Purchase of growth chambers for studying micronutrient dynamics at the soil-plant interface

生物体容易获得一些元素，如O2，CO2和H2O。但其他元素的获取，如氮（N）或微量营养素（金属），可能更困难。固氮作用，即在原核生物固氮酶的催化下将N2（气体）生物还原为铵，是新氮进入自然生态系统的主要途径。N2固定在局部、区域和全球尺度上影响植物生长和碳（C）交换。由于微量金属的生物利用度虽然具有潜在毒性，但会影响关键的酶活性，如固氮酶的活性，因此环境中金属的循环会严重影响主要营养素如N或C的循环。尽管微量营养素和固氮在陆地生态系统中至关重要，但控制其在环境中动态的过程仍然知之甚少。这种认识不足限制了我们全面管理现有生态系统和预测环境对全球气候变化的反应的能力。

Organisms acquire some elements easily, such as O2, CO2 and H2O. But the acquisition of other elements, such as nitrogen (N) or micronutrients (metals), can be more difficult. N2 fixation, the biological reduction of N2(gas) to ammonium catalyzed by the enzyme nitrogenase in prokaryotes, is the main route of entry of new N into natural ecosystems. N2 fixation influences plant growth and carbon (C) exchange at local, regional and global scales. Since trace metal bioavailability, while potentially toxic, affects key enzymatic activities, such as that of nitrogenase, the cycling of metals in the environment can critically impact the cycling of major nutrients such as N or C. Despite the prime importance of micronutrients and N2 fixation in terrestrial ecosystems, the processes controlling their dynamics in the environment remain poorly understood. This poor understanding limits our capacity to manage present ecosystems and predict environmental responses to global climate change in a comprehensive manner.