Influence of 19-3 Oil Spill Accident on Phytoplankton Community in the Liaodong Bay

Abstract:

In this study we investigated the changes and contributing factors of species composition, cell abundance, biological diversity and dominant species of phytoplankton community in the Liaodong Bay, with emphasis on their correlation with the 19-3 oil spill accident in Penglai. Our analysis was based on the field data about phytoplankton community collected in the Liaodong Bay in May (Spring), August (Summer) and October (Autumn) from 2012 to 2014. It was found the number of phytoplankton species was the lowest in May 2012, and the highest in October 2013. Overall the number in 2012 was lower than those in 2013 and 2014. The cell abundance of the phytoplankton community rose unexpectedly in all three summer seasons. The maximum reached 3072×104 ind/m3 in August 2012, and the minimum (27×104 ind/m3) appeared in May 2012. The dominant species in different seasons were nearly unchanged between 2012 and 2014. The dominant species in May were Paralia sulcata, Chaetoceros, Noctiluca scintillans, and it was Skeletonema costatum in August. In October Coscinodiscus, P. sulcata, and Chaetoceros gained the dominance. Interestingly, S. costatum, a dominant microalga, underwent explosive reproduction in August 2012, which might be associated with the increased oil concentration in surface seawater in the Liaodong Bay. Correlation analysis was performed to explore the links between the environmental factors and parameters such as species composition, cell abundance, and biological diversity index. The results indicated that the alteration in phytoplankton community structure was significantly correlated with water temperature, COD, dissolved oxygen and nutrients. Furthermore, the community structure was also strongly affected by the oil concentration in surface seawater.