The Effects of Soil Temperature and Nitrate on Fine Root Construction and Maintenance Costs in Northern Hardwood Forests

超过一半的碳固定在森林的叶子上 树木在光合作用过程中被分配到生产优良 但污染和气候变化对环境的影响， 这些根的产量和寿命是未知的。 我们将研究 土壤温度与土壤硝态氮关系 五大湖地区的常见污染物）和生产， 死亡的细根在糖枫林，以更好地 预测污染增加和/或气候变化可能发生的情况 温暖。 我们的研究地点相隔几百公里 从北到南，有一个内在的温度梯度 它跨越了可能的温度上升范围， 由于全球变暖而发生。 此外，我们将申请 大量的硝酸盐来观察这种特殊的 污染物的根源。 使用小型摄像机， 关节镜手术，我们将观察出生，生长和死亡 根的小型观测管永久安装在 土壤 使用这种方法，我们可以比较 寒冷和温暖的森林，森林之间受到高， 硝酸盐投入少。 我们还将测量 呼吸 因为活细胞的代谢活动加快了 随着温度的升高，根系呼吸速率应该更高 温暖的土壤。 这意味着生长在温暖土壤上的树木 必须消耗更多的能量来维持足够的活根， 水和养分。 我们认为硝酸盐也会增加根 呼吸速率，因为硝酸盐必须转化为 铵（需要更多的能量）之前，植物可以使用它作为一个 氮源的增长。 这种变化的结果是， 污染物在森林生态系统中的沉积增加。

More than half of all carbon fixed in the leaves of forest trees during photosynthesis is allocated to the production of fine roots, but the effects of pollution and climate change on the production and longevity of these roots is unknown. We will study the relationship between soil temperature and soil nitrate (a common pollutant in the Great Lakes region) and the production and death of fine roots in sugar maple forests in order to better predict what might happen in pollution increases and/or the climate warms. Our study sites are separated by several hundred kilometers from north to south, and there is a built-in temperature gradient that spans the possible range of temperature increases that may occur due to global warming. In addition, we are going to apply large amounts of nitrate to see what effect this particular pollutant has on the roots. Using small cameras first developed for use during arthroscopic surgery, we will observe the birth, growth and death of roots from small observation tubes permanently installed in the soil. Using this approach, we can compare root activity between colder and warmer forests, and between forests subject to high and low inputs of nitrate. We will also measure rates of root respiration. Because metabolic activity in living cells speeds up as temperatures increase, root respiration rates should be higher in warmer soils. This means that the trees growing on warmer soils must expend more energy to maintain enough living roots to take up water and nutrients. we think that nitrate will also increase root respiration rates, because the nitrate must be converted to ammonium (requiring more energy) before plants can use it as a source of nitrogen for growth. The results form this change and increased pollutant deposition on forest ecosystems.