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不同氮源对中肋骨条藻(Skeletonema costatum)生长的影响

乔倩,王朝晖*,郭鑫   

  1. (暨南大学生态学系, 水体富营养化与赤潮防治广东普通高校重点实验室, 广州 510632)
  • 出版日期:2016-08-10 发布日期:2016-08-10

Effects of nitrogen sources on the growth of Skeletonema costatum.

QIAO Qian, WANG Zhao-hui*, GUO xin   

  1. (Institution of Hydrobiology, Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China).
  • Online:2016-08-10 Published:2016-08-10

摘要: 中肋骨条藻(Skeletonema costatum)是近岸海洋环境中常见的优势硅藻。为了解氮污染对硅藻生长及海洋初级生产力的影响,本文研究了中肋骨条藻对NO3-、尿素以及5种氨基酸的利用能力,并研究了中肋骨条藻在NO3-和尿素不同比例混合下的生长状况,同时还测定了中肋骨条藻在以NO3-为氮源下的最大生长速率(μmax)和半饱和常数(Ks)。结果表明:中肋骨条藻不仅可以有效利用无机的NO3-,还可以利用尿素以及丙氨酸、甘氨酸、苏氨酸、丝氨酸和天门冬氨酸6种有机氮源,其中NO3-培养组的藻细胞生长最佳,尿素组其次;氨基酸中最易被吸收利用的是丙氨酸,而苏氨酸、丝氨酸和天门冬氨酸的利用率相近,甘氨酸较低。在NO3-和尿素复合氮源条件下,中肋骨条藻的生长状况比单一氮源时更好,最佳生长出现在尿素含量在75%的实验组中。在实验设置的NO3-浓度下(0~1000 μmol·L-1),中肋骨条藻生长速率和环境容量随氮浓度的增加而增加,对NO3-的μmax和Ks分别为0.426 d-1和25.0 μmol·L-1。本研究结果表明,中肋骨条藻可以有效利用多种有机氮源,对无机氮具有较低的亲和能力,适合在高氮环境下生长,而近岸海域丰富的有机氮以及较高的氮浓度可能是其爆发性生长引发赤潮的重要原因。

关键词: 多维贫困度量, 贫困指数-最小方差模型, 生态贫困, 贫困类型, 空间分布, 贫困程度

Abstract: Skeletonema costatum is a common dominant diatom species in the coastal environments. The capacity of S. costatum to utilize nitrate (NO3-), urea, and five amino acids was studied, and the growth of S. costatum under different proportions of NO3- and urea was examined. Furthermore, the maximum specific growth rate (μmax) and halfsaturation constant (Ks) of S. costatum were determined using NO3- as the sole nitrogen (N) source. The purpose of this study is to understand the impact of nitrogen enrichment on the growth of diatoms and primary productivity of marine environments. The tesults showed that S. costatum was able to utilize both dissolved inorganic nitrogen (NO3-) and dissolved organic nitrogen (urea, almandine, glycine, threonine, serine and aspartic acid). The best growth was recorded in culture with NO3-, followed in culture with urea. Alanine was one of the most easily utilized amino forms, followed by threonine, serine and aspartic acid. However, the growth was relatively lower when using glycine as sole N source compared with the other amino acids. Algal cells grew better in culture with both NO3- and urea as nitrogen sources compared with that with NO3- or urea as sole N nutrient. Maximum cell density was found in the culture with 75% urea and 25% NO3-. The specific growth rate and environmental capacity increased with the increasing NO3- concentration (0-1000 μmol·L-1), and the μmax and Ks of S. costatum were 0.426 d-1 and 25.0 μmol·L-1, respectively. The results suggested that S. costatum could use various organic N, and grew well under high N levels. Therefore, the sufficient organic N and high N concentration in the coastal waters might play important roles in the occurrence of algal blooms.

Key words: PI-MVM, ecological poverty, poverty type, multidimensional poverty measurement, spatial distribution., poverty degree