Temperature Control of Spring CO2 Fluxes at a Coniferous Forest and a Peat Bog in Central Siberia

Sung-Bin Park,Mirco Migliavacca,Tea Thum,Olli Peltola,Sang Seo Park,Ivan Mammarella,Timo Vesala,Martin Heimann,Olaf Kolle,Jošt Lavrič,Alexander Knohl,Anatoly Prokushkin

doi:10.3390/atmos12080984

Abstract

Climate change impacts the characteristics of the vegetation carbon-uptake process in the northern Eurasian terrestrial ecosystem. However, the currently available direct CO2 flux measurement datasets, particularly for central Siberia, are insufficient for understanding the current condition in the northern Eurasian carbon cycle. Here, we report daily and seasonal interannual variations in CO2 fluxes and associated abiotic factors measured using eddy covariance in a coniferous forest and a bog near Zotino, Krasnoyarsk Krai, Russia, for April to early June, 2013–2017. Despite the snow not being completely melted, both ecosystems became weak net CO2 sinks if the air temperature was warm enough for photosynthesis. The forest became a net CO2 sink 7–16 days earlier than the bog. After the surface soil temperature exceeded ~1 °C, the ecosystems became persistent net CO2 sinks. Net ecosystem productivity was highest in 2015 for both ecosystems because of the anomalously high air temperature in May compared with other years. Our findings demonstrate that long-term monitoring of flux measurements at the site level, particularly during winter and its transition to spring, is essential for understanding the responses of the northern Eurasian ecosystem to spring warming.

Highlights

Boreal forests and peatlands are the major terrestrial biomes and large carbon (C) reservoirs in northern Eurasia, occupying 49% and 25% of Russia’s land area, respectively [1,2].Both ecosystems are considered essential C sinks in the global C cycle [2,3,4,5,6,7,8]
CO2 flux observations at the Zotino sites showed that distinct differences exist in flux magnitude, the timing of start of net CO2 uptake, and the rate of CO2 uptake between the boreal forest and bog
The boreal forest generally changed from net CO2 source to net CO2 sink approximately 1–2 weeks earlier than the bog

Summary

Introduction

Boreal forests and peatlands are the major terrestrial biomes and large carbon (C) reservoirs in northern Eurasia, occupying 49% and 25% of Russia’s land area, respectively [1,2]. Both ecosystems are considered essential C sinks in the global C cycle [2,3,4,5,6,7,8]. Considering only CO2 exchange processes, both boreal forests and peatlands in northern Eurasia are generally considered as net CO2 sinks during the snow-free season [15,16,17,18].

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