Big Picture: The Polaris Project is focused on some really big questions and the readings below will help you think big: How much carbon is there in the Arctic? How does it move? How is the land surface changing? Could humans change the Artic carbon cycle with animal grazing?

• Cole et al. 2007. Plumbing the Global Carbon Cycle: Integrating Inland Waters into the Terrestrial Carbon Budget. Ecosystems 10, 171-184.
  • Efforts to understand global sources and sinks of atmospheric carbon dioxide have historically been focused on terrestrial and marine ecosystems.  Recent research suggests that freshwater ecosystems such as streams, rivers, wetlands, and lakes play important, yet overlooked roles in the flux of terrestrial organic matter to the atmosphere and world’s oceans.
• McGuire et al. 2010. The carbon budget of the northern cryosphere region. Current Opinion in Environmental Sustainability 2010, 2:231–236.
  • The sources and sinks of arctic carbon are uncertain but the scientific community is working diligently to improve these numbers! This paper outlines what we know and where we need to go. And if you want more check out McGuire’s 2010 monograph on this subject.
• Sturm 2010. Arctic Plants Feel the Heat. Scientific American May 2010,32-39.
  • This is a popular-science write up of how the terrestrial system changing in the Arctic. Fast, fun read.
• Zimov. 2005. Pleistocene Park: Return of the Mammoth’s Ecosystem. Science 308, 796-798.
  • Sergey Zimov is a remarkable scientist who “thinks big”.  This article provides an overview of one of his visions and the ongoing Pleistocene Park experiment.

Terrestrial: We are working in the terrestrial environment more intensively every year and thinking about the linkages between the terrestrial and aquatic carbon cycles.

• Bunn et al. 2007.Northern high-latitude ecosystems respond to climate change. Eos 88, 333–335.
  • A widely held assumption is that high latitude warming will cause increased photosynthesis in boreal forests. This paper calls some of those assumptions into question as it documents declining gross primary productivity in some boreal forest ecosystems.
• Chapin et al. 2005. Role of Land-Surface Changes in Arctic Summer Warming Science 310: 657-660.
  • Chapin and colleagues took a conceptual model of how the Arctic land surface functions in the global climate system and put numbers to the model. It’s an awe inspiring work.
• Loranty et al. 2012. Shrub expansion and climate feedbacks in Arctic tundra. Environ. Res. Lett. 7 011005 doi:10.1088/1748-9326/7/1/011005.
  • We know the Arctic land surface is changing. We know that shrubs are a huge part of it and we know that shrub cover mediates both the radiation budget and the carbon budget. This paper described some of how and what we know.
• Xu et al. 2013. Temperature and vegetation seasonality diminishment over northern lands. Nature Climate Change doi:10.1038/nclimate1836.
  • Maybe Bunn et al got a little ahead of themselves. As the data rolls in it appears that our understanding of taiga greening continues to change –  but that’s science.

Permafrost: We work in Cherskiy ultimately because the fate of permafrost in the Arctic is important and uncertain.

• Knoblauch et al. 2013. Predicting long-term carbon mineralization and trace gas production from thawing permafrost of Northeast Siberia. Global Change Biology (2013) 19, 1160–1172, doi: 10.1111/gcb.12116.
  
  • What is going to happen as microorganisms get a crack at thawing permafrost? Respiration. But where, when, and how fast remain major question marks.
• Schuur et al. 2008. Vulnerability of permafrost carbon to climate change: Implications for the global carbon cycle. Bioscience 58, 701-714.
  • Thawing permafrost and the resulting microbial decomposition of previously frozen organic carbon (C) is one of the most significant potential feedbacks from terrestrial ecosystems to the atmosphere. Here, the authors present an overview of the global permafrost C pool and of the processes and feedbacks that transfer C into the atmosphere.

River and Aquatic Carbon: In a largely roadless area, the rivers and waterways are the roads. It’s true for carbon too. These papers quantify how carbon moves and changes as it moves downstream.

• Frey and McClelland. 2009. Impacts of permafrost degradation on arctic river biogeochemistry. Hydrological Processes 23, 169-182.
  • There are many linkages between permafrost and river biogeochemistry. Over the next century there will be shifts in the river transport of organic matter, inorganic nutrients, and major ions, which might have critical implications for primary production and carbon cycling on arctic shelves and in the Arctic Ocean basin interior.
• Neff et al. 2006. Seasonal changes in the age and structure of dissolved organic carbon in Siberian rivers and streams. Geophysical Research Letters 33,L23401, doi:10.1029/2006GL028222.
  • This paper gets at some important questions relating to the age and origin of dissolved carbon in arctic rivers. Importantly, it shows that there is a switch during the year from modern to old carbon in the Kolyma main stem but the source of that old carbon is unclear.
• Walter et al. 2006. Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming. Nature 443, doi:10.1038/nature05040.
  • Methane is a greenhouse gas that is many times more effective than CO2 in trapping long wave radiation. This paper closes a critical gap in the methane budget by quantifying methane from lakes in Siberia.
• Vonk et al. 2013. High biolability of ancient permafrost carbon upon thaw. GRL doi: 10.1002/grl.50348.
  • This paper describes how some fraction of the carbon flowing past us in the Kolyma is ancient and available for exchange with the atmosphere.