Biogenic silica dynamics of Arctic marine ecosystems
Marine diatoms are the dominant primary producers in coastal and shelf regions, and contribute to about 20% of the annual photosynthesis on Earth. Diatoms also exert a major control on the marine silicon (Si) cycle through the formation of biogenic silica (bSiO2). Continental shelves account for hal...
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ftuvicpubl:oai:dspace.library.uvic.ca:1828/10697 2023-05-15T14:25:09+02:00 Biogenic silica dynamics of Arctic marine ecosystems Giesbrecht, Karina Varela, Diana Esther 2019-04-05 application/pdf http://hdl.handle.net/1828/10697 English en eng http://hdl.handle.net/1828/10697 Giesbrecht, K.E., D.E. Varela, J. Wiktor, J.M. Grebmeier, B. Kelly and J.E. Long. (2018) A decade of summertime measurements of phytoplankton biomass, productivity and assemblage composition in the Pacific Arctic Region from 2006 – 2016. Deep-Sea Research II. doi:10.1016/j.dsr2.2018.06.010 Available to the World Wide Web diatoms silicon marine silicon cycle biogenic silica biogenic silica production biogenic silica dissolution time series Pacific Arctic Region Arctic Thesis 2019 ftuvicpubl https://doi.org/10.1016/j.dsr2.2018.06.010 2022-05-19T06:10:15Z Marine diatoms are the dominant primary producers in coastal and shelf regions, and contribute to about 20% of the annual photosynthesis on Earth. Diatoms also exert a major control on the marine silicon (Si) cycle through the formation of biogenic silica (bSiO2). Continental shelves account for half of the total marine area in the Arctic, yet our knowledge of the cycling of Si for this critically climate-impacted region is limited. The overall objective of this thesis was to improve our understanding of marine bSiO2 dynamics and Si cycling in marine Arctic and Subarctic ecosystems using novel techniques. Phytoplankton and nutrient observations, including dissolved and particulate silica concentrations, are presented from a period of ten years within five biological ‘hotspots’ in the Bering and Chukchi Seas. The first measurements of bSiO2 production and dissolution rates are also presented from a period of four years at the same sites. Results from this work show that (i) although interannual variability is high, diatoms are responsible for most of the high primary productivity in the Bering and Chukchi Seas, (ii) bSiO2 is primarily re-dissolved within the euphotic zone rather than exported, and (iii) phytoplankton phenology and marine Si cycling are affected by short-term climatic changes in this region. We also present the first measurements of bSiO2 production rates along a transect from the Canadian Arctic Archipelago (CAA), through Baffin Bay and into the Labrador Sea. We show that diatoms are both abundant and productive throughout these regions in summer, despite widespread Si limitation in the low-nutrient surface waters. Finally, we also investigated the natural variations in the Si isotopic composition of silicic acid (30Si(OH)4). On a transect through the Bering and Chukchi Seas, Canada Basin and CAA, and finally to Baffin Bay and the Labrador Sea, we found that δ30Si(OH)4 signals reflect water mass composition, the dissolution of bSiO2 throughout the water column, and the biological utilization of ... Thesis Arctic Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin canada basin Canadian Arctic Archipelago Chukchi Labrador Sea Pacific Arctic Phytoplankton Subarctic University of Victoria (Canada): UVicDSpace Arctic Baffin Bay Canada Canadian Arctic Archipelago Pacific Deep Sea Research Part II: Topical Studies in Oceanography 162 93 113 |
institution |
Open Polar |
collection |
University of Victoria (Canada): UVicDSpace |
op_collection_id |
ftuvicpubl |
language |
English |
topic |
diatoms silicon marine silicon cycle biogenic silica biogenic silica production biogenic silica dissolution time series Pacific Arctic Region Arctic |
spellingShingle |
diatoms silicon marine silicon cycle biogenic silica biogenic silica production biogenic silica dissolution time series Pacific Arctic Region Arctic Giesbrecht, Karina Biogenic silica dynamics of Arctic marine ecosystems |
topic_facet |
diatoms silicon marine silicon cycle biogenic silica biogenic silica production biogenic silica dissolution time series Pacific Arctic Region Arctic |
description |
Marine diatoms are the dominant primary producers in coastal and shelf regions, and contribute to about 20% of the annual photosynthesis on Earth. Diatoms also exert a major control on the marine silicon (Si) cycle through the formation of biogenic silica (bSiO2). Continental shelves account for half of the total marine area in the Arctic, yet our knowledge of the cycling of Si for this critically climate-impacted region is limited. The overall objective of this thesis was to improve our understanding of marine bSiO2 dynamics and Si cycling in marine Arctic and Subarctic ecosystems using novel techniques. Phytoplankton and nutrient observations, including dissolved and particulate silica concentrations, are presented from a period of ten years within five biological ‘hotspots’ in the Bering and Chukchi Seas. The first measurements of bSiO2 production and dissolution rates are also presented from a period of four years at the same sites. Results from this work show that (i) although interannual variability is high, diatoms are responsible for most of the high primary productivity in the Bering and Chukchi Seas, (ii) bSiO2 is primarily re-dissolved within the euphotic zone rather than exported, and (iii) phytoplankton phenology and marine Si cycling are affected by short-term climatic changes in this region. We also present the first measurements of bSiO2 production rates along a transect from the Canadian Arctic Archipelago (CAA), through Baffin Bay and into the Labrador Sea. We show that diatoms are both abundant and productive throughout these regions in summer, despite widespread Si limitation in the low-nutrient surface waters. Finally, we also investigated the natural variations in the Si isotopic composition of silicic acid (30Si(OH)4). On a transect through the Bering and Chukchi Seas, Canada Basin and CAA, and finally to Baffin Bay and the Labrador Sea, we found that δ30Si(OH)4 signals reflect water mass composition, the dissolution of bSiO2 throughout the water column, and the biological utilization of ... |
author2 |
Varela, Diana Esther |
format |
Thesis |
author |
Giesbrecht, Karina |
author_facet |
Giesbrecht, Karina |
author_sort |
Giesbrecht, Karina |
title |
Biogenic silica dynamics of Arctic marine ecosystems |
title_short |
Biogenic silica dynamics of Arctic marine ecosystems |
title_full |
Biogenic silica dynamics of Arctic marine ecosystems |
title_fullStr |
Biogenic silica dynamics of Arctic marine ecosystems |
title_full_unstemmed |
Biogenic silica dynamics of Arctic marine ecosystems |
title_sort |
biogenic silica dynamics of arctic marine ecosystems |
publishDate |
2019 |
url |
http://hdl.handle.net/1828/10697 |
geographic |
Arctic Baffin Bay Canada Canadian Arctic Archipelago Pacific |
geographic_facet |
Arctic Baffin Bay Canada Canadian Arctic Archipelago Pacific |
genre |
Arctic Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin canada basin Canadian Arctic Archipelago Chukchi Labrador Sea Pacific Arctic Phytoplankton Subarctic |
genre_facet |
Arctic Arctic Archipelago Arctic Baffin Bay Baffin Bay Baffin canada basin Canadian Arctic Archipelago Chukchi Labrador Sea Pacific Arctic Phytoplankton Subarctic |
op_relation |
http://hdl.handle.net/1828/10697 Giesbrecht, K.E., D.E. Varela, J. Wiktor, J.M. Grebmeier, B. Kelly and J.E. Long. (2018) A decade of summertime measurements of phytoplankton biomass, productivity and assemblage composition in the Pacific Arctic Region from 2006 – 2016. Deep-Sea Research II. doi:10.1016/j.dsr2.2018.06.010 |
op_rights |
Available to the World Wide Web |
op_doi |
https://doi.org/10.1016/j.dsr2.2018.06.010 |
container_title |
Deep Sea Research Part II: Topical Studies in Oceanography |
container_volume |
162 |
container_start_page |
93 |
op_container_end_page |
113 |
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1766297572603854848 |