共查询到19条相似文献，搜索用时 125 毫秒
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海洋浮游生态系统连续介质动力学的模型的建立 总被引：3，自引：0，他引：3
运用质点、连续介质和状态变量等观点来描述海洋浮游生态系统,根据生物生命运动、生化反应、水动力学和物质守恒等基本规律,建立海洋浮游生态系统动力学的模型方程,推广地球流体力学的湍流二阶闭合理论,建立实用的雷诺平均生态系统动力学模型方程及其二阶相关项的闭合模型方程,将生态动力学状态变量的湍扩散参数化,本文还讨论了该模型与通常的Ｎ－Ｐ－Ｚ－Ｄ模型的关系,提出了其适用范围。 相似文献
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胶州湾北部水层生态动力学模型与模拟 Ⅰ.胶州湾北部水层生态动力学模型 总被引：1，自引：0，他引：1
建立了一个包括浮游植物、浮游动物、无机氮和磷、溶解态与悬浮有机物及溶解氧七状态变量的浅海水体生态动力学箱式模型,并且考虑了海面太阳辐照度变化、海水与底泥温度变化以及营养盐海底溶出和陆源流入的影响。初步分析了在胶州湾北部浮游生态系统演变的几个特征时期动力学方程中的物流动态特征。结果是比较合理的。 相似文献
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通过对目前生态动力学模型的总结和综合，以生态系统中氮、磷营养盐循环为主线，建立了适用于海洋围隔浮游生态系统的多变量的营养盐迁移-转化动力学模型。该模型包括浮游植物、浮游动物、溶解无机态营养盐、溶解有机态营养盐和生物碎屑5个模块，涉及溶解无机氮、磷酸盐、溶解有机氮、溶解有机磷、浮游植物、浮游动物和生物碎屑7个状态变量。利用2002年8月末莱州湾围隔生态实验数据进行了模型的验证工作，成功地模拟了富加营养盐条件下围隔浮游生态系统中氮、磷营养盐生物化学迁移-转化过程，并通过灵敏度分析探讨了模型主要状态变量对参数改变的灵敏程度。 相似文献
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通过对目前生态动力学模型的总结和综合,以生态系统中氮、磷营养盐循环为主线,建立了适用于海洋围隔浮游生态系统的多变量的营养盐迁移-转化动力学模型.该模型包括浮游植物、浮游动物、溶解无机态营养盐、溶解有机态营养盐和生物碎屑5个模块,涉及溶解无机氮、磷酸盐、溶解有机氮、溶解有机磷、浮游植物、浮游动物和生物碎屑7个状态变量.分别利用1999年秋季和2000年夏季胶州湾围隔生态实验数据进行了模型和验证工作,成功地模拟了富加营养盐条件下围隔浮游生态系统中氮、磷营养盐生物化学迁移-转化过程,并确定了20余个参数的量值. 相似文献
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初步构建了一个以浮游植物（P）、浮游动物（Z）和营养盐（N,包括无机氮和活性磷酸盐）为生态变量的NPZ简单生态模型,并通过与POM三维水动力模型的耦合,建立了三维浮游生态动力学模型,开展了厦门湾全海域三维浮游生态系统时空变化的模拟研究.结果显示,厦门海域浮游动植物有明显的季节变化,春、夏季生物量最高,秋、冬季较低,但不同的海区达到峰值的季节并不相同;活性磷酸盐含量冬季最高,春季最低,与浮游植物量值有较明显的反位相关系,表明厦门湾海域浮游植物的生长主要受活性磷酸盐含量限制.模拟结果符合历史观测特征,且模拟值与实测值量级比较吻合,因此所建立的三维浮游生态动力学模型可用于描述厦门湾海域浮游生态的时空变化特征. 相似文献
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海洋异养浮游细菌生物量及生产力的制约因素 总被引：15，自引：0，他引：15
根据海洋异养浮游细菌既是分解者，又是生产者的特点，从生态学方面探讨了海洋异养浮游细菌在海洋生态系统中的作用、研究现状及细菌生物量和生产力的制约因素。认为具有重要生态学意义的海洋异养浮游细菌生物量和生产力的主要影响因素有溶解性有机碳的性质及含量、无机营养盐浓度、海水温度、微量金属元素(如铁)含量、海洋异养浮游动物的摄食能力和噬菌体的感染等。 相似文献
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海洋生态系统动力学模型作为定量地认识和分析海洋生态系统现象的有力工具,近年来得到了长足发展。本文首先回顾了海洋生态动力学模型的发展历史,着重介绍了21世纪以来生态系统动力学模型的三大发展趋势:一是进一步探索海洋生态系统复杂性,二是全球气候变化与海洋生态系统的相互作用;三是不再局限于理论研究,而进入于灾害预报与评估、公共决策等应用领域。其次介绍了海洋生态动力学模型的分类及典型海洋生态动力学数值模型COHERENS的特点、功能和最新的应用情况。最后总结归纳了目前海洋生态动力学模型研究领域的几大问题与挑战,展望了该研究领域未来的发展趋势和方向。 相似文献
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We propose a new information technology aimed at modeling of biochemical processes in marine ecosystems and based on the use of logical operators of control (intelligent agents) in the dynamic equations of the models. We develop a conceptual model of an ecosystem reflecting the interaction of 17 biochemical processes and 5 external factors. The equations of the model are obtained by the method of adaptive balance of causes (ABC method), which enables one to simulate complex scenarios of the processes running in the investigated systems and guarantees the possibility of robust calculations. Some examples of the behavior of ecosystems under the conditions of deficiency of oxygen caused by the action of natural and anthropogenic factors are presented. As a result, it is possible to make a conclusion that the combined application of the ABC-equations and intelligent agents of control in models of marine ecosystems is quite promising. 相似文献
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This paper explores several simplified representations of complexity or ecological ‘texture’ in models of the marine planktonic ecosystem. It is relatively straightforward to formulate more complex models to include explicitly different functional groups of phytoplankton, zooplankton and bacteria, and to include regulation by multiple nutrients such a nitrate, ammonium, silica, and iron. However, the number of parameters that must be specified from observations increases approximately as the square of the number of compartments and quickly surpasses our ability to constrain them properly from observations. Moreover, ecosystem models often become unstable for small changes in parameter values, and increasing complexity may not lead to increased stability. Here we consider alternative formulations for ecosystem models that try to represent complex interactions, such as the microbial loop, in simpler, less explicit ways. Results are presented demonstrating diagnostic methods to represent (1) multiple size classes of phytoplankton according to total biomass of a single phytoplankton compartment, and (2) partitioning a single compartment for nitrogen into nitrate and ammonium according to the origin of incoming fluxes, nitrification by bacteria, and a relative preference algorithm for uptake by phytoplankton. Ambient concentrations of ammonium are simulated with this model and evaluated against observations from Ocean Station P in the subarctic Northeast Pacific Ocean. 相似文献
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《Marine Policy》2015
Marine legislation is becoming more complex and marine ecosystem-based management is specified in national and regional legislative frameworks. Shelf-seas community and ecosystem models (hereafter termed ecosystem models) are central to the delivery of ecosystem-based management, but there is limited uptake and use of model products by decision makers in Europe and the UK in comparison with other countries. In this study, the challenges to the uptake and use of ecosystem models in support of marine environmental management are assessed using the UK capability as an example. The UK has a broad capability in marine ecosystem modelling, with at least 14 different models that support management, but few examples exist of ecosystem modelling that underpin policy or management decisions. To improve understanding of policy and management issues that can be addressed using ecosystem models, a workshop was convened that brought together advisors, assessors, biologists, social scientists, economists, modellers, statisticians, policy makers, and funders. Some policy requirements were identified that can be addressed without further model development including: attribution of environmental change to underlying drivers, integration of models and observations to develop more efficient monitoring programmes, assessment of indicator performance for different management goals, and the costs and benefit of legislation. Multi-model ensembles are being developed in cases where many models exist, but model structures are very diverse making a standardised approach of combining outputs a significant challenge, and there is a need for new methodologies for describing, analysing, and visualising uncertainties. A stronger link to social and economic systems is needed to increase the range of policy-related questions that can be addressed. It is also important to improve communication between policy and modelling communities so that there is a shared understanding of the strengths and limitations of ecosystem models. 相似文献
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Towards end-to-end models for investigating the effects of climate and fishing in marine ecosystems 总被引：2，自引：0，他引：2
End-to-end models that represent ecosystem components from primary producers to top predators, linked through trophic interactions and affected by the abiotic environment, are expected to provide valuable tools for assessing the effects of climate change and fishing on ecosystem dynamics. Here, we review the main process-based approaches used for marine ecosystem modelling, focusing on the extent of the food web modelled, the forcing factors considered, the trophic processes represented, as well as the potential use and further development of the models. We consider models of a subset of the food web, models which represent the first attempts to couple low and high trophic levels, integrated models of the whole ecosystem, and size spectrum models. Comparisons within and among these groups of models highlight the preferential use of functional groups at low trophic levels and species at higher trophic levels and the different ways in which the models account for abiotic processes. The model comparisons also highlight the importance of choosing an appropriate spatial dimension for representing organism dynamics. Many of the reviewed models could be extended by adding components and by ensuring that the full life cycles of species components are represented, but end-to-end models should provide full coverage of ecosystem components, the integration of physical and biological processes at different scales and two-way interactions between ecosystem components. We suggest that this is best achieved by coupling models, but there are very few existing cases where the coupling supports true two-way interaction. The advantages of coupling models are that the extent of discretization and representation can be targeted to the part of the food web being considered, making their development time- and cost-effective. Processes such as predation can be coupled to allow the propagation of forcing factors effects up and down the food web. However, there needs to be a stronger focus on enabling two-way interaction, carefully selecting the key functional groups and species, reconciling different time and space scales and the methods of converting between energy, nutrients and mass. 相似文献
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Differences in ecosystem dynamics between the northern and southern parts of the Japan Sea have been investigated with two nitrogen based ecosystem models forced by climatological mixed layer depth and euphotic layer depth. Models having 4 and 9 compartments with the same biochemical parameters were applied to the northern and southern parts. The spring bloom in the southern part is earlier and smaller than that in the northern part according to both models, which is supported by satellite ocean color images. The difference of the timing is related to the variation of mixed layer depth, and the magnitude of blooming is also related to the concentrations of surface nutrient and herbivorous zooplankton in early spring. The simulated seasonal variations of ecosystem characteristics (standing stock of each compartment, primary production and the ratio of export flux of organic particles to the primary production) are not significantly different between two models. The ratio of export flux of organic particles to the primary production are about 36% and 23% in the northern and southern parts according to the 4-compartment model, while the values are 31% and 18% by 9-compartment model. These results suggest that the biological pump in the northern part is more active than that in the southern part of the Japan Sea. Sensitivity analyses have been carried out to examine the differences of the response to the models. 相似文献
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《Marine Policy》2017
Coral reef resource systems are complex adaptive social-ecological systems providing vital and valuable ecosystem services for human societies such as food provision, coastal protection and recreational activities. Their sustainability is questioned in many places around the world as they experience combined effects of multiple chronic anthropogenic and natural drivers at local to global scales. From a management perspective, there is a crucial need to understand how the impact of these drivers cascade through the social-ecological system components. This study develops a transdisciplinary and participatory approach to investigating the social-ecological dynamics of a Polynesian coral reef coastal system. A preliminary conceptual model using the Driver-Pressure-State-Impact (DPSI) framework is first being built through participatory modeling workshops. Then, pressure-state relationships are assessed with the help of empirical datasets as a first step towards the validation of the DPSI model. Results shows striking social-ecological interactions with different patterns in the lagoon and in the fore reef. Local management should be: (1) less resource-focused to account more specifically to the existing typology of actors; (2) more spatially-explicit to better distinguish management objectives and actions for the lagoon and the fore reef sub-systems; and (3) more coordinated with terrestrial agencies for a coherent land-sea connection and integration that would both (i) account for existing land-sea interactions and (ii) better reflect the Polynesian cultural heritage that considers nature from ridge to reef as a whole. Such conceptual models of social-ecological systems are a useful tool to build exploratory scenarios to ultimately support planning decision-making processes. 相似文献
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Salinity in a shallow estuary is affected by upland freshwater inputs (surface runoff, stream/canal flows, groundwater), atmospheric processes (precipitation, evaporation), marine connectivity, and wind patterns. In Everglades National Park (ENP) in South Florida, the unique Everglades ecosystem exists as an interconnected system of fresh, brackish, and salt water marshes, mangroves, and open water. For this effort a coastal aquifer conceptual model of the Everglades hydrologic system was used with traditional correlation and regression hydrologic techniques to create a series of multiple linear regression (MLR) salinity models from observed hydrologic, marine, and weather data. The 37 ENP MLR salinity models cover most of the estuarine areas of ENP and produce daily salinity simulations that are capable of estimating 65–80% of the daily variability in salinity depending upon the model. The Root Mean Squared Error is typically about 2–4 salinity units, and there is little bias in the predictions. However, the absolute error of a model prediction in the nearshore embayments and the mangrove zone of Florida Bay may be relatively large for a particular daily simulation during the seasonal transitions. Comparisons show that the models group regionally by similar independent variables and salinity regimes. The MLR salinity models have approximately the same expected range of simulation accuracy and error as higher spatial resolution salinity models. 相似文献