• Energy Research

AbstractMost studies of the northern hemisphere carbon cycle based on atmospheric CO2concentration have focused on spring and autumn, but the climate change impact on summer carbon cycle remains unclear. Here we used atmospheric CO2record from Point Barrow (Alaska) to show that summer CO2drawdown between July and August, a proxy of summer carbon uptake, is significantly negatively correlated with terrestrial temperature north of 50°N interannually during 1979–2012. However, a refined analysis at the decadal scale reveals strong differences between the earlier (1979–1995) and later (1996–2012) periods, with the significant negative correlation only in the later period. This emerging negative temperature response is due to the disappearance of the positive temperature response of summer vegetation activities that prevailed in the earlier period. Our finding, together with the reported weakening temperature control on spring carbon uptake, suggests a diminished positive effect of warming on high-latitude carbon uptake.

In this study, through the method of rapid controlled precipitation (RCP), the influence of temperature and dissolved CO2 on the scaling capacity of mineral water in the presence of copper and zinc ions was studied in laboratory experiments. The results indicated that with a rise in temperature or concentration of dissolved CO2, the scaling time of Salvetat water greatly decreased and the rate of precipitation considerably increased; therefore, the minimum dosage of copper or zinc ion for achieving total inhibition of scaling needed to be increased, which would provide better guidance for practical use of metal ions in inhibiting the scaling of drinking water.