In:
PLOS ONE, Public Library of Science (PLoS), Vol. 16, No. 4 ( 2021-4-26), p. e0250604-
Abstract:
While primary productivity in the oligotrophic North Pacific Subtropical Gyre (NPSG) is changing, the micro-size plankton community has not been evaluated in the last 4 decades, prompting a re-evaluation. We collected samples over three years (2016–2018) from depths of 10 to 200 m ( n = 127), and the micro-size plankton were identified and counted to understand the heterogeneity of micro-size plankton community structure. The assemblages were consistent to the those of 4 decades ago. Dinophyceae (dinoflagellates) were the most numerically abundant, followed by Cryptophyceae and Bacillariophyceae (diatoms). The other micro-size plankton classes (Cyanophyceae, Haptophyceae, Dictyochophyceae, Euglenophyceae, and Prasinophyceae) were not always detected, whereas only Trichodesmium spp. was counted in the Cyanophyceae. Other unidentified autotrophic and heterotrophic flagellates were also significantly present, and their numeric abundance was higher than or at the same level as was that of the Dinophyceae. In the Dinophyceae, Gymnodiniaceae and Peridiniales were abundant. The chlorophyll a concentration and these class-level assemblages suggested micro-size plankton is not a major primary producer in this area. We applied generalized additive models (GAMs) and principal coordination analyses (PCoAs) to evaluate the habitats of every plankton group and the heterogeneity of the assemblages. The GAMs suggested that every classified plankton abundance showed a similar response to salinity, and we observed differences in habitats in terms of temperature and nitrate concentrations. Based on the PCoAs, we observed unique communities at the 200 m depth layer compared with those at the other sampling layers. The site scores of PCoAs indicated that the micro-size plankton assemblages are most heterogeneous at the 10 m depth layer. At such depth, diazotrophic Cyanophyceae ( Trichodesmium spp.) are abundant, particularly in less-saline water. Therefore, nitrogen fixation may contribute to the heterogeneity in the abundance and assemblages in the western NPSG.
Type of Medium:
Online Resource
ISSN:
1932-6203
DOI:
10.1371/journal.pone.0250604
DOI:
10.1371/journal.pone.0250604.g001
DOI:
10.1371/journal.pone.0250604.g002
DOI:
10.1371/journal.pone.0250604.g003
DOI:
10.1371/journal.pone.0250604.g004
DOI:
10.1371/journal.pone.0250604.g005
DOI:
10.1371/journal.pone.0250604.g006
DOI:
10.1371/journal.pone.0250604.g007
DOI:
10.1371/journal.pone.0250604.g008
DOI:
10.1371/journal.pone.0250604.t001
DOI:
10.1371/journal.pone.0250604.t002
DOI:
10.1371/journal.pone.0250604.s001
DOI:
10.1371/journal.pone.0250604.s002
DOI:
10.1371/journal.pone.0250604.s003
DOI:
10.1371/journal.pone.0250604.r001
DOI:
10.1371/journal.pone.0250604.r002
DOI:
10.1371/journal.pone.0250604.r003
DOI:
10.1371/journal.pone.0250604.r004
DOI:
10.1371/journal.pone.0250604.r005
DOI:
10.1371/journal.pone.0250604.r006
Language:
English
Publisher:
Public Library of Science (PLoS)
Publication Date:
2021
detail.hit.zdb_id:
2267670-3
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