Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions
abstract: The oceans play an essential role in global biogeochemical cycles and in regulating climate. The biological carbon pump, the photosynthetic fixation of carbon dioxide by phytoplankton and subsequent sequestration of organic carbon into deep water, combined with the physical carbon pump, ma...
Other Authors: | , , , , , , |
---|---|
Format: | Doctoral or Postdoctoral Thesis |
Language: | English |
Published: |
2011
|
Subjects: | |
Online Access: | http://hdl.handle.net/2286/R.I.9476 |
id |
ftarizonastateun:item:9476 |
---|---|
record_format |
openpolar |
spelling |
ftarizonastateun:item:9476 2023-05-15T17:36:50+02:00 Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions Amacher, Jessica Anne (Author) Neuer, Susanne (Advisor) Garcia-Pichel, Ferran (Committee member) Lomas, Michael (Committee member) Wojciechowski, Martin (Committee member) Stout, Valerie (Committee member) Arizona State University (Publisher) 2011 233 pages http://hdl.handle.net/2286/R.I.9476 eng eng http://hdl.handle.net/2286/R.I.9476 http://rightsstatements.org/vocab/InC/1.0/ All Rights Reserved Biological Oceanography Doctoral Dissertation 2011 ftarizonastateun 2018-06-23T22:54:27Z abstract: The oceans play an essential role in global biogeochemical cycles and in regulating climate. The biological carbon pump, the photosynthetic fixation of carbon dioxide by phytoplankton and subsequent sequestration of organic carbon into deep water, combined with the physical carbon pump, make the oceans the only long-term net sink for anthropogenic carbon dioxide. A full understanding of the workings of the biological carbon pump requires a knowledge of the role of different taxonomic groups of phytoplankton (protists and cyanobacteria) to organic carbon export. However, this has been difficult due to the degraded nature of particles sinking into particle traps, the main tools employed by oceanographers to collect sinking particulate matter in the ocean. In this study DNA-based molecular methods, including denaturing gradient gel electrophoresis, cloning and sequencing, and taxon-specific quantitative PCR, allowed for the first time for the identification of which protists and cyanobacteria contributed to the material collected by the traps in relation to their presence in the euphotic zone. I conducted this study at two time-series stations in the subtropical North Atlantic Ocean, one north of the Canary Islands, and one located south of Bermuda. The Bermuda study allowed me to investigate seasonal and interannual changes in the contribution of the plankton community to particle flux. I could also show that small unarmored taxa, including representatives of prasinophytes and cyanobacteria, constituted a significant fraction of sequences recovered from sediment trap material. Prasinophyte sequences alone could account for up to 13% of the clone library sequences of trap material during bloom periods. These observations contradict a long-standing paradigm in biological oceanography that only large taxa with mineral shells are capable of sinking while smaller, unarmored cells are recycled in the euphotic zone through the microbial loop. Climate change and a subsequent warming of the surface ocean may lead to a shift in the protist community toward smaller cell size in the future, but in light of these findings these changes may not necessarily lead to a reduction in the strength of the biological carbon pump. Dissertation/Thesis Ph.D. Biology 2011 Doctoral or Postdoctoral Thesis North Atlantic Arizona State University: ASU Digital Repository |
institution |
Open Polar |
collection |
Arizona State University: ASU Digital Repository |
op_collection_id |
ftarizonastateun |
language |
English |
topic |
Biological Oceanography |
spellingShingle |
Biological Oceanography Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
topic_facet |
Biological Oceanography |
description |
abstract: The oceans play an essential role in global biogeochemical cycles and in regulating climate. The biological carbon pump, the photosynthetic fixation of carbon dioxide by phytoplankton and subsequent sequestration of organic carbon into deep water, combined with the physical carbon pump, make the oceans the only long-term net sink for anthropogenic carbon dioxide. A full understanding of the workings of the biological carbon pump requires a knowledge of the role of different taxonomic groups of phytoplankton (protists and cyanobacteria) to organic carbon export. However, this has been difficult due to the degraded nature of particles sinking into particle traps, the main tools employed by oceanographers to collect sinking particulate matter in the ocean. In this study DNA-based molecular methods, including denaturing gradient gel electrophoresis, cloning and sequencing, and taxon-specific quantitative PCR, allowed for the first time for the identification of which protists and cyanobacteria contributed to the material collected by the traps in relation to their presence in the euphotic zone. I conducted this study at two time-series stations in the subtropical North Atlantic Ocean, one north of the Canary Islands, and one located south of Bermuda. The Bermuda study allowed me to investigate seasonal and interannual changes in the contribution of the plankton community to particle flux. I could also show that small unarmored taxa, including representatives of prasinophytes and cyanobacteria, constituted a significant fraction of sequences recovered from sediment trap material. Prasinophyte sequences alone could account for up to 13% of the clone library sequences of trap material during bloom periods. These observations contradict a long-standing paradigm in biological oceanography that only large taxa with mineral shells are capable of sinking while smaller, unarmored cells are recycled in the euphotic zone through the microbial loop. Climate change and a subsequent warming of the surface ocean may lead to a shift in the protist community toward smaller cell size in the future, but in light of these findings these changes may not necessarily lead to a reduction in the strength of the biological carbon pump. Dissertation/Thesis Ph.D. Biology 2011 |
author2 |
Amacher, Jessica Anne (Author) Neuer, Susanne (Advisor) Garcia-Pichel, Ferran (Committee member) Lomas, Michael (Committee member) Wojciechowski, Martin (Committee member) Stout, Valerie (Committee member) Arizona State University (Publisher) |
format |
Doctoral or Postdoctoral Thesis |
title |
Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
title_short |
Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
title_full |
Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
title_fullStr |
Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
title_full_unstemmed |
Protist and Cyanobacterial Contributions to Particle Flux in Oligotrophic Ocean Regions |
title_sort |
protist and cyanobacterial contributions to particle flux in oligotrophic ocean regions |
publishDate |
2011 |
url |
http://hdl.handle.net/2286/R.I.9476 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
http://hdl.handle.net/2286/R.I.9476 |
op_rights |
http://rightsstatements.org/vocab/InC/1.0/ All Rights Reserved |
_version_ |
1766136451007774720 |