Flow enhances photosynthesis in marine benthic autotrophs by increasing the efflux of oxygen from the organism to the water
Flow enhances photosynthesis in marine benthic autotrophs by increasing the efflux of oxygen from the organism to the water
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DOI：
10.1073/pnas.0912348107
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发表时间：
2010-02-09
影响因子：
11.1
通讯作者：
Tchernov, Dan
中科院分区：
文献类型：
--
作者：
Mass, Tali;Genin, Amatzia;Tchernov, Dan
在世界范围内，许多海洋沿海生境正面临着迅速恶化，部分原因是人类驱动的生境特征的变化，包括流动模式的变化，这是一个已知的因素，极大地影响了珊瑚，藻类和海草的初级生产。流量的影响传统上是由于加强流入的营养物质和溶解无机碳（DIC）的底栖边界层从水到生物体，但是，在这里，我们报告说，生物体的光合反应的变化，在流量几乎是瞬时的，既不是营养物质，也不是DIC限制这种快速的反应。使用微电极，双脉冲调幅荧光，粒子图像测速仪，和真实的时间质谱与常见的石珊瑚Favia veroni，江蓠的角膜，和海草盐喜托叶，我们表明，这种增强光合作用是由于流动驱动的增强从生物体到水的氧流出，这增加了亲和性的RuBisCO到CO2。没有增加的光合作用被发现在没有流量或流量发生时，但周围的氧气浓度被人为升高。我们认为，水的运动应被视为一个基本因素，相当于光和营养盐，在确定海洋底栖自养生物的光合速率。
Worldwide, many marine coastal habitats are facing rapid deterioration due in part to human-driven changes in habitat characteristics, including changes in flow patterns, a factor known to greatly affect primary production in corals, algae, and seagrasses. The effect of flow traditionally is attributed to enhanced influx of nutrients and dissolved inorganic carbon (DIC) across the benthic boundary layer from the water to the organism however, here we report that the organism's photosynthetic response to changes in the flow is nearly instantaneous, and that neither nutrients nor DIC limits this rapid response. Using microelectrodes, dual-pulse amplitude-modulated fluorometry, particle image velocimetry, and real time mass-spectrometry with the common scleractinian coral Favia veroni, the alga Gracilaria cornea, and the seagrass Halophila stipulacea, we show that this augmented photosynthesis is due to flow-driven enhancement of oxygen efflux from the organism to the water, which increases the affinity of the RuBisCO to CO2. No augmentation of photosynthesis was found in the absence of flow or when flow occurred, but the ambient concentration of oxygen was artificially elevated. We suggest that water motion should be considered a fundamental factor, equivalent to light and nutrients, in determining photosynthesis rates in marine benthic autotrophs.