Life in the Main Channel: Long-Term Hydrologic Control of Microbial Mat Abundance in McMurdo Dry Valley Streams, Antarctica
Life in the Main Channel: Long-Term Hydrologic Control of Microbial Mat Abundance in McMurdo Dry Valley Streams, Antarctica
复制标题
主河道中的生命：南极洲麦克默多干谷溪流中微生物垫丰度的长期水文控制
DOI：
10.1007/s10021-014-9829-6
复制
发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
D. McKnight
中科院分区：
文献类型：
--
作者：
T. Kohler;L. Stanish;S. Crisp;J. Koch;D. Liptzin;J. Baeseman;D. McKnight
鉴于全球水文制度的变化，我们研究水文在调节流微生物垫丰富的麦克默多干旱河谷，南极洲的作用。在这里，常年垫坚持作为一个干燥的外壳，直到复苏的夏季溪流，这是不同的年际变化，并已增加自20世纪90年代。我们预测高流量冲刷垫，和季节内干燥，以减缓增长。响应被假设为不同的基础上垫内流的位置，沿着与地貌，这可能会促进（高覆盖率）或阻碍（低覆盖率）的积累。我们比较了水文趋势与生物量的绿色和橙子垫，生长在通道，黑色垫生长在流边缘的16个不同的流断面在二十年。我们发现垫生物量集体下降，在第一个十年符合低流量，并增加以下升高排放。绿色垫生物量与水文的相关性最大，在高覆盖度样带中受流量的刺激，但在低覆盖度样带中因生境冲刷而呈负相关。与此相反，橙子垫生物量呈负相关，流量在高覆盖度样带，但正相关，因为侧通道扩张在低覆盖度。黑垫弱相关的所有水文变量，无论覆盖。最后，模型选择表明，最佳组合的预测水文变量的生物量垫类型之间的差异，但也高，低覆盖断面。这些结果表明，地貌和物种组成的重要性，以模拟初级生产力，并将有助于预测底栖生物栖息地改变水文制度的生态响应。
Given alterations in global hydrologic regime, we examine the role of hydrology in regulating stream microbial mat abundance in the McMurdo Dry Valleys, Antarctica. Here, perennial mats persist as a desiccated crust until revived by summer streamflow, which varies inter-annually, and has increased since the 1990s. We predicted high flows to scour mats, and intra-seasonal drying to slow growth. Responses were hypothesized to differ based on mat location within streams, along with geomorphology, which may promote (high coverage) or discourage (low coverage) accrual. We compared hydrologic trends with the biomass of green and orange mats, which grow in the channel, and black mats growing at stream margins for 16 diverse stream transects over two decades. We found mat biomass collectively decreased during first decade coinciding with low flows, and increased following elevated discharges. Green mat biomass showed the greatest correlations with hydrology and was stimulated by discharge in high coverage transects, but negatively correlated in low coverage due to habitat scour. In contrast, orange mat biomass was negatively related to flow in high coverage transects, but positively correlated in low coverage because of side-channel expansion. Black mats were weakly correlated with all hydrologic variables regardless of coverage. Lastly, model selection indicated the best combination of predictive hydrologic variables for biomass differed between mat types, but also high and low coverage transects. These results demonstrate the importance of geomorphology and species composition to modeling primary production, and will be useful in predicting ecological responses of benthic habitats to altered hydrologic regimes.