Tuesday, 6 February 2018

Part 2 - Wetlands against Climate Change! Perfectly Peaty: How Peatlands are an Amazing Carbon Sink


18% of Canada is covered in wetlands,  and they comprise a quarter of all the wetlands on earth!  Canada’s wetlands include peatlands, a specific type of wetland also known as bogs and fens, that produce peat  (See SAM Blog "Know your Wetland Classes" to learn more about types of wetlands!) In Newfoundland and Labrador, bogs and fens are very common and you don’t have to go far in to get your boots stuck in thick peat.

Boots on the ground in the peat bog at Gosse's Pond Management Unit in Torbay, Newfoundland


Climate change scientists have stated that peatlands are very important when it comes to carbon sequestration. The Intergovernmental Panel on Climate Change (IPCC) have listed the restoration of peat soils as a mechanism of mitigation against climate change. But what is peat and how is it formed? How does peat store carbon? And what can we do as communities and individuals to advocate for climate change mitigation?

Peatland in Western Newfoundland
Peat is composed almost entirely of decayed and decomposing organic matter. Depending on the peatland, the organic matter can be made up of different mosses, sedges, and other herbaceous plants. When these plants die they decompose very slowly. Decomposition rates vary across different peatlands, but in general decomposition requires oxygen, and the waterlogged habitats of peatlands reduce the amount of oxygen available, which in turn slows the decomposition process. In northern wetlands the accumulation of slowly decomposing peat happens over a millennia. According to a study at Laval University, it takes thousands of years to develop peat soils between 1.5 – 2.3m thick in northern peatlands. Most of the peatlands that exist today were formed after the last ice age over 15,000 years ago.

In Newfoundland and Labrador a common type of peatland is a sphagnum bog, made up of mostly sphagnum moss. Sphagnum has been referred to as a “bogbuilder” because of its ability to seemingly “create” the wetland. 

Sphagnum moss in Pippy Park, St. John's, NL and
diagram of  individual sphagnum plant
A Sphagnum bog is made up of thousands of individual plants. The tops of the plants are exposed to the sun and photosynthesize, meaning they use carbon dioxide to produce sugars and food, and release oxygen as a bi-product.  Sphagnum is very good at “bog building” or creating peat because underneath the leaves on the surface are a long trails of dead and decomposing leaves (See the brown leaves in the diagram on the right). These dead leaves are specialized to hold up to 3 times their weight in water, which helps to facilitate an anaerobic peatland environment, slow decomposition and the ‘building’ of bogs or peatlands.  

Peatlands naturally expel carbon dioxide and methane, both of which are greenhouse gases, but because the rate of decomposition is so slow, they are able to store much more carbon and then they release, becoming a carbon sink rather than a carbon source. It has been estimated that globally peatlands contain at least 550 Gt of Carbon which is double the amount stored in the world’s forests (see graph below for a comparison of carbon stored in terrestrial habitats!). Peatlands alone cover an estimated 3% of the world’s land area, but they hold 30% of the terrestrial carbon. Also, because it takes thousands of years for peatlands to develop they are considered the most important long term carbon store in the terrestrial biosphere. Some people consider peatlands to be the most efficient carbon sink on the planet!

Carbon stored in terrestrial habitats Source; http://csites.eds.oinl.gov/faqs.html 

As amazing as they are, peatlands and wetlands are also very vulnerable to anthropogenic disturbance. Scientists have estimated that at least 64% of the world’s wetlands have disappeared since 1900. Pressures from agriculture, animal grazing, water diversion, infrastructure, and pollution are driving the loss of wetlands globally 

So what happens if a bog is disturbed?  When peatlands are burned or drained for (i.e. for agriculture) they go from being a carbon sink to a carbon source. According to an assessment of peatlands, biodiversity and climate change prepared for the United Nations Environmental Programme, carbon dioxide emissions from peatland fires, drainage and extraction is equal to 3000 million tonnes per annum or more than 10% of all annual fossil fuel emissions per year. Without careful conservation the mitigating effects of peatlands will be lost and the anthropogenic destruction of peatlands will instead contribute to climate change.

To safeguard these incredible habitats, communities can take action in many ways! For example, organizing clean ups in local wetlands can help keep wetlands healthy and raise their public profile. Also, municipalities and residents can show their support for wetland policies that promote the sustainable use of wetlands and practice sustainable fishing, tourism, and agriculture. 


Municipal Representatives during the SAM Fall Meeting 2017 visiting the
Corduroy Brook Nature Trail, a Management Unit 
in Grand Falls-Windsor, NL
SAM communities have already taken the first step in recognizing the values of wetlands by designating conservation areas within their municipal boundaries. Let’s keep the momentum moving and become Wetland Ambassadors by advocating for the sustainable use of wetlands to help mitigate Climate Change!

So the next time your boot gets stuck in a bog when you are looking for bakeapples remember, peatlands are doing their part to mitigate climate change and by protecting them, we are doing our part for generations to come! Join us next month and learn more about wetlands flood mitigating properties in “Hold back the Gates: Wetlands mitigating flooding”! For more information on peatlands and climate change check out the resources below!

Resources:
1.       “Assessment on peatlands, biodiversity and climate change: Executive summary” 2007 – 2008 UNEP-GEF http://ledsgp.org/wp-content/uploads/2015/12/Assessment-on-peatlands-biodiversity-and-climate-change-executive-summary.compressed.pdf  
3.       Barbier, Edward, Mike Acreman and Duncan Knowler “Economic Valuation of Wetlands: A guide for policy makers and planners” Ramsar Convention Bureau, 1997. https://www.ramsar.org/sites/default/files/documents/pdf/lib/lib_valuation_e.pdf
4.       Bengtsson, Fia, Gustaf Granath, Hakan Rydin “Photosynthesis, growth, and decay traits in Sphagnum – A multispecies comparison”. Ecology and Evolution, 2016 May 6(10):3325-3341. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4833502/
5.       Ducks Unlimited Canada “Researching Peatlands for Restoration” October 2015. http://www.ducks.ca/stories/boreal-forest/researching-and-restoring-peatlands/   
6.       Government of Canada, Environment and Natural Resources “Water Sources: Wetlands” https://www.canada.ca/en/environment-climate-change/services/water-overview/sources/wetlands.html
7.       Irish Peatland Conservation Council, website “Sphagnum Moss – The Bog Builder” http://www.ipcc.ie/a-to-z-peatlands/sphagnum-moss-the-bog-builder/
8.       Hugron, Sandrine, Julie Bussieres and Line Rochefort. “Tree plantations within the context of ecological restoration of peatlands: practical guide. Peatland Ecology research group, Universite Laval. 2013. http://www.gret-perg.ulaval.ca/uploads/tx_centrerecherche/Tree_Plantation_guide.pdf
9.       North Carolina State University (NCSU) Water Quality Group. “Water Shedss: Functions of Wetlands (Processes) http://www.water.ncsu.edu/watershedss/info/wetlands/function.html
10.   Intergovernmental Panel on Climate Change (IPCC) “Climate Change 2007: Synthesis Report 4. Adaptation and mitigation options. https://www.ipcc.ch/publications_and_data/ar4/syr/en/spms4.html
11.   Ovenden, Lynn. “Peat Accumulation in Northern Wetlands” Science Direct, 1990. 33:3 Pg 377-386https://www.sciencedirect.com/science/article/pii/003358949090063Q?showall%3Dtrue%26via%3Dihub
12.   Ramsar Convention on Wetlands, Fact Sheet 8 “Keeping Peatlands wet for a better future” 2015 https://www.ramsar.org/sites/default/files/documents/library/fs_8_peatlands_en_v5.pdf  
13.   Ramsar Convention on Wetlands, Fact Sheet 3 “Wetlands: a global disappearing act” 2015 https://www.ramsar.org/sites/default/files/documents/library/factsheet3_global_disappearing_act_0.pdf
14.   Ramsar Convention on Wetlands, Fact Sheet #1 “Wetlands: Why should I care?” 2015 https://www.ramsar.org/sites/default/files/documents/library/factsheet1_why_should_i_care_0.pdf
15.   Rice, S.K. “Mosses (Bryophytes)” Reference module in earth systems and environmental science, Encyclopedia of inland waters. 2009. Pages 88 – 96. https://www.sciencedirect.com/science/article/pii/B9780123706263002192  
16.   Secretariat, North American wetlands conservation council (Canada) “Wetlands Stewardship in Canada: Contributed papers from the Conference on Canadian Wetlands Stewardship”. 2003/ Canadian Wildlife Services, Environment Canada http://nawcc.wetlandnetwork.ca/Rep03-2e.pdf 


Photo of moss mat: D. Pelley, 2017, Pippy Park, NL

Photo of Lark Harbour Peatland, NL L. King, 2017, Lark Harbour, NL 

Photo of SAM Fall Meeting 2017 D. Pelley, 2017, Grand Falls-Windsor, NL

No comments:

Post a comment