scholarly journals Dissolved Organic Matter Dynamics in the Epipelagic Northwest Pacific Low‐Latitude Western Boundary Current System: Insights From Optical Analyses

2021 ◽  
Vol 126 (9) ◽  
Author(s):  
Chao Wang ◽  
Yizhen Li ◽  
Yan Li ◽  
Hui Zhou ◽  
Aron Stubbins ◽  
...  
2017 ◽  
Vol 44 (20) ◽  
pp. 10,530-10,539 ◽  
Author(s):  
Zhiyu Liu ◽  
Qiang Lian ◽  
Fangtao Zhang ◽  
Lei Wang ◽  
Mingming Li ◽  
...  

2019 ◽  
Vol 12 (7) ◽  
pp. 3329-3355 ◽  
Author(s):  
Franziska U. Schwarzkopf ◽  
Arne Biastoch ◽  
Claus W. Böning ◽  
Jérôme Chanut ◽  
Jonathan V. Durgadoo ◽  
...  

Abstract. The Agulhas Current, the western boundary current of the South Indian Ocean, has been shown to play an important role in the connectivity between the Indian and Atlantic oceans. The greater Agulhas Current system is highly dominated by mesoscale dynamics. To investigate their influence on the regional and global circulations, a family of high-resolution ocean general circulation model configurations based on the NEMO code has been developed. Horizontal resolution refinement is achieved by embedding “nests” covering the South Atlantic and the western Indian oceans at 1/10∘ (INALT10) and 1/20∘ (INALT20) within global hosts with coarser resolutions. Nests and hosts are connected through two-way interaction, allowing the nests not only to receive boundary conditions from their respective host but also to feed back the impact of regional dynamics onto the global ocean. A double-nested configuration at 1/60∘ resolution (INALT60) has been developed to gain insights into submesoscale processes within the Agulhas Current system. Large-scale measures such as the Drake Passage transport and the strength of the Atlantic meridional overturning circulation are rather robust among the different configurations, indicating the important role of the hosts in providing a consistent embedment of the regionally refined grids into the global circulation. The dynamics of the Agulhas Current system strongly depend on the representation of mesoscale processes. Both the southward-flowing Agulhas Current and the northward-flowing Agulhas Undercurrent increase in strength with increasing resolution towards more realistic values, which suggests the importance of improving mesoscale dynamics as well as bathymetric slopes along this narrow western boundary current regime. The exploration of numerical choices such as lateral boundary conditions and details of the implementation of surface wind stress forcing demonstrates the range of solutions within any given configuration.


2009 ◽  
Vol 29 (2) ◽  
pp. 154-158 ◽  
Author(s):  
Alexandre M. Fernandes ◽  
Ilson C.A. da Silveira ◽  
Leandro Calado ◽  
Edmo J.D. Campos ◽  
Afonso M. Paiva

Ocean Science ◽  
2017 ◽  
Vol 13 (2) ◽  
pp. 209-222 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Till Jens Jörg Hanebuth ◽  
Renata Hanae Nagai ◽  
Marcia Caruso Bícego ◽  
Rubens Cesar Lopes Figueira ◽  
...  

Abstract. In this study, we use inorganic (metal) and organic (bulk and molecular) markers in sediment samples of the south-eastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply.Metal contents and especially the ln(Ti ∕ Al) and ln(Fe ∕ K) ratios make it possible to recognise the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K ∕ Sc) and ln(K ∕ Al) ratios used as proxies of illite–kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.


2016 ◽  
Author(s):  
Michel Michaelovitch de Mahiques ◽  
Till Jens Jörg Hanebuth ◽  
Renata Hanae Nagai ◽  
Marcia Caruso Bícego ◽  
Rubens Cesar Lopes Figueira ◽  
...  

Abstract. In this study, we use inorganic (metals) and organic (bulk and molecular) markers in sediment samples of the southeastern Brazilian margin to investigate the response of geochemical fingerprints to the complex hydrodynamic processes present in the area. Results indicate the potential of export of terrigenous siliciclastic and organic constituents to the upper slope, even in an area with limited fluvial supply. Metal contents and especially the ln(Ti/Al) and ln(Fe/K) ratios make it possible to recognize the extension of shelf sediments toward the upper slope. Potassium, here expressed as ln(K/Sc) and ln(K/Al) ratios used as proxies of illite–kaolinite variations, proved to be an important parameter, especially because it allowed us to decipher the imprint of the northward flow of the Intermediate Western Boundary Current (IWBC) in comparison to the southward flows of the Brazil Current (BC) and Deep Western Boundary Current (DWBC). Using organic matter analyses, we were able to evaluate the extent of terrestrial contributions to the outer shelf and slope, even without the presence of significant fluvial input. In addition, molecular markers signify a slight increase in the input of C4-derived plants to the slope sediments, transported from distant areas by the main alongshore boundary currents, indicating that the terrestrial fraction of the organic matter deposited on the slope has a distinct origin when compared to shelf sediments.


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