pH alters the swimming behaviors of the raphidophyte Heterosigma akashiwo: Implications for bloom formation in an acidified ocean
pH alters the swimming behaviors of the raphidophyte Heterosigma akashiwo: Implications for bloom formation in an acidified ocean
复制标题
DOI：
10.1016/j.hal.2013.03.004
复制
发表时间：
2013-06-01
期刊：
影响因子：
6.6
通讯作者：
Menden-Deuer, Susanne
中科院分区：
文献类型：
--
作者：
Kim, Hyewon;Spivack, Arthur J.;Menden-Deuer, Susanne
研究了pH值对赤潮藻异弯藻运动行为的影响。运动参数从>8000游泳轨迹的单个细胞进行了量化，使用3D数字视频分析在6小时内在3个pH值的处理，反映了海洋碳酸盐化学在工业化前的时代，目前，和2100年。运动行为进行了研究，在两个不同的适应目标pH值的条件下：瞬时暴露和驯化的细胞至少11代。当暴露于升高的PCO 2时，细胞运动性没有受到负面损害（即，低pH）条件下，但有显着的行为反应。无论在何种驯化条件下，低pH均显著增加了游泳细胞的下行速度和频率（p < 0.001）。快速暴露于较低的pH值导致向下的垂直速度加快9%，向下游泳的细胞增加19%（p < 0.001）。与pH冲击实验相比，细胞对目标pH的预适应导致类似于快30%的游泳速度和快高达46%的向下速度（所有p < 0.001）。2100年PCO 2水平对预适应培养物中种群扩散率的影响是pH冲击处理的2倍以上（2.2 x 10（5）mu m（2）s（-1）vs. 8.4 x 10（4）mu m（2）s（-1））。对流扩散模型的预测表明，随着PCO 2的增加，聚集在地表的种群比例下降，并在水柱中移动得更深。加强向下游泳的H。akashiwo在低pH值下的行为表明，这些对PCO 2升高的行为反应可以降低H. Akashiwo通过减少光暴露或生长独立的表面聚集。我们推测，赤潮藻的反应，以较高的PCO 2可能利用高PCO 2的信号功能，作为指示净异养系统中，从而指示高捕食率或耗尽的营养物质。(c)2013爱思唯尔有限公司版权所有。
We investigated the effects of pH on movement behaviors of the harmful algal bloom causing raphidophyte Heterosigma akashiwo. Motility parameters from >8000 swimming tracks of individual cells were quantified using 3D digital video analysis over a 6-h period in 3 pH treatments reflecting marine carbonate chemistry during the pre-industrial era, currently, and the year 2100. Movement behaviors were investigated in two different acclimation-to-target-pH conditions: instantaneous exposure and acclimation of cells for at least 11 generations. There was no negative impairment of cell motility when exposed to elevated PCO2 (i.e., low pH) conditions but there were significant behavioral responses. Irrespective of acclimation condition, lower pH significantly increased downward velocity and frequency of downward swimming cells (p < 0.001). Rapid exposure to lower pH resulted in 9% faster downward vertical velocity and up to 19% more cells swimming downwards (p < 0.001). Compared to pH-shock experiments, pre-acclimation of cells to target pH resulted in similar to 30% faster swimming speed and up to 46% faster downward velocities (all p < 0.001). The effect of year 2100 PCO2 levels on population diffusivity in pre-acclimated cultures was >2-fold greater than in pH-shock treatments (2.2 x 10(5) mu m(2) s(-1) vs. 8.4 x 10(4) mu m(2) s(-1)). Predictions from an advection-diffusion model, suggest that as PCO2 increased the fraction of the population aggregated at the surface declined, and moved deeper in the water column. Enhanced downward swimming of H. akashiwo at low pH suggests that these behavioral responses to elevated PCO2 could reduce the likelihood of dense surface slick formation of H. akashiwo through reductions in light exposure or growth independent surface aggregations. We hypothesize that the HAB alga's response to higher PCO2 may exploit the signaling function of high PCO2 as indicative of net heterotrophy in the system, thus indicative of high predation rates or depletion of nutrients. (c) 2013 Elsevier B.V. All rights reserved.