芦苇叶片中总氮同位素及游离氨基酸浓度对水淹的响应

Total nitrogen content,total nitrogen isotope(δ15 N),and free amino acid concentration in leaf of Phragmites australis(Cav.)Trin.ex Steud.under flooding for 0-11 d were studied.The results show that with the increase of flooding days,there is no significant variation in total nitrogen content in leaf of P.australis,δ15 N value shows a gradual tend to be negative,and concentrations of total free amino acids,Ser,Asp,and Asn first increase and then decrease.Under flooding for 1 d,δ15 N value decreases obviously and free amino acid concentration increases obviously compared with those under flooding for 0 d.It is indicated thatδ15 N value and free amino acid concentration are good indicators of P.australis under flooding condition.

近百年来楚科奇海域沉积环境变化的有机碳、氮记录

对"中国第五次北极科考"和"中国第六次北极科考"采集的楚科奇海陆架、海台及海盆区的5个多管样品进行210 Pb、粒度、有机碳(OC)和总氮(TN)含量及有机碳同位素(δ13 C)、总氮同位素组成(δ15 N)分析,初步获得5个多管样品近百年来的沉积速率,陆架区沉积速率为0.19~0.41cm/a,海台和海盆区沉积速率为0.03~0.04cm/a;近百年来陆架有机碳、总氮含量分别为1.21%~1.62%、0.17%~0.21%,有机碳、总氮同位素组成分别为-22.30‰^-22.25‰PDB、7.24‰~8.12‰;海台与海盆区有机碳、总氮含量分别为0.80%~1.26%、0.13%~0.16%,有机碳、总氮同位素组成分别为-22.52‰^-22.07‰PDB、7.38‰~7.81‰。陆架与海台和海盆相比,具有沉积速率高、沉积物颗粒粗、有机碳和总氮含量高的特点。近百年来楚科奇海域陆架、海台和海盆区有机碳以海洋生源输入为主,反映了北极气候变暖,水体初级生产力增加。