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We found that significant errors occurred when diurnal data instead of diurnal–nocturnal data were used to calculate the daily sea-air CO2 flux (F). As the errors were mainly associated with the partial pressure of CO2 in seawater (pCO2w) and the sea surface temperature (SST) in the control experiment, pCO2w and SST equations were established, which are called the nocturnal effect of the CO2 flux. The root-mean-square error between the real daily CO2 flux (Freal) and the daily CO2 flux corrected for the nocturnal effect (Fcom) was 11.93 mmol m−2 d−1, which was significantly lower than that between the Freal value and the diurnal CO2 flux (Fday) (46.32 mmol m−2 d−1). Thus, the errors associated with using diurnal data to calculate the CO2 flux can be reduced by accounting for the nocturnal effect. The mean global daily CO2 flux estimated based on the nocturnal effect and the sub-regional pCO2w algorithm (cor_Fcom) was −6.86 mol m−2 y−1 (September 2020–August 2021), which was smaller by 0.75 mol m−2 y−1 than that based solely on the sub-regional pCO2w algorithm (day_Fcom). That is, compared with day_Fcom, the global cor_Fcom value overestimated the CO2 sink of the global ocean by 10.89%.

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Nutrient antagonism typically refers to the fact that too high a concentration of one nutrient inhibits the absorption of another nutrient. In plants, Ca 2+ (Calcium) and Mg 2+ (Magnesium) are the two most abundant divalent cations, which are known to have antagonistic interactions. Hence, maintaining their homeostasis is crucial for plant growth and development. In this study, we showed that MTP10 (Metal Tolerance Protein 10) is an important regulator for maintaining homeostasis of Mg and Ca in Arabidopsis. The mtp10 mutant displayed severe growth retardation in the presence of excess Mg 2+ , to which the addition of Ca 2+ was able to rescue the phenotype of mtp10 mutant. Additionally, the deficiency of Ca 2+ in the culture medium accelerated the high-Mg sensitivity of the mtp10 mutant. The yeast complementation assay suggested that AtMTP10 had no Ca 2+ transport activity. And the ICP-MS data further confirmed the antagonistic relationship between Ca 2+ and Mg 2+ , with the addition of Ca 2+ reducing the excessive accumulation of Mg 2+ and high-Mg inhibiting the uptake of Ca 2+ . We conclude that the Arabidopsis MTP10 is essential for the regulation of Mg and Ca homeostasis.

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Using data from the European remote sensing scatterometer (ERS-2) from July 1997 to August 1998, global distributions of the air-sea CO 2 transfer velocity and flux are retrieved. A new model of the air-sea CO 2 transfer velocity with surface wind speed and wave steepness is proposed. The wave steepness (δ) is retrieved using a neural network (NN) model from ERS-2 scatterometer data, while the wind speed is directly derived by the ERS-2 scatterometer. The new model agrees well with the formulations based on the wind speed and the variation in the wind speed dependent relationships presented in many previous studies can be explained by this proposed relation with variation in wave steepness effect. Seasonally global maps of gas transfer velocity and flux are shown on the basis of the new model and the seasonal variations of the transfer velocity and flux during the 1 a period. The global mean gas transfer velocity is 30 cm/h after area-weighting and Schmidt number correction and its accuracy remains calculation with in situ data. The highest transfer velocity occurs around 60 • N and 60 • S, while the lowest on the equator. The total air to sea CO 2 flux (calculated by carbon) in that year is 1.77 Pg. The strongest source of CO 2 is in the equatorial east Pacific Ocean, while the strongest sink is in the 68 • N. Full exploration of the uncertainty of this estimate awaits further data. An effectual method is provided to calculate the effect of waves on the determination of air-sea CO 2 transfer velocity and fluxes with ERS-2 scatterometer data.

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