The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

Abstract. Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought-tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that peat DOC that had been exposed to oxygen was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on the amount of DOC production from vegetation litters; however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought-tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter layer effects. Long-term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas pulses related to drought may be observed in peat soils and are likely to become more common in the future. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch blocking to raise water tables.

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The effect of drought on dissolved organic carbon (DOC) release from peatland soil and vegetation sources

10.5194/bg-2016-517 ◽

2017 ◽

Author(s):

Jonathan P. Ritson ◽

Richard E. Brazier ◽

Nigel J. D. Graham ◽

Chris Freeman ◽

Michael R. Templeton ◽

...

Keyword(s):

Water Treatment ◽

Organic Carbon ◽

Dissolved Organic Carbon ◽

Unit Weight ◽

Catchment Management ◽

Litter Layer ◽

Peat Soils ◽

Drought Tolerant ◽

Doc Production ◽

The Impact

Abstract. Drought conditions are expected to increase in frequency and severity as the climate changes, representing a threat to carbon sequestered in peat soils. Downstream water treatment works are also at risk of regulatory compliance failures and higher treatment costs due to the increase in riverine dissolved organic carbon (DOC) often observed after droughts. More frequent droughts may also shift dominant vegetation in peatlands from Sphagnum moss to more drought tolerant species. This paper examines the impact of drought on the production and treatability of DOC from four vegetation litters (Calluna vulgaris, Juncus effusus, Molinia caerulea and Sphagnum spp.) and a peat soil. We found that mild droughts caused a 39.6 % increase in DOC production from peat and that this DOC was harder to remove by conventional water treatment processes (coagulation/flocculation). Drought had no effect on DOC production from vegetation litters, however large variation was observed between typical peatland species (Sphagnum and Calluna) and drought tolerant grassland species (Juncus and Molinia), with the latter producing more DOC per unit weight. This would therefore suggest the increase in riverine DOC often observed post-drought is due entirely to soil microbial processes and DOC solubility rather than litter-layer effects. Long term shifts in species diversity may, therefore, be the most important impact of drought on litter layer DOC flux, whereas more immediate effects are observed in peat soils. These results provide evidence in support of catchment management which increases the resilience of peat soils to drought, such as ditch-blocking to raise water-tables.

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The impact of dissolved organic carbon and bacterial respiration on pCO2 in experimental sea ice

Progress In Oceanography ◽

10.1016/j.pocean.2015.12.005 ◽

2016 ◽

Vol 141 ◽

pp. 153-167 ◽

Cited By ~ 1

Author(s):

J. Zhou ◽

M. Kotovitch ◽

H. Kaartokallio ◽

S. Moreau ◽

J.-L. Tison ◽

...

Keyword(s):

Organic Carbon ◽

Sea Ice ◽

Dissolved Organic Carbon ◽

Bacterial Respiration ◽

The Impact

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Effects of managed burning in comparison with vegetation cutting on dissolved organic carbon concentrations in peat soils

Hydrological Processes ◽

10.1002/hyp.9474 ◽

2012 ◽

Vol 27 (26) ◽

pp. 3994-4003 ◽

Cited By ~ 10

Author(s):

Fred Worrall ◽

James Rowson ◽

Simon Dixon

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Peat Soils ◽

Carbon Concentrations

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Modelling the impact of drainage and drain-blocking on dissolved organic carbon release from peatlands

Journal of Hydrology ◽

10.1016/j.jhydrol.2007.02.016 ◽

2007 ◽

Vol 338 (1-2) ◽

pp. 15-27 ◽

Cited By ~ 22

Author(s):

F. Worrall ◽

H.S. Gibson ◽

T.P. Burt

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Carbon Release ◽

The Impact

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Small-scale drinking water treatment unit of filtration and UV disinfection for remote area

Water Science & Technology Water Supply ◽

10.2166/ws.2020.109 ◽

2020 ◽

Vol 20 (6) ◽

pp. 2106-2118

Author(s):

Kassim Chabi ◽

Jie Zeng ◽

Lizheng Guo ◽

Xi Li ◽

Chengsong Ye ◽

...

Keyword(s):

Water Quality ◽

Drinking Water ◽

Water Treatment ◽

Organic Carbon ◽

Dissolved Organic Carbon ◽

Bacterial Community Composition ◽

Drinking Water Treatment ◽

Small Scale ◽

Treatment Unit ◽

Remote Areas

Abstract People in remote areas are still drinking surface water that may contain certain pollutants including harmful microorganisms and chemical compounds directly without any pretreatment. In this study, we have designed and operated a pilot-scale drinking water treatment unit as part of our aim to find an economic and easily operable technology for providing drinking water to people in those areas. Our small-scale treatment unit contains filtration and disinfection (UV–C irradiation) stages to remove pollutants from source water. The water quality index was determined based on various parameters such as pH, temperature, dissolved oxygen, nitrate, nitrite, ammonium, phosphorus, dissolved organic carbon and bacteria. Water and media samples after DNA extraction were sequenced using Illumina MiSeq throughput sequencing for the determination of bacterial community composition. After the raw water treatment, the reduction of bacteria concentration ranged from 1 to 2 log10. The average removal of the turbidity, ammonium, nitrite, phosphorus and dissolved organic carbon reached up to 95.33%, 85.71%, 100%, 28.57%, and 45%, respectively. In conclusion, multiple biological stages in our designed unit showed an improvement of the drinking water quality. The designed drinking treatment unit produces potable water meeting standards at a lower cost of operation and it can be used in remote areas.

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Open water metabolism and dissolved organic carbon in response to environmental watering in a lowland river–floodplain complex

Marine and Freshwater Research ◽

10.1071/mf15318 ◽

2016 ◽

Vol 67 (9) ◽

pp. 1346 ◽

Cited By ~ 1

Author(s):

Todd A. Wallace ◽

Deborah Furst

Keyword(s):

Organic Carbon ◽

Dissolved Organic Carbon ◽

Food Webs ◽

Ecosystem Respiration ◽

Open Water ◽

Relative Role ◽

Eastern Australia ◽

Return Flows ◽

Receiving Waters ◽

The Impact

The relative importance of autochthonous and allochthonous organic material in fuelling ecosystem metabolism is increasingly understood for some river systems. However, in south-eastern Australia, the majority of studies have been conducted during low flows when the supply of allochthonous carbon was limited. Consequently, the importance of episodic inputs of terrestrially derived material in supporting these food webs remains poorly understood. We assessed the influence of return flows from two different scales of environmental watering actions on dissolved organic carbon and open-water productivity in receiving waters adjacent to the watered area. For the wetland-scale event, gross primary productivity and ecosystem respiration increased in the receiving waters during the period of return flows. During the floodplain-scale watering, differences were observed among sites. Within the managed inundation zone, values for net ecosystem productivity switched from near zero during the baseline to strongly negative during the impact period, whereas values at the river sites were either near zero or positive. The results contribute to our understanding of the relative role of allochthonous material in supporting aquatic food webs in lowland rivers, and demonstrate potential for watering actions to have a positive influence on riverine productivity during periods of low water availability.

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