海洋生态与环境科学重点实验室知识库

抗生素的滥用问题引起了人们的广泛关注。海洋是大量抗生素最终会汇入的地方，因此，抗生素对海洋生态系统的影响值得大家的关注。同时，大量营养元素也会进入海洋，造成营养盐结构的严重失衡，影响海洋生态系统的生态平衡。作为海洋中的重要生产者，微藻对环境的变化非常敏感。本文将米氏凯伦藻（Karenia mikimotoi）、东海原甲藻（Prorocentrum donghaiense）、中肋骨条藻（Skeletonema costatum）、旋链角毛藻（Chaetoceros curvisetus）和赤潮异弯藻 （Heterosigma akashiwo） 作为研究对象，将红霉素作为代表抗生素，研究了红霉素和不同营养盐比例对微藻的生物量、光合色素含量、可溶性蛋白质含量、丙二醛(malondialdehyde，MDA)含量和超氧化物歧化酶(superoxide dismutase，SOD)活性的影响，分析了红霉素和营养盐对微藻的复合影响；此外，本文还将米氏凯伦藻和东海原甲藻、米氏凯伦藻和中肋骨条藻以及中肋骨条藻和赤潮异弯藻进行了混合培养，分析了红霉素与营养盐对微藻种间竞争的复合影响。研究表明：

1. 实验范围内(0~1 000 μg/L)，红霉素浓度高于100 μg/L时，红霉素会显著抑制东海原甲藻、中肋骨条藻和旋链角毛藻的生长。红霉素对米氏凯伦藻的生长无显著影响，红霉素会促进赤潮异弯藻的生长。米氏凯伦藻、东海原甲藻、中肋骨条藻、旋链角毛藻和赤潮异弯藻的最适营养盐比例均为N∶P=16∶1。缺氮和缺磷都会抑制微藻的生长。

2. 红霉素会抑制中肋骨条藻叶绿素a的合成；当红霉素浓度高于0.5 μg/L时，红霉素会对东海原甲藻、旋链角毛藻和米氏凯伦藻叶绿素a的合成有抑制作用；红霉素高于10 μg/L时会对赤潮异弯藻叶绿素a的合成有抑制作用。红霉素会促进旋链角毛藻类胡萝卜素的合成。除旋链角毛藻外，红霉素对米氏凯伦藻、东海原甲藻、中肋骨条藻和赤潮异弯藻类胡萝卜素的合成有低促高抑的作用。营养盐限制时，微藻在光合色素的合成方面对红霉素的敏感性更高，微藻的光合作用更容易受到抑制。

3. 红霉素对米氏凯伦藻可溶性蛋白质存在低促高抑的现象；氮限制时，红霉素会抑制其可溶性蛋白质的合成。红霉素会抑制中肋骨条藻的可溶性蛋白质合成，但会促进旋链角毛藻可溶性蛋白质的合成。红霉素会促进赤潮异弯藻可溶性蛋白质的合成；但营养盐限制时，红霉素会抑制其可溶性蛋白质的合成。

4. 红霉素会加重米氏凯伦藻、东海原甲藻、中肋骨条藻、旋链角毛藻和赤潮异弯藻的氧化损伤。氮限制时，红霉素对米氏凯伦藻、旋链角毛藻和赤潮异弯藻的氧化胁迫比其他营养条件更严重。与其他营养条件相比，磷限制时红霉素对东海原甲藻造成的氧化胁迫是最严重的。氮限制和磷限制时，中肋骨条藻对红霉素的耐受性会降低。营养盐限制会降低微藻对红霉素的耐受限度，降低微藻的抗氧化能力。

5. 不同的微藻对红霉素的敏感性是有差异的，旋链角毛藻对红霉素最敏感，米氏凯伦藻对红霉素的敏感性最低。同一种微藻在不同的营养盐比例下对红霉素的响应是存在差异的。营养盐限制会降低微藻对红霉素的耐受限度。

   米氏凯伦藻和东海原甲藻或中肋骨条藻混合培养时，东海原甲藻或中肋骨条藻是优势种，但红霉素可以为米氏凯伦藻提供一定的竞争优势；中肋骨条藻和赤潮异弯藻混合培养时，中肋骨条藻是优势种，但红霉素可以为赤潮异弯藻提供一定的竞争优势。不同的微藻对于营养盐限制的适应性不同，中肋骨条藻的适应性最低。红霉素和营养盐限制会影响微藻的种间竞争。

The abuse of antibiotics has caused widespread concern. The ocean is the place where large amounts of antibiotics eventually flow into. And antibiotics pose a potential threat to the marine ecosystem. At the same time, a large number of nutrients also enter the ocean, provoking a serious imbalance in the structure of nutrients and affecting the balance of the marine ecosystem. Microalgae are important producers in marine ecosystems and are very sensitive to environmental changes. In this paper, we selected Skeletonema costatum, Chaetoceros curvisetus, Karenia mikimotoi, Prorocentrum donghaiense and Heterosigma akashiwo. And we selected erythromycin as the representative antibiotic. We investigated the effects of erythromycin and nutrients on the biomass, photosynthetic pigment content, soluble protein content, MDA, and SOD activity of microalgae. And we could analyze whether erythromycin and nutrients would have combined effects on microalgae or not. In this paper, Karenia mikimotoi and Prorocentrum donghaiense, Karenia mikimotoi and Skeletonema costatum, and Skeletonema costatum and Heterosigma akashiwo mixed culture were further analyzed. It could be analyzed whether erythromycin and nutrients would have combined effects on algal interspecies competition. The experimental results are as shows:

1. In the experimental range (0-1 000 μg/L), when the concentration of erythromycin is higher than 100 μg/L, erythromycin can significantly restrain the growth of Prorocentrum donghaiense, Skeletonema costatum and Chaetoceros curvisetus. Erythromycin does not significantly restrain the growth of Karenia mikimotoi, and erythromycin can promote the growth of Heterosigma akashiwo. Optimal nutrient ratios of Karenia mikimotoi, Skeletonema costatum, Prorocentrum donghaiense, Chaetoceros curvisetus and Heterosigma akashiwo are N∶P=16∶1. Both nitrogen and phosphorus deficiency can inhibit the growth of microalgae.

2. Erythromycin can inhibit the synthesis of chlorophyll a in Skeletonema costatum. When the concentration is higher than 0.5 μg/L, erythromycin can inhibit the synthesis of chlorophyll a by Karenia mikimotoi, Prorocentrum donghaiense and Chaetoceros curvisetus. When the concentration is higher than 10 μg/L, the synthesis of chlorophyll a in Heterosigma akashiwo can be inhibited. Erythromycin promotes carotenoid synthesis of Chaetoceros curvisetus. In addition to Chaetoceros curvisetus, erythromycin has a low-promoting and high-inhibiting effect on carotenoid synthesis of Karenia mikimotoi, Skeletonema costatum, Prorocentrum donghaiense and Heterosigma akashiwo. When nutrients are limited, microalgae is more sensitive to erythromycin in the synthesis of photosynthetic pigments, and photosynthesis of microalgae is more easily inhibited.

3. Erythromycin has a low-promoting and high-inhibiting effect on soluble protein of Karenia mikimotoi; when nitrogen is limited, erythromycin can inhibit the synthesis of soluble protein. Erythromycin inhibits the soluble protein synthesis of Skeletonema costatum, but promotes the soluble protein synthesis of Chaetoceros curvisetus. Erythromycin can promote the synthesis of soluble proteins in Heterosigma akashiwo; but when nutrients are limited, erythromycin can inhibit the synthesis of soluble proteins.

4. Erythromycin will aggravate the oxidative damage of Skeletonema costatum, Chaetoceros curvisetus, Karenia mikimotoi, Prorocentrum donghaiense and Heterosigma akashiwo. Under nitrogen limitation, the oxidative stress of erythromycin on Karenia mikimotoi, Chaetoceros curvisetus and Heterosigma akashiwo is more severe than other nutritional conditions. Under phosphorus limitation, the oxidative stress of erythromycin on Prorocentrum donghaiense is more severe than other nutritional conditions. When nitrogen and phosphorus were limited, Skeletonema costatum reduced its resistance to erythromycin. Nutrient restriction will reduce the tolerance of microalgae to erythromycin and reduce the anti-oxidative ability of microalgae.

5. Different microalgae have different sensitivities to erythromycin. Chaetoceros curvisetus is the most sensitive to erythromycin, and Karenia mikimotoi is the least sensitive to erythromycin. The response of the same microalgae to erythromycin is different under different nutrient ratios. Nutrient restriction reduces the tolerance of microalgae to erythromycin.

6. When Karenia mikimotoi and Prorocentrum donghaiense or Karenia mikimotoi and Skeletonema costatum are mixed species, Prorocentrum donghaiense or Skeletonema costatum is the dominant species, but erythromycin can give a certain competitive advantage for Karenia mikimotoi. When mixed culture of Skeletonema costatum and Heterosigma akashiwo, Skeletonema costatum is the dominant species, but erythromycin can provide a certain competitive advantage for Heterosigma akashiwo. Different microalgae have different adaptability to nutrient limitation, and Skeletonema costatum has the lowest adaptability. Erythromycin and nutrient restrictions can affect interspecies competition in microalgae.

第1章 绪论 1

1.1 抗生素概述 1

1.1.1 抗生素的特征 1

1.1.2 抗生素的滥用 1

1.1.3 抗生素在海水中的分布 2

1.2 抗生素对微藻的影响 3

1.2.1 抗生素对微藻的影响 3

1.2.2 抗生素对微藻的作用机理 4

1.3 营养盐限制的现状 5

1.4 营养盐限制对微藻的影响 6

1.5 研究目的与意义 7

1.5.1 实验藻种与抗生素 7

1.5.2 研究内容、目的与意义 8

第2章 红霉素与营养盐对单种微藻的复合影响 9

2.1 引言 9

2.2 材料与方法 9

2.3 实验结果 10

2.3.1 红霉素和营养盐对单种微藻生长的复合影响 10

2.3.2 红霉素和营养盐对单种微藻光合色素含量的复合影响 13

2.3.3 红霉素和营养盐对单种微藻可溶性蛋白质含量的复合影响 16

2.3.4 红霉素和营养盐对单种微藻SOD和MDA的复合影响 19

2.4 分析与讨论 24

2.5 小结 27

第3章 红霉素与营养盐对微藻的种间竞争的复合影响 29

3.1 引言 29

3.2 材料与方法 29

3.3 实验结果 30

3.3.1 红霉素和营养盐对米氏凯伦藻和东海原甲藻种间竞争的复合影响 30

3.3.2 红霉素和营养盐对米氏凯伦藻和中肋骨条藻种间竞争的复合影响 33

3.3.3 红霉素和营养盐对中肋骨条藻和赤潮异弯藻种间竞争的复合影响 35

3.4 分析与讨论 38

3.5 小结 40

第4章 结论与展望 43

参考文献 45

致谢 53

作者简历及攻读学位期间发表的学术论文与研究成果 55