Distribution and seasonal variation in the partial pressure of CO2 during autumn and winter in Jiaozhou Bay, a region of high urbanization

► In situ pCO2 in Jiaozhou Bay was reported for the first time. ► Biological and respiration accounted for the distribution of pCO2 in two seasons. ► Temperature and biological effect controlled the seasonal variation of pCO2. ► Increasing sewage input would strengthen the biogeochemical response.