Combined effects of light and naphthalene on marine microalgae

在这项研究中，我调查了光和萘对海洋微藻的联合作用。由于光抑制和毒性的综合作用，许多浮游植物群体的生长被强光照射（2000 μmol m^<-2>s^<-1>）和萘（0.05-5 ppm）的组合强烈抑制。微藻的叶黄素循环被认为可以防止光抑制：已知超过光合能力的光会迅速改变绿色藻类的叶黄素色素，从紫黄质经由花药黄质到玉米黄质，以及硅藻的叶黄素色素从硅藻黄质到硅藻黄质。在<-2><-1>四种条件（200或2000 μ mol m^ s^和0或&gt;15 ppm萘）中，在暴露于&gt; 15 ppm萘的同时以2000 μ mol m ^s^照射微藻导致叶黄素色素变化最快<-2><-1>。萘减少了溶解氧的产生，这是光合作用的一个指标。因此，萘抑制光合作用，并迅速激活叶黄素循环。微藻产生类菌孢素氨基酸（MAAs），其最大吸收位于紫外线（UV）区域，以保护免受UV辐射的抑制。UV-A（~360 nm）、强光照射和萘的协同作用降低了溶解氧的产生。不清楚UV-A和萘是否改变了MAAs与叶绿素a的比例。在本实验中使用的微藻中的MAAs的产生似乎不受UV-A和萘的影响。

In this study, I investigated the combined effects of light and naphthalene on marine microalgae. The growth of many groups of phytoplankton is strongly inhibited by combined high light irradiation(2000 μmol m^<-2> s^<-1>) and naphthalene(0.05-5 ppm) because of the combined effects of photoinhibition and toxicity. The xanthophyll cycle of microalgae is thought to protect against photoinhibition : light in excess of photosynthetic capacity is known to rapidly change xanthophyll pigments of green algae from violaxanthin via antheraxanthin to zeaxanthin, and those of diatoms from diadinoxanthin to diatoxanthin. Irradiation of microalgae at 2000 μmol m^<-2> s^<-1> during exposure to naphthalene at >15ppm caused the fastest change in xanthophyll pigments among four conditions(200 or 2000 μmol m^<-2> s^<-1> and 0 or >15 ppm naphthalene). Naphthalene decreased the production of dissolved oxygen, an indicator of photosynthesis. Therefore naphthalene inhibited photosynthesis, and rapidly activated the xanthophyll cycle. Microalgae produce mycosporine-like amino acids(MAAs), whose absorbance maxima lie in the ultraviolet(UV) region, to protect against inhibition by UV radiation. The production of dissolved oxygen was decreased by the synergistic effects of UV-A(~360 nm), high light irradiation, and naphthalene. It was not clear whether the ratio of MAAs to chlorophyll a was changed by UV-A and naphthalene. It appears that the production of MAAs in microalgae used in this experiment was not influenced by UV-A and naphthalene.