A new mathematical model to explore microbial processes and their constraints in phytoplankton colonies and sinking marine aggregates
A new mathematical model to explore microbial processes and their constraints in phytoplankton colonies and sinking marine aggregates
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DOI：
10.1126/sciadv.aat1991
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发表时间：
2018-10-01
期刊：
影响因子：
13.6
通讯作者：
Khalili, Arzhang
中科院分区：
文献类型：
--
作者：
Moradi, Nasrollah;Liu, Bo;Khalili, Arzhang
每天下沉数百米的蓝藻和浮游植物聚集体以及碎屑对海洋从大气中隔离二氧化碳起到了重要作用。因此，了解与浮游植物群体和聚集体有关的小规模微生物过程对于了解海洋中的大规模生物地球化学过程至关重要。浮游植物群落和下沉聚集体的特点是其内部气体和营养物质的浓度梯度很大。在这里，我们提出了一个机械数学模型，旨在执行小尺度通量的建模，并评估浮游植物群落和下沉的多孔聚集体中共同出现的过程的物理、化学和生物约束。该模型准确地再现了在下沉集合体中测量的O-2浓度和通量的经验测量结果。关于整个表面的恒定浓度或恒定通量的常见理论假设不适用于下沉的聚集体。因此，以前的理论模型高估了这些集合体中的O-2通量高达15倍。
N-2-fixing colonies of cyanobacteria and aggregates of phytoplankton and detritus sinking hundreds of meters per day are instrumental for the ocean's sequestration of CO2 from the atmosphere. Understanding of small-scale microbial processes associated with phytoplankton colonies and aggregates is therefore crucial for understanding large-scale biogeochemical processes in the ocean. Phytoplankton colonies and sinking aggregates are characterized by steep concentration gradients of gases and nutrients in their interior. Here, we present a mechanistic mathematical model designed to perform modeling of small-scale fluxes and evaluate the physical, chemical, and biological constraints of processes that co-occur in phytoplankton colonies and sinking porous aggregates. The model accurately reproduced empirical measurements of O-2 concentrations and fluxes measured in sinking aggregates. Common theoretical assumptions of either constant concentration or constant flux over the entire surface did not apply to sinking aggregates. Consequently, previous theoretical models overestimate O-2 flux in these aggregates by as high as 15-fold.