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温度和光照强度对海藻场瓦氏马尾藻碎屑分解的影响

邹敏,章守宇*,周曦杰   

  1. (上海海洋大学海洋科学学院, 上海 201306)
  • 出版日期:2017-02-10 发布日期:2017-02-10

The influence of temperature and light intensity on Sargassum vachellianum detritus decomposition.

ZOU Min, ZHANG Shou-yu*, ZHOU Xi-jie   

  1. (College of Marine Science and Technology, Shanghai Ocean University, Shanghai 201306, China).
  • Online:2017-02-10 Published:2017-02-10

摘要: 通过气候培养箱在室内模拟不同光照强度及温度条件,测定海藻场瓦氏马尾藻碎屑(简称海藻碎屑)分解速率变化及海藻碎屑对海藻场海域无机营养盐贡献度,旨在为探究大型海藻碎屑的生态服务效能提供科学依据。结果表明:海藻碎屑剩余物质干重和分解速率受温度影响不显著(P>0.05),而光照强度影响显著(P<0.05);不同温度、光强条件下,海藻碎屑质量损失率在2个月的实验周期内皆大于60%,且温度25.15 ℃、光强3200 lx条件更有利于海藻碎屑分解;温度对海藻碎屑分解释放氮磷营养盐影响不显著(P>0.05);在同一温度(25.15 ℃)条件下,有无光照条件对水体铵态氮、硝态氮和亚硝态氮营养盐浓度变化影响不显著(P>0.05),但对正磷酸盐浓度影响显著(P<0.05);光照强度对水体内铵态氮和正磷酸盐浓度变化具有显著影响(P<0.05),对硝态氮和亚硝态氮浓度变化影响不显著(P>0.05);根据海藻场瓦氏马尾藻碎屑量估算出对现场海域水体溶解无机氮累积贡献量为4.597~17.321 mg·L-1,溶解无机磷累积贡献27.989~76.304 mg·L-1。研究表明,不同温度条件下,瓦氏马尾藻碎屑分解释放铵态氮和正磷酸盐的量大于硝态氮和亚硝态氮,温度越高越利于铵态氮释放,而正磷酸盐则更利于在低温下分解释放;随光照强度的升高,氮磷营养盐释放趋势相反,正磷酸盐释放量随光照强度增大而受到抑制。

Abstract: In this paper, light intensity and temperature gradients were simulated in a climate incubator, to measure the decomposition rate of Sargassum vachellianum detritus and the contribution of seaweed detritus to inorganic nutrients in seaweed field. The purpose of this study was to provide scientific support for exploring the ecological service effectiveness of large seaweed detritus. The results showed that temperature had no significant effect on mass remaining and the decomposition rate of seaweed detritus (P>0.05); however, the effect of light intensity was significant (P<0.05). The mass loss rate of seaweed detritus was over 60% under different temperature and light intensity conditions in twomonth experimental period, and seaweed detritus decomposed faster under conditions of 25.15 ℃ and 3200 lx. Temperature had no significant effect on the release of nitrogen and phosphorus nutrients during seaweed detritus decomposition (P>0.05). Light had no significant effect on the concentrations of ammonium, nitrate and nitrite under the same temperature (25.15 ℃) (P>0.05), but had a significant effect on the concentration of orthophosphate (P<0.05). Light intensity had a significant effect on the concentrations of ammonium nitrogen and orthophosphate (P<0.05), and had no significant effect on nitrate and nitrite nitrogen concentrations (P>0.05). The cumulative contribution of dissolved inorganic nitrogen to waters was 4.597 to 17.321 mg·L-1 and the dissolved inorganic phosphorus was 27.989 to 76.304 mg·L-1 according to the amount of S. vachellianum detritus in study field. In conclusion, the amount of ammonium nitrogen and orthophosphate released from S. vachellianum detritus decomposition was higher than that of nitrate nitrogen and nitrite nitrogen under different temperature conditions. Higher temperature was more favorable for ammonium nitrogen release, while orthophosphate release was more favorable at low temperature. The release of nitrogen and phosphorus nutrients declined with the increase of light intensity, and the release of orthophosphate was inhibited with the increase of light intensity.