Premium
Interannual‐to‐Decadal Variations of Particulate Organic Carbon and the Contribution of Phytoplankton in the Tropical Pacific During 1981–2016: A Model Study
Author(s) -
Yu Jun,
Wang Xiujun,
Murtugudde Raghu,
Tian Feng,
Zhang RongHua
Publication year - 2021
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2020jc016515
Subject(s) - environmental science , phytoplankton , pacific decadal oscillation , oceanography , climatology , carbon cycle , forcing (mathematics) , sea surface temperature , atmospheric sciences , ecosystem , geology , nutrient , ecology , biology
The tropical Pacific plays an important role in the global carbon cycle. However, little is known on the large‐scale variability of particulate organic carbon (POC) and the contribution of phytoplankton carbon (PhyC) in this region. Here, we used a basin‐scale model to study the spatio‐temporal variability of POC and PhyC contribution over 1981–2016 in the tropical Pacific. The model reproduces the spatial and temporal variability of the observed POC in this region. Both satellite and modeled POC show a clear west‐to‐east increase (from 40 to 60 mg m −3 ) in the equatorial Pacific. The contribution of PhyC to POC is greater in the iron‐limited eastern region (∼30%) than in the nitrogen‐limited western region (∼20%). There are strong interannual variabilities in both POC and the contribution of PhyC to POC, which are largely associated with the El Niño–Southern Oscillation (ENSO) events. POC stock and downward flux show significant increases (10%–20%) in the frontal region (near the dateline) but smaller changes in the eastern equatorial Pacific post‐1998, due to the Pacific Decadal Oscillation (PDO) regime shift. There were significant increases (∼5–10% to the west and ∼5% to the east) in the transfer efficiency of POC across the basin during 1999–2014 due to the PDO regime shift. This study highlights the impacts of iron and nitrogen co‐limitations on phytoplankton dynamics and physical forcing on the carbon cycle of the tropical Pacific, with implications for the global carbon cycle.