当前位置: X-MOL 学术Sci. Rep. › 论文详情
Our official English website, www.x-mol.net, welcomes your feedback! (Note: you will need to create a separate account there.)
Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics.
Scientific Reports ( IF 4.6 ) Pub Date : 2020-03-27 , DOI: 10.1038/s41598-020-60424-5
Melissa M Omand 1 , Rama Govindarajan 2 , Jing He 3, 4 , Amala Mahadevan 4
Affiliation  

The sinking of organic particles produced in the upper sunlit layers of the ocean forms an important limb of the oceanic biological pump, which impacts the sequestration of carbon and resupply of nutrients in the mesopelagic ocean. Particles raining out from the upper ocean undergo remineralization by bacteria colonized on their surface and interior, leading to an attenuation in the sinking flux of organic matter with depth. Here, we formulate a mechanistic model for the depth-dependent, sinking, particulate mass flux constituted by a range of sinking, remineralizing particles. Like previous studies, we find that the model does not achieve the characteristic ‘Martin curve’ flux profile with a single type of particle, but instead requires a distribution of particle sizes and/or properties. We consider various functional forms of remineralization appropriate for solid/compact particles, and aggregates with an anoxic or oxic interior. We explore the sensitivity of the shape of the flux vs. depth profile to the choice of remineralization function, relative particle density, particle size distribution, and water column density stratification, and find that neither a power-law nor exponential function provides a definitively superior fit to the modeled profiles. The profiles are also sensitive to the time history of the particle source. Varying surface particle size distribution (via the slope of the particle number spectrum) over 3 days to represent a transient phytoplankton bloom results in transient subsurface maxima or pulses in the sinking mass flux. This work contributes to a growing body of mechanistic export flux models that offer scope to incorporate underlying dynamical and biological processes into global carbon cycle models.



中文翻译:

海洋中颗粒状有机物的下沉通量:对颗粒特征的敏感性。

海洋上部阳光照射层中产生的有机颗粒的下沉形成了海洋生物泵的重要分支,这影响了中弹性海洋中碳的固存和养分的补充。从上层海洋中下雨的颗粒由于在其表面和内部定殖的细菌而被再矿化,从而导致有机物的下沉通量随深度而减弱。在这里,我们为与深度相关的下沉颗粒质量通量制定了力学模型,该模型由一系列下沉的矿化颗粒组成。像以前的研究一样,我们发现该模型无法通过单一类型的粒子获得特征性的“马丁曲线”通量曲线,而是需要分配粒径和/或特性的分布。我们认为各种功能形式的再矿化适用于固体/紧凑型颗粒,并且具有内部或内部缺氧聚集体。我们探索了通量形状与深度分布的关系曲线对再矿化功能,相对颗粒密度,粒径分布和水柱密度分层的选择的敏感性,并发现幂律和指数函数均不能提供绝对优越的性能适合建模的轮廓。轮廓也对粒子源的时间历史敏感。在3天内变化的表面粒度分布(通过粒子数谱的斜率)代表瞬态浮游植物水华,导致瞬态地下最大值或下沉质量通量的脉冲。

更新日期:2020-03-27
down
wechat
bug