Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater
Abstract Sinking marine particles drive the biological pump that naturally sequesters carbon from the atmosphere. Despite their small size, the compartmentalized nature of particles promotes intense localized metabolic activity by their bacterial colonizers. Yet the mechanisms promoting the onset of...
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2023-07-01
|
| Series: | Communications Earth & Environment |
| Online Access: | https://doi.org/10.1038/s43247-023-00935-x |
| _version_ | 1827890240343244800 |
|---|---|
| author | Davide Ciccarese Omar Tantawi Irene H. Zhang Desiree Plata Andrew R. Babbin |
| author_facet | Davide Ciccarese Omar Tantawi Irene H. Zhang Desiree Plata Andrew R. Babbin |
| author_sort | Davide Ciccarese |
| collection | DOAJ |
| description | Abstract Sinking marine particles drive the biological pump that naturally sequesters carbon from the atmosphere. Despite their small size, the compartmentalized nature of particles promotes intense localized metabolic activity by their bacterial colonizers. Yet the mechanisms promoting the onset of denitrification, a metabolism that arises once oxygen is limiting, remain to be established. Here we show experimentally that slow sinking aggregates composed of marine diatoms—important primary producers for global carbon export—support active denitrification even among bulk oxygenated water typically thought to exclude anaerobic metabolisms. Denitrification occurs at anoxic microsites distributed throughout a particle and within microns of a particle’s boundary, and fluorescence-reporting bacteria show nitrite can be released into the water column due to segregated dissimilatory reduction of nitrate and nitrite. Examining intact and broken diatoms as organic sources, we show slowly leaking cells promote more bacterial growth, allow particles to have lower oxygen, and generally support greater denitrification. |
| first_indexed | 2024-03-12T21:06:51Z |
| format | Article |
| id | doaj.art-510ef60411714c5a8d7d1da2213694ac |
| institution | Directory Open Access Journal |
| issn | 2662-4435 |
| language | English |
| last_indexed | 2024-03-12T21:06:51Z |
| publishDate | 2023-07-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Communications Earth & Environment |
| spelling | doaj.art-510ef60411714c5a8d7d1da2213694ac2023-07-30T11:25:25ZengNature PortfolioCommunications Earth & Environment2662-44352023-07-014111310.1038/s43247-023-00935-xMicroscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawaterDavide Ciccarese0Omar Tantawi1Irene H. Zhang2Desiree Plata3Andrew R. Babbin4Department of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of TechnologyDepartment of Civil and Environmental Engineering, Massachusetts Institute of TechnologyDepartment of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of TechnologyDepartment of Civil and Environmental Engineering, Massachusetts Institute of TechnologyDepartment of Earth, Atmospheric & Planetary Sciences, Massachusetts Institute of TechnologyAbstract Sinking marine particles drive the biological pump that naturally sequesters carbon from the atmosphere. Despite their small size, the compartmentalized nature of particles promotes intense localized metabolic activity by their bacterial colonizers. Yet the mechanisms promoting the onset of denitrification, a metabolism that arises once oxygen is limiting, remain to be established. Here we show experimentally that slow sinking aggregates composed of marine diatoms—important primary producers for global carbon export—support active denitrification even among bulk oxygenated water typically thought to exclude anaerobic metabolisms. Denitrification occurs at anoxic microsites distributed throughout a particle and within microns of a particle’s boundary, and fluorescence-reporting bacteria show nitrite can be released into the water column due to segregated dissimilatory reduction of nitrate and nitrite. Examining intact and broken diatoms as organic sources, we show slowly leaking cells promote more bacterial growth, allow particles to have lower oxygen, and generally support greater denitrification.https://doi.org/10.1038/s43247-023-00935-x |
| spellingShingle | Davide Ciccarese Omar Tantawi Irene H. Zhang Desiree Plata Andrew R. Babbin Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater Communications Earth & Environment |
| title | Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| title_full | Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| title_fullStr | Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| title_full_unstemmed | Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| title_short | Microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| title_sort | microscale dynamics promote segregated denitrification in diatom aggregates sinking slowly in bulk oxygenated seawater |
| url | https://doi.org/10.1038/s43247-023-00935-x |
| work_keys_str_mv | AT davideciccarese microscaledynamicspromotesegregateddenitrificationindiatomaggregatessinkingslowlyinbulkoxygenatedseawater AT omartantawi microscaledynamicspromotesegregateddenitrificationindiatomaggregatessinkingslowlyinbulkoxygenatedseawater AT irenehzhang microscaledynamicspromotesegregateddenitrificationindiatomaggregatessinkingslowlyinbulkoxygenatedseawater AT desireeplata microscaledynamicspromotesegregateddenitrificationindiatomaggregatessinkingslowlyinbulkoxygenatedseawater AT andrewrbabbin microscaledynamicspromotesegregateddenitrificationindiatomaggregatessinkingslowlyinbulkoxygenatedseawater |