Atmospheric reactive nitrogen (N) deposition has more than doubled over the past century. It is very important to estimate the rates and sources of N deposition because it’s considered as a main factor of ecosystem structure changes, such as soil acidification, water eutrophication and biodiversity losses, especially in countries with high N deposition, such as China. However, it is very difficult to obtain monitoring data of atmospheric N deposition because of the complexity of N species and the diversity of deposition forms.
Mosses are very widespread. Almost all of nitrogen for mosses growth are from air and rainfall. Therefore, many researchers investigate N deposition levels and its effects by using moss, especially in Europe and Southwest China. However, whether mosses can be used to monitor atmospheric N deposition in the Yangtze River Delta (YRD) region has yet to be determined.
“We collected rainwater and moss tissue at six monitoring sites in the YRD with three land-use types–urban, suburban, and rural and analyzed moss (
Haplocladium microphyllum
) N content, wet N deposition rate, and their N isotope signatures.” says Dr. Tao Huang, from the School of Geography, Nanjing Normal University.
Based on this study, they found a significant linear relationship between moss N content and wet N deposition rate. In addition, they also determined a consistent decreasing trend for moss N content and wet N deposition from urban to suburban to rural areas. The more negative N isotopic signature of suburban and rural mosses indicated N is mainly released from agricultural ammonia, while the less negative N isotopic signature of urban mosses highlighted a main influence from fossil fuel combustion and traffic emissions. The findings are published in
Atmospheric and Oceanic Science Letters
.
“The important revelation of our study is that the epilithic moss
Haplocladium microphyllum
can bio-monitor the rates and sources of atmospheric N deposition in the YRD, making up for the lack of monitoring data of N deposition,” concludes Dr. Huang.
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This part of information is sourced from https://www.eurekalert.org/pub_releases/2019-11/ioap-mab111519.php
Ms. Zheng Lin
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