Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios
The Labrador Sea is an ideal region to study the biogeographical, physiological, and biogeochemical implications of phytoplankton community composition due to sharp transitions between distinct water masses across its shelves and central basin. We have investigated the multi-year (2005–2014) distrib...
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2017
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article Verlagsveröffentlichung Fragoso, Glaucia M. Poulton, Alex J. Yashayaev, Igor M. Head, Erica J. H. Purdie, Duncan A. Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
topic_facet |
article Verlagsveröffentlichung |
description |
The Labrador Sea is an ideal region to study the biogeographical, physiological, and biogeochemical implications of phytoplankton community composition due to sharp transitions between distinct water masses across its shelves and central basin. We have investigated the multi-year (2005–2014) distributions of late spring and early summer (May to June) phytoplankton communities in the various hydrographic settings of the Labrador Sea. Our analysis is based on pigment markers (using CHEMTAX analysis), and photophysiological and biogeochemical characteristics associated with each phytoplankton community. Diatoms were the most abundant group, blooming first in shallow mixed layers of haline-stratified Arctic shelf waters. Along with diatoms, chlorophytes co-dominated at the western end of the section (particularly in the polar waters of the Labrador Current (LC)), whilst Phaeocystis co-dominated in the east (modified polar waters of the West Greenland Current (WGC)). Pre-bloom conditions occurred in deeper mixed layers of the central Labrador Sea in May, where a mixed assemblage of flagellates (dinoflagellates, prasinophytes, prymnesiophytes, particularly coccolithophores, and chrysophytes/pelagophytes) occurred in low-chlorophyll areas, succeeding to blooms of diatoms and dinoflagellates in thermally stratified Atlantic waters in June. Light-saturated photosynthetic rates and saturation irradiance levels were highest at stations where diatoms were the dominant phytoplankton group ( > 70 % of total chlorophyll a), as opposed to stations where flagellates were more abundant (from 40 up to 70 % of total chlorophyll a). Phytoplankton communities from the WGC (Phaeocystis and diatoms) had lower light-limited photosynthetic rates, with little evidence of photoinhibition, indicating greater tolerance to a high light environment. By contrast, communities from the central Labrador Sea (dinoflagellates and diatoms), which bloomed later in the season (June), appeared to be more sensitive to high light levels. Ratios of accessory pigments (AP) to total chlorophyll a (TChl a) varied according to phytoplankton community composition, with polar phytoplankton (cold-water related) having lower AP : TChl a. Polar waters (LC and WGC) also had higher and more variable particulate organic carbon (POC) to particulate organic nitrogen (PON) ratios, suggesting the influence of detritus from freshwater input, derived from riverine, glacial, and/or sea ice meltwater. Long-term observational shifts in phytoplankton communities were not assessed in this study due to the short temporal frame (May to June) of the data. Nevertheless, these results add to our current understanding of phytoplankton group distribution, as well as an evaluation of the biogeochemical role (in terms of C : N ratios) of spring phytoplankton communities in the Labrador Sea, which will assist our understanding of potential long-term responses of phytoplankton communities in high-latitude oceans to a changing climate. |
format |
Article in Journal/Newspaper |
author |
Fragoso, Glaucia M. Poulton, Alex J. Yashayaev, Igor M. Head, Erica J. H. Purdie, Duncan A. |
author_facet |
Fragoso, Glaucia M. Poulton, Alex J. Yashayaev, Igor M. Head, Erica J. H. Purdie, Duncan A. |
author_sort |
Fragoso, Glaucia M. |
title |
Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
title_short |
Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
title_full |
Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
title_fullStr |
Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
title_full_unstemmed |
Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
title_sort |
spring phytoplankton communities of the labrador sea (2005–2014): pigment signatures, photophysiology and elemental ratios |
publisher |
Copernicus Publications |
publishDate |
2017 |
url |
https://doi.org/10.5194/bg-14-1235-2017 https://noa.gwlb.de/receive/cop_mods_00042637 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042257/bg-14-1235-2017.pdf https://bg.copernicus.org/articles/14/1235/2017/bg-14-1235-2017.pdf |
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ENVELOPE(43.000,43.000,73.500,73.500) |
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Arctic Central Basin Greenland |
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Arctic Central Basin Greenland |
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Arctic Greenland Labrador Sea Phytoplankton Sea ice |
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Arctic Greenland Labrador Sea Phytoplankton Sea ice |
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Biogeosciences -- http://www.bibliothek.uni-regensburg.de/ezeit/?2158181 -- http://www.copernicus.org/EGU/bg/bg.html -- 1726-4189 https://doi.org/10.5194/bg-14-1235-2017 https://noa.gwlb.de/receive/cop_mods_00042637 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042257/bg-14-1235-2017.pdf https://bg.copernicus.org/articles/14/1235/2017/bg-14-1235-2017.pdf |
op_rights |
uneingeschränkt info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.5194/bg-14-1235-2017 |
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Biogeosciences |
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14 |
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00042637 2023-05-15T15:19:36+02:00 Spring phytoplankton communities of the Labrador Sea (2005–2014): pigment signatures, photophysiology and elemental ratios Fragoso, Glaucia M. Poulton, Alex J. Yashayaev, Igor M. Head, Erica J. H. Purdie, Duncan A. 2017-03 electronic https://doi.org/10.5194/bg-14-1235-2017 https://noa.gwlb.de/receive/cop_mods_00042637 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042257/bg-14-1235-2017.pdf https://bg.copernicus.org/articles/14/1235/2017/bg-14-1235-2017.pdf eng eng Copernicus Publications Biogeosciences -- http://www.bibliothek.uni-regensburg.de/ezeit/?2158181 -- http://www.copernicus.org/EGU/bg/bg.html -- 1726-4189 https://doi.org/10.5194/bg-14-1235-2017 https://noa.gwlb.de/receive/cop_mods_00042637 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00042257/bg-14-1235-2017.pdf https://bg.copernicus.org/articles/14/1235/2017/bg-14-1235-2017.pdf uneingeschränkt info:eu-repo/semantics/openAccess article Verlagsveröffentlichung article Text doc-type:article 2017 ftnonlinearchiv https://doi.org/10.5194/bg-14-1235-2017 2022-02-08T22:40:58Z The Labrador Sea is an ideal region to study the biogeographical, physiological, and biogeochemical implications of phytoplankton community composition due to sharp transitions between distinct water masses across its shelves and central basin. We have investigated the multi-year (2005–2014) distributions of late spring and early summer (May to June) phytoplankton communities in the various hydrographic settings of the Labrador Sea. Our analysis is based on pigment markers (using CHEMTAX analysis), and photophysiological and biogeochemical characteristics associated with each phytoplankton community. Diatoms were the most abundant group, blooming first in shallow mixed layers of haline-stratified Arctic shelf waters. Along with diatoms, chlorophytes co-dominated at the western end of the section (particularly in the polar waters of the Labrador Current (LC)), whilst Phaeocystis co-dominated in the east (modified polar waters of the West Greenland Current (WGC)). Pre-bloom conditions occurred in deeper mixed layers of the central Labrador Sea in May, where a mixed assemblage of flagellates (dinoflagellates, prasinophytes, prymnesiophytes, particularly coccolithophores, and chrysophytes/pelagophytes) occurred in low-chlorophyll areas, succeeding to blooms of diatoms and dinoflagellates in thermally stratified Atlantic waters in June. Light-saturated photosynthetic rates and saturation irradiance levels were highest at stations where diatoms were the dominant phytoplankton group ( > 70 % of total chlorophyll a), as opposed to stations where flagellates were more abundant (from 40 up to 70 % of total chlorophyll a). Phytoplankton communities from the WGC (Phaeocystis and diatoms) had lower light-limited photosynthetic rates, with little evidence of photoinhibition, indicating greater tolerance to a high light environment. By contrast, communities from the central Labrador Sea (dinoflagellates and diatoms), which bloomed later in the season (June), appeared to be more sensitive to high light levels. Ratios of accessory pigments (AP) to total chlorophyll a (TChl a) varied according to phytoplankton community composition, with polar phytoplankton (cold-water related) having lower AP : TChl a. Polar waters (LC and WGC) also had higher and more variable particulate organic carbon (POC) to particulate organic nitrogen (PON) ratios, suggesting the influence of detritus from freshwater input, derived from riverine, glacial, and/or sea ice meltwater. Long-term observational shifts in phytoplankton communities were not assessed in this study due to the short temporal frame (May to June) of the data. Nevertheless, these results add to our current understanding of phytoplankton group distribution, as well as an evaluation of the biogeochemical role (in terms of C : N ratios) of spring phytoplankton communities in the Labrador Sea, which will assist our understanding of potential long-term responses of phytoplankton communities in high-latitude oceans to a changing climate. Article in Journal/Newspaper Arctic Greenland Labrador Sea Phytoplankton Sea ice Niedersächsisches Online-Archiv NOA Arctic Central Basin ENVELOPE(43.000,43.000,73.500,73.500) Greenland Biogeosciences 14 5 1235 1259 |