Description: Publication date: 1 August 2018 Source: Quaternary Science Reviews, Volume 193 Author(s): F. Alayne Street-Perrott, Jonathan A. Holmes, Iain Robertson, Katherine J. Ficken, Tiiu Koff, Neil J. Loader, Jim D. Marshall, Tõnu Martma The well characterized oxygen-isotopic fractionation during cellulose biosynthesis has been utilised by numerous studies of stable isotopes in fine-grained aquatic cellulose. We measured the δ 13 C cellulose and δ 18 O cellulose values of bulk cellulose and moss fragments from an ∼11.4ka-long core obtained from a shallow, productive, spring-fed, hardwater lake, Äntu Sinijärv, Estonia (59˚3.8′N; 26˚14.5′E; 94.6 m a.s.l.; maximum depth 7.3 m), in order to reconstruct regional Holocene climate and lake-basin evolution. Isotopically, the modern waterbody is a well-behaved, open, hydrological system with negligible evaporative effects. Cellulose-isotope records were compared with down-core measurements of loss-on-ignition (LOI), carbonate and mineral contents, total organic carbon (TOC), total nitrogen (TN), C/N ratio, δ 13 C TOC , biomarker indices (P alg and P aq ), published palaeoecological data and a δ 18 O carbonate record from the same palaeolake. Green microalgae, freshwater macroalgae ( Chara ) and aquatic bryophytes were important sources of sedimentary cellulose during different phases in the environmental history of the lake. Although a strong palaeoclimatic imprint can be detected in the δ 18 O cellulose record from Äntu Sinijärv, notably the Preboreal oscillation, the 8.2ka event and an unnamed cold oscillation ∼3.25ka BP, the isotopic signal of these events may have been amplified by increases in 18 O-depleted spring snowmelt. In contrast, δ 13 C cellulose was tightly coupled to the Holocene evolution of terrestrial ecosystems and soils by significant inputs of biogenic carbon from the catchment and sublacustrine springs. During the early Holocene, ∼11 – 9ka BP, the δ 18 O cellulose and δ 18 O carbonate records diverge markedly, which can be attributed to “no-analogue” seasonal, climatic, hydrological and isotopic conditions resulting from orbital forcing and residual ice-sheet impacts.