营养条件对微藻碳、氮稳定同位素组成的影响

以5种微藻(甲藻3种,硅藻、绿藻各1种)为试验材料,探讨了不同营养条件对微藻不同生长阶段碳氮稳定同位素组成的影响.结果表明,不同纲微藻的d13C值和d15N值在稳定生长期高于指数生长期,且与生长速率没有相关性(P>0.05).硅藻的d13C值低于甲藻和绿藻,绿藻和甲藻的d13C值比较相近;甲藻的d15N值低于硅藻和绿藻,绿藻和硅藻的d15N值比较相近,且同属甲藻纲的海洋原甲藻、塔玛亚历山大藻和强壮前沟藻的d15N值有较大的差异. 5种微藻在不同营养条件(营养盐充足、缺氮、缺磷)下培养,氮限制和磷限制导致微藻具有更正的d13C和d15N,磷限制的影响不明显,且弱于氮抑制.

Effects of nutritional conditions on the stable carbon and nitrogen isotope of microalgae

With five microalgae (dinoflagellates, diatoms, green algae species) as test materials, the effect of different nutrient conditions had been explored on the stable carbon and nitrogen isotopic throughout the growth phases. The result showed that among different classes of microalgae the d13C and d15N at the exponential phase were lower than those at the stable phase, indicating no correlation with growth velosity (P>0.05). Bacillariophyceae presented a higher d13C than dinophyceae and chlorophyceae, while the d13C of dinophyceae was nearly identical to that of chlorophyceae. In terms of d15N, the dinophyceae falls behind both bacillariophyceae and chlorophyceae, with bacillariophyceae approximating to chlorophyceae. In addition, significant d15N differences have been discovered among Prorocentrum micans, Alexandrium tamarense and Amphidinium carterae Hulburt. In this study, all five classes were grown under three distinctive cultures—nutrient sufficiency, nitrogen deficiency and phosphorus deficiency; either nitrogen or phosphorus limitation contributed to a more positive d13C and d15N, yet less obvious effect was observed in phosphorus-deficiency culture than in nitrogen-deficiency condition.