海洋生态系统净生产力研究进展

Research progress of net ecosystem production of marine ecosystem

海洋生态系统净生产力(net ecosystem production,NEP)表示总初级生产力(gross primary production,GPP)和呼吸作用(respiration,R)过程之间的差异,它对碳收支平衡、海洋生态系统营养状态乃至气候变化等研究具有十分重要的指示意义。影响海洋NEP的因素有细菌、浮游生物、温度、太阳辐射、海冰融化、水团迁移、富营养有机质排放以及海水酸化等。目前计算NEP的方法可分为实验培养测定及数据模型计算两种。溶解氧培养法及同位素标记法等是经典的培养测定方法,但存在误差较大且重现性较差等问题。数据模型计算即借助养分质量平衡、响应面模型、O2/Ar示踪等方法,通过将现场实测数据和生物地球化学模型结合,进行高时间分辨率的连续性观测,这也是目前测算NEP的主流应用手段。然而,相较于发达国家,我国在NEP的研究设备、技术、测定方法等方面仍存在一定差距。今后的研究重点将是建立NEP指标与表征海洋环境、气候变化之间的耦合关系以及NEP测定方法的改进,这将有助于深入理解和探索全球变化背景下海洋生态系统响应机制及变化趋势。

Marine net ecosystem production (NEP) is the difference between gross primary production (GPP) and respiration (R). NEP is an important indicator of carbon budget in the marine environment, trophic state and even climate change. Factors influencing the marine NEP include bacteria, plankton, temperature, solar radiation, ice melting, water masses, discharge of eutrophic organic matter and ocean acidification. The methods of calculating NEP can be divided into two categories: experimental culture measurement and data modeling calculation. Culture measurements based on dissolved oxygen and isotope labeling are the classic incubation methods, which have problems such as big magnitude of error and poor reproducibility. The data model calculation is based on the methods such as nutrient mass balance, response surface difference and O2/Ar tracing, combining the field measurement data with biogeochemical models to carry out continuous high time resolution observation. The data modeling calculation is the mainstream method of NEP estimation, and will also be used extensively in future. However, compared with developed countries, China still has certain gaps in research equipment, technology and measurement methods of NEP. Future research will focus on establishing a coupling relationship between NEP indicators and characterization of the marine environment and climate change, as well as improvements in NEP measurements, which will help to understand and explore the response mechanisms and trends of marine ecosystems in the context of global change.