North Temperate Lakes
US Long-Term Ecological Research Network

Lake snow removal experiment phytoplankton community data, under ice, 2019-2021

Abstract
Although it is a historically understudied season, winter is now recognized as a time
of biological activity and relevant to the annual cycle of north-temperate lakes. Emerging
research points to a future of reduced ice cover duration and changing snow conditions that
will impact aquatic ecosystems. The aim of the study was to explore how altered snow and ice
conditions, and subsequent changes to under-ice light environment, might impact ecosystem
dynamics in a north, temperate bog lake in northern Wisconsin, USA. This dataset resulted from
a snow removal experiment that spanned the periods of ice cover on South Sparkling Bog during
the winters of 2019, 2020, and 2021. During the winters 2020 and 2021, snow was removed from
the surface of South Sparkling Bog using an ARGO ATV with a snow plow attached. The 2019
season served as a reference year, and snow was not removed from the lake. This dataset
represents phytoplankton community samples (pooled epilimnion and hypolimnion samples
representative of 7 m water column) both under-ice and during some shoulder-season (open
water) dates. Samples were collected into amber bottles and preserved with Lugol's solution
before they were sent to Phycotech Inc. (St. Joseph MI, USA) for phytoplankton taxonomic
identification and quantification.<br/>
Core Areas
Creator
Dataset ID
418
Data Sources
Date Range
-
Methods
Phytoplankton samples were obtained from the epilimnion and hypolimnion by
slowly lowering weighted Tygon tubing through the water column to a depth of 7 m, such
that the tubing was filled with a representative water column sample. Based on the inner
diameter of the tubing, 205 mL of water was pumped from the tubing for the epilimnion
sample. Next, 267 mL of water was pumped from the tubing for the hypolimnion sample. Each
sample was collected into a 250 mL amber bottle that contained 2 mL of Lugol’s solution.
Phytoplankton samples were pooled by sampling date and sent to Phycotech Inc. (St. Joseph
MI, USA) for phytoplankton identification, and concentration and biovolume
quantification.<br/>
Publication Date
Related Sites
Version Number
1

Cascade project at North Temperate Lakes LTER - High Frequency Data for Whole Lake Nutrient Additions 2013-2015

Abstract
High frequency continuous data for temperature, dissolved oxygen, pH, chlorophyll a, and phycocyanin in Paul, Peter, and Tuesday lakes from mid-May to early September for the years 2013, 2014 and 2015. Inorganic nitrogen and phosphorus were added to Peter and Tuesday lakes each year while Paul Lake was an unfertilized reference.
Contact
Dataset ID
371
Date Range
-
LTER Keywords
Maintenance
complete
Methods
Methods are described in Wilkinson et al. 2018 (Ecological Monographs 88:188-203) and Pace et al. 2017 (Proceedings of the National Academy of Sciences USA 114: 352-357). These publications including supplements should be consulted for details.
In Paul, Peter and Tuesday lakes two sondes were deployed at 0.75 meters near lake center. One sonde was a Hydrolab (model DS5X) with temperature, oxygen, pH, phycocyanin, and chlorophyll a sensors. One sonde was a Yellow Springs Instruments (YSI) 6600-V2-4 with temperature, dissolved oxygen, pH, phycocyanin, and chlorophyll a sensors. Measurements were made every five minutes. Brief gaps in the data record due to calibration or sensor malfunction were interpolated using a bivariate autoregressive state-space model with the MARSS package in R version 3.9 to create a continuous daily time series.
Version Number
1

Cascade Project at North Temperate Lakes LTER Core Data Phytoplankton 1984 - 2015

Abstract
Data on epilimnetic phytoplankton from 1984-2015, determined by light microscopy from pooled Van Dorn samples at 100 percent, 50 percent, and 25 percent of surface irradiance. St. Amand (1990) and Cottingham (1996) describe the counting protocols in detail. Samples after 1995 were counted by Phycotech Inc. (http://www.phycotech.com). Sampling Frequency: varies; Number of sites: 5
Dataset ID
353
Date Range
-
Methods
Samples counted prior to 1996 were assigned one taxon name with all taxonomic information. This taxon name was split into distinct columns of genus, species and description for archival as best possible. Samples from 2013-2015 were sent to Phycotech inc. (http://www.phycotech.com/) to be counted.
Version Number
16

Cascade Project at North Temperate Lakes LTER: Phytoplankton 1984 - 1995

Abstract
Data on epilimnetic phytoplankton from 1984-95, determined by light microscopy from pooled Van Dorn samples at 100percent, 50percent, and 25percent of surface irradiance. There have been 4 counters during this period, with the same counter from 1991-95. Standardization among counters is difficult, so I recommend sticking to the 1991-95 data if possible. Cottingham (1996) describes the counting protocols in detail. Sampling Frequency: varies Number of sites: 5
Core Areas
Dataset ID
80
Date Range
-
LTER Keywords
Maintenance
completed
Metadata Provider
Methods
See for detail: Cottingham, K.L., and S.E. Knight. 1995. Effects of grazer size on the response of mesotrophic lakes to experimental enrichment. Water Science and Technology 32(4): 157-163.
Short Name
CPHYT1
Version Number
3

North Temperate Lakes LTER: Phytoplankton - Madison Lakes Area 1995 - current

Abstract
Phytoplankton samples for the 4 southern Wisconsin LTER lakes (Mendota, Monona, Wingra, Fish) have been collected for analysis by LTER since 1995 (1996 Wingra, Fish) when the southern Wisconsin lakes were added to the North Temperate Lakes LTER project. Samples are collected as a composite whole-water sample and are preserved in gluteraldehyde. Composite sample depths are 0-8 meters for Lake Mendota (to conform to samples collected and analyzed since 1990 for a UW/DNR food web research study), and 0-2 meters for the other three lakes. A tube sampler is used for the 0-8 m Lake Mendota samples; samples for the other lakes are obtained by collecting water at 1-meter intervals using a Kemmerer water sampler and compositing the samples in a bucket. Samples are taken in the deep hole region of each lake at the same time and location as other limnological sampling. Phytoplankton samples are analyzed by PhycoTech, Inc., a private lab specializing in phytoplankton analyses (see data protocol for procedures). Samples for Wingra and Fish lakes are archived but not routinely counted. Permanent slide mounts (3 per sample) are prepared for all analyzed Mendota and Monona samples as well as 6 samples per year for Wingra and Fish; the slide mounts are archived at the University of Wisconsin - Madison Zoology Museum. Phytoplankton are identified to species using an inverted microscope (Utermohl technique) and are reported as natural unit (i.e., colonies, filaments, or single cells) densities per mL, cell densities per mL, and algal biovolume densities per mL. Multiple entries for the same species on the same date may be due to different variants or vegetative states - (e.g., colonial or attached vs. free cell.) Biovolumes for individual cells of each species are determined during the counting procedure by obtaining cell measurements needed to calculate volumes for geometric solids (e.g., cylinders, spheres, truncated cones) corresponding to actual cell shapes. Biovolume concentrations are then computed by mulitplying the average cell biovolume by the cell densities in the water sample. Note that one million cubicMicrometers of biovolume PerMilliliter of water are equal to a biovolume concentration of one cubicMillimeterPerMilliliter. Assuming a cell density equal to water, a cubicMillimeterPerMilliliter of biovolume converts to a biomass concentration of one milligramPerLiter. Sampling Frequency: bi-weekly during ice-free season from late March or early April through early September, then every 4 weeks through late November; sampling is conducted usually once during the winter (depending on ice conditions). Number of sites: 4
Several taxonomic updates have been made to this dataset February 2013, see methods for details.
Dataset ID
88
Date Range
-
Maintenance
ongoing
Metadata Provider
Methods
Water samples are taken along routine sampling and then prepared into permanent slides by the company Phyco Tech. Slides are available for all years, however, species may not have been determined for all available slides.
several taxonomic updates were implemented in February 2013, this includes simple name changes to currently accepted names, changes from genus level to species based on long term experience by Phyco Tech, and some slides were revisited to resolve taxonomic uncertainty.
1) Converted all Melosira entries to Aulacoseira. The species names have been changed appropriately. 2) Converted all Oscillatoria entries to Psuedanabaena. The species names have been changed appropriately. 3) Converted all Synedra tenera to Synedra filiformis. 4) Converted all Phacotus entries without a species name to Phacotus lendneri. 5) Converted all Phormidium mucicola to Psuedanabaena 6) Converted Glenodinium entries without a species name to Glenodinium quadridens 7) Assume that all other entries with genera names but not species names cannot be resolved to species. 8) Converted all Chrysococcus entries to Chrysocccus minutus 9) Changed some single-celled Microcystis entries so that they would match the format of the colonial entries (genus + species) 10) Resolved some entries to species that were previously coded incorrectly by genus. 11) Added in Cylindrospermopsis raciborskii entries that were recently recounted and changed from Anabaenopsis raciborskii. 12) Converted all entries of genus Erkenia to Erkenia subaequiciliata
Short Name
NTLPL05
Version Number
30

North Temperate Lakes LTER: Phytoplankton - Trout Lake Area 1984 - 2006

Abstract
Phytoplankton samples from the seven LTER lakes in the Trout Lake area (Allequash, Big Muskellunge, Crystal, Sparkling, and Trout lakes and bog lakes 27-02 [Crystal Bog], and 12-15 [Trout Bog]) are collected six times per year at the deep hole sampling station at the same time our other limnological sampling is conducted. Sampling dates include winter under ice, spring mixis, June, July, August, and fall mixis. Phytoplankton samples are made into permanent slide mounts, 3 slides per sample, and are archived at the University of Wisconsin - Madison Zoology Museum. Slides are available for all years, however species identification and counts have not been done for all available slides. Sampling Frequency: 6 samples per year. Number of sites: 7
Dataset ID
238
Date Range
-
LTER Keywords
Maintenance
ongoing
Metadata Provider
Methods
Phytoplankton samples are collected using a peristaltic pump and tubing, collecting a separate sample from the epilimnion, metalimnion and hypolimnion for most of the lakes. For 27-2 Bog Lake, which is only 2m deep, we collect one 0-2m composite sample. The samples are preserved with Lugol's iodine solution. We create a single hypsometrically pooled composite sample per lake from subsamples of the epi, meta, and hypo samples. The pooled samples are sent to PhycoTech, Inc., a private lab specializing in plankton analysis, to be made into permanent slide mounts. The slides are archived, and no wet samples are saved.
Short Name
NTLPL08
Version Number
19
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National Science Foundation | LTER Network | Center for Limnology        

This material is based upon work supported by the National Science Foundation under Cooperative Agreement #DEB-2025982, NTL LTER (ROR: 04gq8q482). Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.