Dissolved oxygen and carbonate system in a southern nearshore marine aquaculture area in the North Yellow Sea in May, June, July, August and September 2017

Around the North Yellow Sea, Liaoning and Shandong Provinces in China are involved in fast-developing and highly populated marine aquacultural activities. For example, its southern nearshore waters are occupied by an important mariculture area in Shandong, where the water depth is only 10−21 m. Sea cucumbers <i>Apostichopus japonicus</i>, and scallops <i>Chlamys Farreri</i>, are cultured in this area where summertime hypoxia and pH decline have been observed in 2015 and 2016.<br>From May to September, five southern nearshore surveys (monthly from May to September) were carried out in the North Yellow Sea in 2017. During the nearshore surveys, discrete water samples were collected using a 5-L Niskin bottle at the surface (2 m below sea surface) and 2 m above the seafloor, while depth profiles of temperature and salinity (practical salinity scale of 1978) were determined using a calibrated RBR profiler (RBR Ltd., Canada). <br>Sampling surveys were supported by the Yantai Institute of Coastal Zone Research, the Chinese Academy of Sciences, via the Strategic Priority Research Program of the Chinese Academy of Sciences (grant no. XDA11020702).<br>