Impacts of global climate change on vulnerable ecosystems

Background/Question/Methods

Global climate change effects on various ecosystems in various way. Especially, wetland and arctic soils are vulnerable to global climate change and contain a large amount of undecomposed carbon. Responses of these vulnerable ecosystems to global climate change should be considered because the responses can further accelerate global climate change by adding extra carbon into the atmosphere in the form of CO₂ or methane. In this study, we examined the effects of temperature increase on vulnerable ecosystems such as wetlands and arctic regions. We conducted temperature rising experiments in two different ways: in situ and incubation approach. We examined methane fluxes and microbial community structure at fourteen wetlands with 7 different latitudes from 30°N to 37°N in Mississippi basin for determining the effects of temperature on wetland ecosystems. The difference between the highest and the lowest latitude on a given day is about 4 ˚C during both the summer and winter for daily mean temperature. In addition, we also conducted the incubation experiments with the soils from arctic region and measured the greenhouse gas fluxes and microbial community structure as well.

Results/Conclusions

CH₄ fluxes for wetland soils were large in middle latitude and positively correlated with soil organic matter level which can be affected by temperature increase. However, community composition and species richness of methane-related microorganisms did not show any differences among the latitudes. For the arctic incubation experiment, the largest emission rates of CO₂ and N₂O were found at 10°C, while the lowest values were demonstrated at 0°C and -20°C, respectively. However, the pattern of CH₄ emission was different from the other gases. The difference was caused by diverse responses of CH₄ production and oxidation processes at different temperature. The changes of CH₄ related microorganisms were distinct as the temperature rise. Temperature increase impacts on vulnerable ecosystems in diverse way.