An individual based model spatial distribution, production and biomass for Calanus finmarchicus in the Norwegian Sea@en

The copepod Calanus finmarchicus is the dominant species of the meso-zooplankton in the Norwegian Sea, and constitutes an important link between the phytoplankton and the higher trophic levels in the Norwegian Sea food chain. An individualbased model for C. finmarchicus, based on super-individuals and evolving traits for behaviour, stages, etc., is two-way coupled to the NORWegian ECOlogical Model system (NORWECOM). One year of modelled C. finmarchicus spatial distribution, production and biomass are found to represent observations reasonably well. High C. finmarchicus abundance is found along the Norwegian shelf-break in the early summer, while the overwintering population is found along the slope and in the deeper Norwegian Sea basins. The timing of the spring bloom is generally later than in the observations. Annual Norwegian Sea production is found to be 29 million tonnes of carbon and a production to biomass (P/B) ratio of 4.3 emerges. Sensitivity tests show that the modelling system is robust to initial values of behavioural traits and with regards to the number of super-individuals simulated given that this is above about 50,000 individuals. Experiments with the model system indicate that it provides a valuable tool for studies of ecosystem responses to causative forces such as prey density or overwintering population size. For example, introducing C. finmarchicus food limitations reduces the stock dramatically, but on the other hand, a reduced stock may rebuild in one year under normal conditions. […]

桡足类（copepod）飞马哲水蚤（Calanus finmarchicus）是挪威海中型浮游动物的优势物种，在挪威海食物链中扮演着连接浮游植物与更高营养级生物的关键纽带角色。本研究针对该物种构建了基于超个体（super-individuals）、涵盖行为与发育阶段等可演化性状的个体模型，并将其与挪威生态模型系统（NORWegian ECOlogical Model system，NORWECOM）实现双向耦合。模拟得到的为期一年的该物种空间分布、生产量与生物量结果，与实测观测数据吻合度良好。初夏时节，挪威陆架坡折带区域的该物种丰度显著偏高；而越冬种群则分布于大陆坡与挪威海深海海盆区域。模型模拟的春季水华发生时间普遍晚于实测观测结果。研究估算挪威海年度碳生产量为2900万吨，且得出生产量与生物量（P/B）比值为4.3。敏感性试验结果表明，当模拟超个体数量高于约5万个体时，该模型系统对行为性状初始值与超个体模拟数量均表现出良好的稳健性。基于该模型系统开展的各类试验显示，其可作为探究生态系统对各类驱动因子（如猎物密度或越冬种群规模）响应的有效研究工具。例如，引入食物限制条件会使该物种种群生物量大幅降低；但反之，在正常环境条件下，种群规模可在一年内完成恢复。[……]