Scotland: climate change and drinking peatlands water could increase DOC issue?

The peat bog is an environment characterized by an abundance of slow-moving, low-temperature water

by Lorenzo Ciotti
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Scotland: climate change and drinking peatlands water could increase DOC issue?

The peat bog is an environment characterized by an abundance of slow-moving, low-temperature water. In this environment, a mainly herbaceous vegetation develops, typical of humid places, bryophytes but also Graminea, Cyperaceae and others.

The term is used either to mean a bog on peat-rich soil or a high or intermediate bog. Consequently, every bog is also a bog, but not all bogs are classifiable as bogs. In a humid and cold environment in the presence of large quantities of tannic compounds and acid substances, the activity of the bacteria which naturally degrade the organic substance is strongly inhibited, moreover the silty environment with poor circulation of water and therefore poor in oxygen makes the environment inhospitable for microorganisms.

The plant material that derives from the biological cycle of the plants that live in the peat bog therefore tends progressively to accumulate in layers giving rise to peat, together with the remains of animals such as insects.

The study Climate change and drinking water from Scottish pealands: Where increasing DOC is an issue?, published in the Journal of environmental management, told: "Increasing levels of dissolved organic carbon (DOC) have been detected in the last decades in water bodies of the Northern hemisphere, and climate change might fuel this rise.

For drinking water reservoirs located in peatland catches, already subjected to elevated amounts of DOC that needs to be removed, this might pose a further problem. Scotland is predicted to face warmer temperatures and a change in rainfall patterns, which will result in more frequent and severe summer droughts and in heavier winter precipitation.

These conditions are not ideal for peatlands, which may undergo a drastic reduction in area.Using two bioclimatic envelope models (Blanket bog Tree model and Lindsay Modified model) that project blanket bog distribution in Scotland in the 2050s, we extracted the area of blanket bog that is at risk of loss.Assuming that part of the carbon stored in this area is likely to be lost, we calculated how much of it could be added to DOC in catchments that contain public dr inking water reservoirs each year.

This analysis is a first estimate of the risk for the provision of drinking water from peatlands in Scotland due to climate change. The aim is to identify the catches that may face the highest consequences of future climates in terms of the concentration of DOC ([DOC]), where more sophisticated water treatments might be needed.

Our results show a great variability among the catches, with only a few being unaffected by this problem, whereas others could experience substantial seasonal increase in [DOC]. This highlights the necessity to frequently monitor DOC levels in the reservoirs located in catchments where the major problems could arise, and to take the necessary measures to reduce it.

Given that peatland condition and vegetation cover play a fundamental role in influencing DOC losses, this study also offers an indication of where peatland restoration might be useful to counteract the projected DOC increase and bring the highest benefits in terms of safe drinking water provision."