Making the ecosystem approach operational—Can regime shifts in ecological- and governance systems facilitate the transition?

Effectively reducing cumulative impacts on marine ecosystems requires co-evolution between science, policy and practice. Here, long-term social–ecological changes in the Baltic Sea are described, illustrating how the process of making the ecosystem approach operational in a large marine ecosystem can be stimulated. The existing multi-level governance institutions are specifically set up for dealing with individual sectors, but do not adequately support an operational application of the ecosystem approach. The review of ecosystem services in relation to regime shifts and resilience of the Baltic Sea sub-basins, and their driving forces, points to a number of challenges. There is however a movement towards a new governance regime. Bottom-up pilot initiatives can lead to a diffusion of innovation within the existing governance framework. Top-down, enabling EU legislation, can help stimulating innovations and re-organizing governance structures at drainage basin level to the Baltic Sea catchment as a whole. Experimentation and innovation at local to the regional levels is critical for a transition to ecosystem-based management. Establishing science-based learning platforms at sub-basin scales could facilitate this process.     

A new direction in coastal management

This paper argues for a stronger integration of marine sciences and coastal management studies that generates better formulated marine policies and viable policy implementation strategies. Integration of natural and social sciences in environmental management has surfaced as a key issue recently in the fields of sustainability science, ecosystem-based management, and social–ecological resilience. This paper promotes such trend in marine studies, and examines the rationale, progress, and examples of the integration.     

Incentives,social–ecological feedbacks and European fisheries

The European Common Fisheries Policy (CFP) has failed to deliver on social, economic and ecological goals. This failure is in part the result of a number of social–ecological feedback mechanisms. The policy is currently undergoing reform, with unknown practical outcomes. Here, relatively successful fisheries policies outside the European Union are reviewed. Through interviews and workshops with scientists, managers and other stakeholders, complemented with literature reviews, practices that can create incentives for long-term sustainability are investigated. The focus is on how the provision of clear and trusted scientific evidence can stimulate defensible decisions, in turn creating incentives for compliance, leading to positive social–ecological outcomes. Despite differences between Europe and the investigated case studies, the prospects of an increased regionalization within the European CFP provides the best starting point for implementing best practice identified in this study.     

Amodified discrete element model for sea ice dynamics

Considering the discontinuous characteristics of sea ice on various scales,a modified discrete element model（DEM） for sea ice dynamics is developed based on the granular material rheology.In this modified DEM,a soft sea ice particle element is introduced as a self-adjustive particle size function.Each ice particle can be treated as an assembly of ice floes,with its concentration and thickness changing to variable sizes under the conservation of mass.In this model,the contact forces among ice particles are calculated using a viscous-elastic-plastic model,while the maximum shear forces are described with the Mohr-Coulomb friction law.With this modified DEM,the ice flow dynamics is simulated under the drags of wind and current in a channel of various widths.The thicknesses,concentrations and velocities of ice particles are obtained,and then reasonable dynamic process is analyzed.The sea ice dynamic process is also simulated in a vortex wind field.Taking the influence of thermodynamics into account,this modified DEM will be improved in the future work.     

海冰动力过程的改进离散元模型及在渤海的应用

海冰的断裂、重叠和堆积等离散分布特性广泛地存在于极区和副极区的不同海域,并对海冰的生消、运移过程有着重要影响。针对海冰在不同尺度下的离散分布特点,发展海冰动力过程的离散元方法有助于完善海冰数值模式,提高海冰数值模拟的计算精度。为此,本文针对海冰生消运移过程中的非连续分布和形变特性,发展了适用于海冰动力过程的改进离散元模型(MDEM)。不同于传统离散元方法,该模型将海冰离散为具有一定厚度、尺寸和密集度的圆盘单元。海冰单元设为诸多浮冰块的集合体,其在运移和相互接触碰撞过程中,依照质量守恒发生单元尺寸、密集度和厚度的相应变化。基于海冰离散性和流变性的特点,该模型采用黏弹性接触本构模型计算单元间的作用力,并依据Mohr-Coulomb准则计算海冰法向作用下的塑性变形及切向摩擦力。为验证该模型的可靠性,本文对海冰在规则水域内的运移和堆积过程进行了分析,离散元计算结果与解析值相一致;此外,对旋转风场下海冰漂移规律的模拟进一步验证了本文方法的精确性。在此基础上,对渤海辽东湾的海冰动力过程进行了48h数值分析,计算结果与卫星遥感资料和油气作业区的海冰现场监测数据吻合良好。在下一步工作中将考虑海冰离散元模拟中的热力因素影响,发展具有冻结、断裂效应的海冰离散元模型,更精确地模拟海冰动力-热力耦合作用下的生消和运移过程。     

Sea ice–ocean coupling using a rescaled vertical coordinate z

Realistic representation of sea ice in ocean models involves the use of a non-linear free-surface, a real freshwater flux and observance of requisite conservation laws. We show here that these properties can be achieved in practice through use of a rescaled vertical coordinate “z^*” in z-coordinate models that allows one to follow undulations in the free-surface under sea ice loading. In particular, the adoption of “z^*” avoids the difficult issue of vanishing levels under thick ice.Details of the implementation within MITgcm are provided. A high resolution global ocean sea ice simulation illustrates the robustness of the z^* formulation and reveals a source of oceanic variability associated with sea ice dynamics and ice-loading effects. The use of the z^* coordinate allows one to achieve perfect conservation of fresh water, heat and salt, as shown in extended integration of coupled ocean sea ice atmospheric model.     

Tidal ice drift in the White Sea: Results of a numerical experiment

The tidal ice drift is considered as an element of the tidal dynamics in a sea covered with ice. The appropriate problem is solved with the use of a combination of a simple viscoelastic continuum model of the tidal ice drift with the QUODDY-4 three-dimensional finite-element hydro-thermodynamical model. The combined model is used for simultaneous calculations of the tidal regime and the tidal ice drift in the White Sea. The calculated distributions of the characteristics of the semidiurnal (M₂ wave) tidal ice drift such as the ice drift velocity and the tidal variations of the ice concentration and the pressure of the ice compression are discussed. The distributions are used for detecting the zones of the quasi-steady tidal compression and extension of ice and regions of ridging of ice floes. Particular attention is paid to the residual tidal ice drift, a phenomenon that has remained almost unnoticed so far.     

Effect of ice cover on the dynamics and energetics of surface and internal tides in the white sea: Model estimates

The effect of ice cover on the dynamics and energetics of surface and internal tides in the White Sea is investigated using the three-dimensional finite-element hudrothermodynamic model QUODDY-4. The sea ice is represented as a continuous and motionless ice cover that can move vertically but not horizontally. It is assumed that the resulting changes in the tidal regime are the maximum possible in reference to those occurring in real conditions when, in the cold season, a continuous and motionless ice cover is ubiquitous only in Kandalaksha, Dvina, and Onega bays, while drift ices prevail in all other areas of the White Sea. It is shown that the effect of sea ice does not lead to a qualitative restructuring of the tidal regime. However, its quantitative changes prove to be significant, which indicates that the ice-induced seasonal variation in tidal characteristics in the White Sea is important.     

北极海冰的年代际转型与中国冻雨年代际变化的关系

基于1961-2013年HadISST海冰密集度资料,定义了北极海冰的季节性融冰指数,结果显示近几十年来北极季节性融冰范围呈显著的上升趋势,并分别在20世纪70年代末和90年代中期存在显著的年代际转型,相应地,中国冻雨发生频数总体上呈现出显著的减少趋势,但也存在显著的年代际转型。在20世纪70年代末之前,北极季节性融冰范围较小但显著增长,中国冻雨频数年际变化振幅较大,且主要受巴伦支海、喀拉海海冰的影响;20世纪70年代末至90年代中期北极季节性融冰范围维持振荡特征,没有显著的线性趋势,中国冻雨频数变化振幅减小,与北极海冰相关较弱,主要相关因子为北大西洋及北太平洋海表温度变化;而90年代中期以后,北极海冰融化加快,特别是2007年以后,季节性融冰范围大大增加,而中国冻雨频数处于低发时段,其变化与太平洋扇区海冰及堪察加半岛附近海温呈显著负相关,季节性融冰的显著区域也从东西伯利亚海逆时针旋转向波弗特海-加拿大群岛北部扩张,同时向北极中央区扩张。不同年代影响冻雨的海温或海冰关键海区不同,产生特定的大气环流异常响应,进而影响到我国冻雨。     

Modelling carbon cycling through phytoplankton and microbes in the Scotia—Weddell Sea area during sea ice retreat

An ecological model to calculate phytoplankton development and microbial loop dynamics in the marginal ice zone of the antarctic ecosystem has been established on the basis of physical and biological (phyto- and bacterioplankton biomass and activity and counting of two classes of heterotrophic nanoplankton) measurements carried out in the marginal ice zone of the Scotia-Weddell Sea sector of the Southern Ocean during sea ice retreat 1988 (EPOS 1 and 2 expeditions). Application of this model at latitudes where sea ice retreat occurs and in adjacent open sea and permanently ice-covered areas demonstrated that the marginal ice zone is a region of enhanced primary and bacterioplankton production. Combining the results of the phyto- and bacterioplankton models allowed the quantitative estimate of the carbon fluxes through the lower level of the planktonic food web of the Weddell Sea marginal ice zone during the sea ice retreat period. The resulting carbon budget revealed the quantitative importance of microbial and micrograzing processes in the pathways of net primary production, 71% of this latter being assimilated in the microbial food web. However, total net microbial food web secondary production contributed 28% of‘marginal ice zone produced’ food resources available to krill and other Zooplankton.     

Geophysics of sea ice in the Baltic Sea: A review

With improved observation methods, increased winter navigation, and increased awareness of the climate and environmental changes, research on the Baltic Sea ice conditions has become increasingly active. Sea ice has been recognized as a sensitive indicator for changes in climate. Although the inter-annual variability in the ice conditions is large, a change towards milder ice winters has been detected from the time series of the maximum annual extent of sea ice and the length of the ice season. On the basis of the ice extent, the shift towards a warmer climate took place in the latter half of the 19th century. On the other hand, data on the ice thickness, which are mostly limited to the land-fast ice zone, basically do not show clear trends during the 20th century, except that during the last 20 years the thickness of land-fast ice has decreased. Due to difficulties in measuring the pack-ice thickness, the total mass of sea ice in the Baltic Sea is, however, still poorly known. The ice extent and length of the ice season depend on the indices of the Arctic Oscillation and North Atlantic Oscillation. Sea ice dynamics, thermodynamics, structure, and properties strongly interact with each other, as well as with the atmosphere and the sea. The surface conditions over the ice-covered Baltic Sea show high spatial variability, which cannot be described by two surface types (such as ice and open water) only. The variability is strongly reflected to the radiative and turbulent surface fluxes. The Baltic Sea has served as a testbed for several developments in the theory of sea ice dynamics. Experiences with advanced models have increased our understanding on sea ice dynamics, which depends on the ice thickness distribution, and in turn redistributes the ice thickness. During the latest decade, advance has been made in studies on sea ice structure, surface albedo, penetration of solar radiation, sub-surface melting, and formation of superimposed ice and snow ice. A high vertical resolution has been found as a prerequisite to successfully model thermodynamic processes during the spring melt period. A few observations have demonstrated how the river discharge and ice melt affect the stratification of the oceanic boundary layer below the ice and the oceanic heat flux to the ice bottom. In general, process studies on ice–ocean interaction have been rare. In the future, increasingly multidisciplinary studies are needed with close links between sea ice physics, geochemistry and biology.     

Modeling the tidal ice drift and ice-induced changes in tidal dynamics on the Siberian continental shelf

The tidal ice drift is treated as an element of the three-dimensional tidal dynamics in a sea covered by ice. This dynamics is described by the QUODDY-4 finite-element model, and the tidal ice drift is described by a continuous viscous-elastic approximation. We present the results of modeling not only the tidal ice drift (M ₂ wave) (its velocity, direction, and tidal variations in the concentration and pressure of ice compression) but also ice-induced changes in tidal dynamics and the residual tidal ice drift. The modeling results indicate that the maximum velocity of tidal ice drift, which is determined by a combination of various factors responsible for ice evolution and primarily by the horizontal gradient of the level and local tidal velocity, can be higher or lower than the velocity of the surface tidal current in the ice-free sea. This depends on the sign of deviations of tidal sea level elevations in the sea covered by ice from their values in the ice-free sea. In addition, it has been found that ice cover has a stronger effect on the energetics of tides than on their dynamics: the area-mean relative deviations constitute 1.5% for the density of the total tidal energy, 61.5% for the dissipation, 0.1% for the amplitudes of tidal sea level elevations, and 0.9% for the amplitudes of maximum barotropic tidal velocity. In this sense, the conclusion that the role of sea ice is insignificant in the formation of tides can be justified only partially. The main results of this paper are as follows: (1) the development of a module for tidal ice drift, (2) the inclusion of this module into the three-dimensional finite-element hydrothermodynamic model QUODDY-4 to extend its capabilities, and (3) the reproduction (on the basis of the modified model) of qualitative features of the practically important tidal ice drift and ice-induced changes in the tidal dynamics of marginal seas on the Siberian continental shelf.     

应用北太平洋表层水温及环流场进行海冰预报

渤海及黄海北部处在中纬度地带,每年冬季都有不同程度的结冰现象。以辽东湾结冰时间最长,全部结冰日数平均为100多天,约占全年的三分之一。从全海区看,建国后冰情较重的有1957、1968、1969、1977年的1、2月份,尤其是1969年,渤海海面发生了该海区历史上罕见的冰封,整个海面几乎全部被海冰所覆盖,严重阻碍了海上的航运交通及海上石油开采工作,从而给国民经济带来很大损失。     

The human dimensions of marine mammal management in a time of rapid change: comparing policies in Canada,Finland and the United States

Arctic coastal populations share a close relationship with their environment consisting of linkages among communities, landscapes and seascapes, and the social institutions developed to sustain the system. This cultural–biogeophysical dynamic is termed throughout the section as a social–ecological system (SES). Marine mammals constitute a large portion of the subsistence diet for these communities, and as such represent key ecological services provided by the system. At the same time, marine mammals have gained iconic status as symbols for climate change in the North. A tension results between the demands of balancing on one hand good policy optics consistent with national and international norms and, on the other hand, flexible and adaptive institutions able to take on the task of managing resources in a dynamic, changing North. This tension and associated policy solutions such as co-management are explored in a series of papers focusing on marine mammal management dilemmas and policy practices around the circumpolar North. This introduction communicates the problem context and describes the five papers making up this special section. A guiding premise to this work is that new international pressures to implement moratoria on marine mammal hunting in the North ignore critical human dimensions of marine mammal management. Such policy proposals are unlikely to succeed in areas that require collaboration across scales. Simultaneously, new local-scale participation in multi-level management regimes holds promise for creating more resilient marine mammal SESs.     

新时代我国海岛的生态保护和开发利用

为促进我国海岛的生态保护和开发利用,实现新时代海岛的可持续发展,文章概述海岛生态系统的特性以及我国相关立法过程和管理措施;重点围绕我国海岛生态保护和开发利用实践,以南麂列岛、獐子岛和舟山群岛为例,分别分析保护修复、生态利用和绿色开发3种海岛生态发展模式。研究结果表明:保护修复型以保护区建设和管理、生物资源及其生境修复为主,生态利用型以坚持生态理念、提升产业科技含量、重视环境保护和生态建设以及科学规划和管理为主,绿色开发型以制定规划、构建合理产业体系、发展循环经济以及加强基础设施和人才建设为主;3种模式的共同点为海岛资源的优化配置,可交叉选择和综合应用。在此基础上,提出海岛生态发展的6点建议,即完善法律制度体系、发展绿色能源技术、加强动态监视监测和大数据整合、建立全链条标准化体系、培养和引进专业人才以及推动应对全球挑战的国际合作。     

渤海海冰漂移过程的数值模拟和试验

建立了一个包含潮流作用的准定常海冰动力学模式，利用实测风资料和计算的潮流场对辽东湾中部的冰块漂移过程进行数值模拟，模拟的冰块漂移过程和实况基本一致。表明模式具有反映冰漂移过程动力特征的能力。通过对各动力因子的数值试验，说明引入潮流作用的必要性，并分析了各动力因子在冰漂移过程中的作用。     

Climate change and coral reef bleaching: An ecological assessment of long-term impacts,recovery trends and future outlook

Since the early 1980s, episodes of coral reef bleaching and mortality, due primarily to climate-induced ocean warming, have occurred almost annually in one or more of the world's tropical or subtropical seas. Bleaching is episodic, with the most severe events typically accompanying coupled ocean–atmosphere phenomena, such as the El Niño-Southern Oscillation (ENSO), which result in sustained regional elevations of ocean temperature. Using this extended dataset (25+ years), we review the short- and long-term ecological impacts of coral bleaching on reef ecosystems, and quantitatively synthesize recovery data worldwide. Bleaching episodes have resulted in catastrophic loss of coral cover in some locations, and have changed coral community structure in many others, with a potentially critical influence on the maintenance of biodiversity in the marine tropics. Bleaching has also set the stage for other declines in reef health, such as increases in coral diseases, the breakdown of reef framework by bioeroders, and the loss of critical habitat for associated reef fishes and other biota. Secondary ecological effects, such as the concentration of predators on remnant surviving coral populations, have also accelerated the pace of decline in some areas. Although bleaching severity and recovery have been variable across all spatial scales, some reefs have experienced relatively rapid recovery from severe bleaching impacts. There has been a significant overall recovery of coral cover in the Indian Ocean, where many reefs were devastated by a single large bleaching event in 1998. In contrast, coral cover on western Atlantic reefs has generally continued to decline in response to multiple smaller bleaching events and a diverse set of chronic secondary stressors. No clear trends are apparent in the eastern Pacific, the central-southern-western Pacific or the Arabian Gulf, where some reefs are recovering and others are not. The majority of survivors and new recruits on regenerating and recovering coral reefs have originated from broadcast spawning taxa with a potential for asexual growth, relatively long distance dispersal, successful settlement, rapid growth and a capacity for framework construction. Whether or not affected reefs can continue to function as before will depend on: (1) how much coral cover is lost, and which species are locally extirpated; (2) the ability of remnant and recovering coral communities to adapt or acclimatize to higher temperatures and other climatic factors such as reductions in aragonite saturation state; (3) the changing balance between reef accumulation and bioerosion; and (4) our ability to maintain ecosystem resilience by restoring healthy levels of herbivory, macroalgal cover, and coral recruitment. Bleaching disturbances are likely to become a chronic stress in many reef areas in the coming decades, and coral communities, if they cannot recover quickly enough, are likely to be reduced to their most hardy or adaptable constituents. Some degraded reefs may already be approaching this ecological asymptote, although to date there have not been any global extinctions of individual coral species as a result of bleaching events. Since human populations inhabiting tropical coastal areas derive great value from coral reefs, the degradation of these ecosystems as a result of coral bleaching and its associated impacts is of considerable societal, as well as biological concern. Coral reef conservation strategies now recognize climate change as a principal threat, and are engaged in efforts to allocate conservation activity according to geographic-, taxonomic-, and habitat-specific priorities to maximize coral reef survival. Efforts to forecast and monitor bleaching, involving both remote sensed observations and coupled ocean–atmosphere climate models, are also underway. In addition to these efforts, attempts to minimize and mitigate bleaching impacts on reefs are immediately required. If significant reductions in greenhouse gas emissions can be achieved within the next two to three decades, maximizing coral survivorship during this time may be critical to ensuring healthy reefs can recover in the long term.     

High Arctic sea ice conditions influence marine birds wintering in Low Arctic regions

Ocean climate change is having profound biological effects in polar regions. Such change can also have far-reaching downstream effects in sub-polar regions. This study documents an environmental relationship between High Arctic sea ice changes and mortality events of marine birds in Low Arctic coastal regions. During April 2007 and March 2009, hundreds of beached seabird carcasses and moribund seabirds were found along the east and northeast coasts of Newfoundland, Canada. These seabird “wrecks” (i.e. dead birds on beaches) coincided with a period of strong, persistent onshore winds and heavily-accumulated sea ice that blocked bays and trapped seabirds near beaches. Ninety-two percent of wreck seabirds were Thick-billed Murres (Uria lomvia). Body condition and demographic patterns of wreck murres were compared to Thick-billed Murres shot in the Newfoundland murre hunt. Average body and pectoral masses of wreck carcasses were 34% and 40% lighter (respectively) than shot murres, indicating that wreck birds had starved. The acute nature of each wreck suggested that starvation and associated hypothermia occurred within 2–3 days. In 2007, first-winter murres (77%) dominated the wreck. In 2009, there were more adults (78%), mostly females (66%). These results suggest that spatial and temporal segregation in ages and sexes can play a role in differential survival when stochastic weather conditions affect discrete areas where these groups aggregate. In wreck years, southward movement of Arctic sea ice to Low Arctic latitudes was later and blocked bays longer than in most other years. These inshore conditions corresponded with recent climate-driven changes in High Arctic ice break-up and ice extent; coupled with local weather conditions, these ice conditions appeared to be the key environmental features that precipitated the ice-associated seabird wrecks in the Low Arctic region.     

基于MODIS 影像渤海2012 年海冰变化分析

海冰是影响渤海冬季海运的严重灾害,研究年度周期内海冰时空变化具有重要意义。依据研究内容选择11期具有代表性的中分辨率成像光谱仪(MODerate-resolution Imaging Spectroradiometer,MODIS)影像数据,采用ENVI(The Environment for Visualizing Images)软件进行预处理,利用目视解译方法提取海冰面积与空间位置信息,采用ArcGIS软件制作了海冰时空变化图、海冰结冻与融化过程变化图。最后,对海冰面积变化、海冰结冻与融化过程进行了详细分析。研究结果表明,利用MODIS影像进行年度周期内海冰变化分析技术方法是可行的。     

Circumpolar connections between Antarctic krill (Euphausia superba Dana) populations: Investigating the roles of ocean and sea ice transport

Antarctic krill, Euphausia superba Dana, has a heterogeneous circumpolar distribution in the Southern Ocean. Krill have a close association with sea ice which provides access to a critical food source and shelter, particularly in the early life stages. Advective modelling of transport pathways of krill have until now been on regional scales and have not taken explicit account of sea ice. Here we present Lagrangian modelling studies at the circumpolar scale that include interaction with sea ice. The advection scheme uses ocean velocity output from the Ocean Circulation and Climate Advanced Modelling (OCCAM) project model together with satellite-derived sea ice motion vectors to examine the potential roles of the ocean and sea ice in maintaining the observed circumpolar krill distribution. We show that the Antarctic Coastal Current is likely to be important in generating the large-scale distribution and that sea ice motion can substantially modify the ocean transport pathways, enhancing retention or dispersal depending upon location. Within the major krill region of the Scotia Sea, the effect of temporal variability in both the ocean and sea ice velocity fields is examined. Variability in sea ice motion increases variability of influx to South Georgia, at times concentrating the influx into pulses of arrival. This variability has implications for the ecosystem around the island. The inclusion of sea ice motion leads to the identification of source regions for the South Georgia krill populations additional to those identified when only ocean motion is considered. This study indicates that the circumpolar oceanic circulation and interaction with sea ice is important in determining the large-scale distribution of krill and its associated variability.