Dynamics of the transition zone in coastal zone color scanner-sensed ocean color in the North Pacific during oceanographic spring

1994 ◽  
Vol 99 (C4) ◽  
pp. 7501 ◽  
Author(s):  
David M. Glover ◽  
J. S. Wroblewski ◽  
Charles R. McClain
Keyword(s):  
Transition Zone ◽  
Coastal Zone ◽  
North Pacific ◽  
Ocean Color ◽  
The North ◽  
Color Scanner ◽  
The North Pacific

scholarly journals The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

2010 ◽  
Vol 7 (10) ◽  
pp. 3139-3151 ◽  
Author(s):  
A. Morel ◽  
H. Claustre ◽  
B. Gentili
Keyword(s):  
North Pacific ◽  
Ocean Color ◽  
Global Ocean ◽  
Main Process ◽  
Seasonal Cycles ◽  
The North ◽  
Yellow Substance ◽  
Color Sensors ◽  
North And South ◽  
The North Pacific

Abstract. The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account for this clarity. The oligotrophic waters of the North and South Pacific gyres, the North and South Atlantic gyres, and the South Indian gyre have been comparatively studied with respect to both [Chl] and CDOM contents, by using 10-year data (1998–2007) of the Sea-viewing Wide field-of-view Sensor (SeaWiFS, NASA). Albeit similar these oligotrophic zones are not identical regarding their [Chl] and CDOM contents, as well as their seasonal cycles. According to the zone, the averaged [Chl] value varies from 0.026 to 0.059 mg m−3, whereas the ay(443) average (the absorption coefficient due to CDOM at 443 nm) is between 0.0033 and 0.0072 m−1. The CDOM-to-[Chl] relative proportions also differ between the zones. The clearest waters, corresponding to the lowest [Chl] and CDOM concentrations, are found near Easter Island and near Mariana Islands in the western part of the North Pacific Ocean. In spite of its low [Chl], the Sargasso Sea presents the highest CDOM content amongst the six zones studied. Except in the North Pacific gyre (near Mariana and south of Hawaii islands), a conspicuous seasonality appears to be the rule in the other 4 gyres and affects both [Chl] and CDOM; both quantities vary in a ratio of about 2 (maximum-to-minimum). Coinciding [Chl] and CDOM peaks occur just after the local winter solstice, which is also the period of the maximal mixed layer depth in these latitudes. It is hypothesized that the vertical transport of unbleached CDOM from the subthermocline layers is the main process enhancing the CDOM concentration within the upper layer in winter. In summer, the CDOM experiences its minimum which is delayed with respect to the [Chl] minimum; apparently, the solar photo-bleaching of CDOM is a slower process than the post-bloom algal Chl decay. Where they exist, the seasonal cycles are repeated without notable change from year to year. Long term (10 y) trends have not been detected in these zones. These oligotrophic gyres can conveniently be used for in-flight calibration and comparison of ocean color sensors, provided that their marked seasonal variations are accounted for.

Habitats of two albatross species during the non-breeding season in the North Pacific Transition Zone

2015 ◽  
Vol 162 (4) ◽  
pp. 743-752 ◽  
Author(s):  
Bungo Nishizawa ◽  
Daisuke Ochi ◽  
Hiroshi Minami ◽  
Kotaro Yokawa ◽  
Sei-Ichi Saitoh ◽  
...  
Keyword(s):  
Transition Zone ◽  
Breeding Season ◽  
North Pacific ◽  
The North ◽  
The North Pacific

scholarly journals Summertime Tintinnid Community in the Surface Waters Across the North Pacific Transition Zone

2021 ◽  
Vol 12 ◽  
Author(s):  
Haibo Li ◽  
Jun Xuan ◽  
Chaofeng Wang ◽  
Zhaohui Chen ◽  
Gérald Grégori ◽  
...  
Keyword(s):  
Transition Zone ◽  
North Pacific ◽  
Warm Water ◽  
Type I ◽  
Water Type ◽  
The North ◽  
Important Region ◽  
Oceanic Species ◽  
The Common ◽  
The North Pacific

Located from 35° to 45° latitude in both hemispheres, the transition zone is an important region with respect to the planktonic biogeography of the sea. However, to the best of our knowledge, there have been no reports on the existence of a tintinnid community in the transition zone. In this research, tintinnids along two transects across the North Pacific Transition Zone (NPTZ) were investigated in summer 2016 and 2019. Eighty-three oceanic tintinnid species were identified, 41 of which were defined as common oceanic species. The common oceanic species were further divided into five groups: boreal, warm water type I, warm water type II, transition zone, and cosmopolitan species. Undella californiensis and Undella clevei were transition zone species. Other species, such as Amphorides minor, Dadayiella ganymedes, Dictyocysta mitra, Eutintinnus pacificus, Eutintinnus tubulosus, Protorhabdonella simplex, and Steenstrupiella steenstrupii, were the most abundant in the NPTZ but spread over a much larger distribution region. Species richness showed no obvious increase in the NPTZ. Boreal, transition zone, and warm water communities were divided along the two transects. Tintinnid transition zone community mainly distributed in regions with water temperatures between 15 and 20°C. The tintinnid lorica oral diameter size classes were dominated by the 24–28 μm size class in three communities, but the dominance decreased from 66.26% in the boreal community to 48.85% in the transition zone community and then to 22.72% in the warm water community. Our research confirmed the existence of tintinnid transition zone species and community. The abrupt disappearance of warm water type I species below 15°C suggested that this group could be used as an indicator of the northern boundary of the NPTZ.

scholarly journals Seasonal photoacclimation in the North Pacific Transition Zone

2021 ◽  
Author(s):  
Gregory L Britten ◽  
Christine Padalino ◽  
Gaël Forget ◽  
Michael J. Follows
Keyword(s):  
Transition Zone ◽  
North Pacific ◽  
The North ◽  
The North Pacific

scholarly journals The most oligotrophic subtropical zones of the global ocean: similarities and differences in terms of chlorophyll and yellow substance

2010 ◽  
Vol 7 (4) ◽  
pp. 5047-5079 ◽  
Author(s):  
A. Morel ◽  
H. Claustre ◽  
B. Gentili
Keyword(s):  
North Pacific ◽  
Ocean Color ◽  
Global Ocean ◽  
Main Process ◽  
Seasonal Cycles ◽  
The North ◽  
Yellow Substance ◽  
Color Sensors ◽  
North And South ◽  
The North Pacific

Abstract. The cores of the subtropical anticyclonic gyres are characterized by their oligotrophic status and minimal chlorophyll concentration, compared to that of the whole ocean. These zones are unambiguously detected by space borne ocean color sensors thanks to their typical spectral reflectance, which is that of extremely clear and deep blue waters. Not only the low chlorophyll (denoted [Chl]) level, but also a reduced amount of colored dissolved organic matter (CDOM or "yellow substance") account for this clarity. The oligotrophic waters of the North and South Pacific gyres, the North and South Atlantic gyres, and the South Indian gyre have been comparatively studied with respect to both [Chl] and CDOM contents, by using 10-year data (1998–2007) of the Sea-viewing Wide field-of-view Sensor (SeaWiFS, NASA). Albeit similar these oligotrophic zones are not identical regarding their [Chl] and CDOM contents, as well as their seasonal cycles. According to the zone, the averaged [Chl] value varies from 0.026 to 0.059 mg m−3, whereas the ay(443) average (the absorption coefficient due to CDOM at 443 nm) is comprised between 0.0033 and 0.0072 m−1. The CDOM-to-[Chl] relative proportions also differ between the zones. The clearest waters, corresponding to the lowest [Chl] and CDOM concentrations, are found near Easter Island and near Mariana Islands in the western part of the North Pacific Ocean. In spite of its low [Chl], the Sargasso Sea presents the highest CDOM content amongst the six zones studied. Except in the North Pacific gyre (near Mariana and south of Hawaii islands), a conspicuous seasonality appears to be the rule in the other 4 gyres and affects both [Chl] and CDOM; both quantities vary in a ratio of about 2 (maximum-to-minimum). Coinciding [Chl] and CDOM peaks occur just after the local winter solstice, which is also the period of the maximal mixed layer depth in these latitudes. It is hypothesized that the vertical transport of unbleached CDOM from the subthermocline layers is the main process enhancing the CDOM concentration within the upper layer in winter. In summer, the CDOM experiences its minimum which is delayed with respect to the [Chl] minimum; apparently, the solar photo-bleaching of CDOM is a slower process than the post-bloom algal Chl decay. Where they exist, the seasonal cycles are repeated without notable change from year to year; long term (10 years) trends have not been detected in these zones. These oligotrophic gyres can conveniently be used for in-flight calibration and comparison of ocean color sensors, provided that their marked seasonal variations are accounted for.

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