DOI: 10.5061/dryad.5x69p8dg1
title: Cyanobacterial blooms in a warming climate: Paleolimnological assessments of three Boreal Shield lakes in central Ontario, Canada

description: Paleolimnological techniques were used to assess long-term water quality
 changes in three cyanobacterial bloom-impacted lakes in Algoma, Ontario,
 Canada. Since the 2000s, frequent cyanobacterial blooms have been reported
 in these lakes despite stable nutrient levels, allowing investigation of
 recent climate warming as a possible environmental driver of the blooms.
 While diatom and chironomid community changes varied among the lakes,
 accelerated warming (~1990) led to near-synchronous shifts in
 paleolimnological indicators, including increased sedimentary chlorophyll
 a, planktonic diatoms (Discostella stelligera, elongate taxa), and
 chrysophyte scales. Diatom-inferred total phosphorus and
 chironomid-inferred hypolimnetic oxygen models indicate oligo-mesotrophic
 conditions prior to ~1950, with slightly higher late-summer oxygen
 concentrations in Desbarats and Bright lakes. Our results suggest a shift
 towards enhanced thermal stability due to regional warming, supported by
 instrumental records documenting rising air temperature, reduced wind
 speed, and a longer ice-free period observed in the last half century.
 While nutrient availability plays a key role, our paleolimnological
 inferences suggest that climate-driven changes in fundamental lake
 physicochemical properties may be contributing to, or even triggering,
 recent cyanobacterial blooms in these lakes.
description: # Cyanobacterial blooms in a warming climate: Paleolimnological
 assessments of three Boreal Shield lakes in central Ontario, Canada
 Dataset DOI: [10.5061/dryad.5x69p8dg1](10.5061/dryad.5x69p8dg1) ##
 Description of the data and file structure These data were collected for
 [E.J. Favot's PhD
 thesis](https://qspace.library.queensu.ca/items/78c3ca76-5c02-4785-994f-25593762d355), Investigating Long-term Environmental Trends in Central Ontario Lakes Impacted by Cyanobacterial Blooms. Queen's University. 2021. Raw species count data for diatoms and chironomids are presented within this thesis in Appendix D and Appendix E, respectively. ### Files and variables #### File: Pb-210_Dates.csv **Description:** Lead-210 CRS dates and isotope activities used to establish sediment core chronologies for Bright, Desbarats and Caribou lakes. Null values are indicated where Pb-210 isotope activities were too low to allow estimation of dates and sedimentation rates (i.e. beyond "background" concentrations). ##### Variables * Lake Name: indicates the lake name * Midpoint Depth: represents the midpoint of the sediment core depth interval analyzed, in centimetres (cm) * Sedimentation Rate (Column C) and Sedimentation Rate Error (Column D) are presented in g/cm^2 * Age (Column E), Year (Column H) and date errors (Column F for top of the depth interval, and column G for the bottom of the depth interval) are for the Constant Rate of Supply (CRS) model and are presented in years * Columns I:N present isotope activities and errors for Pb-210, Bi-214, and Cs-137 in Bq/kg #### File: Algoma_Lakes_Chironomid_Data_CANOCO_Ordination_Results.csv **Description:** Chironomid PCA results for three Algoma study lakes (Bright, Desbarats, and Caribou). ##### Variables * Column A indicates the lake name * Column B values represent sediment core depth interval analyzed, in centimetres (cm) * Columns C, D, E, and F report Principal Component Analysis Axis 1, 2, 3, and 4, sample scores, respectively #### File: Algoma_Lakes_diatoms_ordination_data.csv **Description:** Diatom PCA results for three Algoma study lakes (Bright, Desbarats, and Caribou). ##### Variables * Column A indicates the lake name * Column B values represent sediment core depth interval analyzed, in centimetres (cm) * Columns C, D, E, and F report Principal Component Analysis Axis 1, 2, 3, and 4, sample scores, respectively #### File: Algoma_Water_Chemistry_Multiple_Years.csv **Description:** MOE water chemistry data for three Algoma study lakes (Bright, Desbarats, and Caribou). Null indicates that no value was recorded for that parameter. ##### Variables * Lake Name: which of the study lakes the row pertains to * Sample Date: the date that the water sample was taken in DD-MMM-YY format * Site: MOE code for the site on the lake; all were included in the analyses of this study * SECCHI_DEPTH: Secchi disk depth measuring water clarity, in meters * DOC: Dissolved Organic Carbon in mg/L * FEUT: Total iron (unfiltered) in ppb * MNUT: Total manganese (unfiltered) in ppb * NNTKUR: Total Kjeldahl nitrogen in ppb * NNOTUR: Nitrate plus nitrite in ppb * NNHTUR: Ammonia and ammonium in ppb * PH: pH (no units) * PPUT1 & PPUT2: duplicate total phosphorus samples in ppb #### File: Bright_Chl-a_spectral_data.csv **Description:** Spectral data to calculate sedimentary chlorophyll a for Bright Lake. Numbers in column A are sediment core depths (cm), Row 1 are electromagnetic spectrum wavelength values (nm), and values within the matrix are spectral reflectance values of the sediment. #### File: Desbarats_Chl-a_spectral_data.csv **Description:** Spectral data to calculate sedimentary chlorophyll a for Desbarats Lake. Numbers in column A are sediment core depths (cm), Row 1 are electromagnetic spectrum wavelength values (nm), and values within the matrix are spectral reflectance values of the sediment. #### File: Caribou_Chl-a_spectral_data.csv **Description:** Spectral data to calculate sedimentary chlorophyll a for Caribou Lake. Numbers in column A are sediment core depths (cm), Row 1 are electromagnetic spectrum wavelength values (nm), and values within the matrix are spectral reflectance values of the sediment. #### File: Bright_VNIRS-cyano_input_spectral_data.csv **Description:** Spectral reflectance data from 400-2498 nm (Row 1) to calculate the [Favot et al. (2020) VNIRS-inferred cyanobacteria model](https://link.springer.com/article/10.1007/s10933-020-00140-2). Rows 2-16 have data for the calibration sediments that the model is built off of, and subsequent rows contain the sample data for Bright Lake. Column A contains the concentration of cyanobacteria inoculated in the sediment (in square root of parts per thousand) for the calibration set rows 2-16, and sediment core depth of the test set sample (cm) in rows 17-end. #### File: Desbarats_VNIRS-cyano_input_spectral_data.csv **Description:** Spectral reflectance data from 400-2498 nm (Row 1) to calculate the [Favot et al. (2020) VNIRS-inferred cyanobacteria model](https://link.springer.com/article/10.1007/s10933-020-00140-2). Rows 2-16 have data for the calibration sediments that the model is built off of, and subsequent rows contain the sample data for Desbarats Lake. Column A contains the concentration of cyanobacteria inoculated in the sediment (in square root of parts per thousand) for the calibration set rows 2-16, and sediment core depth of the test set sample (cm) in rows 17-end. #### File: Caribou_VNIRS-cyano_input_spectral_data.csv **Description:** Spectral reflectance data from 400-2498 nm (Row 1) to calculate the [Favot et al. (2020) VNIRS-inferred cyanobacteria model](https://link.springer.com/article/10.1007/s10933-020-00140-2). Rows 2-16 have data for the calibration sediments that the model is built off of, and subsequent rows contain the sample data for Caribou Lake. Column A contains the concentration of cyanobacteria inoculated in the sediment (in square root of parts per thousand) for the calibration set rows 2-16, and sediment core depth of the test set sample (cm) in rows 17-end. #### File: Algoma_Lakes_WA_DI-TP_Reconstructions.csv **Description:** Diatom-inferred total phosphorus reconstructions (C2 output) for three Algoma study lakes (Bright, Desbarats, and Caribou). ##### Variables * Sample Name: Letter codes are BL for Bright Lake, DES for Desbarats Lake, and CL for Caribou Lake. The number indicates sediment core depth of the sample in centimetres. * WA_Inv: Estimated TP by WA (inverse deshrinking) * WA_Cla: Estimated TP by WA (classical deshrinking) * WAT_Inv: Estimated TP by WA (tol. downweighted / inverse deshrinking) * WAT_Cla: Estimated TP by WA (tol. downweighted / classical deshrinking) * WA_Inv_X: Bootstrap estimated TP by WA (inverse deshrinking) * WA_Cla_X: Bootstrap estimated TP by WA (classical deshrinking) * WAT_Inv_X: Bootstrap estimated TP by WA (tol. downweighted / inverse deshrinking) * WAT_Cla_X: Bootstrap estimated TP by WA (tol. downweighted / classical deshrinking) * SEB_WA_Inv: Standard error of TP bootstrap estimates by WA inverse deshrinking) * SEB_WA_Cla: Standard error of TP bootstrap estimates by Wa (classical deshrinking) * SEB_WAT_Inv: Standard error of TP bootstrap estimates by WA (tol. downweighted / inverse deshrinking) * SEB_WAT_Cla: Standard error of TP bootstrap estimates by WA (tol. downweighted / classical deshrinking) * eSEP_WA_Inv: Bootstrap estimated SEP for TP by WA (inverse deshrinking) * eSEP_WA_Cla: Bootstrap estimated SEP for TP by WA (classical deshrinking) * eSEP_WAT_Inv: Bootstrap estimated SEP for TP by WA (tol. downweighted / inverse deshrinking) * eSEP_WAT_Cla: Bootstrap estimated SEP for TP by WA (tol. downweighted / classical deshrinking) * Columns R:AG with "_backtransform" in the title are 10^ of the corresponding models and error estimates described above in columns B:Q #### File: AlgomaVWHOResults.csv **Description:** Chironomid-inferred volume-weighted hypolimnetic oxygen (VWHO) reconstruction results for three Algoma study lakes (Bright, Desbarats, and Caribou). Column A indicates the sample lake (BRIGHT, DES for Desbarats, and CARIBOU) and depth interval in the sediment core (in centimetres). Column B indicates the chironomid-inferred end-of-summer VWHO for that interval in the sediment core in mg/L, and Column C indicates the inferred VWHO reported as a deviation from the time series mean. #### File: Ice_Turkey_s.csv **Description:** [Turkey Lakes Watershed](https://catalogue.ec.gc.ca/geonetwork/srv/api/records/292dc9a8-71d0-4372-a12c-dedc380d45e2) ice phenology data including ice-on and ice-off dates for 5 lakes from 1980-2015. Column A indicates the lake name, Column B represents the year of observation, OFF (Column C) represents the day of year number that the lake was ice-free, ON (Column D) represents the day of year number that the lake froze, and "Ice-free" (Column E) indicates the number of days that the lake had no ice cover in that year. ## Code/software n/a ## Access information Other publicly accessible locations of the data: * Pb-210 dates, and raw diatom and chironomid counts: [E.J. Favot PhD thesis](https://qspace.library.queensu.ca/items/78c3ca76-5c02-4785-994f-25593762d355) Data was derived from the following sources: * [Adjusted and homogenized Canadian climate data](https://www.canada.ca/en/environment-climate-change/services/climate-change/science-research-data/climate-trends-variability/adjusted-homogenized-canadian-data.html) for Sault Ste. Marie