Decomposition of dissolved DMSP and DMS in estuanne waters: dependence on temperature and substrate concentration
Decomposition of dissolved DMSP and DMS in estuanne waters: dependence on temperature and substrate concentration
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DOI：
10.3354/meps076001
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发表时间：
1991
影响因子：
2.5
通讯作者：
R. Kiene
中科院分区：
文献类型：
--
作者：
R. Kiene
二甲基硫（DMS）是一种重要的微量气体，它是由海水排放到大气中的。DMS被认为主要来源于植物渗透剂3-（二甲基锍）丙酸盐（DMSP）。本研究探讨了溶解DMSP（DMSPDIS）的分解，从DMSPDIS的生产，和消费的DMS在河口沃茨附近的萨佩洛岛，格鲁吉亚，美国。在测试的浓度范围内（20至100 nM），DMSPd 1 Ss从海水中消失的速率与DMSPd 1 Ss的浓度成正比，并且是温度的函数;速率在4 ℃时非常低，在16、23和30 ℃时逐渐增加。在49°C下，DMSPd 2代谢的速率显著降低。从DMSPDi产生DMS显示出类似的浓度和温度依赖性。然而，在暗孵育期间总DMSP的质量平衡表明，在实验期间消耗的< 30 μ l/”的DMSP转化为DMS，即使当包括氯仿（500 μ M）以防止DMS消耗时。氯仿不影响DMSP分解或从该化合物产生DMS。因此，我们的结论是，DMS是不是DMSP代谢的主要硫产品在河口沃茨。DMSP代谢的替代途径，可能涉及去甲基化，建议。DMS的消耗速率直接取决于DMS浓度和孵育温度。氯仿（500 μ M）和叠氮化物（0.25%）对DMS代谢有强烈的抑制作用.结果表明，二甲基硫醚的生产和消费可能是密切相关的天然海水，因为这两个过程显示出类似的浓度和温度依赖性。参与二甲基硫醚生产和消费的酶系统的特性（动力学参数）可能在控制海水中二甲基硫醚的浓度方面发挥重要作用。
Dimethylsulfide (DMS) is an important trace gas which is emitted from seawater to the atmosphere. DMS is believed to be derived primarily from the plant osmolyte 3-(dimethylsulfonium)propionate (DMSP). This study examined the decomposition of dissolved DMSP (DMSPdiss), the production of DMS from DMSPdiss, and the consumption of DMS in estuarine waters near Sapelo Island, Georgia, USA. Rate of DMSPdiSs disappearance from seawater was directly proportional to the concentration of DMSPd,,,, over the range of concentrations tested (20 to 100 nM), and was a function of temperature; rates were very low at 4 "C and increased progressively at 16, 23 and 30 "C. At 49°C the rate of DMSPdi,, metabolism was substantially lower. The production of DMS from DMSPdi,, displayed similar concentration and temperature dependence. However, a mass balance of total DMSP during dark incubations indicated that < 30 'I/" of the DMSP consumed during the experiments was converted to DMS, even when chloroform (500 1tM) was included to prevent DMS consumption. Chloroform did not affect DMSP decomposition or DMS production from this compound. Thus, we conclude that DMS is not the major sulfur product of DMSP metabolism in estuarine waters. An alternative route for DMSP metabolism, possibly involving demethylation, is suggested. Rate of DMS consumption was directly dependent on DMS concentration and incubation temperature. DMS metabolism was strongly inhibited by chloroform (500 1tM) and azide (0.25 %). Results suggest that DMS production and consumption may be closely coupled in natural seawater since both these processes displayed similar concentration and temperature dependence. The characteristics (kinetic parameters) of the enzyme systems involved in DMS production and consumption are likely to play a major role in controlling the concentration of DIMS in seawater.