Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific
The offshore Gulf of Alaska—in the northeastern subarctic Pacific—is a high-nitrate, low-chlorophyll (HNLC) oceanic region where concentrations of dissolved iron (DFe) and zinc (DZn) are of the order ~0.1 nmol kg−1 in surface waters. At the average winter mixed layer depth of ~120 m, DFe and DZn are...
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2022
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Online Access: | https://doi.org/10.3389/fmars.2022.933823 https://doaj.org/article/91b0db18b77342e3b59e426e3f32356d |
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ftdoajarticles:oai:doaj.org/article:91b0db18b77342e3b59e426e3f32356d 2023-05-15T15:44:00+02:00 Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific David W. Crawford Duncan A. Purdie Maeve C. Lohan Peter J. Statham Tawnya D. Peterson Hilary A. Kennedy Michael S. Lipsen Jennifer N. Putland Frank A. Whitney 2022-09-01T00:00:00Z https://doi.org/10.3389/fmars.2022.933823 https://doaj.org/article/91b0db18b77342e3b59e426e3f32356d EN eng Frontiers Media S.A. https://www.frontiersin.org/articles/10.3389/fmars.2022.933823/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2022.933823 https://doaj.org/article/91b0db18b77342e3b59e426e3f32356d Frontiers in Marine Science, Vol 9 (2022) Northeastern Subarctic Pacific phytoplankton cryptophytes mixotrophic protists trace metals zinc Science Q General. Including nature conservation geographical distribution QH1-199.5 article 2022 ftdoajarticles https://doi.org/10.3389/fmars.2022.933823 2022-12-30T20:33:59Z The offshore Gulf of Alaska—in the northeastern subarctic Pacific—is a high-nitrate, low-chlorophyll (HNLC) oceanic region where concentrations of dissolved iron (DFe) and zinc (DZn) are of the order ~0.1 nmol kg−1 in surface waters. At the average winter mixed layer depth of ~120 m, DFe and DZn are of the orders ~0.1–0.2 nmol kg−1 and ~1–2 nmol kg−1, respectively. Vertical supply of Fe to surface waters is therefore limited, with phytoplankton blooms driven by episodic atmospheric and lateral inputs of Fe. In contrast, DZn is presumably replenished through seasonal vertical mixing, though maintained at low levels in surface waters, even in winter, implying that removal processes are in operation. Previous supplementation experiments have demonstrated that phytoplankton biomass (chl-a), growth, and drawdown of nitrate (NO3-) are stimulated strongly by Fe but only minimally, if at all, by Zn alone. Using on-deck bioassay incubations of surface waters, we confirm that the addition of Fe stimulates significant increases in chl-a and large diatoms, and drawdown of NO3- and silicic acid [Si(OH)4]. Associated drawdown of DZn and dissolved cadmium (DCd) indicated Zn stress in the control and +Fe treatment. Supplementation with Zn alone had no significant impact on NO3- and commonly monitored pigments such as chl-a and fucoxanthin. However, in the +Zn treatment, DFe and coccolithophore abundance were significantly lower, and the concentration of particulate organic carbon (POC) and that of the pigments alloxanthin and chlorophyll c1+2 were significantly higher than those in control incubations. Our experiment corroborates previously observed relationships between DZn and alloxanthin and chlorophyll c across the subarctic north Pacific and Bering Sea and could help to explain the low or undetectable concentrations of alloxanthin frequently observed in this region. Alloxanthin is a pigment specific to the cryptophytes, either within free-living cells or within functional plastids retained by mixotrophic protists. Both ... Article in Journal/Newspaper Bering Sea Subarctic Alaska Directory of Open Access Journals: DOAJ Articles Bering Sea Gulf of Alaska Pacific Frontiers in Marine Science 9 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Northeastern Subarctic Pacific phytoplankton cryptophytes mixotrophic protists trace metals zinc Science Q General. Including nature conservation geographical distribution QH1-199.5 |
spellingShingle |
Northeastern Subarctic Pacific phytoplankton cryptophytes mixotrophic protists trace metals zinc Science Q General. Including nature conservation geographical distribution QH1-199.5 David W. Crawford Duncan A. Purdie Maeve C. Lohan Peter J. Statham Tawnya D. Peterson Hilary A. Kennedy Michael S. Lipsen Jennifer N. Putland Frank A. Whitney Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
topic_facet |
Northeastern Subarctic Pacific phytoplankton cryptophytes mixotrophic protists trace metals zinc Science Q General. Including nature conservation geographical distribution QH1-199.5 |
description |
The offshore Gulf of Alaska—in the northeastern subarctic Pacific—is a high-nitrate, low-chlorophyll (HNLC) oceanic region where concentrations of dissolved iron (DFe) and zinc (DZn) are of the order ~0.1 nmol kg−1 in surface waters. At the average winter mixed layer depth of ~120 m, DFe and DZn are of the orders ~0.1–0.2 nmol kg−1 and ~1–2 nmol kg−1, respectively. Vertical supply of Fe to surface waters is therefore limited, with phytoplankton blooms driven by episodic atmospheric and lateral inputs of Fe. In contrast, DZn is presumably replenished through seasonal vertical mixing, though maintained at low levels in surface waters, even in winter, implying that removal processes are in operation. Previous supplementation experiments have demonstrated that phytoplankton biomass (chl-a), growth, and drawdown of nitrate (NO3-) are stimulated strongly by Fe but only minimally, if at all, by Zn alone. Using on-deck bioassay incubations of surface waters, we confirm that the addition of Fe stimulates significant increases in chl-a and large diatoms, and drawdown of NO3- and silicic acid [Si(OH)4]. Associated drawdown of DZn and dissolved cadmium (DCd) indicated Zn stress in the control and +Fe treatment. Supplementation with Zn alone had no significant impact on NO3- and commonly monitored pigments such as chl-a and fucoxanthin. However, in the +Zn treatment, DFe and coccolithophore abundance were significantly lower, and the concentration of particulate organic carbon (POC) and that of the pigments alloxanthin and chlorophyll c1+2 were significantly higher than those in control incubations. Our experiment corroborates previously observed relationships between DZn and alloxanthin and chlorophyll c across the subarctic north Pacific and Bering Sea and could help to explain the low or undetectable concentrations of alloxanthin frequently observed in this region. Alloxanthin is a pigment specific to the cryptophytes, either within free-living cells or within functional plastids retained by mixotrophic protists. Both ... |
format |
Article in Journal/Newspaper |
author |
David W. Crawford Duncan A. Purdie Maeve C. Lohan Peter J. Statham Tawnya D. Peterson Hilary A. Kennedy Michael S. Lipsen Jennifer N. Putland Frank A. Whitney |
author_facet |
David W. Crawford Duncan A. Purdie Maeve C. Lohan Peter J. Statham Tawnya D. Peterson Hilary A. Kennedy Michael S. Lipsen Jennifer N. Putland Frank A. Whitney |
author_sort |
David W. Crawford |
title |
Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
title_short |
Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
title_full |
Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
title_fullStr |
Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
title_full_unstemmed |
Apparent shifts in the microplankton community in response to zinc and iron enrichments in the Northeastern Subarctic Pacific |
title_sort |
apparent shifts in the microplankton community in response to zinc and iron enrichments in the northeastern subarctic pacific |
publisher |
Frontiers Media S.A. |
publishDate |
2022 |
url |
https://doi.org/10.3389/fmars.2022.933823 https://doaj.org/article/91b0db18b77342e3b59e426e3f32356d |
geographic |
Bering Sea Gulf of Alaska Pacific |
geographic_facet |
Bering Sea Gulf of Alaska Pacific |
genre |
Bering Sea Subarctic Alaska |
genre_facet |
Bering Sea Subarctic Alaska |
op_source |
Frontiers in Marine Science, Vol 9 (2022) |
op_relation |
https://www.frontiersin.org/articles/10.3389/fmars.2022.933823/full https://doaj.org/toc/2296-7745 2296-7745 doi:10.3389/fmars.2022.933823 https://doaj.org/article/91b0db18b77342e3b59e426e3f32356d |
op_doi |
https://doi.org/10.3389/fmars.2022.933823 |
container_title |
Frontiers in Marine Science |
container_volume |
9 |
_version_ |
1766378222058995712 |