Remotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica
Remotely characterizing photosynthetic biocrust in snowpack-fed microhabitats of Taylor Valley, Antarctica
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DOI：
10.1016/j.srs.2024.100120
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发表时间：
2024-02-24
影响因子：
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通讯作者：
Barrett，J. E.
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文献类型：
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作者：
Power，Sarah N.;Salvatore，Mark R.;Barrett，J. E.
微生物群落是南极洲麦克默多干谷碳循环的主要驱动力。密集的微生物垫，主要由光合蓝藻组成，占据与溪流和湖泊相关的水域。其他微生物群落也以较低的密度出现在陆地景观中，作为斑块状的表面生物土壤结皮（以下简称生物结皮）。多光谱卫星数据已被用于模拟高密度地区（如河流和湖泊边缘）的微生物垫丰度，但以前的研究没有调查生物结壳的检测下限。在这里，我们描述了遥感和实地调查和采样的方法来研究的可探测性和分布的生物结壳在麦克默多干旱山谷。使用多光谱和高光谱工具和光谱线性解混相结合，我们模拟了泰勒谷东部生物结壳的丰度。我们的光谱方法可以在实验室微观世界中检测低质量的生物结壳材料，低至1%质量的生物结壳浓度。这些技术还可以区分生物壳的光谱与轨道上的表面岩石和矿物特征。我们发现，生物结壳存在于整个泰勒谷东部的土壤，并与不同的底层土壤群落。在这项研究中确定的dendrobial生物壳群落的总有机碳含量比典型的干旱土壤的含量高5倍。最具生产力的生物结壳位于独特的土壤生态系统中融化的积雪的下坡，与周围的干旱景观不同。积雪和河流沉积物群落（土壤无脊椎动物的高度多样性）及其生态系统特性（例如，与干旱河谷典型的干旱陆地生态系统相比，干旱河谷具有液态水的持久性、可利用养分的高转移性、冲刷产生的较低盐度等特点。我们的方法扩展了轨道遥感光合群落的水生边缘和干燥的土壤，包括大部分的景观的能力。这一跨学科工作对于测量和监测陆地碳储量以及预测这一目前水资源有限但日益活跃的南极景观未来的生态系统动态至关重要，这一景观对气候特别敏感，难以进入。
Microbial communities are the primary drivers of carbon cycling in the McMurdo Dry Valleys of Antarctica. Dense microbial mats, consisting mainly of photosynthetic cyanobacteria, occupy aquatic areas associated with streams and lakes. Other microbial communities also occur at lower densities as patchy surface biological soil crusts (hereafter, biocrusts) across the terrestrial landscape. Multispectral satellite data have been used to model microbial mat abundance in high-density areas like stream and lake margins, but no previous studies have investigated the lower detection limits of biocrusts. Here, we describe remote sensing and field-based survey and sampling approaches to study the detectability and distribution of biocrusts in the McMurdo Dry Valleys. Using a combination of multi- and hyperspectral tools and spectral linear unmixing, we modeled the abundances of biocrust in eastern Taylor Valley. Our spectral approaches can detect low masses of biocrust material in laboratory microcosms down to biocrust concentrations of 1% by mass. These techniques also distinguish the spectra of biocrust from both surface rock and mineral signatures from orbit. We found that biocrusts are present throughout the soils of eastern Taylor Valley and are associated with diverse underlying soil communities. The densest biocrust communities identified in this study had total organic carbon 5x greater than the content of typical arid soils. The most productive biocrusts were located downslope of melting snowpacks in unique soil ecosystems that are distinct from the surrounding arid landscape. There are similarities between the snowpack and stream sediment communities (high diversity of soil invertebrates) as well as their ecosystem properties (e.g., persistence of liquid water, high transfer of available nutrients, lower salinity from flushing) compared to the typical arid terrestrial ecosystem of the dry valleys. Our approach extends the capability of orbital remote sensing of photosynthetic communities out of the aquatic margins and into the drier soils which comprise most of this landscape. This interdisciplinary work is critical for measuring and monitoring terrestrial carbon stocks and predicting future ecosystem dynamics in this currently water-limited but increasingly dynamic Antarctic landscape, which is particularly climate-sensitive and difficult to access.