6\u201310 March 2024<\/p>\n\n\n\n
Location of sites<\/strong><\/p>\n\n\n\n Epena Forest Edge (code EFE), 1.347618\u00b0N, 17.43732\u00b0E, 5 chambers, 3 sessions<\/p>\n\n\n\n Epena Forest Interior (code EFI), 1.3567112\u00b0N, 17.4369014,5771\u00b0E, 6 chambers, 4 sessions<\/p>\n\n\n\n Epena Grassland A (code EGA), 1.342428\u00b0N, 17.442750\u00b0E, 6 chambers, 3 sessions<\/p>\n\n\n\n Epena Grassland B (code EGB),\u00a01.347639\u00b0N, 17.43819\u00b0E, 6 chambers, 3 sessions<\/p>\n\n\n\n Activity report<\/strong><\/p>\n\n\n\n <\/p>\n","protected":false},"excerpt":{"rendered":" Campaign Report by Jaan P\u00e4rn, Mikk Espenberg, Kaido Soosaar, Sten Mander, and \u00dclo Mander Duration of campaign 6\u201310 March 2024 Location of sites Epena Forest Edge (code EFE), 1.347618\u00b0N, 17.43732\u00b0E, 5 chambers, 3 sessions Epena Forest Interior (code EFI), 1.3567112\u00b0N, …<\/p>\n","protected":false},"author":325,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"inline_featured_image":false,"footnotes":""},"class_list":["post-156","page","type-page","status-publish","hentry"],"acf":[],"_links":{"self":[{"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/pages\/156","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/users\/325"}],"replies":[{"embeddable":true,"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/comments?post=156"}],"version-history":[{"count":5,"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/pages\/156\/revisions"}],"predecessor-version":[{"id":174,"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/pages\/156\/revisions\/174"}],"wp:attachment":[{"href":"https:\/\/sisu.ut.ee\/peatlandn2o\/wp-json\/wp\/v2\/media?parent=156"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
During the expedition, we measured fluxes of three gases: carbon dioxide (CO2<\/sub>), methane (CH4<\/sub>) and nitrous oxide (N2<\/sub>O) in the four sites using opaque soil chambers. Each site received 6 soil chambers randomly placed in a radius of ~50 meters from the centre of the site. The CO2<\/sub>, CH4<\/sub> and N2<\/sub>O gas concentrations were sampled using the static chamber method with PVC collars of 0.5 m diameter and 0.1 m depth installed in the soil (Figures 1\u20134). We used white 65 L PVC truncated conical gas sampling chambers. Gas concentration will be measured at 20-minute intervals (0, 20, 40 and 60 minutes). We conducted up to 3 sessions per day \u2013 from 8 am to 6 pm \u2013 to represent the full day.
Figure 1. Gas, soil and plant sampling by Mikk Espenberg, Berveri Mboungu and Sten Mander at the EFI site.
<\/td>![\"\"](\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/659\/fig-1.png\")
<\/td><\/tr>![\"\"](\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/659\/fig.4-1.png\")
<\/td>To measure tree stem gas fluxes in the two forest sites, we used the static closed tree stem chamber method (Figures 5\u20137). We equipped 3 trees per site. At each measurement level, two chambers were placed on the opposite side of the tree stem. The installation was done on the first day of fieldwork before measurements. The rectangular chambers were made of transparent plastic containers, including removable airtight lids (Lock & Lock, South Korea). Before the installation, the bottom of the chamber was cut and hot-glued with a neoprene band. The chambers were sealed to the smoothened stem surface with the cord and checked for gas-tightness with an EGM-5 portable CO2<\/sub> gas analyser (PP Systems). The chambers were installed at each tree stem\u2019s base, as close to the ground as possible (25\u201335 cm). In addition, to assess the tree stem vertical flux profile, on three stems per plant species, the fluxes were also studied at the heights of 75\u201385 and 165\u2013175 cm above the ground.
During each measurement session, four gas samples (25 ml) were collected through septa from both closed chambers (12.5 ml from either chamber) as the mixed gas samples in a 60 min interval (a 0\u201360\u2013120\u2013180 min sequence) and stored in pre-evacuated (0.3 bar) gas-tight glass vials (Labco Limited, Lampeter, United Kingdom). After the sample collection, the chamber remained open till the next measurement session.
Figure 2. Gas sampling by Jaan P\u00e4rn at EGA site
<\/td><\/tr>All gas samples were transported to a laboratory at the University of
Tartu and analysed by gas chromatography (GC-2014; Shimadzu, Ky\u014dto, Japan)
instrumented with an electron capture detector for the detection of N2O
and a flame ionisation detector for CH4, and Loftfield-type
autosamplers.
Additionally, each site was equipped with a 1 m deep observation well (a
0.075m perforated PP-HT pipe wrapped in filter textile). Water table height was
recorded from the observation wells during the gas sampling. Soil moisture was
measured with a Teros 12 sensor (Figure 2). Soil temperature was measured
between 0.1 to 0.4 m depth at an interval of 0.1 m. Soil oxygen content was
measured with a stand-alone fibre optic oxygen meter (PreSens, Regensburg,
Germany) at 0.1m depth. A ~200 g peat sample was collected from each chamber at
0\u20260.1m and 0.2\u20260.4m depths after the gas flux measurements (Figures 8\u201310). The
peat samples were transported to Estonia for laboratory chemical and
microbiological analyses.
Figure 3. Peat sampling by \u00dclo Mander and Berveri Mboungou at the EFE site
<\/td>![\"\"](\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/659\/fig.3.png\")
<\/td><\/tr>![\"\"](\"https:\/\/sisu.ut.ee\/wp-content\/uploads\/sites\/659\/Fig.-5.png\")
<\/td>All the gas analyses and soil physical-chemical analyses are done; the
soil microbiome qPCR analysis is also completed and high-throughput metagenomic
the analysis is almost completed.
At present, we are analysing data. Greenhouse gas (GHG; CO2,
CH4 and N2O) fluxes were very low, most probably due to
the severely dry conditions during our study period. Only the forest soil
showed remarkable N2O emission. In all sites, CH4 was
consumed. N-cycle and CH4-cycle control gene abundancies we accordingly
low.
As a whole, the campaign successfully identified the peatlands
characteristic of Congo (Figures 11 and 12), and established four study sites.
The next field campaign is planned for the wet season of the year (November
2024).
Figure 4. Preparation and installation of stem chambers by Kaido Soosaar, Mikk Espenberg and Berveri Mboungou on a Guibourtia <\/em>tree at the EFE site<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n