DOI: 10.5061/dryad.8sf7m0ckw
title: Data from: Holocene lake phosphorus species and primary producers reflect catchment processes in a small, temperate lake

description: This palaeo data set consists of a Holocene record from a small, temperate
 lake (Lake Fuglsø, Denmark). It comprises radiocarbon (14C)-dating,
 pollen, X-ray fluorescence scanning, carbon and nitrogen (contents and
 stable isotopes), phosphorus (P) pools (from sequential P extraction and
 31P nuclear magnetic resonance spectroscopy), pigment, diatom, and plant
 macrofossil data. Our multi-proxy palaeolimnological study aimed to
 investigate how natural processes and anthropogenic land-use changes have
 affected sedimentary P forms and primary producers. We found three periods
 of human impact: (1) low disturbance from domestic grazing during the
 Early/Mid Neolithic (~3600 – ~2600 BC), (2) higher disturbance because of
 animal husbandry and some grain cultivation during the Late Bronze and
 Pre-Roman Iron Age (~800 BC – AD ~100) and (3) strong disturbance caused
 by domestic grazing, intensified crop cultivation and, in particular, by
 retting of fibre plants during the Middle Ages and Renaissance (AD ~1000 –
 ~1700). Cultural eutrophication during the latter phase caused
 unprecedented changes in the lake, including altered species composition,
 high production and strongly accelerated sediment accumulation rates.
 Generally, catchment deforestation was related to elevated proportions of
 metal (iron, aluminium, calcium)-bound P forms in the sediment, while high
 tree cover correlated with elevated proportions of P forms associated with
 organic material (“organic” P, humic-bound P, refractory organic P) and
 loosely bound P. During phases with forest in the catchment, silicon (Si)
 inputs to the lake were insufficient and diatom frustules were mostly
 absent in the sediments. In contrast, diatoms thrived in the lake when the
 landscape was open and erosional Si influx was high. This study is the
 first to show long-term (~eight millennia) and recurring Si limitation of
 diatoms, a finding that may explain the absence of diatoms in sediment
 records of other sites too. In summary, human land-use with preceding
 deforestation accelerated the transport of nutrients and elements from the
 terrestrial to the aquatic environment, leading to substantial and
 irreversible changes in Lake Fuglsø. Our study is a good example of the
 tight links between catchment processes and lake status, indicating that
 catchment dynamics should be considered in lake restoration projects,
 particularly for lowland lakes with high catchment:lake area ratios.
description: The sediment core was taken from a
 platform at the centre of the lake, using Kajak, Russian and Usinger
 corers. All proxies were determined according to standard methods, as
 described in the “Material and methods” section of the associated
 article.
description: We provide an Excel file
 which contains all data needed to plot figures 2 - 5 as well as figures S1
 - S7 of appendix S1. All data are raw data, except for scores of PCA
 (Principal Components Analysis) axes. PCAs were performed using the
 program R (package “vegan”) and data of phosphorus forms (accumulation
 rates and percentage data) and pigments (accumulation rates). Prior to
 PCAs, data were square-root transformed. Abbreviations used in the Excel
 file, are explained in the last sheet.