Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific
Anoxic marine zones (AMZs) constitute pelagic systems distinguished from the oxygen minimum zones (OMZs) by the complete absence of detectable oxygen and the accumulation of nitrite in mid-waters. At the top of the oxygen-depleted layer and below the oxycline, nutrients are abundant; light intensity...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2022-05-01
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| Series: | Frontiers in Marine Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fmars.2022.858308/full |
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| author | Montserrat Aldunate Montserrat Aldunate Montserrat Aldunate Peter von Dassow Peter von Dassow Peter von Dassow Cristian A. Vargas Cristian A. Vargas Osvaldo Ulloa Osvaldo Ulloa |
| author_facet | Montserrat Aldunate Montserrat Aldunate Montserrat Aldunate Peter von Dassow Peter von Dassow Peter von Dassow Cristian A. Vargas Cristian A. Vargas Osvaldo Ulloa Osvaldo Ulloa |
| author_sort | Montserrat Aldunate |
| collection | DOAJ |
| description | Anoxic marine zones (AMZs) constitute pelagic systems distinguished from the oxygen minimum zones (OMZs) by the complete absence of detectable oxygen and the accumulation of nitrite in mid-waters. At the top of the oxygen-depleted layer and below the oxycline, nutrients are abundant; light intensity is very much reduced (<1% of incident light) and a secondary chlorophyll maximum (SCM) is developed. The shoaling of the oxygen-depleted layer, product of the AMZ expansion, could enhance this SCM, which has little-known biogeochemical effects. Here, we show that the SCM is contributing a measurable signal in the particulate organic carbon (POC), enough to alter the δ13CPOC in the top of the oxygen-depleted layer. This data showed significant differences among stations with and without the development of a SCM, being 3.0‰ heavier when a SCM is developed, and indicating photosynthetic activity and/or remineralization in the top of the AMZ. More depleted δ13CPOC values were also found when no SCM was present indicating stronger chemoautotrophic activity, potentially driven by anammox and sulfur-oxidizing bacteria activity. Assimilation rate data show that when sufficient light and Prochlorococcus are present, photosynthesis exceeds chemoautotrophic carbon fixation, and can exceed heterotrophic assimilation of glucose or acetate. However, in the majority of the stations, assimilation rates of both glucose and acetate exceeded carbon fixation rates under light stimulation, suggesting that often the SCM is still a net heterotrophic system. |
| first_indexed | 2024-04-14T00:45:12Z |
| format | Article |
| id | doaj.art-70b6faf8e6a9449296b50a95ba445840 |
| institution | Directory Open Access Journal |
| issn | 2296-7745 |
| language | English |
| last_indexed | 2024-04-14T00:45:12Z |
| publishDate | 2022-05-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Marine Science |
| spelling | doaj.art-70b6faf8e6a9449296b50a95ba4458402022-12-22T02:22:02ZengFrontiers Media S.A.Frontiers in Marine Science2296-77452022-05-01910.3389/fmars.2022.858308858308Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South PacificMontserrat Aldunate0Montserrat Aldunate1Montserrat Aldunate2Peter von Dassow3Peter von Dassow4Peter von Dassow5Cristian A. Vargas6Cristian A. Vargas7Osvaldo Ulloa8Osvaldo Ulloa9Department of Oceanography, University of Concepción, Concepción, ChileGraduate Program in Oceanography, University of Concepción, Concepción, ChileMillennium Institute of Oceanography (IMO), University of Concepcion, Concepción, ChileMillennium Institute of Oceanography (IMO), University of Concepcion, Concepción, ChileDepartment of Ecology, Pontificia Universidad Católica de Chile, Santiago, ChileDepartment of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Naples, ItalyMillennium Institute of Oceanography (IMO), University of Concepcion, Concepción, ChileCoastal Ecosystems & Global Environmental Change Lab (ECCALab), Department of Aquatic Systems, Faculty of Environmental Sciences, Universidad de Concepción, Concepción, ChileDepartment of Oceanography, University of Concepción, Concepción, ChileMillennium Institute of Oceanography (IMO), University of Concepcion, Concepción, ChileAnoxic marine zones (AMZs) constitute pelagic systems distinguished from the oxygen minimum zones (OMZs) by the complete absence of detectable oxygen and the accumulation of nitrite in mid-waters. At the top of the oxygen-depleted layer and below the oxycline, nutrients are abundant; light intensity is very much reduced (<1% of incident light) and a secondary chlorophyll maximum (SCM) is developed. The shoaling of the oxygen-depleted layer, product of the AMZ expansion, could enhance this SCM, which has little-known biogeochemical effects. Here, we show that the SCM is contributing a measurable signal in the particulate organic carbon (POC), enough to alter the δ13CPOC in the top of the oxygen-depleted layer. This data showed significant differences among stations with and without the development of a SCM, being 3.0‰ heavier when a SCM is developed, and indicating photosynthetic activity and/or remineralization in the top of the AMZ. More depleted δ13CPOC values were also found when no SCM was present indicating stronger chemoautotrophic activity, potentially driven by anammox and sulfur-oxidizing bacteria activity. Assimilation rate data show that when sufficient light and Prochlorococcus are present, photosynthesis exceeds chemoautotrophic carbon fixation, and can exceed heterotrophic assimilation of glucose or acetate. However, in the majority of the stations, assimilation rates of both glucose and acetate exceeded carbon fixation rates under light stimulation, suggesting that often the SCM is still a net heterotrophic system.https://www.frontiersin.org/articles/10.3389/fmars.2022.858308/fullautotrophysecondary chlorophyll maximumoxygen minimum zonesanoxiaProchlorococcusheterotrophy |
| spellingShingle | Montserrat Aldunate Montserrat Aldunate Montserrat Aldunate Peter von Dassow Peter von Dassow Peter von Dassow Cristian A. Vargas Cristian A. Vargas Osvaldo Ulloa Osvaldo Ulloa Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific Frontiers in Marine Science autotrophy secondary chlorophyll maximum oxygen minimum zones anoxia Prochlorococcus heterotrophy |
| title | Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific |
| title_full | Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific |
| title_fullStr | Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific |
| title_full_unstemmed | Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific |
| title_short | Carbon Assimilation by the Picoplanktonic Community Inhabiting the Secondary Chlorophyll Maximum of the Anoxic Marine Zones of the Eastern Tropical North and South Pacific |
| title_sort | carbon assimilation by the picoplanktonic community inhabiting the secondary chlorophyll maximum of the anoxic marine zones of the eastern tropical north and south pacific |
| topic | autotrophy secondary chlorophyll maximum oxygen minimum zones anoxia Prochlorococcus heterotrophy |
| url | https://www.frontiersin.org/articles/10.3389/fmars.2022.858308/full |
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