Variations in Seawater pCO2 Associated With Vertical Mixing During Tropical Cyclone Season in the Northwestern Subtropical Pacific Ocean

Abstract

This study examines interannual variations in the seawater CO2 partial pressure (pCO2) for months (August–October) with frequent tropical cyclone (TC) events in the northwestern subtropical Pacific Ocean (22°N–28°N, 135°E–145°E) between 2007 and 2017. The temperature-normalized pCO2 averaged over August–October showed a year-to-year variation ranging from 346 to 359 μatm over the 11 study years, which appeared to be related to the variation in vertical mixing that likely results from the TC activity in these months. Sea surface temperature and wind data consistently supported the association between mixing and TC intensity. Nonetheless, the pCO2 reduction caused by negative sea-surface temperature anomalies found over the TC season (July–October) shifted the study area from a CO2 source to a CO2 sink over these months. In the south (17°N–22°N) of the study area, mixing-driven variations in pCO2 were smaller during the same months, which appeared to be caused by the relatively deeper mixed layer depth and the more homogenous profile of CO2 in this tropical region. These results suggest that more extensive pCO2 measurements are required to fully resolve the effect of TCs on the carbonate system from the regional- to the basin-scale in the western Pacific Ocean, where TC intensity is expected to increase in the future.

Contrasting projections of the ENSO-driven CO2flux variability in the equatorial Pacific under high-warming scenario

“…This decomposition is well known and extensively used at regional and global scale (e.g. Landschützer et al, 2018;Jiménez-López et al, 2019;Ko et al, 2021).…”

Storm‐Driven pCO2 Feedback Weakens the Response of Air‐Sea CO2 Fluxes in the Sub‐Antarctic Southern Ocean

“…A possible explanation is that the increasing wind stress generated deep mixing, deepening the MLD (up to ∼50 m day −1 , Figure 2b) and possibly entraining DIC into the surface mixed layer (as observed in Ko et al. (2021) and Nicholson et al. (2022)).…”

“…During W1 to W6, the pCO 2sea showed a small increase and consequent decrease (±5-22 μatm) with the synoptic wind stress cycle. A possible explanation is that the increasing wind stress generated deep mixing, deepening the MLD (up to ∼50 m day 1 , Figure 2b) and possibly entraining DIC into the surface mixed layer (as observed in Ko et al (2021) and Nicholson et al (2022)). As the wind stress decreases post-storm, in situations where wind stress remained low for a long period of time (e.g., between W3 and W4) the mixed layer re-stratified (N 2 > 0.1 × e 4 s 1 at 130-150 m) and the MLD shoaled (∼24 m day 1 , Figure 2b) until the next storm and the cycle repeats itself.…”

Integrated organismal responses induced by ecologically-relevantpCO2and temperature exposures in developing lake sturgeon

“…Variability of pCO 2 in flowing freshwater over time can be more than an order of magnitude greater than in marine systems 11,17,[44][45][46] . While researchers may expect adaptations to CO 2 flucuations in freshwater organisms 2,3,7 , this variability has nevertheless been shown to induce physiological responses in the lake sturgeon and other species 1 .…”