Lakes and the Arctic Carbon Cycle

Lead Research Organisation: University of Southampton
Department Name: School of Geography

Abstract

The Arctic is changing rapidly, and it is predicted that areas which are today tundra will become tree-covered as warming progresses, with, for example, forest spreading northwards to the coast of northern European Russia by 2100. In some parts of the Arctic, such as Alaska, this process, commonly referred to as "greening", has already been observed over the past few decades; woody shrubs are expanding their distribution northwards into tundra. Such vegetation changes influence nutrient cycling in soils, including carbon cycling, but the extent to which they will change the storage or release of carbon at a landscape scale is debated. Nor do we fully understand the role that lakes play in this system although it is known that many lakes in the tundra and northern forests are today releasing carbon dioxide and methane into the atmosphere in significant amounts, and a proportion of this carbon comes into the lake from the vegetation and soils of the surrounding landscape. Lakes form an important part of arctic landscapes: there are many thousands of them in our study areas in Russia and west Greenland, and they act as focal points for carbon cycling within in the wider landscape.

It is vital that we understand the interactions between plants, soils, nutrients, and lakes because there are massive carbon stores in the high northern latitudes, particularly in frozen soils, and if this carbon is transferred into the atmosphere (as carbon dioxide (CO2) or methane) it will create a positive feedback, driving further global warming. For this reason, the Arctic represents a critical component of the Earth System, and understanding how it will it respond to global environmental change is crucial. Lakes are a key link in this process.

As lakes are tightly coupled with terrestrial carbon cycling, changes in the flows of carbon to a lake are faithfully recorded in lake sediment records, as are changes in the biological processing of that carbon within the lake. We also know that similar vegetation changes to those observed or predicted today occurred in the past when climate was warmer than today, and thus past events can provide an analogue for future changes. This project will examine lake sediment records, using techniques that extract a range of chemical signals and microscopic plant and animal remains, to see how vegetation changes associated with past natural climate warming, such as migration of the tree-line northwards, affected lake functioning in terms of the overall biological productivity, the species composition, and the types of carbon processing that were dominant. Depending upon the balance between different biological processes, which in turn are linked to surrounding vegetation and soils, lakes may have contributed mostly to carbon storage or mostly to carbon emissions ?at a landscape scale.

Changes in vegetation type also influence decomposition of plant remains and soil development, and this is linked to nitrogen cycling and availability. Nitrogen is an important control over productivity and hence of carbon fixation and storage, and thus it is important to study the dynamics of nitrogen along with those of carbon.

Due to the spatial variability of climate and geology, the pace of vegetation development (and of species immigration) and the types of plants involved have not been uniform around the Arctic. By examining several lakes in each of three regions (Alaska, Greenland, Russia) we will be able to describe a broad range of different vegetation transitions and the associated responses of the lakes. Our results can be used to inform our understanding of the likely pathways of recently initiated and future changes. They can also be up-scaled to the whole Arctic and so contribute to the broader scientific goal of understanding feedbacks to global warming.

Planned Impact

We have identified three main impact themes: i) contribution of scientific knowledge to national agencies; ii) knowledge exchange with indigenous communities; and iii) public education and awareness. Our geographical focus is on Alaska and Russia. Our partners in these themes are the US Geological Survey (USGS), the US National Park Service (NPS), and the Alaska Quaternary Center (AQC) in the USA, and the Komi Science Centre in Russia. This fundamental research is primarily of interest to governments of the countries in which we are working and their scientific organizations, such as geological surveys, who are engaged in research on arctic regions and on the functioning/management of the carbon cycle within their national boundaries. The USA is the most active in this respect, and we will work closely with the USGS and the NPS to ensure our findings benefit these organizations. Activities include working with Park scientists on the choice and sampling design of lakes to be studied and contributing data to the Park's monitoring programme and working with a USGS team linked into the USGS carbon program, sharing data and contributing to a USGS modelling effort.
Our work would take place in remote regions that are the traditional lands of indigenous people and/or managed as public conservations lands (Alaska). It is our experience in both Russia and Alaska that meetings with local communities and a sharing of knowledge about the local environment are appreciated by local people and advance the regard with which science is held in these communities. Detailed local knowledge of landscape and biota can contribute to the study design at the start of a project; findings discussed at the end of a project generate new local knowledge and provide a theme for educational activities in the local communities. We will establish contact with local communities via working in our study areas who best understand the local socio-political situation. Activities include community meetings prior to the start of fieldwork and at the end of the project, and development of materials for the NPS schools' programme in Native villages (Alaska) and meetings with local communities (Russia).
Science research concerning global warming and environmental issues is of general interest to the public at large. In Alaska, we will work with the Alaska Quaternary Center [AQC] at the University of Alaska, which specializes in public outreach for science, and the NPS. Activities include developing NPS public outreach materials, contributing information to subsistence boards, and working with the UAF-AQC on public lectures and media spots (Alaska), and informational meetings and media spots organized by our Russian partners. Both the USGS and NPS have excellent public websites, to which we will contribute.
Success in impact will be reflected in the following: development of work on catchment carbon modelling, contribution to the USGS carbon program via joint publication of reports, and establishment of a presence on the USGS website; successful input of observations and results to the monitoring programme and their evaluation in relation to other Park datasets; adaptation of our materials for the NPS schools programme and presence on their website and in other outreach materials; turnout at and feedback from local meetings and public lectures. A project PDRA will take training in public communication of science during the course of the project.

Publications

10 25 50
 
Description We are investigating how carbon is processed in arctic lakes over decades to centuries (and longer) in relation to changes in landscape and vegetation. The past changes in question mimic current change, the so-called "arctic greening". The historical patterns we observe indicate the kinds of change likely to occur in lakes across the Arctic with the propagation of vegetation changes northward if arctic warming continues at the present rate. These changes will have influenced historical carbon budgets in the lakes we studied, particularly the amount of the greenhouse gases carbon dioxide and methane emitted from lakes. 1. We observed changes in lake nutrient cycling, lake productivity, and lake ecology that appear to be linked to changes in catchment vegetation over time. Lake changes tend to be sudden, suggesting that lake ecology encounters a "tipping point" and then reacts strongly to the slower pattern of vegetation change that alters conditions in the lake catchment and hence the lake. 2. We applied a new algorithm to pollen data that reflect past vegetation change to develop a more accurate reconstruction of vegetation changes in the area surrounding the lake. 3. The work has led to the development of a new proxy (quantifiable indicator) that can be retrieved from lake sediments to indicate variation in the amount of methane generated in the lake sediments and emitted to the atmosphere. 4. We used remote sensing to estimate key lake properties linked to warming. We showed that across some regions of the Arctic, the lake-ice season is diminishing at an average rate of 1-2 days per year.
Exploitation Route Our key findings can be used by modellers of the carbon system, which is a crucial part of the climate system. Our proxy for historical methane emission, if it can be developed, could provide the first long-term historical records of local-to-regional trace-gas emissions and thus help unravel the sources of past emissions as preserved in ice-core records. Findings also relate to those people using the arctic region -- either as home or for various forms of resource exploitation, particularly in relation to our findings about the way ice on lakes is melting earlier each year at a very high rate. .
Sectors Environment

URL http://arp.arctic.ac.uk/projects/lakes-and-arctic-carbon-cycle/
 
Description Previous: Our findings are currently in the process of being incorporated into a policy document by Public Policy at Southampton; the document will be delivered to governmental groups working on UK arctic policy. Our findings have been used in public visitor information materials by the US National Park Service. New: the Public Policy document is now published and has been distributed to the APG on Polar Regions and also by NERC. See "other outputs" for more details.
First Year Of Impact 2017
Sector Environment
Impact Types Societal,Policy & public services

 
Description Alaska Quaternary Center, University of Alaska, Fairbanks--logistical support for porject 
Organisation University of Alaska Fairbanks
Department Alaska Quaternary Center
Country United States 
Sector Academic/University 
PI Contribution Presentations in the university, reporting to the department on activities, contribution of field gear to department at end of field season
Collaborator Contribution Provided equipment that would otherwise have had to be purchased and/or shipped; provision of accommodation, free storage facilities.
Impact Presentation of academic seminar, UAF; public meeting in Fairbanks; meeting with Elders in Fairbanks. See reported activities.
Start Year 2013
 
Description US National Park Service 
Organisation US National Park Service
Country United States 
Sector Public 
PI Contribution NPS provided logistic help and support for 2103 fieldwork.
Collaborator Contribution We will collaborate with them a trip to first nation villages to discuss park science next year.
Impact still in progress
Start Year 2013
 
Description Coring & Microscope workshop Effie Kokrine College 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Coring & Microscope workshop with 25 Effie Kokrine College students, Fairbanks Alaska

Included field trip and lab work; students not previous exposed to this work, showed interest and questions -- will be going on to University to this showed them what they might do there

M van Hardenbroek and E. Hopla
Year(s) Of Engagement Activity 2015
 
Description 10,000 years of vegetation in models and sediments. Lecture at the Museum of the North, Fairbanks, Alaska, 23 March 2015. 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Given by E. Hopla. public talk
Year(s) Of Engagement Activity 2015
 
Description BBC Radio 4 broadcast: climate change and me 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact 15-minute broadcast about climate chang in Arctic including personal experience of working in region including activities and observations related to this research
Year(s) Of Engagement Activity 2018
 
Description Botanic Garden talk 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Talk generated many questions and post-talk discussion

Asked to talk to another group
Year(s) Of Engagement Activity 2014
 
Description Coring & Microscope workshop with 20 students of the Nunamiut School Anaktuvuk Pass, Alaska 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact Coring & Microscope workshop with 20 students of the Nunamiut School Anaktuvuk Pass, Alaska
Remote Native Alaskan community, interested in their local environment, lacking extensive science curriculum.
M van Hardenbroek and E. Hopla
Year(s) Of Engagement Activity 2015
 
Description News 13 in Fairbanks about public outreach activities 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Interview, local news channel Fairbanks about the project and outreach: M van Hardenbroek and E Hopla
Year(s) Of Engagement Activity 2015
URL https://vimeo.com/123842458
 
Description Public discussion meeting, Morris Thompson Cultural and Visitors Centre, Fairbanks, Alaska, 26 March 2015 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact van Hardenbroek, M., 2015. Scientists, the Lake, and You - 12,000 years of environmental change:
scientific results and your own personal experience. Public discussion .
meeting, Morris Thompson Cultural and Visitors Centre, Fairbanks, Alaska,
26 March 2015
Talk and consultation with elders about climate change in interior Alaska
Year(s) Of Engagement Activity 2015
 
Description Radio interview for "Love and Science" on BCfm (March 2015) 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Public/other audiences
Results and Impact Media interview about project and outreach M van Hardenbroek
http://www.maartenvanhardenbroek/media/BCfm radio Love?ience.mp3
Year(s) Of Engagement Activity 2015
 
Description Royal Geographic Society Regional Lecture -- Thawing Arctic 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Public Lecture in S Region program. About Arctic and climate change including elements of this work
Year(s) Of Engagement Activity 2018
 
Description van Hardenbroek, M. (2014) "Bugs, bears, and bushplanes - LAC fieldwork in Alaska". 
Form Of Engagement Activity A broadcast e.g. TV/radio/film/podcast (other than news/press)
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact Palaeoenvironmental Laboratory at the University of Southampton blog
Year(s) Of Engagement Activity 2015
URL https://plusresearch.wordpress.com/2014/11/01/bears-bugs-and-bush-planes-lac-fieldwork-in-alaska/