measured for comparative purposes since leucine is considered a universal substrate for bacteria, which use it for protein synthesis. Samples were collected at 3 m depth, through a hole in the ice, in the CASES (Canadian Arctic Shelf Ecosystem Study) overwintering station in Franklin Bay (eastern Beaufort Sea) in March and May 2004 to compare two contrasting situations: winter and early spring. FISH counts indicated that the bacterial assemblage consisted of α- (up to 60% of the EUB positive cells), β- (up to 10%) and γ-proteobacteria (around 20%), and Bacteroidetes (up to 60%). The β-proteobacteria were not active with any of the two substrates tested. The remaining groups were much less efficient at assimilating DMSP-sulfur (5% of the cells) than leucine (20–35%) both in winter and in spring. Only the Roseobacter group of α-proteobacteria showed a similar assimilation of both substrates.     

One-dimensional modelling of the plankton ecosystem of the north-western Corsican coastal area in relation to meteorological constraints

In order to study the influence of wind mixing on the spring variability of the plankton production of the north western Corsican coastal area, a one-dimensional (1D), vertical, coupled hydrodynamic/biological model (ECOHYDROMV) is used. A hydrodynamic 1D model of the water column with a k–l turbulent closure is applied. The biological model comprises six state variables, representing the plankton ecosystem in the spring period: phytoplankton, copepods, nitrate, ammonium, particulate organic matter of phytoplanktonic origin and particulate organic matter of zooplanktonic origin. The system is influenced by turbulence (expressed by the vertical eddy diffusivity), temperature and irradiance. The model takes into account momentum and heat surface fluxes computed from meteorological data in order to simulate a typical spring atmospheric forcing for the considered area. Results show that primary production vertical structure is characterised by a subsurface maximum which deepens with time and is regulated by the opposite gradients of nitrate concentration and irradiance. Surface plankton productivity is mainly controlled by turbulent vertical transport of nutrients into the mixed layer. The short time scale variability of turbulent mixing generated by the wind appears to be responsible for the plurimodal shape of plankton blooms, observed in the considered area. Furthermore, the model is applied to the study of the spring evolution of the plankton communities off the bay of Calvi (Corsica) for the years 1986 and 1988. In order to initiate and validate the model, time series of hydrological, chemical and biological data have been used. The model reproduces accurately the spring evolution of the phytoplankton biomass measured in situ and illustrates that its strong variability in those years was in close relation to the variability of the wind intensity.     

聚焦北极航道之二:生态环境 没有破坏的发展

<正>各国剑拔弩张,暗战不断,皆为利来。北极冰层加速融化,使之蕴藏的能源挖掘成为可能。这块令世界怦然心动的地方将是地球最后的宝库。到底北极蕴藏着什么让世界各国纷纷将至?     

Impact of freshwater on a subarctic coastal ecosystem under seasonal sea ice (southeastern Hudson Bay, Canada). III. Feeding success of marine fish larvae

We monitored the feeding success (percent feeding incidence at length and mean feeding ratio at length) of Arctic cod (Boreogadus saida) and sand lance (Ammodytes sp.) larvae in relation to prey density, light, temperature and potential predator density under the ice cover of southeastern Hudson Bay in the spring of 1988, 1989 and 1990. Both prey density and light limited larval fish feeding. The relationship between feeding success and actual food availability (nauplii density X irradiance) was adequately described by an Ivlev function which explained 64 and 76% of the variance in Arctic cod and sand lance feeding success respectively. By affecting both prey density and irradiance, the thickness of the Great Whale River plume (as defined by the depth of the 25 isohaline) was the main determinant of prey availability. Arctic cod and sand lance larvae stopped feeding when the depth of the 25 isohaline exceeded 9 m. Limitation of feeding success attributable to freshwater inputs occurred exclusively in 1988, the only time when the depth of the 25 isohaline exceeded the 9 m threshold. The close dependence of larval fish feeding success on the timing of the freshet and plume dynamics suggests a direct link between climate and survival of Arctic cod and sand lance larvae. The actual impact of climate fluctuations and/or hydro-electric developments on recruitment will depend on the fraction of the larval dispersal area of the two species that is affected by river plumes.     

Uncertainty in predictions of oil spill trajectories in a coastal zone

A method is introduced to determine the uncertainties in the predictions of oil spill trajectories using a classic oil spill model. The method considers the output of the oil spill model as a function of random variables, which are the input parameters, and calculates the standard deviation of the output results which provides a measure of the uncertainty of the model as a result of the uncertainties of the input parameters.In addition to a single trajectory that is calculated by the oil spill model using the mean values of the parameters, a band of trajectories can be defined when various simulations are done taking into account the uncertainties of the input parameters. This band of trajectories defines envelopes of the trajectories that are likely to be followed by the spill given the uncertainties of the input.The method was applied to an oil spill that occurred in 1989 near Sines in the southwestern coast of Portugal. This model represented well the distinction between a wind driven part that remained offshore, and a tide driven part that went ashore. For both parts, the method defined two trajectory envelopes, one calculated exclusively with the wind fields, and the other using wind and tidal currents. In both cases reasonable approximation to the observed results was obtained.The envelope of likely trajectories that is obtained with the uncertainty modelling proved to give a better interpretation of the trajectories that were simulated by the oil spill model.     

Three-dimensional hydrostatic modeling of a bay coastal area

This article describes the development of a three-dimensional (3D) multilayer hydrostatic model of tidal motions in the Ariake Sea and its application. The governing equations were derived from 3D Navier-Stokes equations and were solved using the fractional step method, which combines the finite difference method in the horizontal plane and the finite element method in the vertical plane. This study introduced a 3D, time-dependent, hydrostatic, tidal current model that can compute wetting and drying in tidal flats due to tidal motion. The 3D model was first tested against analytical solutions for three standard cases in a rectangular basin in order to investigate the performance of the model. Then, the model was applied to Saigo fishery port and the Ariake Sea. For standard cases, the numerical solutions were almost identical to the analytical solutions. Finally, the model results for Saigo port and the Ariake Sea show good agreement with the field observations.     

北极地区磁罗经适用能力

针对磁罗经在北极地区的适用能力问题,根据世界地磁模型(World Magnetic Model,WMM)2019,通过分析极区地磁场、地磁场水平分量和磁差等要素在极区的大小分布和变化趋势,以地磁水平分量6 000 nT为界,指出磁罗经在极区的适用范围,特别是东北航道附近海区可正常使用磁罗经;分析"雪龙"号科考船在2017年北极考察的磁罗经和陀螺罗经数据。研究结果表明:地磁水平分量大于6 000 nT的区域,磁罗经是可正常使用的;为保证北极地区正常使用磁罗经,纬度每变化5°,应重新组织校正剩余自差工作;为应对北极地区磁差随经度变化的速率较大的问题,在磁航向转真航向过程中,应根据WMM自动计算并补偿磁差。     

冰区运输船极地海域航行阻力的模型试验研究（英文）

为了考查冰区运输船在北极结冰海域航行时所受到的航行阻力,进行了一系列室内物理模型试验。试验中船体模型通过一个单向测力传感器与主拖车上的刚性拖曳臂相连。试验包含三种主要的冰条件,即船体独立航行的平整冰条件、在破冰船引导下航行的航道碎冰条件和独立航行的浮冰条件。平整冰及航道碎冰条件下对多种船体航行速度进行考察,而浮冰条件下则针对不同的冰覆盖率展开研究。试验中对冰-船相互作用模式、冰排在船体不同位置处的破坏进程以及碎冰沿船体的运动状态进行了详尽的观测,并对船体的航行阻力进行了有效的测量。此外,文中还对航行阻力均值与极值之间的差异进行了详尽的讨论与分析。结果表明,冰条件与船体航行速度是影响船体航行阻力的重要因素。     

聚焦北极航道之一:北极航道 改写海运格局

从16世纪起,欧洲国家就一直梦想能打通经北冰洋到达东方的便捷通道,但由于自然条件限制,北极航道探险虽兴盛一时,终因不具备商业航运价值而沉寂。近20年来,随着全球气候变暖,北极海冰加速融化,一些科学家乐观预测,在未来30年内北冰洋将出现夏季无冰年,北极航道将从遥远走近现实。北极航道成为了国际海事界的热点之一,该航道一旦打通,吸引全球目光的不仅仅是北冰洋区域蕴藏的丰富资源以及随之带来的巨大商业利益,它的开通还将影响整个世界的海运格局。为此,本刊记者马艳玲走访了相关专家和研究机构,采写编辑了一组北极航道的稿件以飨读者。     

The potential for British coastal shipping in a multimodal chain

A strategy to revitalize coastal shipping within Great Britain is investigated. An examination of the regulatory environment shows government, at both the EU and British levels, aware of the environmental benefits of coastal shipping compared to road freight transport, if only mildly supportive in tangible terms. The geography of Great Britain and the modern preference for just-in-time deliveries have severely restricted the ability of coastal shipping to compete effectively with road freight transport. The primary objective of the paper is to investigate whether coastal shipping could be integrated into a multimodal door-to-door supply chain, where it is currently hampered by high costs of transhipment, slow transport speeds, and the incongruity of load sizes between land and sea modes. Integration requires the co-operation of all organizations within the multi-modal supply chain. However, coastal shipping companies have been known to be individualistic and mistrusting of alliances. Therefore, a Delphi study is undertaken to investigate the standpoint of leading managers in such companies towards multimodal integration. The results of the Delphi study indicate that managers are in favour of multimodal developments, in particular cooperation between coastal shipping and road haulage. However, there was agreement that the business is highly competitive, and this may prevent the forms of collaboration required for multimodal systems. The secretive nature of the coastal shipping sector could impede joint marketing to promote a mode of transport that is often ‘invisible’ to shippers. There was little consensus on the relationship that should exist between coastal shipping and ports, a topic worthy of further investigation.     

设计人员在海工项目成本管理中的重要作用

文章简要介绍了设计人员的主要职责:图纸的绘制;材料请购单(MTO)的预定;技术问题的澄清(TQR);现场要求(SI)、技术变更的跟踪(DCF);车间红图的处理等。结合项目成本管理,分析了设计人员在海工项目成本管理中所发挥的重要作用。     

The potential for British coastal shipping in a multimodal chain

A strategy to revitalize coastal shipping within Great Britain is investigated. An examination of the regulatory environment shows government, at both the EU and British levels, aware of the environmental benefits of coastal shipping compared to road freight transport, if only mildly supportive in tangible terms. The geography of Great Britain and the modern preference for just-in-time deliveries have severely restricted the ability of coastal shipping to compete effectively with road freight transport. The primary objective of the paper is to investigate whether coastal shipping could be integrated into a multimodal door-to-door supply chain, where it is currently hampered by high costs of transhipment, slow transport speeds, and the incongruity of load sizes between land and sea modes. Integration requires the co-operation of all organizations within the multi-modal supply chain. However, coastal shipping companies have been known to be individualistic and mistrusting of alliances. Therefore, a Delphi study is undertaken to investigate the standpoint of leading managers in such companies towards multimodal integration. The results of the Delphi study indicate that managers are in favour of multimodal developments, in particular cooperation between coastal shipping and road haulage. However, there was agreement that the business is highly competitive, and this may prevent the forms of collaboration required for multimodal systems. The secretive nature of the coastal shipping sector could impede joint marketing to promote a mode of transport that is often 'invisible' to shippers. There was little consensus on the relationship that should exist between coastal shipping and ports, a topic worthy of further investigation.     

Performance Indicator Importance in MPA Management Using a Multi-Criteria Approach

Much has been written about the usefulness of marine protected areas (MPAs) as a management tool. Their performance has been measured using biological and ecological indicators. However, objectives of management also include economic and social responsibilities. As such, stakeholder objectives in MPA management are frequently incompatible. This has been attributed to the variety of stakeholders with an interest in how MPAs are managed. This article considers the development of a performance indicator hierarchy for the Egadi Islands Marine Reserve, and a multi-criteria approach implemented to define compromise positions between stakeholders in decision-making. Data was obtained from a pairwise comparison survey using the analytic hierarchy process to investigate preferences of stakeholder groups for performance indicators in evaluating marine protected area management. The analysis showed that although there are five key stakeholder groups, none are homogenous in prioritizing performance indicators and that none are clear with respect to what the MPA means for them.     

一种纯隐格式在近海潮流数值模拟中的应用

为分析纯隐格式的混合有限分析法在工程实际应用中的可行性,文章采用二维近海区域浅水数学模型,应用fortran语言和该数值离散方法编写了二维潮流场数值模拟程序,并将冻结法与ADI数值模式中的干-湿网格判别标准结合起来有效地处理了计算区域的浅滩。选取湛江湾为例,对其潮流场进行了数值模拟计算,通过与已有的潮位及流速测站的实际测量值进行比较分析,显示采用的数学模型及混合有限分析离散方法能准确有效地模拟实际流态,效果较好,结果准确可信,显示该隐格式方法值得在工程实际应用中推广。