Luca Belelli Marchesini, Sergey Korovitckii, Alina Totskaya, Dmitry Sherstnev, Valentina Tregubova. Soil greenhouse gas fluxes of natural and artificial land cover types within the FEFU campus area on Russky Island (Vladivostok, Russia)

Oral presentation

Soil greenhouse gas fluxes of natural and artificial land cover types within the FEFU campus area on Russky Island (Vladivostok, Russia)

Luca Belelli Marchesini^1,2,3, Sergey Korovitckii¹, Alina Totskaya¹, Dmitry Sherstnev¹ & Valentina Tregubova¹

¹ Far Eastern Federal University, Vladivostok, Russia
² VU University, Amsterdam, the Netherlands
³ Euro-Mediterranean Centre for Climate Change (CMCC), Lecce, Italy

The commitment to reduce greenhouse gas (GHG) emissions to the atmosphere is currently a priority in the global environmental policy agenda. Gaining knowledge on the effect of land management over land- atmosphere GHG fluxes and individuating the most suitable strategies for the preservation of existing carbon pools in managed ecosystems is therefore of utmost importance. In this respect studies about GHG fluxes over urbanized areas are still a minority despite the plethora of existing initiatives aiming at helping society to reach carbon neutrality. Here we present the first step towards the assessment of the GHG budget of the campus area of the Far Eastern Federal University, focusing on biogenic fluxes of CO2 and CH4 from soils. Soil fluxes were monitored since spring 2017 through replicated measurements over five different land cover/management types including both pre-existing and transformed areas within the campus territory of the FEFU (natural forest, natural meadow, artificial pond, urban forest park, artificial meadow). Laser spectroscopy based measurements were carried out with a state of the art portable analyzer and a chamber set-up allowing mean uncertainty levels of 0.7% (std.err.) on CO2 fluxes computation and 2% on CH4 fluxes, the latter conditional to fluxes larger than 0.5 nmolCH4 m-2 s-1. Meadow soils showed the largest CO2 emission rates, with maximum values up to 7-8 µmolCO2 m-2 s-1, partly due to systematically warmer soil conditions. Soil temperature was indeed found the most important driver of soil respiration and together with soil organic carbon pools and fine root biomass best explained the observed spatial and temporal variability (R2=0.67). A temperature independent comparison of soil respiration fluxes determined the meadows and ponds as the highest and lowest CO2 emitters, although soil CO2 fluxes in the natural forest exhibited a larger temperature sensitivity (Q10=2.29-natural forest; 1.48-natural meadow; 1.61-pond). Methanotrophic activity in soils was observed widely and it was most intense in the natural forest, generating fluxes up to -1.7 nmol CH4 m-2 s-1, twofold larger than in the natural meadow. Significant methane emissions (0.5 nmol CH4 m-2 s-1 )were observed only along the pond banks after the start of the summer monsoon.