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Data for continuous and discrete measurements of carbonate parameters in a productive coastal region in the Northwestern Pacific (36°09'13.5''N, 129°24'04.9''E) from January to September in 2019 and from March to December in 2020

Citation

Lee, Kitack; Kim, Ja-Myung (2022), Data for continuous and discrete measurements of carbonate parameters in a productive coastal region in the Northwestern Pacific (36°09'13.5''N, 129°24'04.9''E) from January to September in 2019 and from March to December in 2020, Dryad, Dataset, https://doi.org/10.5061/dryad.5qfttdz85

Abstract

Photosynthetic organisms shift the dynamics of surface pCO2 driven by the sea surface temperature change (thermodynamic driver) by assimilating C from seawater. Here we measured net C uptake in a macroalgal habitat of coastal Korea for two years (2019–2020) and found that the macroalgal habitat contributed 5.8 g C m-2 month-1 of the net C uptake during the growing period (the cooling period, September-May). This massive C uptake changed the thermodynamics-driven seasonal dynamics such that the air-sea equilibrium of pCO2 was pushed into disequilibrium. The surface pCO2 dynamics during the cooling period were mostly influenced by the seasonal decrease in temperature and the proliferation of macroalgae, while the dynamics during the warming period (the stagnant period, June-August) closely followed that predicted based solely on the change in sea surface temperature only (thermodynamic driver). In contrast to the phytoplankton-dominated offshore waters (where phytoplankton populations are large in spring and summer), the impact of coastal water macroalgae on surface pCO2 dynamics was most pronounced during the cooling period, when the magnitude of pCO2 change was as much as twice that resulting from temperature change. Our study shows that the distinctive features of the macroalgal habitat—in particular the seasonal temperature extremes (~18°C difference), the active macroalgal metabolism, and anthropogenic nutrient inputs—collectively influenced the seasonal decoupling of seawater and air pCO2 dynamics.

Methods

Continuous measurement

Surface-water pCO2 was continuously measured from January to September in 2019 and from March to December in 2020. The mooring system was anchored to the bottom of the macroalgal habitat (10 m depth), and the pCO2 sensor package was submerged approximately 0.5 m below the surface. Surface-water pCO2 (or pH), temperature and salinity were concurrently measured at 1-h intervals.

Discrete measurement

Discrete surface samples for seawater C parameters (pH, total alkalinity, and total dissolved inorganic carbon) and nutrients were measured at 3–4 d intervals.

Funding

Korea National Institute of Fisheries Science, Award: R2022056

Korea Fisheries Resources Agency