State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China.
Environ Pollut. 2010 Jun;158(6):2273-81. doi: 10.1016/j.envpol.2010.02.005. Epub 2010 Mar 4.
Epilithic mosses are characterized by insulation from substratum N and hence meet their N demand only by deposited N. This study investigated tissue C, total Chl and delta13C of epilithic mosses along 2 transects across Guiyang urban (SW China), aiming at testing their responses to N deposition. Tissue C and total Chl decreased from the urban to rural, but delta13C(moss) became less negative. With measurements of atmospheric CO2 and delta13CO2, elevated N deposition was inferred as a primary factor for changes in moss C and isotopic signatures. Correlations between total Chl, tissue C and N signals indicated a nutritional effect on C fixation of epilithic mosses, but the response of delta13C(moss) to N deposition could not be clearly differentiated from effects of other factors. Collective evidences suggest that C signals of epilithic mosses are useful proxies for N deposition but further works on physiological mechanisms are still needed.
附生苔藓的特点是与基质 N 隔离，因此只能通过沉积的 N 来满足其 N 需求。本研究通过在中国西南部贵阳城市的 2 条横断面上对附生苔藓的组织 C、总 Chl 和 delta13C 进行了调查，旨在测试它们对 N 沉积的响应。组织 C 和总 Chl 从城市到农村减少，但 delta13C（苔藓）变得不那么负。通过对大气 CO2 和 delta13CO2 的测量，推断出升高的 N 沉积是苔藓 C 和同位素特征变化的主要因素。总 Chl、组织 C 和 N 信号之间的相关性表明，N 沉积对附生苔藓的 C 固定具有营养作用，但 delta13C（苔藓）对 N 沉积的响应不能明显区分于其他因素的影响。综合证据表明，附生苔藓的 C 信号是 N 沉积的有用指标，但仍需要进一步研究生理机制。
