Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean
The diversity and abundances of diazotrophic organisms were determined in field samples from the Atlantic Ocean. A nested PCR technique, amplifiying the structural nifH gene of nitrogenase, and subsequent phylogenetic analysis was used to determine diazotroph diversity. The abundances of seven diazo...
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ftunivkiel:oai:macau.uni-kiel.de:diss_mods_00003397 2024-06-23T07:55:11+00:00 Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean Langlois-Warnat, Rebecca Judith LaRoche, J. Schmitz-Streit, Ruth 2008 https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-33974 https://macau.uni-kiel.de/receive/diss_mods_00003397 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00002648/Rebecca_Thesis_Final.pdf eng eng https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-33974 https://macau.uni-kiel.de/receive/diss_mods_00003397 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00002648/Rebecca_Thesis_Final.pdf https://rightsstatements.org/page/InC/1.0/ info:eu-repo/semantics/openAccess ddc:500 thesis nifH diazotroph real-time PCR Atlantic Ocean Saharan dust dissertation Text doc-type:PhDThesis 2008 ftunivkiel 2024-06-12T14:21:16Z The diversity and abundances of diazotrophic organisms were determined in field samples from the Atlantic Ocean. A nested PCR technique, amplifiying the structural nifH gene of nitrogenase, and subsequent phylogenetic analysis was used to determine diazotroph diversity. The abundances of seven diazotrophic phylotypes were estimated by real-time PCR. TaqMan qPCR primers and probes were designed to target four cyanobacterial (one filamentous and three unicellular), two putative gamma-proteobacterial, and one putative anaerobic nifH phylotype(s). Over half of the total nifH copies detected were filamentous, indicating that this is an important diazotroph. The potential for diazotrophy above 30°N and at nitrate concentrations above 0.5 µM was demonstrated by the presence of nifH genes under these conditions. Results of nutrient addition bioassay experiments showed that nitrogen fixation was phosphorus and iron co-limited, however increases in nifH copy numbers was seen only with the addition of Saharan dust indicating that Saharan dust influences diazotroph distributions. A laboratory experiment conducted with Trichodesmium erythraeum demonstrated that this organism can utilize iron from Saharan dust. Bioassay experiments also revealed that primary production was nitrogen limited and heterotrophic bacterial production was nitrogen and phosphorus co-limited throughout the Northern Atlantic Ocean, emphasizing the important role diazotrophs have by providing fixed nitrogen in this system. Doctoral or Postdoctoral Thesis North Atlantic MACAU: Open Access Repository of Kiel University |
institution |
Open Polar |
collection |
MACAU: Open Access Repository of Kiel University |
op_collection_id |
ftunivkiel |
language |
English |
topic |
ddc:500 thesis nifH diazotroph real-time PCR Atlantic Ocean Saharan dust |
spellingShingle |
ddc:500 thesis nifH diazotroph real-time PCR Atlantic Ocean Saharan dust Langlois-Warnat, Rebecca Judith Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
topic_facet |
ddc:500 thesis nifH diazotroph real-time PCR Atlantic Ocean Saharan dust |
description |
The diversity and abundances of diazotrophic organisms were determined in field samples from the Atlantic Ocean. A nested PCR technique, amplifiying the structural nifH gene of nitrogenase, and subsequent phylogenetic analysis was used to determine diazotroph diversity. The abundances of seven diazotrophic phylotypes were estimated by real-time PCR. TaqMan qPCR primers and probes were designed to target four cyanobacterial (one filamentous and three unicellular), two putative gamma-proteobacterial, and one putative anaerobic nifH phylotype(s). Over half of the total nifH copies detected were filamentous, indicating that this is an important diazotroph. The potential for diazotrophy above 30°N and at nitrate concentrations above 0.5 µM was demonstrated by the presence of nifH genes under these conditions. Results of nutrient addition bioassay experiments showed that nitrogen fixation was phosphorus and iron co-limited, however increases in nifH copy numbers was seen only with the addition of Saharan dust indicating that Saharan dust influences diazotroph distributions. A laboratory experiment conducted with Trichodesmium erythraeum demonstrated that this organism can utilize iron from Saharan dust. Bioassay experiments also revealed that primary production was nitrogen limited and heterotrophic bacterial production was nitrogen and phosphorus co-limited throughout the Northern Atlantic Ocean, emphasizing the important role diazotrophs have by providing fixed nitrogen in this system. |
author2 |
LaRoche, J. Schmitz-Streit, Ruth |
format |
Doctoral or Postdoctoral Thesis |
author |
Langlois-Warnat, Rebecca Judith |
author_facet |
Langlois-Warnat, Rebecca Judith |
author_sort |
Langlois-Warnat, Rebecca Judith |
title |
Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
title_short |
Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
title_full |
Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
title_fullStr |
Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
title_full_unstemmed |
Distribution and abundances of diazotrophs and microbial nutrient limitations in the North Atlantic Ocean |
title_sort |
distribution and abundances of diazotrophs and microbial nutrient limitations in the north atlantic ocean |
publishDate |
2008 |
url |
https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-33974 https://macau.uni-kiel.de/receive/diss_mods_00003397 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00002648/Rebecca_Thesis_Final.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://nbn-resolving.org/urn:nbn:de:gbv:8-diss-33974 https://macau.uni-kiel.de/receive/diss_mods_00003397 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/dissertation_derivate_00002648/Rebecca_Thesis_Final.pdf |
op_rights |
https://rightsstatements.org/page/InC/1.0/ info:eu-repo/semantics/openAccess |
_version_ |
1802647645160734720 |