Stronger impact of dispersant plus crude oil on natural plankton assemblages inshort-term marine mesocosms
Year of Publication
Jung WS, Kwon YO, Joo KC, Kang JH, Kim M, Shim JW, Kim YO
Journal of Hazardous Materials
mesocosm, Crude oil, Dispersant, Planktonic communities, Total petroleum hydrocarbon, Geoje island, Korea, 1 m3
To assess the effects of crude oil and dispersant on marine planktonic ecosystems, analyses were performedin 1000-L mesocosm over a period of nine days. Triplicate experiments were conducted for twodifferent treatments, namely, addition of crude oil alone and oil plus dispersant. In the mesocosm with oilplus dispersant, high concentrations of total petroleum hydrocarbon (TPH) were soon found in the bottomlayer. In addition, most planktonic communities responded drastically to the presence of dispersantacting to disperse TPH: total bacterial abundances increased for the first two days and then decreasedrapidly for the remainder of the experiment. The abundance of heterotrophic flagellates increased rapidlyin association with the increase in bacterial cells. The abundance of phytoplankton and zooplanktoncommunities decreased clearly within two days. Time-delayed relationship also revealed that the TPHconcentration had a significant negative relationship with phyto- and zooplankton communities withintwo days. However, most planktonic communities were affected less adversely in the mesocosms treatedwith crude oil alone than in those treated with both crude oil and dispersant. The present results demonstratethat the planktonic ecosystem was damaged more severely by the introduction of dispersant thanby the harmful effects of crude oil itself. Therefore, caution should be taken when considering the directapplication of dispersant in natural environments, even though it has the advantage of rapidly removingcrude oil.
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