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The air–sea exchange of carbon dioxide (CO2) on a global scale is a key factor in understanding climate change and predicting its effects. The magnitude of sea spray’s contribution to this flux is currently highly uncertain. Constraining CO2’s diffusion in sea spray droplets is important for reducing error margins in global estimates of oceanic CO2 uptake and release. The timescale for CO2 gas diffusion within sea spray is known to be shorter than the timescales for the droplets’ physical changes to take place while aloft. However, the rate of aqueous carbonate reactions relative to these timescales has not been assessed. This study investigates the timescales of droplet physical changes to those of chemical transformations across the H2CO3/HCO3−/CO32− sequence. We found that physical timescales are rate limiting and that evaporation drives carbonate species into gaseous CO2, promoting the production and evasion of CO2 from sea spray droplets. This has important implications for carbon cycling and feedback in the surface ocean. 

The data provided here are from cruise SKQ2021-08S onboard the R/V Sikuliaq from May 21-June11, 2021 in the Bering and Chukchi Seas. The objective of the study was to evaluate the spatiotemporal dynamics of the carbon dioxide seawater system in the Pacific Arctic during the time of active sea ice retreat. This dataset includes discrete water column data for dissolved inorganic carbon and spectrophotometric pH on the total scale (measured at 25 degrees Celsius) along with nutrients, dissolved organic carbon, and in-situ hydrographic parameters. The outputs from carbonate system calculations (e.g., aragonite saturation state, in-situ pH) are also included. The dataset also includes continuous surface partial pressure of carbon dioxide (pCO2) data in both ppm and uatm measured at 15 minute intervals. 

This is the raw data collected in the Bering and Chukchi Seas that support our publication in Nature Communications - Earth and Environment 2022. The Arctic Ocean is experiencing a net loss of sea ice. Ice-free Septembers are predicted by 2050 with intensified seasonal melt and freshening. Accurate CO2 uptake estimates rely on meticulous assessments of carbonate parameters including total alkalinity. The third largest contributor to oceanic alkalinity is boron (as borate ions). Boron has been shown to be conservative in open ocean systems, and the boron to salinity ratio (boron/salinity) is therefore used to account for boron alkalinity in lieu of in situ boron measurements. Here we provide this ratio in the marginal ice zone of the Bering and Chukchi seas during late spring of 2021. We found considerable variation in born/salinity values in ice cores and brine, representing either excesses or deficits of boron relative to salinity. This variability should be considered when accounting for borate contributions to total alkalinity (up to 10 µmol kg-1) in low salinity melt regions. 

Abstract The Arctic Ocean is experiencing a net loss of sea ice. Ice-free Septembers are predicted by 2050 with intensified seasonal melt and freshening. Accurate carbon dioxide uptake estimates rely on meticulous assessments of carbonate parameters including total alkalinity. The third largest contributor to oceanic alkalinity is boron (as borate ions). Boron has been shown to be conservative in open ocean systems, and the boron to salinity ratio (boron/salinity) is therefore used to account for boron alkalinity in lieu of in situ boron measurements. Here we report this ratio in the marginal ice zone of the Bering and Chukchi seas during late spring of 2021. We find considerable variation in born/salinity values in ice cores and brine, representing either excesses or deficits of boron relative to salinity. This variability should be considered when accounting for borate contributions to total alkalinity (up to 10 µmol kg⁻¹) in low salinity melt regions. 

The United States Department of Energy (DOE)’s Ocean Margins Program (OMP) cruise EN279 in March 1996 provides an important baseline for assessing long-term changes in the carbon cycle and biogeochemistry in the Mid-Atlantic Bight (MAB) as climate and anthropogenic changes have been substantial in this region over the past two decades. The distributions of O 2 , nutrients, and marine inorganic carbon system parameters are influenced by coastal currents, temperature gradients, and biological production and respiration. On the cross-shelf direction, pH decreases seaward, but carbonate saturation state (Ω Arag ) does not exhibit a clear trend. In contrast, Ω Arag increases from north to south, while pH has no clear spatial patterns in the along-shelf direction. In order to distinguish between the effects of physical mixing of various water masses and those of biological activities on the marine inorganic carbon system, we use the potential temperature-salinity diagram to identify water masses, and differences between observations and theoretical mixing concentrations to measure the non-conservative (primarily biological) effects. Our analysis clearly shows the degree to which ocean margin pH and Ω Arag are regulated by biological activities in addition to water mass mixing, gas exchange, and temperature. The correlations among anomalies in dissolved inorganic carbon, phosphate, nitrate, and apparent oxygen utilization agree with known biological stoichiometry. Biological uptake is substantial in nearshore waters and in shelf-slope mixing areas. This work provides valuable baseline information to assess the more recent changes in the marine inorganic carbon system and the status of coastal ocean acidification.