Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific
On-deck CO2-Fe-manipulated incubation experiments were conducted using surface seawater collected from the Western Subarctic Gyre of the NW Pacific in the summer of 2008 to elucidate the impacts of ocean acidification and Fe enrichment on the abundance and community composition of phytoplankton and...
Published in: | Journal of Experimental Marine Biology and Ecology |
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Online Access: | http://hdl.handle.net/2115/52673 https://doi.org/10.1016/j.jembe.2012.11.003 |
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fthokunivhus:oai:eprints.lib.hokudai.ac.jp:2115/52673 2023-05-15T17:50:20+02:00 Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific Endo, H. Yoshimura, T. Kataoka, T. Suzuki, K. http://hdl.handle.net/2115/52673 https://doi.org/10.1016/j.jembe.2012.11.003 eng eng Elsevier http://www.sciencedirect.com/science/article/pii/S0022098112003875 http://hdl.handle.net/2115/52673 Journal of Experimental Marine Biology and Ecology, 439: 160-175 http://dx.doi.org/10.1016/j.jembe.2012.11.003 Eubacteria Iron enrichment Ocean acidification Pacific Ocean Phytoplankton 452 article (author version) fthokunivhus https://doi.org/10.1016/j.jembe.2012.11.003 2022-11-18T01:02:47Z On-deck CO2-Fe-manipulated incubation experiments were conducted using surface seawater collected from the Western Subarctic Gyre of the NW Pacific in the summer of 2008 to elucidate the impacts of ocean acidification and Fe enrichment on the abundance and community composition of phytoplankton and eubacteria in the study area. During the incubation, excluding the initial period, the mean partial pressures of CO2 in non-Fe-added bottles were 230, 419, 843, and 1124 mu atm, whereas those in Fe-added treatments were 152, 394, 791, and 1008 mu atm. Changes in the abundance and community composition of phytoplankton were estimated using HPLC pigment signatures with the program CHEMTAX and flow cytometry. A DGGE fingerprint technique targeting 16S rRNA gene fragments was also used to estimate changes in eubacterial phylotypes during incubation. The Fe addition induced diatom blooms, and subsequently stimulated the growth of heterotrophic bacteria such as Roseobacter, Phaeobacter, and Alteromonas in the post-bloom phase. In both the Fe-limited and Fe-replete treatments, concentrations of 19'-hexanoyloxyfucoxanthin, a haptophyte marker, and the cell abundance of coccolithophores decreased at higher CO2 levels (750 and 1000 ppm), whereas diatoms exhibited little response to the changes in CO2 availability. The abundances of Synechococcus and small eukaryotic phytoplankton (<10 mu m) increased at the higher CO2 levels. DGGE band positions revealed that Methylobacterium of Alphaproteobacteria occurred solely at lower CO2 levels (180 and 380 ppm) during the post-bloom phase. These results suggest that increases in CO2 level could affect not only the community composition of phytoplankton but also that of eubacteria. As these microorganisms play critical roles in the biological carbon pump and microbial loop, our results indicate that the progression of ocean acidification can alter the biogeochemical processes in the study area. (C) 2012 Elsevier B.V. All rights reserved. Article in Journal/Newspaper Ocean acidification Subarctic Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) Pacific Journal of Experimental Marine Biology and Ecology 439 160 175 |
institution |
Open Polar |
collection |
Hokkaido University Collection of Scholarly and Academic Papers (HUSCAP) |
op_collection_id |
fthokunivhus |
language |
English |
topic |
Eubacteria Iron enrichment Ocean acidification Pacific Ocean Phytoplankton 452 |
spellingShingle |
Eubacteria Iron enrichment Ocean acidification Pacific Ocean Phytoplankton 452 Endo, H. Yoshimura, T. Kataoka, T. Suzuki, K. Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
topic_facet |
Eubacteria Iron enrichment Ocean acidification Pacific Ocean Phytoplankton 452 |
description |
On-deck CO2-Fe-manipulated incubation experiments were conducted using surface seawater collected from the Western Subarctic Gyre of the NW Pacific in the summer of 2008 to elucidate the impacts of ocean acidification and Fe enrichment on the abundance and community composition of phytoplankton and eubacteria in the study area. During the incubation, excluding the initial period, the mean partial pressures of CO2 in non-Fe-added bottles were 230, 419, 843, and 1124 mu atm, whereas those in Fe-added treatments were 152, 394, 791, and 1008 mu atm. Changes in the abundance and community composition of phytoplankton were estimated using HPLC pigment signatures with the program CHEMTAX and flow cytometry. A DGGE fingerprint technique targeting 16S rRNA gene fragments was also used to estimate changes in eubacterial phylotypes during incubation. The Fe addition induced diatom blooms, and subsequently stimulated the growth of heterotrophic bacteria such as Roseobacter, Phaeobacter, and Alteromonas in the post-bloom phase. In both the Fe-limited and Fe-replete treatments, concentrations of 19'-hexanoyloxyfucoxanthin, a haptophyte marker, and the cell abundance of coccolithophores decreased at higher CO2 levels (750 and 1000 ppm), whereas diatoms exhibited little response to the changes in CO2 availability. The abundances of Synechococcus and small eukaryotic phytoplankton (<10 mu m) increased at the higher CO2 levels. DGGE band positions revealed that Methylobacterium of Alphaproteobacteria occurred solely at lower CO2 levels (180 and 380 ppm) during the post-bloom phase. These results suggest that increases in CO2 level could affect not only the community composition of phytoplankton but also that of eubacteria. As these microorganisms play critical roles in the biological carbon pump and microbial loop, our results indicate that the progression of ocean acidification can alter the biogeochemical processes in the study area. (C) 2012 Elsevier B.V. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Endo, H. Yoshimura, T. Kataoka, T. Suzuki, K. |
author_facet |
Endo, H. Yoshimura, T. Kataoka, T. Suzuki, K. |
author_sort |
Endo, H. |
title |
Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
title_short |
Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
title_full |
Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
title_fullStr |
Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
title_full_unstemmed |
Effects of CO2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic Pacific |
title_sort |
effects of co2 and iron availability on phytoplankton and eubacterial community compositions in the northwest subarctic pacific |
publisher |
Elsevier |
url |
http://hdl.handle.net/2115/52673 https://doi.org/10.1016/j.jembe.2012.11.003 |
geographic |
Pacific |
geographic_facet |
Pacific |
genre |
Ocean acidification Subarctic |
genre_facet |
Ocean acidification Subarctic |
op_relation |
http://www.sciencedirect.com/science/article/pii/S0022098112003875 http://hdl.handle.net/2115/52673 Journal of Experimental Marine Biology and Ecology, 439: 160-175 http://dx.doi.org/10.1016/j.jembe.2012.11.003 |
op_doi |
https://doi.org/10.1016/j.jembe.2012.11.003 |
container_title |
Journal of Experimental Marine Biology and Ecology |
container_volume |
439 |
container_start_page |
160 |
op_container_end_page |
175 |
_version_ |
1766157034091184128 |