Short-term temperature effects on oxygen and sulfide cycling in a hypersaline cyanobacterial mat (Solar Lake, Egypt)
Short-term temperature effects on oxygen and sulfide cycling in a hypersaline cyanobacterial mat (Solar Lake, Egypt)
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短期温度对高盐蓝藻垫中氧和硫化物循环的影响（埃及太阳湖）
DOI：
10.3354/meps196087
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发表时间：
2000
影响因子：
2.5
通讯作者：
M. Kühl
中科院分区：
文献类型：
--
作者：
A. Wieland;M. Kühl
利用O2、pH和H2S微传感器，在实验室条件下，研究了光照强度（Ed（PAR））为425 μ mol photons m-2s-1的条件下，在黑暗条件下培养的高盐蓝藻培养皿中，温度对氧和硫化物循环的短期影响.孵育温度以5 ° C的间隔从25 ° C升高至40 ° C。总光合作用和净光合作用的面积速率、无光区的O2消耗和暗O2消耗在30 ° C时最大，即接近自然栖息地的原位温度。暗氧消耗的面积率显示只有一个很小的温度依赖性的O2消耗扩散限制在所有温度下。在黑暗和光照孵育的垫中，硫化物的产生随着温度的增加而强烈增加（Q10 = 1.8至3.2），这导致硫化物氧化的饱和和从黑暗孵育的垫中流出的硫化物的增加，其在35 ° C下最大。在最上层的黑暗孵育垫，pH值下降，由于有氧呼吸，硫化物氧化和发酵，这种下降与温度增强。在光孵育垫，透光区的厚度随温度从0.9至0.5毫米。氧渗透和峰值氧浓度随温度下降，而上硫化物边界，因此硫化物氧化区上升更接近光孵育垫的垫表面。在光温育垫中，从25 ° C至40 ° C，硫化物氧化的面积速率增加超过2倍。硫化物氧化对无光区耗氧量的相对贡献随温度的升高而显著增加，表明在高温下，光孵育垫中发生不完全硫化物氧化。光合诱导的pH值最大值和整体pH值的垫随着温度的升高而下降，由于增强异养活性，硫化物氧化，和这些过程的深度分布的变化。我们的数据表明，在高盐微生物垫，这是强烈的温度调节的氧和硫循环的密切耦合。
We investigated short-term temperature effects on oxygen and sulfide cycling with O 2 , pH, and H 2 S microsensors in a hypersaline cyanobacterial mat, incubated in darkness and at a down-welling irradiance, E d (PAR), of 425 μmol photons m -2 s -1 in a laboratory. The incubation temperature was increased from 25 to 40°C in 5°C intervals. Areal rates of gross and net photosynthesis, of O 2 consumption in the aphotic zone and of dark O 2 consumption were maximal at 30°C, i.e. close to the in situ temperature of the natural habitat. Areal rates of dark oxygen consumption showed only a minor temperature dependence as O 2 consumption was diffusion limited at all temperatures. Sulfide production increased strongly with temperature in both the dark and light incubated mat (Q 10 = 1.8 to 3.2), and this led to saturation of sulfide oxidation and an increased sulfide efflux out of the dark incubated mat, which was maximal at 35°C. In the uppermost layer of the dark incubated mat, pH decreased due to aerobic respiration, sulfide oxidation and fermentation, and this decrease was enhanced with temperature. In the light incubated mat, the thickness of the photic zone decreased with temperature from 0.9 to 0.5 mm. Oxygen penetration and peak oxygen concentration decreased with temperature, whereas the upper sulfide boundary and thus the zone of sulfide oxidation rose closer to the mat surface in the light incubated mat. Areal rates of sulfide oxidation increased more than 2-fold from 25 to 40°C in the light incubated mat. The relative contribution of sulfide oxidation to oxygen consumption in the aphotic zone increased significantly with temperature, indicating that at elevated temperatures incomplete sulfide oxidation occurred in the light incubated mat. Both the photosynthetically induced pH maximum and the overall pH of the mat decreased with increasing temperature due to enhanced heterotrophic activity, sulfide oxidation, and a changed depth distribution of these processes. Our data demonstrate a close coupling of oxygen and sulfur cycling in hypersaline microbial mats, that is strongly regulated by temperature.