Phytoplankton Growth Rates in the Ross Sea, Antarctica
The Ross Sea is a highly productive region of the Southern Ocean characterized by spatially variable distribution of phytoplankton, primarily Phaeocystis antarctica, but phytoplankton growth rates in the region have not been thoroughly investigated. Variability in growth rates was investigated from...
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ftwilliammarycol:oai:scholarworks.wm.edu:etd-3065 2023-06-11T04:05:36+02:00 Phytoplankton Growth Rates in the Ross Sea, Antarctica Mosby, Anna Ford 2013-01-01T08:00:00Z application/pdf https://scholarworks.wm.edu/etd/1539617935 https://doi.org/10.25773/v5-x9vw-t938 https://scholarworks.wm.edu/context/etd/article/3065/viewcontent/10632088.pdf English eng W&M ScholarWorks https://scholarworks.wm.edu/etd/1539617935 doi:doi:10.25773/v5-x9vw-t938 https://scholarworks.wm.edu/context/etd/article/3065/viewcontent/10632088.pdf © The Author Dissertations, Theses, and Masters Projects Marine Biology Oceanography text 2013 ftwilliammarycol https://doi.org/10.25773/v5-x9vw-t938 2023-05-04T17:39:34Z The Ross Sea is a highly productive region of the Southern Ocean characterized by spatially variable distribution of phytoplankton, primarily Phaeocystis antarctica, but phytoplankton growth rates in the region have not been thoroughly investigated. Variability in growth rates was investigated from January to February 2012 on a cruise to the Ross Sea using two methods: 14C-isotopic tracer incubations and dilution experiments. Because all methods of measuring growth rates may not be appropriate in all systems due to errors inherent to each method, I assessed and compared the two methods for possible sources of error by examining the effect of extended incubations on measured growth rates in 14C-incubations, quantifying phytoplankton growth and grazing mortality rates through dilution experiments, and analyzing the effect of irradiance in incubations on carbon:chlorophyll ratios in dilution experiments. I found that dilution experiments yielded variable growth rates based on chlorophyll and cell abundance; the mean growth rate based on chlorophyll was 0.11 d-1 while mean growth rate based on abundance was 0.12 d-1. Chlorophyll-based growth rates may be inaccurate due to carbon:chlorophyll ratios of phytoplankton changing during incubations. This unbalanced growth is likely due to variable mixed layer depth and subsequent variability in light history of phytoplankton. Grazing mortality rates were non-significant in 7 of the 11 dilution experiments conducted and significant mortality rates were low with a mean mortality rate of 0.09 d-1, most likely because of low temperatures rather than the presence of P. antarctica. Growth rates measured in 14C-incubations did not change in extended incubations, indicating that loss of fixed 14C through grazing and respiration was not a major source of error. Growth rates were below those predicted based on temperature alone (p<0.001), and mean growth rate in 14C-incubations was 0.14 d-1. Structural equation modeling indicated that growth rates in 14C-incubations did not ... Text Antarc* Antarctica Ross Sea Southern Ocean W&M ScholarWorks Ross Sea Southern Ocean |
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Open Polar |
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W&M ScholarWorks |
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ftwilliammarycol |
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English |
topic |
Marine Biology Oceanography |
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Marine Biology Oceanography Mosby, Anna Ford Phytoplankton Growth Rates in the Ross Sea, Antarctica |
topic_facet |
Marine Biology Oceanography |
description |
The Ross Sea is a highly productive region of the Southern Ocean characterized by spatially variable distribution of phytoplankton, primarily Phaeocystis antarctica, but phytoplankton growth rates in the region have not been thoroughly investigated. Variability in growth rates was investigated from January to February 2012 on a cruise to the Ross Sea using two methods: 14C-isotopic tracer incubations and dilution experiments. Because all methods of measuring growth rates may not be appropriate in all systems due to errors inherent to each method, I assessed and compared the two methods for possible sources of error by examining the effect of extended incubations on measured growth rates in 14C-incubations, quantifying phytoplankton growth and grazing mortality rates through dilution experiments, and analyzing the effect of irradiance in incubations on carbon:chlorophyll ratios in dilution experiments. I found that dilution experiments yielded variable growth rates based on chlorophyll and cell abundance; the mean growth rate based on chlorophyll was 0.11 d-1 while mean growth rate based on abundance was 0.12 d-1. Chlorophyll-based growth rates may be inaccurate due to carbon:chlorophyll ratios of phytoplankton changing during incubations. This unbalanced growth is likely due to variable mixed layer depth and subsequent variability in light history of phytoplankton. Grazing mortality rates were non-significant in 7 of the 11 dilution experiments conducted and significant mortality rates were low with a mean mortality rate of 0.09 d-1, most likely because of low temperatures rather than the presence of P. antarctica. Growth rates measured in 14C-incubations did not change in extended incubations, indicating that loss of fixed 14C through grazing and respiration was not a major source of error. Growth rates were below those predicted based on temperature alone (p<0.001), and mean growth rate in 14C-incubations was 0.14 d-1. Structural equation modeling indicated that growth rates in 14C-incubations did not ... |
format |
Text |
author |
Mosby, Anna Ford |
author_facet |
Mosby, Anna Ford |
author_sort |
Mosby, Anna Ford |
title |
Phytoplankton Growth Rates in the Ross Sea, Antarctica |
title_short |
Phytoplankton Growth Rates in the Ross Sea, Antarctica |
title_full |
Phytoplankton Growth Rates in the Ross Sea, Antarctica |
title_fullStr |
Phytoplankton Growth Rates in the Ross Sea, Antarctica |
title_full_unstemmed |
Phytoplankton Growth Rates in the Ross Sea, Antarctica |
title_sort |
phytoplankton growth rates in the ross sea, antarctica |
publisher |
W&M ScholarWorks |
publishDate |
2013 |
url |
https://scholarworks.wm.edu/etd/1539617935 https://doi.org/10.25773/v5-x9vw-t938 https://scholarworks.wm.edu/context/etd/article/3065/viewcontent/10632088.pdf |
geographic |
Ross Sea Southern Ocean |
geographic_facet |
Ross Sea Southern Ocean |
genre |
Antarc* Antarctica Ross Sea Southern Ocean |
genre_facet |
Antarc* Antarctica Ross Sea Southern Ocean |
op_source |
Dissertations, Theses, and Masters Projects |
op_relation |
https://scholarworks.wm.edu/etd/1539617935 doi:doi:10.25773/v5-x9vw-t938 https://scholarworks.wm.edu/context/etd/article/3065/viewcontent/10632088.pdf |
op_rights |
© The Author |
op_doi |
https://doi.org/10.25773/v5-x9vw-t938 |
_version_ |
1768377141159788544 |