Self-shading protects phytoplankton communities against H2O2-induced oxidative damage
Self-shading protects phytoplankton communities against H2O2-induced oxidative damage
复制标题
DOI：
10.3354/ame030275
复制
发表时间：
2003-01-23
影响因子：
1.4
通讯作者：
Snoeijs, P
中科院分区：
文献类型：
--
作者：
Barros, MP;Pedersén, M;Snoeijs, P
本研究的目的是调查是否浮游植物生长速度和生物量的增加是由更高的养分利用率引起的，从而通过减少有效光暴露（一种称为自遮阳的过程）来降低微藻的氧化应激。2001年6月在德国Zingst海洋站（波罗的海南部，8 - 9 psu）进行的6 d中观实验验证了这一假设。采用每日添加硝酸盐和磷酸盐（NP处理）和硝酸盐、磷酸盐和硅酸盐（NPSi处理）两种处理方法，对室外中生态系统进行处理。每天监测的氧化应激参数是海水中H2O2浓度和浮游植物中超氧化物歧化酶（SOD）活性、过氧化氢酶活性和脂质过氧化产物（硫代巴比妥酸活性物质，TBARS）的浓度。在整个实验过程中测量叶绿素a （chl a）浓度、pH和光合作用（O-2进化），以描述浮游植物的生理状态。我们的数据表明，营养饱和微藻的快速生长通过自遮光强烈地限制了氧化应激。营养处理的SOD和过氧化氢酶活性显著低于不添加营养的对照处理。两种营养处理（含或不含硅）之间没有差异，尽管富含硅藻的中胚乳（NPSi）的光合速率更高。我们的发现有助于更好地理解富营养化、藻华发生和微藻抗氧化活性之间的密切关系。
The aim of this study was to investigate whether increased phytoplankton growth rates and biomass caused by higher nutrient availability will result in lower oxidative stress in microalgae by reducing effective-light exposure, a process called self-shading. This hypothesis was tested by a 6 d mesocosm experiment carried out at the Zingst Marine Station, Germany (southern Baltic Sea, 8 to 9 psu) in June 2001. Out-door mesocosms filled with 1400 1 of natural seawater sieved through a 100 mum plankton net were manipulated by daily additions of nitrate and phosphate (NP treatment), and nitrate, phosphate and silicate (NPSi treatment). Oxidative stress parameters monitored daily were H2O2 concentrations in the seawater and concentrations of superoxide dismutase (SOD) activity, catalase activity and lipoperoxidation products (thiobarbituric acid-reactive substances, TBARS) in the phytoplankton. Chlorophyll a (chl a) concentration, pH and photosynthesis (O-2 evolution) were measured throughout the experiment to describe the physiological status of the phytoplankton. Our data suggest that fast growth of nutrient-saturated microalgae strongly limits oxidative stress by self-shading. This was shown by significantly lower SOD and catalase activities in the nutrient treatments than in the control treatment without nutrient additions. No differences were observed between the 2 nutrient treatments (with or without Si), despite higher photosynthetic rates in the diatom-rich mesocosms (NPSi). Our findings may contribute to a better understanding of the close relationships between eutrophication, the occurrence of algal blooms and antioxidant activity in microalgae.