Spatial and temporal distribution of nutrient in Jiaozhou bay in 2013

Spatial and temporal distributions of dissolved inorganic nutrients in the Jiaozhou bay were discussed, based on the data collected monthly from November 2012 to November 2013.NO₃-N is the predominantspeciation of DIN, while NO₂-N is the lowest speciation.Influenced by the terrestrial input, the concentration of dissolved inorganic nutrients inside Jiaozhou bay is higher than that of outside.Concentrations of different dissolved inorganic nutrients displayed obviously seasonal variability inside the Jiaozhou bay.Highest concentrations of dissolved inorganic nutrients were in summer (July), and the lowest were in winter and spring.No obviously seasonal variabilityof dissolved inorganic nutrients were found in the middle and outside of the bay due to the influence of terrestrial input is not as strong as that inside the bay.Compared with 1990s, the concentrations of NH₄-N and PO₄-P decreased, while the concentrations of NO₃-N and SiO₃-Si increased totwice of those in 1990s'.The concentration of NO₂-N wasrelatively stable.