Effects of temperature and nutrients on the emissions of biogenic volatile sulfur compounds from Ulva prolifera during the bloom decline period

Environmental context Blooms of Ulva prolifera have recurred annually in the Yellow Sea since 2007, causing economic losses and severe ecological problems. We conducted laboratory incubation experiments to examine the effects of temperature and nutrients on its biogenic sulfur emissions during its decline period. Increasing temperature and nutrients affected the decay of U. prolifera, resulting in respective decreased and increased emission of biogenic sulfur compounds. The Ulva prolifera blooms have recurred annually in the Yellow Sea (YS) since 2007, causing huge economic losses and severe ecological problems. So far, few studies have investigated the release of volatile biogenic sulfur compounds by the U. prolifera blooms. In this study, laboratory incubation experiments were conducted to examine the effects of temperature and nutrient concentrations on the emissions of biogenic sulfur compounds during the green tide decline period. Under simulated conditions, higher incubation temperatures and nutrient concentrations promoted the decay of U. prolifera. When the incubation temperature was increased from 20 degrees C to 25 degrees C, the mean concentrations of dimethylsulfide (DMS), dissolved dimethylsulfoniopropionate (DMSPd) and particulate dimethylsulfoniopropionate (DMSPp) in the culture medium decreased by similar to 20 %, 55 % and 20 % respectively; in addition, these values increased by similar to 40 %, 70 % and 240 % respectively when exogenous nutrients were added to the culture medium. Moreover, a high concentration of nitrate (NO3-) (>50 mu M) could promote the release of biogenic sulfur by U. prolifera in the absence of other nutrients. The findings of this study provide insight into the roles of macroalgae on changes to the environment and shed light on the potential impact of DMSP and other degradation products of DMS produced by the green tide on the environment and ecosystem.

Automated summary

Blooms of Ulva prolifera have been recurring annually in the Yellow Sea since 2007, causing significant economic losses and severe ecological problems. Laboratory experiments showed that increased temperature and nutrient concentrations promoted the decay of U. prolifera, resulting in changes to the emission of biogenic sulfur compounds. These findings provide insights into the environmental impact of green tide and the potential consequences of sulfur compounds on the ecosystem.