Lakes are active processors and collectors of carbon (C) and thus recognized as quantitatively important within the terrestrial C cycle. Better integration of palaeolimnology (lake sediment core analyses) with limnological C budgeting approaches has the potential to enhance understanding of lacustrine C processing and sequestration. Palaeolimnology simultaneously assimilates materials from across lake habitats, terrestrial watersheds, and airsheds to provide a uniquely broad overview of the terrestrial-atmospheric-aquatic linkages across different spatial scales. The examination of past changes over decadal-millennial timescales via palaeolimnology can inform understanding and prediction of future changes in C cycling. With a particular, but not exclusive, focus on northern latitudes we examine the methodological approaches of palaeolimnology, focusing on how relatively standard and well-tested techniques might be applied to address questions of relevance to the C cycle. We consider how palaeolimnology, limnology, and sedimentation studies might be linked to provide more quantitative and holistic estimates of lake C cycling and budgets. Finally, we use palaeolimnological examples to consider how changes such as terrestrial vegetation shifts, permafrost thaw, the formation of new lakes and reservoirs, hydrological modification of inorganic C processing, land use change, soil erosion and disruption to global nitrogen and phosphorus cycles might influence lake C cycling. © 2015 The Authors. WIREs Water published by Wiley Periodicals, Inc.
How to cite this article:WIREs Water 2016Water , 3:211-234. doi: 10.1002Water /wat2.1130 INTRODUCTION Q uantification of the terrestrial carbon (C) cycle is paramount to understanding global climate change, and lakes, as 'landscape chimneys,' play a key role in terrestrial C processing.1 Most lakes are considered to be net C sources to the atmosphere, emitting carbon dioxide (CO 2 ) and methane (CH 4 ), and are highly active C processing hotspots.1-4 Yet lakes also simultaneously sequester C in their sediments, comprising one of the largest stores of organic C (OC) on the continents. [5][6][7][8] A major challenge therefore exists in trying to quantify relative rates of C evasion versus sequestration in lakes and the influence this has on C fluxes from land, through river basins and to the ocean. Global estimates suggest that annual net lake C evasion exceeds sequestration and inland waters receive 1.9 PgC year −1 from streams and rivers of which 0.2 PgC year −1 accumulates as sediment, 0.8 PgC year −1 is evaded to the atmosphere and 0.9 PgC year −1 is delivered to the oceans, 9 although the rates of C evasion in lakes 4 and rivers 10 might be higher. Therefore, the 'active pipe model' highlights that lakes are not simply passive vessels for C transport, but play a critical role in C processing of sufficient magnitude to alter regional C budgets. 9 In this review, we outline the contribution that the long-term and integrative perspective offered by palaeolimnology can make in un...