Effects of temperature on biogenic sulfur production of Ulva prolifera during the decline period

Abstract

In order to study the characteristics of the release of biogenic sulfur of Ulva prolifera, laboratory simulations were conducted on the Ulva prolifera collected in the middle and late green tides of the Yellow Sea. The effects of different temperatures on the release of biogenic sulfides from Ulva prolifera were investigated. The results are as follows:under the condition of 10-25℃, the increase of temperature can promote the decline of Ulva prolifera. The average release rate of DMS ranged from 2.79-150.70 nmol/(L·g·d), the average release rate of DMSP ranged from 2.16-113.26 nmol/(L·g·d). On the other hand, the high temperature can accelerate the releasing rates of dimethysulfide (DMS) and dimethylsulfonionpropionate (DMSP), and increase the releasing amount. The maximum average release rate of DMS is increased by about 60% at 25℃ compared with 10℃, and the concentration of DMS in culture fluid is increased by 2-3 times. The concentration of DMS and DMSP collected in the culture fluid of Ulva prolifera at the end of green tide was increased compared with that of Ulva prolifera taken during the mid-green tide. The highest concentration of DMS in the culture fluid at the end of green tide of Ulva prolifera was 418.41 nmol/L, which was about 4 times of that in the middle period. The highest concentration of DMS in DMSP was 316.14 nmol/L, which was 3 times of the middle period. The outbreak of the green tide of the Enteromorpha will affect the circulation of the sulfur system in the water body and thus affect the ecological environment of the sea area.