Abstract
The Northeast Pacific coastal ocean, as a typical river-influenced coastal upwelling system, is characterized by significant variability of sea surface partial pressure of carbon dioxide (pCO2, 1000 μatm). This study reviewed the pCO2 variability and its underlying controlling mechanism in this highly dynamic region by bringing together previous scientific findings and historical data. The large pCO2 variability reflects the complex interactions between physical processes (riverine input and coastal upwelling) and the biological responses to the nutrient transportation associated with these physical processes, while temperature and air-sea gas exchange play a minor role in affecting pCO2. Both the river water and upwelled subsurface water are characterized by higher concentrations of pCO2 and nutrients when compared to the coastal surface water. The presence of high chlorophyll-a and low pCO2 in river plumes and areas adjacent to upwelling locations showed the intense biological CO2 uptake. The influences of riverine input and coastal upwelling thus mainly depend on the competing effect of high background pCO2 of river water and upwelled subsurface water vs. the biological dropdown of pCO2 resulting from the riverine- and upwelling-associated nutrient supplies. The strength of upwelling-favorable wind plays an important role in the pCO2 variability by affecting the intensity of coastal upwelling, with stronger wind speed causing more intense upwelling. The long-term pCO2 increasing rate in the Northeast Pacific coast is observed to be lower than that in the North Pacific open ocean.
Highlights
Since the industrial revolution, the carbon dioxide (CO2) in the atmosphere has increased from 280 ppm to the present level of 415 ppm (January 2021) due to anthropogenic activities (Keeling et al, 2004; Takahashi et al, 2009; IPCC, 2013; Takahashi et al, 2014)
This study reviewed the pCO2 variability and its underlying controlling mechanism in this highly dynamic region by bringing together previous scientific findings and historical data
The large pCO2 variability reflects the complex interactions between physical processes and the biological responses to the nutrient transportation associated with these physical processes, while temperature and air-sea gas exchange play a minor role in affecting pCO2
Summary
The carbon dioxide (CO2) in the atmosphere has increased from 280 ppm to the present level of 415 ppm (January 2021) due to anthropogenic activities (Keeling et al, 2004; Takahashi et al, 2009; IPCC, 2013; Takahashi et al, 2014). The surface ocean pCO2 variability is strongly influenced by changes in temperature (Takahashi et al, 2006; Bates, 2007; Takahashi et al, 2009; Rödenbeck et al, 2013; Sutton et al, 2017), physical processes (Friederich et al, 2002; Hales et al, 2005; Fiechter et al, 2014) and biological activities (Thomas et al, 2005; Zhai et al, 2005; Yoshikawa Inoue et al, 2017). Estimates based on available data showed that the coastal ocean could either act as a sink (DeGrandpre et al, 2002; Hales et al, 2005; Borges et al, 2006; Chen and Borges, 2009; Hales et al, 2012; Jiang et al, 2013; Turi et al, 2014; Evans et al, 2019; Jiménez-López et al, 2019) or source (Friederich et al, 2002; Borges et al, 2005; Wang et al, 2005; Xue et al, 2012; Robbins et al, 2018; Li et al, 2020) for atmospheric CO2 depending on the dominant controlling mechanism of sea surface pCO2 in a specific system
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
