Jan Karlsson

Climate change induced regime shifts in Northern lake ecosystems

Sunset over lake Törnetrask (as seen from the Abisko Scientific Research Station)

Sunset over lake Törnetrask (as seen from the Abisko Scientific Research Station)

Climate change induced regime shifts in Northern lake ecosystems

Project Summary

A present major scientific challenge is to understand and predict effects of climate change on lake ecosystems and the services they deliver. Globally, lakes are concentrated at northern latitudes where the magnitude of climate change is expected to be strongest. Recent advances in lake research suggest that responses of Northern lakes to global warming are fundamentally different from the expectations based on conventional knowledge. This project brings together new tools and concepts in biogeochemistry and ecology, with the aims of understanding and predicting the effects of climate change on the delivery of two major ecosystem services, fish production and the net greenhouse gas balance of Northern lakes.

Specific objectives include:

  1. Assessment of long vs. short term effects of climate change;
  2. Assessment of nonlinear dynamics and regime shifts; and,
  3. Projection of responses to future climate conditions.

The project’s core is made up of a multi-scale (pond to whole-lake) experimental test of ecosystem responses to increases in temperature and precipitation/runoff. Further, we will use aDNA techniques to address past regime shifts and ecosystem resilience to climate change from paleolimnological sediment records. Finally, the project will develop process-based models to be used in the projection of future conditions in lakes at the whole ecosystem scale.

Project Dates: 2017-2021

Funding Organizations

Knut and Alice Wallenberg Foundation

Collaborators

David Bastviken, Linköping University
Ann-Kristin Bergström, Umeå University
Christian Bigler, Umeå University
Richard Bindler, Umeå University
Åke Brännström, Umeå University
Pär Byström, Umeå University
Sebastian Diehl, Umeå University
Isabelle Domaizon, French National Institute for Agricultural Research
Göran Englund, Umeå University
Cristian Gudasz, Umeå University
Dag Hessen, Oslo University, Norway
Jonatan Klaminder, Umeå University
Sally MacIntyre, University of California Santa Barbara, USA
Frank Peeters, University of Konstanz, Germany
André de Roos, University of Amsterdam, The Netherlands
Martin Rosvall, Umeå University
David Seekell, Umeå University
Ryan Sponseller, Umeå University
Xiau-Ru Wang, Umeå University
Marcus Klaus, Umeå University

Monitoring and management of Arctic lakes in a changing climate

Jan Karlson monitoring Arctic lakes

Monitoring and management of Arctic lakes in a changing climate

Project Summary

There is a lack of scientific based monitoring and management strategies of Arctic lakes where climate change effects are expected to be especially pronounced. The purpose of this study is to improve knowledge and monitoring of climate impacts on Arctic lakes. Specific aims include to quantify and provide threshold variables for climate change induced regime shifts in fish resource use and production, and to develop tools and guidelines to be used in monitoring programs. By experimental and comparative studies across climate gradients we test predictions of rapid changes in fish production and resource use with climate change, and by developing new analytical and statistical tools we test predictions that changes in lake function following climate change could be rapidly detected using automatized and cost efficient methods suitable for use in monitoring. Based on the results we will develop methods and guidelines together with stakeholders for use in monitoring of Arctic lake ecosystems. The outcome of the project will be of fundamental importance for society as this will provide knowledge and tools for sustainable management of a unique and attractable resource sensitive to environmental perturbations. The project is financed by FORMAS and carried out in collaboration with the county boards in Northern Sweden.

Project Dates: 2016 to 2018

Funding Organization

FORMAS (2015-723)

Collaborators

Jan Karlsson, Umeå University
Jens Andersson, Jämtland County Administrative Board
Ann-Kirstin Bergström, Umeå University
Pär Byström, Umeå University
Sally MacIntyre, University of California Santa Barbara, USA
David Seekell, Umeå University

Climate impact on sources and sinks of greenhouse gases in high-latitude lakes

Törnetrask in the Autumn (as viewed from the Abisko Scientific Research Station)

Törnetrask in the Autumn (as viewed from the Abisko Scientific Research Station)

Climate impact on sources and sinks of greenhouse gases in high-latitude lakes

Project Summary

Arctic and subarctic lakes play an important role in the global carbon (C) cycle by burying C in sediments and emitting greenhouse gases as carbon dioxide and methane to the atmosphere. The relative magnitude of these different pathways has large implications for their role in the C cycle, i.e. to what extent they act as C sources or sinks. Still, the knowledge of C cycling in lakes is in many important aspects incomplete, preventing accurate quantification and predictions of their C source-sink function and response to climate change. The aim of the project is to assess climate impacts on C emission and burial in arctic–subarctic lakes. We will specifically investigate direct impacts by temperature and precipitation, and indirect impacts via changes in terrestrial surroundings, and how these various drivers influence the C source-sink function of lakes depending on the rate and magnitude of change. An important part is to assess the various sources and pathways underpinning emission and burial in lakes. The core of the project is made up of (i) comparative studies of lakes across gradients in temperature and precipitation and (ii) large-scale experimental test of responses in C emission and burial to increases in temperature and precipitation/runoff.

Project Dates: 2017-2020

Funding Organization

The Swedish Research Council (VR)

Collaborators

Jan Karlsson, Umeå University
David Bastviken, Linköpings University
Blaize Denfeld, Umeå University (Post Doctoral Researcher)
Cristian Gudasz, Umeå University
Sally MacIntyre, University of California Santa Barbara, USA
Oleg S. Pokrovsky, University Toulouse, France
Chris Soulsby, University of Aberdeen, UK
Bror Holmgren, Umeå University (PhD Student)

 

Climate impact on the carbon emission and export from Siberian inland waters

Arctic Lake Jan Karlsson.jpg

Climate impact on the carbon emission and export from Siberian inland waters

Project Summary

Siberia contains vast carbon (C) stocks potentially vulnerable to mobilization following permafrost thawing, and inland waters draining these regions are largely understudied. Thus, research on inland waters of Siberia is of particular importance for understanding climate change. This interdisciplinary project link expertise in aquatic biogeochemistry, hydrology and permafrost dynamics with the aim to improve the knowledge of the role of high latitude inland waters in emitting C to atmosphere and in exporting C to downstream coastal regions and how this varies between different climate regimes. We will carry out a comparative study of lake-stream networks across a climate gradient in western Siberia covering a large range of permafrost conditions. We will quantify to what extent terrestrial C export is evaded vs. exported downstream in the river networks along the gradient, and how these fluxes are related to differences in hydrological dynamics. This is a JPI Climate collaborative research project on Russian Arctic and Boreal systems (www.jpi-climate.eu/projects).

Project Dates: 2014-2017

Funding Organizations

The Swedish Research Council (VR)
The Natural Environment Research Council (NERC, UK)

Collaborators

Sergey Kirpotin, Tomsk University, Russia
Hjalmar Laudon, Swedish University of Agricultural Sciences, Umeå
Oleg Pokrovsky, University Toulouse, France
Doerthe Tetzlaff, University of Aberdeen, UK
Chris Soulsby, University of Aberdeen, UK
Pertti Ala-Aho, University of Aberdeen, UK (Post doc)
Svetlana Serikova, Umeå University (PhD student)

A cross-system analysis of ecological change in Kangerlussuaq (SW Greenland) and Torneträsk (Northern Sweden)

A cross-system analysis of ecological change in Kangerlussuaq (SW Greenland) and Torneträsk (Northern Sweden)

Project Summary

One of the major constraints on critically evaluating the causes of ecological change in sensitive arctic ecosystems is the lack of long-term monitoring. The area around Torneträsk in Northern Sweden and Kangerlussuaq in south-west Greenland are two of the more extensively studied arctic lake districts. As well as the benefits associated with long-term monitoring and having contrasting climates (low versus sub-arctic; precipitation), the two areas also differ in some key characteristics, most notably, surface water hydrology, in-lake DOC concentration and characteristics, terrestrial vegetation. However, as well as these climate and ecological differences, both areas have had the benefits of palaeolimnological studies, field experiments and integrated lake-catchment studies. In this project we will synthesize the available data from these areas using novel statistical approaches to understand the key drivers of ecological changes at a range of timescales.

Collaborators

Jan Karlsson, Umeå University
Jonatan Klaminder, Umeå University
Bror Holmgren (PhD student), Umeå University

 

Taking the pulse of Swedish rivers: using metabolism to monitor ecosystem responses to environmental change

Taking the pulse of Swedish rivers: using metabolism to monitor ecosystem responses to environmental change

Project Summary

Streams and rivers carry out multiple ecosystem services that respond to and integrate natural and anthropogenic perturbations across landscapes. In northern regions, a critical aspect of this ‘integration’ involves the regulation of carbon (C) transfer from land to the atmosphere and sea. In this context, the degree to which streams and rivers transform terrestrial organic carbon (OC) and act as sources of CO2 to the atmosphere is subject to much current debate. National monitoring programs have the potential to shed light on this issue, yet these efforts rarely assess aquatic ecosystem processes. As a solution, we propose adding high frequency measurements of dissolved oxygen (DO) to current monitoring programs, which allow for the calculation of fundamental metabolic rates at daily time scales. Such measures reveal the ‘pulse’ of biological activity in running waters with the temporal resolution needed to capture changes in the degradation of terrestrial OC and CO2 production and fixation in response to diverse environmental changes. The goals of this research are to 1) determine how the rates and patterns of metabolism in Swedish rivers are shaped by regional climatic gradients and anthropogenic stressors, 2) Quantify the extent to which streams and rivers in arctic, boreal, and hemi-boreal zones degrade terrestrial OC, and contribute to CO2 evasion, and 3) Advance a simple and cost efficient method to assess metabolism that will complement current monitoring programs in Sweden by adding functional metrics

Funding Organization

Formas

Collaborators

Jan Karlsson, Umeå University
Erin Hotchkiss, Virginia Polytechnic Institute
Hjalmar Laudon, Swedish University of Agricultural Sciences, Umeå

The invisible carbon: an early indication of ecosystem change!

The invisible carbon: an early indication of ecosystem change!

Project Summary

Streams are sensitive sentinels for environmental change by their integration of processes in terrestrial and aquatic systems. Upland headwater streams in the north Swedish tundra show seasonally exceptional high concentrations of uncolored dissolved organic carbon (DOC) and high CO2 concentrations. We suggest that this reflects on-going changes in the terrestrial environment responding in their delivery of carbon (C) to the recipient aquatic systems. This is a hitherto unknown effect of a changing tundra landscape that will have large implications for the positive feedback on the global climate warming because of the large quantities of C that is stored in tundra soils. Current climate change mobilizes the stored C in upland tundra soils and cause a substantial increase in headwater stream C emissions and water-borne C losses.

We are studying stream CO2 fluxes mainly across a 42-km long stream network in the Miellajokka catchment near Abisko to better understand how stream functional traits and landscape features affects CO2 emissions. We are amongst others using different isotopic approaches (13C, 15N, 87Sr/86/Sr, 34S18O4 and water isotopes) and high-resolution measurements of stream CO2 and oxygen to disentangle different sources and processes that affects stream CO2 concentrations and emissions. We are also studying spatiotemporal variations in stream DOC across different tundra streams to unravel how different landscape features and hydrological conditions affect stream DOC concentrations, its degradability and qualitative characteristics. We are particularly interested in pulses of high stream DOC concentrations that has occurred irregularly during early autumns.

Collaborators

Carl-Magnus Mörth, Stockholm University
Steve Lyon, Stockholm University
Ann-Kristin Bergström, Umeå University
Ryan Sponseller, Umeå University
Jan Karlsson, Umeå University
Martin Berggren, Lund University
Gerard Rocher Ros, Umeå University

Funding organizations

The Swedish Research Council (VR) 2013-5001
FORMAS 2014-970

Impact of permafrost thawing on aquatic ecosystems: quantification of chemical compounds inputs

Impact of permafrost thawing on aquatic ecosystems: quantification of chemical compounds inputs

Project Summary

Over half the below-ground terrestrial organic carbon (C) pool resides in permafrost soils that are currently thawing because of recent climate change. As a result, vast amounts of terrestrial carbon (C) are mobilized, having the potential to accelerate global warming. The enhanced transport of other elements (e.g. nutrients and pollutants) with thawing may also cause dramatic biogeochemical impacts such as eutrophication or high-latitude pollution in aquatic ecosystems. Despite the dramatic ecological effects of thawing permafrost, how this process occurs and the strength of the export of biochemical compounds to surface waters still represents one of the biggest uncertainties in our climate impact models. My project will fill this gap by providing the first quantification of both spatial and temporal variations in permafrost groundwater discharge (PGD) and its importance for both the C cycle and the quality of surface waters. The estimation of these fluxes will be assessed by applying a novel technique based on using radium (Ra) isotopes and radon (222Rn) as tracers of groundwater inputs.

Collaborators

Jan Karlsson, Umeå University
Jordi Garcia-Orellana, Universitat Autònoma de Barcelona, Spain
Valentí Rodellas i Vila, Aix-Marseille Université, France