The Subsurface Water Masses in the Western South Pacific Ocean

1962 ◽  
Vol 13 (1) ◽  
pp. 18 ◽  
Author(s):  
K Wyrtki
Keyword(s):  
Pacific Ocean ◽  
Extreme Values ◽  
Core Layer ◽  
South Pacific ◽  
Water Masses ◽  
Water Salinity ◽  
Subsurface Water ◽  
Intermediate Water ◽  
South Pacific Ocean ◽  
Oxygen Minimum

An analysis is made of subsurface water masses in the subtropical western South Pacific Ocean, using temperature-salinity and temperature-oxygen relations. Seven major water masses, characterized by extreme values of salinity and oxygen, are distinguished. These are the Subtropical Lower Water (salinity maximum), the upper oxygen minimum, the Subantarctic Intermediate Water (oxygen maximum), the Antarctic Intermediate Water (salinity minimum and oxygen maximum), the deep oxygen minimum, the Deep Water (salinity maximum), and the Bottom Water. The core layer method is used to describe the distribution of the different water masses and to draw conclusions on their spreading.

scholarly journals Anthropogenic carbon in the eastern South Pacific Ocean

2007 ◽  
Vol 4 (3) ◽  
pp. 1815-1837 ◽  
Author(s):  
L. Azouzi ◽  
R. Gonçalves Ito ◽  
F. Touratier ◽  
C. Goyet
Keyword(s):  
Pacific Ocean ◽  
General Trend ◽  
South Pacific ◽  
Hydrodynamic Characteristics ◽  
Eastern Pacific Ocean ◽  
Previous Knowledge ◽  
Oxygen Minimum Zones ◽  
South Pacific Ocean ◽  
Anthropogenic Carbon ◽  
Oxygen Minimum

Abstract. We present results from the BIOSOPE cruise in the eastern South Pacific Ocean. In particular, we present estimates of the anthropogenic carbon CantTrOCA distribution in this area using the TrOCA method recently developed by Touratier and Goyet (2004a, b) and Touratier et al. (2007). We study the distribution of this anthropogenic carbon taking into account of the hydrodynamic characteristics of this region. We then compare these results with earlier estimates in nearby areas of the anthropogenic carbon as well as other anthropogenic tracer (CFC-11). The highest concentrations of CantTrOCA are located around 13° S 132° W and 32° S 91° W, and their concentrations are larger than 80 μmol kg−1 and 70 μmol kg−1, respectively. The lowest concentrations were observed below 800 m depths (≤2 μ mol kg−1) and at the Oxygen Minimum Zones (OMZ), mainly around 140° W (<11 μmol kg−1). The comparison with earlier work in nearby areas provides a general trend and indicates that the results presented here are in general agreement with previous knowledge. This work further improves our understanding on the penetration of anthropogenic carbon in the eastern Pacific Ocean.

scholarly journals N<sub>2</sub> fixation in eddies of the eastern tropical South Pacific Ocean

2016 ◽  
Vol 13 (10) ◽  
pp. 2889-2899 ◽  
Author(s):  
Carolin R. Löscher ◽  
Annie Bourbonnais ◽  
Julien Dekaezemacker ◽  
Chawalit N. Charoenpong ◽  
Mark A. Altabet ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
N2 Fixation ◽  
South Pacific ◽  
Open Ocean ◽  
Cyclonic Eddy ◽  
Geochemical Data ◽  
Intermediate Water ◽  
N Loss ◽  
Mode Water ◽  
South Pacific Ocean

Abstract. Mesoscale eddies play a major role in controlling ocean biogeochemistry. By impacting nutrient availability and water column ventilation, they are of critical importance for oceanic primary production. In the eastern tropical South Pacific Ocean off Peru, where a large and persistent oxygen-deficient zone is present, mesoscale processes have been reported to occur frequently. However, investigations into their biological activity are mostly based on model simulations, and direct measurements of carbon and dinitrogen (N2) fixation are scarce.We examined an open-ocean cyclonic eddy and two anticyclonic mode water eddies: a coastal one and an open-ocean one in the waters off Peru along a section at 16° S in austral summer 2012. Molecular data and bioassay incubations point towards a difference between the active diazotrophic communities present in the cyclonic eddy and the anticyclonic mode water eddies.In the cyclonic eddy, highest rates of N2 fixation were measured in surface waters but no N2 fixation signal was detected at intermediate water depths. In contrast, both anticyclonic mode water eddies showed pronounced maxima in N2 fixation below the euphotic zone as evidenced by rate measurements and geochemical data. N2 fixation and carbon (C) fixation were higher in the young coastal mode water eddy compared to the older offshore mode water eddy. A co-occurrence between N2 fixation and biogenic N2, an indicator for N loss, indicated a link between N loss and N2 fixation in the mode water eddies, which was not observed for the cyclonic eddy. The comparison of two consecutive surveys of the coastal mode water eddy in November 2012 and December 2012 also revealed a reduction in N2 and C fixation at intermediate depths along with a reduction in chlorophyll by half, mirroring an aging effect in this eddy. Our data indicate an important role for anticyclonic mode water eddies in stimulating N2 fixation and thus supplying N offshore.

scholarly journals Anthropogenic carbon distribution in the eastern South Pacific Ocean

2009 ◽  
Vol 6 (2) ◽  
pp. 149-156 ◽  
Author(s):  
C. Goyet ◽  
R. Ito Gonçalves ◽  
F. Touratier
Keyword(s):  
Pacific Ocean ◽  
South Pacific ◽  
Eastern Pacific ◽  
Eastern Pacific Ocean ◽  
Carbon Distribution ◽  
Carbonate System ◽  
South Pacific Ocean ◽  
Anthropogenic Carbon ◽  
Minimum Zone ◽  
Oxygen Minimum

Abstract. We present results of the CO2/carbonate system from the BIOSOPE cruise in the Eastern South Pacific Ocean, in an area not sampled previously. In particular, we present estimates of the anthropogenic carbon (C>TrOCAant) distribution in the upper 1000 m of this region using the TrOCA method. The highest concentrations of CTrOCAant found around 13° S, 132° W and 32° S, 91° W, are higher than 80 μmol.kg−1 and 70 μmol.kg−1, respectively. The lowest concentrations are observed below 800 m depth (≤2 μmol.kg−1) and within the Oxygen Minimum Zone (OMZ), mainly around 140° W (<11 μmol.kg−1). As a result of the anthropogenic carbon penetration there has been decrease in pH by over 0.1 on an average in the upper 200 m. This work further improves our understanding on the penetration of anthropogenic carbon in the Eastern Pacific Ocean.

Vertical and horizontal extension of the oxygen minimum zone in the eastern South Pacific Ocean

2009 ◽  
Vol 56 (16) ◽  
pp. 992-1003 ◽  
Author(s):  
Rosalino Fuenzalida ◽  
Wolfgang Schneider ◽  
José Garcés-Vargas ◽  
Luis Bravo ◽  
Carina Lange
Keyword(s):  
Pacific Ocean ◽  
South Pacific ◽  
Oxygen Minimum Zone ◽  
South Pacific Ocean ◽  
Minimum Zone ◽  
Oxygen Minimum

scholarly journals N<sub>2</sub> fixation in eddies of the eastern tropical South Pacific Ocean

2015 ◽  
Vol 12 (22) ◽  
pp. 18945-18972 ◽  
Author(s):  
C. R. Löscher ◽  
A. Bourbonnais ◽  
J. Dekaezemacker ◽  
C. N. Charoenpong ◽  
M. A. Altabet ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
N2 Fixation ◽  
South Pacific ◽  
Open Ocean ◽  
Cyclonic Eddy ◽  
Geochemical Data ◽  
Intermediate Water ◽  
N Loss ◽  
Mode Water ◽  
South Pacific Ocean

Abstract. Mesoscale eddies play a major role in controlling ocean biogeochemistry. By impacting nutrient availability and water column ventilation, they are of critical importance for oceanic primary production. In the eastern tropical South Pacific Ocean off Peru, where a large and persistent oxygen deficient zone is present, mesoscale processes have been reported to occur frequently. However, investigations on their biological activity are mostly based on model simulations, and direct measurements of carbon and dinitrogen (N2) fixation are scarce. We examined an open ocean cyclonic eddy and two anticyclonic mode water eddies: a coastal one and an open ocean one in the waters off Peru along a section at 16° S in austral summer 2012. Molecular data and bioassay incubations point towards a difference between the active diazotrophic communities present in the cyclonic eddy and the anticyclonic mode water eddies. In the cyclonic eddy, highest rates of N2 fixation were measured in surface waters but no N2 fixation signal was detected at intermediate water depths. In contrast, both anticyclonic mode water eddies showed pronounced maxima in N2 fixation below the euphotic zone as evidenced by rate measurements and geochemical data. N2 fixation and carbon (C) fixation were higher in the young coastal mode water eddy compared to the older offshore mode water eddy. A co-occurrence between N2 fixation and biogenic N2, an indicator for N loss, indicated a link between N loss and N2 fixation in the mode water eddies, which was not observed for the cyclonic eddy. The comparison of two consecutive surveys of the coastal mode water eddy in November and December 2012 revealed also a reduction of N2 and C fixation at intermediate depths along with a reduction in chlorophyll by half, mirroring an aging effect in this eddy. Our data indicate an important role for anticyclonic mode water eddies in stimulating N2 fixation and thus supplying N offshore.

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