Release of CO2 and CH4 from lakes and drainage ditches in temperate wetlands

Abstract

Shallow fresh water bodies in peat areas are important contributors to greenhouse gas fluxes to the atmosphere. In this study we determined the magnitude of CH 4 and CO 2 fluxes from 12 water bodies in Dutch wetlands during the summer season and studied the factors that might regulate emissions of CH 4 and CO 2 from these lakes and ditches. The lakes and ditches acted as CO 2 and CH 4 sources of emissions to the atmosphere; the fluxes from the ditches were significantly larger than the fluxes from the lakes. The mean greenhouse gas flux from ditches and lakes amounted to 129.1 ± 8.2 (mean ± SE) and 61.5 ± 7.1 mg m -2 h -1 for CO 2 and 33.7 ± 9.3 and 3.9 ± 1.6 mg m -2 h -1 for CH 4 , respectively. In most water bodies CH 4 was the dominant greenhouse gas in terms of warming potential. Trophic status of the water and the sediment was an important factor regulating emissions. By using multiple linear regression 87% of the variation in CH 4 could be explained by PO 4 3-concentration in the sediment and Fe 2?concentration in the water, and 89% of the CO 2 flux could be explained by depth, EC and pH of the water. Decreasing the nutrient loads and input of organic substrates to ditches and lakes by for example reducing application of fertilizers and manure within the catchments and decreasing upward seepage of nutrient rich water from the surrounding area will likely reduce summer emissions of CO 2 and CH 4 from these water bodies.

High net CO<sub>2</sub> and CH<sub>4</sub> release at a eutrophic shallow lake on a formerly drained fen

“…The importance of small open water bodies in wetlands as considerable GHG sources was highlighted in previous studies (e.g. by Schrier-Uijl et al, 2011;Zhu et al, 2012;IPCC, 2014) and in the case of CH 4 even for landscape-scale budgets (e.g. by Repo et al, 2007).…”

An embodied carbon and embodied energy appraisal of a section of Irish motorway constructed in peatlands

“…Emission rates in a temperate climate ranged from 12.7 to 27.3 tCO 2 eqha -1 yr -1 (Table 4), thus an average emission rate of 20 tCO 2 eqha -1 yr -1 was assumed for the ditches and ponds at Pollboy for the 120-year life cycle. [49] Mesotropic/eurotrophic status 27.3 Schrier-Uijl et al [47] Eutrophic fen (intensive) 25.4 Schrier-Uijl et al [47] Eutrophic fen (less intensive) 12.3 Hendriks et al [46] Restored agricultural peat meadow 12.7 Average 19.4 (~20) Figure 6 -Clogged stream diversion shown at front and peat disposal area in background at Pollboy 3 years after construction…”

Microbial biomass in sediments affects greenhouse gas effluxes in Poyang Lake in China

“…Lake sediments produce large quantities of greenhouse gases (GHGs), including carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O), through biological processes (Bastviken et al 2004;Schrier-Uijl et al 2011). Previous studies have shown that, globally, lakes have emitted 71.6 Tg CH 4 /yr and 1943 Tg CO 2 /yr into the atmosphere (Tranvik et al 2009;Bastviken et al 2010Bastviken et al , 2011.…”

“…However, it is reported that GHG emissions from global lakes are still underestimated and poorly constrained due to the spatial variation of GHG emissions and an impoverished understanding of the mechanisms behind GHG production (Yang et al 2011;IPCC 2013). Especially, past studies about GHG emissions in lake ecosystems have mainly focused on the sources and sinks of GHGs or the relationships between GHG effluxes and various abiotic factors (Bastviken et al 2011;Schrier-Uijl et al 2011;Liu et al 2013). In fact, abiotic factors influence GHG effluxes by affecting microbes which degrade organic matter to produce GHGs in lake sediments.…”