| Mercury is a global pollutant. Mercury in sea existed with different species, itnot only affect bioavailability, but also affect mercury emission. The research onmercury species and emission flux in offshore in our country was be helpful to learnthe biogeochemical behavior of offshore mercury, especially the research on cycle ofregional mercury.In this paper, Mercury speciations in the Jiaozhou Bay were determined toanalyze the temporal and spatial distribution characteristics of mercury. Mercuryemission fluxes were determined with the method of dynamic flux box within oneyear in Jiaozhou Bay to study the season and daily change characteristics of mercuryemission.1. In space, the concentration of different speciations of mercury in JiaozhouBay was lower in the central, but was higher in the eastern and northern coastal area.The order of mercury speciations concentration in ocean surface was particlemercury> dissolve mercury. Particle mercury contents were6.2times higher thandissolve mercury contents. The Particle mercury was higer in the northern andnortheast, then in the eastern.Reactive mercury and dissolve mercury distributed consistently. Reactivemercury was higher than dissolve mercury, so there was relatively high bioavailabilityin Jiaozhou Bay. DEM concentration accounted for3.51%~28.4%of dissolvemercury, average for15.3%.2. In time, Reactive mercury and dissolve mercury appeared fluctuant, itsconcentration order was summer> spring> winter> autumn. Apart from autumn,reactive mercury contents in sea were limited by dissolve mercury. The variationtrends of RHg and DHg were consistent. DEM concentration of surface seawater inJiaozhou Bay in summer and autumn was higher than in spring and winter, itsconcentration order was autumn>summer>winter>spring. DEM contents in seawere affected by the reactive mercury/dissolve mercury obviously. Methylmercury content is very low. The order of methylmercury concentration was April2010<November2009<December2009. The variation trends of particle mercury appearedfluctuation, its concentration order was spring> autumn> summer> winter. Exceptthe summer, particle mercury of seawater of Jiaozhou Bay was mainspecie.3. In vertical profile, the variation trend of DHg was consistent in spring andsummer similar to RHg. Their concentration ranges were both small. Methylmercurycontent appeared maximum at different depth of the bottom, so the methylmercury atthe upper derived from the seawater at the bottom. The variation trends of particlemercury concentration both were consistent at12:00and16:00apart from December2009, July2010.4. Mercury emission fluxes of Jiaozhou Bay by dynamic flux box were:0.26ng/(m~2·h) in November2009,0.46ng/(m~2·h) in April2010,1.03ng/(m~2·h) in July2010,0.95ng/(m~2·h) in October2010. Mercury was emitted from sea to air in thedaytime of four seasons in the Jiaozhou Bay. Mercury emission fluxes appearedmaximum in the day, it was lower in the evening. Mercury exchange fluxes insummer and autumn were higher than that in spring and winter.5. Mercury emission fluxes of Jiaozhou Bay calculated by gaseous exchangemodel were: averaged for0.63ng/(m~2·h) in November2009,1.37ng/(m~2·h) inDecember2009,1.34ng/(m~2·h) in April2010,4.84ng/(m~2·h) in July2010,1.37ng/(m~2·h) in October2010. The mercury emission fluxes estimated by modelwere higher than determined by dynamic flux box. And the ratio of estimate value todetermination value in summer was higher than other seasons.6. Except for the effect of ship and Enteromorpha, tide was one of the mainfactors affecting the mercury exchange fluxes between sea-air interfaces in JiaozhouBay. In addition, the mercury emission fluxes of Jiaozhou Bay have a significantpositive correlation with temperature, water temperature. The mercury emissionfluxes of Jiaozhou Bay have a significant negative correlation with wind speed,mainly were influenced by atmosphere mercury which came from land source. |
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