Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand
Off the eastern coast of New Zealand, warm, saline, nutrient-poor Subtropical Waters (STW) are separated from cool, fresher, relatively nutrient-rich Sub-Antarctic Waters (SAW) by the Subtropical Convergence (STC). The Chatham Rise, a submarine rise, restricts the latitudinal movement of the STC as...
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fthighwire:oai:open-archive.highwire.org:plankt:fbm047v1 2023-05-15T13:57:29+02:00 Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand Delizo, Liza Smith, Walker O. Hall, Julie 2007-06-02 05:54:04.0 text/html http://plankt.oxfordjournals.org/cgi/content/short/fbm047v1 https://doi.org/10.1093/plankt/fbm047 en eng Oxford University Press http://plankt.oxfordjournals.org/cgi/content/short/fbm047v1 http://dx.doi.org/10.1093/plankt/fbm047 Copyright (C) 2007, Oxford University Press Article TEXT 2007 fthighwire https://doi.org/10.1093/plankt/fbm047 2016-11-16T18:35:37Z Off the eastern coast of New Zealand, warm, saline, nutrient-poor Subtropical Waters (STW) are separated from cool, fresher, relatively nutrient-rich Sub-Antarctic Waters (SAW) by the Subtropical Convergence (STC). The Chatham Rise, a submarine rise, restricts the latitudinal movement of the STC as well as mixing of STW and SAW. Due to this restriction, this sector of the STC is characterized by sharp gradients in temperature, macro- (nitrate, silicate, and phosphate) and micro- (iron) nutrient concentrations. Shipboard incubations were conducted during austral spring 2000 and 2001 to test the hypothesis that these gradients affect the taxonomic composition and/or growth rates of phytoplankton on either side of and at the STC. Maximum chlorophyll a concentrations during 2000 were 0.39 μg L−1, but were an order of magnitude higher in 2001. During both years STC phytoplankton were dominated by diatoms (77% of the total chlorophyll a during austral spring 2000 and 70% during spring 2001), whereas cryptophytes and prasinophytes dominated STW assemblages (27 and 36% during 2000, and 63 and 17% during 2001). Chlorophyll in the SAW was dominated by procaryotes and photosynthetic nanoflagellates during 2000 (17% procaryotes, 68% nanoflagellates), and by diatoms during the austral spring 2001 cruise (53%). Growth rates of the phytoplankton assemblage were determined by 14C-labeling of chlorophyll a and photosynthetic pigments. During 2000 temperature-normalized growth rates were near maximal at the STC, and decreased on average to less than half of the maximum north and south of that front, whereas in 2001 both absolute and relative growth rates were low at all stations. Growth rates did not closely parallel biomass of the various taxa, suggesting that nutrient limitation and/or grazing were significantly impacting standing stocks. It appeared that growth was strongly influenced by nutrients and light, but that biomass was more strongly influenced by grazing. The Subtropical Convergence is a globally important region of ... Text Antarc* Antarctic HighWire Press (Stanford University) Antarctic Austral New Zealand Journal of Plankton Research 29 8 655 670 |
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Article Delizo, Liza Smith, Walker O. Hall, Julie Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
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Article |
description |
Off the eastern coast of New Zealand, warm, saline, nutrient-poor Subtropical Waters (STW) are separated from cool, fresher, relatively nutrient-rich Sub-Antarctic Waters (SAW) by the Subtropical Convergence (STC). The Chatham Rise, a submarine rise, restricts the latitudinal movement of the STC as well as mixing of STW and SAW. Due to this restriction, this sector of the STC is characterized by sharp gradients in temperature, macro- (nitrate, silicate, and phosphate) and micro- (iron) nutrient concentrations. Shipboard incubations were conducted during austral spring 2000 and 2001 to test the hypothesis that these gradients affect the taxonomic composition and/or growth rates of phytoplankton on either side of and at the STC. Maximum chlorophyll a concentrations during 2000 were 0.39 μg L−1, but were an order of magnitude higher in 2001. During both years STC phytoplankton were dominated by diatoms (77% of the total chlorophyll a during austral spring 2000 and 70% during spring 2001), whereas cryptophytes and prasinophytes dominated STW assemblages (27 and 36% during 2000, and 63 and 17% during 2001). Chlorophyll in the SAW was dominated by procaryotes and photosynthetic nanoflagellates during 2000 (17% procaryotes, 68% nanoflagellates), and by diatoms during the austral spring 2001 cruise (53%). Growth rates of the phytoplankton assemblage were determined by 14C-labeling of chlorophyll a and photosynthetic pigments. During 2000 temperature-normalized growth rates were near maximal at the STC, and decreased on average to less than half of the maximum north and south of that front, whereas in 2001 both absolute and relative growth rates were low at all stations. Growth rates did not closely parallel biomass of the various taxa, suggesting that nutrient limitation and/or grazing were significantly impacting standing stocks. It appeared that growth was strongly influenced by nutrients and light, but that biomass was more strongly influenced by grazing. The Subtropical Convergence is a globally important region of ... |
format |
Text |
author |
Delizo, Liza Smith, Walker O. Hall, Julie |
author_facet |
Delizo, Liza Smith, Walker O. Hall, Julie |
author_sort |
Delizo, Liza |
title |
Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
title_short |
Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
title_full |
Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
title_fullStr |
Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
title_full_unstemmed |
Taxonomic Composition and Growth Rates of Phytoplankton Assemblages at the Subtropical Convergence East of New Zealand |
title_sort |
taxonomic composition and growth rates of phytoplankton assemblages at the subtropical convergence east of new zealand |
publisher |
Oxford University Press |
publishDate |
2007 |
url |
http://plankt.oxfordjournals.org/cgi/content/short/fbm047v1 https://doi.org/10.1093/plankt/fbm047 |
geographic |
Antarctic Austral New Zealand |
geographic_facet |
Antarctic Austral New Zealand |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
http://plankt.oxfordjournals.org/cgi/content/short/fbm047v1 http://dx.doi.org/10.1093/plankt/fbm047 |
op_rights |
Copyright (C) 2007, Oxford University Press |
op_doi |
https://doi.org/10.1093/plankt/fbm047 |
container_title |
Journal of Plankton Research |
container_volume |
29 |
container_issue |
8 |
container_start_page |
655 |
op_container_end_page |
670 |
_version_ |
1766265148892250112 |