Juice Stephanie M, Schaberg Paul G, Kosiba Alexandra M, Waite Carl E, Hawley Gary J, Wang Deane, Perdrial Julia N, Adair E Carol
Department of Biology, West Virginia University, Morgantown, West Virginia, USA.
Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, Vermont, USA.
Glob Chang Biol. 2025 Aug;31(8):e70447. doi: 10.1111/gcb.70447.
In seasonally snow-covered ecosystems, changing temperatures and snowpack dynamics under climate change have increased the occurrence and duration of soil temperatures that support microbial activity during plant dormancy. During these periods of microbial activity without plant activity (i.e., plant-microbe asynchronies), soil nutrients that build up are vulnerable to leaching loss, with potentially important consequences for ecosystem productivity. Furthermore, asynchronies likely do not occur uniformly in space; rather, their occurrence may be modulated by subsurface characteristics. Soil texture, for example, moderates biogeochemical cycles and water holding capacity, and could mitigate or exacerbate nutrient losses during plant-microbe asynchronies. Here, we quantified how climate change treatments and soil characteristics alter the synchrony of plant and microbial activity, and the associated impacts on leaching of soil nutrients-carbon, nitrogen, phosphorus-and cations prone to mobilization following environmental perturbation-calcium, magnesium, and aluminum. To do this, we conducted a forest sapling mesocosm experiment that imposed replicated warming and snow exclusion treatments on two soils. To estimate the extent and effect of asynchrony, we measured soil temperature and plant phenology over 2 years to develop an index for asynchrony duration, which we correlated with measured nutrient and cation leachate losses. We found that warming consistently increased the duration of plant-microbe asynchrony, with an average increase of 25% across the experiment. Snow exclusion shortened asynchrony duration by 8% on coarse soils in the second year of the experiment. Climate treatments generally elevated nutrient losses from fine but not coarse soils during asynchronies. Longer asynchronies resulted in increased carbon, nitrogen, and magnesium losses, with variation across time, soil type, and nutrient. Our results demonstrate that longer periods of microbial activity in the absence of plant uptake generally compound nutrient losses, but the magnitude of these losses depends on soil type and individual nutrients.
在季节性积雪覆盖的生态系统中，气候变化下不断变化的温度和积雪动态增加了土壤温度出现的频率和持续时间，这些温度在植物休眠期间支持微生物活动。在这些没有植物活动的微生物活动时期（即植物 - 微生物不同步），积累的土壤养分容易遭受淋失，这可能对生态系统生产力产生重要影响。此外，不同步现象在空间上可能并非均匀发生；相反，其发生可能受到地下特征的调节。例如，土壤质地会调节生物地球化学循环和持水能力，并可能减轻或加剧植物 - 微生物不同步期间的养分损失。在这里，我们量化了气候变化处理和土壤特征如何改变植物和微生物活动的同步性，以及对土壤养分（碳、氮、磷）和环境扰动后易迁移的阳离子（钙、镁和铝）淋失的相关影响。为此，我们进行了一项森林幼树中尺度实验，对两种土壤施加了重复的升温及除雪处理。为了估计不同步的程度和影响，我们在两年内测量了土壤温度和植物物候，以建立一个不同步持续时间指数，并将其与测量的养分和阳离子淋失损失相关联。我们发现，升温持续增加了植物 - 微生物不同步的持续时间，整个实验期间平均增加了25%。在实验的第二年，除雪使粗质地土壤上的不同步持续时间缩短了8%。气候处理通常在不同步期间提高了细质地土壤而非粗质地土壤的养分损失。更长的不同步时间导致碳、氮和镁的损失增加，且随时间、土壤类型和养分而变化。我们的结果表明，在没有植物吸收的情况下，更长时间的微生物活动通常会加剧养分损失，但这些损失的程度取决于土壤类型和个别养分。
