Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific
Primary production and carbon export connect biogeochemical cycles in the surface waters to the deep. Quantifying rates of production and carbon export are important to understanding the global carbon cycle. There are multiple productivity rate methods, but each measures a different fraction of prod...
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ftuvicpubl:oai:dspace.library.uvic.ca:1828/11210 2023-05-15T14:56:45+02:00 Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific Timmerman, Amanda Hamme, Roberta Claire 2019-10-03 application/pdf http://hdl.handle.net/1828/11210 English en eng http://hdl.handle.net/1828/11210 Available to the World Wide Web primary production carbon export Line P Arctic in situ methods in vitro methods Thesis 2019 ftuvicpubl 2022-05-19T06:14:02Z Primary production and carbon export connect biogeochemical cycles in the surface waters to the deep. Quantifying rates of production and carbon export are important to understanding the global carbon cycle. There are multiple productivity rate methods, but each measures a different fraction of production. The first type of method is in vitro methods that involve removing water samples from the environment and incubating with an isotopically labelled tracer, such as a nutrient. At the end of the incubation, the amount of enrichment in either the particulates (phytoplankton) or the dissolved oxygen are measured to determine productivity. The second type of method is in situ methods that measure the natural environmental parameters instead of incubations. In this study, the natural isotopic composition and the ratio of gases in the surface water are measured. Comparing in situ versus in vitro methods in the Arctic on a GEOTRACES cruise (July 2015), we identified five reasons to explain why methods do not agree: time of integration, depth of integration, recently shoaled mixed layer, mixing at the base of the mixed layer, and methodological issues. When comparing in vitro methods to each other, filter handling and some as yet unidentified bias causes differences. Comparing methods along Line P (over three years), we hypothesize that excretion of dissolved organic nitrogen, upwelling, bottle effects, mixing, and time of integration are the most important factors that cause disagreement between methods. End of bloom dynamics created an extreme case where method disagreement was most severe. Applying method comparison in the NE subarctic Pacific (August 2014 – June 2017) helps to understand what drives variability in primary production. Historical data show that chlorophyll-a is low and invariant offshore in the high nutrient low chlorophyll area (HNLC), where iron is limiting. We used satellites and models, which compare well with shipboard data, to expand our spatial and temporal coverage of the offshore HNLC area. ... Thesis Arctic Phytoplankton Subarctic University of Victoria (Canada): UVicDSpace Arctic Pacific |
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Open Polar |
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University of Victoria (Canada): UVicDSpace |
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ftuvicpubl |
language |
English |
topic |
primary production carbon export Line P Arctic in situ methods in vitro methods |
spellingShingle |
primary production carbon export Line P Arctic in situ methods in vitro methods Timmerman, Amanda Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
topic_facet |
primary production carbon export Line P Arctic in situ methods in vitro methods |
description |
Primary production and carbon export connect biogeochemical cycles in the surface waters to the deep. Quantifying rates of production and carbon export are important to understanding the global carbon cycle. There are multiple productivity rate methods, but each measures a different fraction of production. The first type of method is in vitro methods that involve removing water samples from the environment and incubating with an isotopically labelled tracer, such as a nutrient. At the end of the incubation, the amount of enrichment in either the particulates (phytoplankton) or the dissolved oxygen are measured to determine productivity. The second type of method is in situ methods that measure the natural environmental parameters instead of incubations. In this study, the natural isotopic composition and the ratio of gases in the surface water are measured. Comparing in situ versus in vitro methods in the Arctic on a GEOTRACES cruise (July 2015), we identified five reasons to explain why methods do not agree: time of integration, depth of integration, recently shoaled mixed layer, mixing at the base of the mixed layer, and methodological issues. When comparing in vitro methods to each other, filter handling and some as yet unidentified bias causes differences. Comparing methods along Line P (over three years), we hypothesize that excretion of dissolved organic nitrogen, upwelling, bottle effects, mixing, and time of integration are the most important factors that cause disagreement between methods. End of bloom dynamics created an extreme case where method disagreement was most severe. Applying method comparison in the NE subarctic Pacific (August 2014 – June 2017) helps to understand what drives variability in primary production. Historical data show that chlorophyll-a is low and invariant offshore in the high nutrient low chlorophyll area (HNLC), where iron is limiting. We used satellites and models, which compare well with shipboard data, to expand our spatial and temporal coverage of the offshore HNLC area. ... |
author2 |
Hamme, Roberta Claire |
format |
Thesis |
author |
Timmerman, Amanda |
author_facet |
Timmerman, Amanda |
author_sort |
Timmerman, Amanda |
title |
Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
title_short |
Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
title_full |
Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
title_fullStr |
Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
title_full_unstemmed |
Comparing marine primary production and carbon export methods in the Arctic and NE subarctic Pacific |
title_sort |
comparing marine primary production and carbon export methods in the arctic and ne subarctic pacific |
publishDate |
2019 |
url |
http://hdl.handle.net/1828/11210 |
geographic |
Arctic Pacific |
geographic_facet |
Arctic Pacific |
genre |
Arctic Phytoplankton Subarctic |
genre_facet |
Arctic Phytoplankton Subarctic |
op_relation |
http://hdl.handle.net/1828/11210 |
op_rights |
Available to the World Wide Web |
_version_ |
1766328829366763520 |