Transparent exopolymer particles and dissolved organic carbon production by Emiliania huxleyi exposed to different CO2 concentrations:: a mesocosm experiment
Transparent exopolymer particles and dissolved organic carbon production by Emiliania huxleyi exposed to different CO2 concentrations:: a mesocosm experiment
复制标题
DOI：
10.3354/ame034093
复制
发表时间：
2004-01-16
影响因子：
1.4
通讯作者：
Zondervan, I
中科院分区：
文献类型：
--
作者：
Engel, A;Delille, B;Zondervan, I
在使用球石藻进行中生态实验期间，研究了透明外聚物颗粒（TEP）和溶解有机碳（DOC）在不同二氧化碳条件下对有机碳分配的作用。我们设计了 9 个室外围栏（类似于 11 m(3)）来模拟估计的“2100 年”（类似于 710 ppm CO2）、“当前”（类似于 410 ppm CO2）和“冰川”（类似于 190 ppm CO2）环境的 CO2 浓度，并用硝酸盐和磷酸盐施肥以促进水华发育。我们的结果表明，花期期间 TEP 和 DOC 动态存在根本不同。在所有中生态系统中，TEP 浓度在养分耗尽后增加，并稳定积累直至研究结束。 TEP 浓度与 E. huxleyi 的丰度密切相关，并且导致营养限制开始后 POC 浓度增加 35 +/- 2 %。根据赫胥黎大肠杆菌的细胞丰度标准化的 TEP 产量在 2100 年处理中最高。相比之下，DOC 浓度在整个研究过程中表现出相当大的短期波动。在所有中生态系统中，DOC 与 E. huxleyi 的丰度和 TEP 浓度均无关。尚未确定 CO2 处理对 DOC 浓度的统计学显着影响。然而，在水华过程中，2100年3个中生态系统中的2个和当前中生态系统中的1个中DOC浓度增加，但在冰期中生态系统中没有增加。有人认为，TEP 和 DOC 之间观察到的差异是由它们不同的生物利用度决定的，微生物食物网的快速反应可能掩盖了 CO2 对自养细胞产生 DOC 的影响。
The role of transparent exopolymer particles (TEP) and dissolved organic carbon (DOC) for organic carbon partitioning under different CO2 conditions was examined during a mesocosm experiment with the coccolithophorid Emiliania huxleyi. We designed 9 outdoor enclosures (similar to11 m(3)) to simulate CO2 concentrations of estimated 'Year 2100' (similar to710 ppm CO2), 'present' (similar to410 ppm CO2) and 'glacial' (similar to190 ppm CO2) environments, and fertilized these with nitrate and phosphate to favor bloom development. Our results showed fundamentally different TEP and DOC dynamics during the bloom. In all mesocosms, TEP concentration increased after nutrient exhaustion and accumulated steadily until the end of the study. TEP concentration was closely related to the abundance of E. huxleyi and accounted for an increase in POC concentration of 35 +/- 2 % after the onset of nutrient limitation. The production of TEP normalized to the cell Abundance of E. huxleyi was highest in the Year 2100 treatment. In contrast, DOC concentration exhibited considerable short-term fluctuations throughout the study. In all mesocosms, DOC was neither related to the abundance of E. huxleyi nor to TEP concentration. A statistically significant effect of the CO2 treatment on DOC concentration was not determined. However, during the course of the bloom, DOC concentration increased in 2 of the 3 Year 2100 mesocosms and in 1 of the present mesocosms, but in none of the glacial mesocosms. It is suggested that the observed differences between TEP and DOC were determined by their different bioavailability and that a rapid response of the microbial food web may have obscured CO2 effects on DOC production by autotrophic cells.