Cargando…
Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics
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...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Nature Publishing Group UK
2020
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7101343/ https://www.ncbi.nlm.nih.gov/pubmed/32221314 http://dx.doi.org/10.1038/s41598-020-60424-5 |
_version_ | 1783511598354137088 |
---|---|
author | Omand, Melissa M. Govindarajan, Rama He, Jing Mahadevan, Amala |
author_facet | Omand, Melissa M. Govindarajan, Rama He, Jing Mahadevan, Amala |
author_sort | Omand, Melissa M. |
collection | PubMed |
description | 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. |
format | Online Article Text |
id | pubmed-7101343 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | Nature Publishing Group UK |
record_format | MEDLINE/PubMed |
spelling | pubmed-71013432020-03-31 Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics Omand, Melissa M. Govindarajan, Rama He, Jing Mahadevan, Amala Sci Rep Article 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. Nature Publishing Group UK 2020-03-27 /pmc/articles/PMC7101343/ /pubmed/32221314 http://dx.doi.org/10.1038/s41598-020-60424-5 Text en © The Author(s) 2020 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. |
spellingShingle | Article Omand, Melissa M. Govindarajan, Rama He, Jing Mahadevan, Amala Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title | Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title_full | Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title_fullStr | Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title_full_unstemmed | Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title_short | Sinking flux of particulate organic matter in the oceans: Sensitivity to particle characteristics |
title_sort | sinking flux of particulate organic matter in the oceans: sensitivity to particle characteristics |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7101343/ https://www.ncbi.nlm.nih.gov/pubmed/32221314 http://dx.doi.org/10.1038/s41598-020-60424-5 |
work_keys_str_mv | AT omandmelissam sinkingfluxofparticulateorganicmatterintheoceanssensitivitytoparticlecharacteristics AT govindarajanrama sinkingfluxofparticulateorganicmatterintheoceanssensitivitytoparticlecharacteristics AT hejing sinkingfluxofparticulateorganicmatterintheoceanssensitivitytoparticlecharacteristics AT mahadevanamala sinkingfluxofparticulateorganicmatterintheoceanssensitivitytoparticlecharacteristics |