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

Abstract

Environmental contextBlooms 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. AbstractThe 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 °C to 25 °C, the mean concentrations of dimethylsulfide (DMS), dissolved dimethylsulfoniopropionate (DMSPd) and particulate dimethylsulfoniopropionate (DMSPp) in the culture medium decreased by ~20 %, 55 % and 20 % respectively; in addition, these values increased by ~40 %, 70 % and 240 % respectively when exogenous nutrients were added to the culture medium. Moreover, a high concentration of nitrate (NO3–) (>50 μM) 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.