scholarly journals Evolution of the North Pacific Subtropical Gyre during the past 190 kyr through the interaction of the Kuroshio Current with the surface and intermediate waters

2016 ◽  
Vol 31 (11) ◽  
pp. 1498-1513 ◽  
Author(s):  
Yurika Ujiié ◽  
Hirofumi Asahi ◽  
Takuya Sagawa ◽  
Franck Bassinot
Keyword(s):  
North Pacific ◽  
Kuroshio Current ◽  
Subtropical Gyre ◽  
North Pacific Subtropical Gyre ◽  
The Past ◽  
The North ◽  
Intermediate Waters ◽  
The Kuroshio ◽  
The North Pacific

226Ra evidence for the ecosystem shift over the past 40 years in the North Pacific Subtropical Gyre

2007 ◽  
Vol 52 (6) ◽  
pp. 832-838 ◽  
Author(s):  
JunHong Yang ◽  
Min Chen ◽  
YuSheng Qiu ◽  
YanPing Li ◽  
Qiang Ma ◽  
...  
Keyword(s):  
North Pacific ◽  
Subtropical Gyre ◽  
North Pacific Subtropical Gyre ◽  
The Past ◽  
The North ◽  
Ecosystem Shift ◽  
The North Pacific

scholarly journals Heterotrophic prokaryote distribution along a 2300 km transect in the North Pacific subtropical gyre during a strong La Niña conditions: relationship between distribution and hydrological conditions

2015 ◽  
Vol 12 (11) ◽  
pp. 3607-3621 ◽  
Author(s):  
M. Girault ◽  
H. Arakawa ◽  
A. Barani ◽  
H. J. Ceccaldi ◽  
F. Hashihama ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
North Pacific ◽  
Subtropical Gyre ◽  
Nucleic Acid Content ◽  
North Pacific Subtropical Gyre ◽  
The North ◽  
Warm Core ◽  
Heterotrophic Prokaryotes ◽  
The Kuroshio ◽  
The North Pacific

Abstract. The spatial distribution of heterotrophic prokaryotes was investigated during the Tokyo–Palau cruise in the western part of the North Pacific subtropical gyre (NPSG) along a north–south transect between 33.60 and 13.25° N. The cruise was conducted in three different hydrological areas identified as the Kuroshio region, the subtropical gyre area and the transition zone. Two eddies were crossed along the transect: one cold-core cyclonic eddy and one warm-core anticyclonic eddy and distributions of the heterotrophic prokaryotes were recorded. By using analytical flow cytometry and a nucleic acid staining protocol, heterotrophic prokaryotes were discriminated into three subgroups depending on their nucleic acid content (low, high and very high nucleic acid contents labelled LNA, HNA and VHNA, respectively). Statistical analyses performed on the data set showed that LNA, mainly associated with low temperature and low salinity, were dominant in all the hydrological regions. In contrast, HNA distribution seemed to be associated with temperature, salinity, Chl a and silicic acid. A latitudinal increase in the HNA / LNA ratio was observed along the north–south transect and was related to higher phosphate and nitrate concentrations. However, the opposite relationship observed for the VHNA / HNA ratio suggested that the link between nucleic acid content and oligotrophic conditions is not linear, underlying the complexity of the biodiversity in the VHNA, HNA and LNA subgroups. In the Kuroshio Current, it is suggested that the high concentration of heterotrophic prokaryotes observed at station 4 was linked to the path of the cold cyclonic eddy core. In contrast, it is thought that low concentrations of heterotrophic prokaryotes in the warm core of the anticyclonic gyre (Sta. 9) are related to the low nutrient concentrations measured in the seawater column. Our results showed that the high variability between the various heterotrophic prokaryote cluster abundances depend both on the mesoscale structures and the oligotrophic gradient.

scholarly journals Heterotrophic prokaryote distribution along a 2300 km transect in the North Pacific subtropical gyre during strong La Niña conditions: relationship between distribution and hydrological conditions

2014 ◽  
Vol 11 (11) ◽  
pp. 15793-15826
Author(s):  
M. Girault ◽  
H. Arakawa ◽  
A. Barani ◽  
H. J. Ceccaldi ◽  
F. Hashihama ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
North Pacific ◽  
Subtropical Gyre ◽  
Cyclonic Eddy ◽  
North Pacific Subtropical Gyre ◽  
The North ◽  
Warm Core ◽  
Heterotrophic Prokaryotes ◽  
The Kuroshio ◽  
The North Pacific

Abstract. The spatial distribution of heterotrophic prokaryotes was investigated during the Tokyo–Palau cruise in the western part of the North Pacific subtropical gyre (NPSG) along a north–south transect between 33.60 and 13.25° N. The cruise was conducted in three different hydrological areas identified as the Kuroshio region, the Subtropical gyre area and the Transition zone. Two eddies were crossed along the transect: one cold core cyclonic eddy and one warm core anticyclonic eddy and distributions of the heterotrophic prokaryotes were recorded. By using analytical flow cytometry and a nucleic acid staining protocol, heterotrophic prokaryotes were discriminated into three subgroups depending on their nucleic acid content (low, high and very high nucleic acid contents labeled LNA, HNA and VHNA, respectively). Statistical analyses performed on the dataset showed that LNA, mainly associated with temperature and salinity, were dominant in all the hydrological regions. In contrast, HNA distribution seemed to be associated with temperature, salinity, Chl a and silicic acid. A latitudinal increase in the HNA / LNA ratio was observed along the north–south transect and was related to higher phosphate and nitrate concentrations. In the Kuroshio Current, it is suggested that the high concentration of heterotrophic prokaryotes observed at station 4 was linked to the path of the cold cyclonic eddy core. In contrast, it is thought that low concentrations of heterotrophic prokaryotes in the warm core of the anticyclonic gyre (Sta. 9) are related to the low nutrient concentrations measured in the seawater column. Our results showed that the high variability between the various heterotrophic prokaryote cluster abundances depend both on the mesoscale structures and the oligotrophic gradient.

scholarly journals Euphotic zone metabolism in the North Pacific Subtropical Gyre based on oxygen dynamics

2020 ◽  
Author(s):  
Sara Ferron ◽  
Benedetto Barone ◽  
Matthew J Church ◽  
Angelicque E. White ◽  
David M. Karl
Keyword(s):  
North Pacific ◽  
Euphotic Zone ◽  
Subtropical Gyre ◽  
North Pacific Subtropical Gyre ◽  
The North ◽  
Oxygen Dynamics ◽  
The North Pacific

Weakening and Poleward Shifting of the North Pacific Subtropical Fronts from 1980 to 2018

2021 ◽  
Keyword(s):  
Mixed Layer ◽  
North Pacific ◽  
Subtropical Gyre ◽  
Hadley Cell ◽  
North Pacific Subtropical Gyre ◽  
Mode Water ◽  
Mode Waters ◽  
The North ◽  
The North Pacific ◽  
Subtropical Fronts

Abstract Recent evidence shows that the North Pacific subtropical gyre, the Kuroshio Extension (KE) and Oyashio Extension (OE) fronts have moved poleward in the past few decades. However, changes of the North Pacific Subtropical Fronts (STFs), anchored by the North Pacific subtropical countercurrent in the southern subtropical gyre, remain to be quantified. By synthesizing observations, reanalysis, and eddy-resolving ocean hindcasts, we show that the STFs, especially their eastern part, weakened (20%±5%) and moved poleward (1.6°±0.4°) from 1980 to 2018. Changes of the STFs are modified by mode waters to the north. We find that the central mode water (CMW) (180°-160°W) shows most significant weakening (18%±7%) and poleward shifting (2.4°±0.9°) trends, while the eastern part of the subtropical mode water (STMW) (160°E-180°) has similar but moderate changes (10% ± 8%; 0.9°±0.4°). Trends of the western part of the STMW (140°E-160°E) are not evident. The weakening and poleward shifting of mode waters and STFs are enhanced to the east and are mainly associated with changes of the northern deep mixed layers and outcrop lines—which have a growing northward shift as they elongate to the east. The eastern deep mixed layer shows the largest shallowing trend, where the subduction rate also decreases the most. The mixed layer and outcrop line changes are strongly coupled with the northward migration of the North Pacific subtropical gyre and the KE/OE jets as a result of the poleward expanded Hadley cell, indicating that the KE/OE fronts, mode waters, and STFs change as a whole system.

scholarly journals 2P271 Flow cytometry identification of nanocyanobacteria and their limiting factors in the North Pacific Subtropical Gyre(23. Ecology & Environment,Poster)

2013 ◽  
Vol 53 (supplement1-2) ◽  
pp. S203
Author(s):  
Mathias Girault ◽  
Hisayuki Arakawa ◽  
Gerald Gregori ◽  
Fuminori Hashihama ◽  
Hyonchol Kim ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
North Pacific ◽  
Subtropical Gyre ◽  
Limiting Factors ◽  
North Pacific Subtropical Gyre ◽  
The North ◽  
The North Pacific
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