US Long-Term Ecological Research Network

Cascade project at North Temperate Lakes LTER - Daily data for key variables in whole lake experiments on early warnings of critical transitions, Paul and Peter Lakes, 2008-2011

Abstract
Peter Lake's food web was altered by adding largemouth bass at a slow rate while monitoring key food web constituents including littoral minnow abundance indexed as catch per trap per hour, zooplankton biomass, and concentration of chlorophyll a. Paul Lake was manipulated and the same variables were measured there.
In Peter Lake, we expected littoral catch of minnows to first increase as minnows moved into the littoral zone due to the threat of bass predation and then decrease due to bass predation. We expected zooplankton biomass to increase as minnows moved into the littoral zone. We expected chlorophyll to decrease due to increased grazing by zooplankton. We expected that variance and autocorrelation of chlorophyll would increase as the food web passed a critical transition.
We expected that the time series in Paul Lake would represent the normal variability of an unmanipulated lake
Dataset ID
374
Date Range
-
Methods
Primary publications that provide more information about taxa, methods, and data are:
Carpenter, S.R., J.J. Cole, M.L. Pace, R.D. Batt, W.A. Brock, T. Cline, J. Coloso, J.R. Hodgson, J.F. Kitchell, D.A. Seekell, L. Smith and B. Weidel. 2011. Early warnings of regime shifts: A whole-ecosystem experiment. Science 332: 1079-1082.
Cline, T.J., D. A. Seekell, S. R. Carpenter, M. L. Pace, J. R. Hodgson, J. F. Kitchell, and B. C. Weidel 2014. Early warnings of regime shifts: evaluation of spatial indicators from a whole-ecosystem experiment. Ecosphere 5:art102. http://dx.doi.org/10.1890/ES13-00398.1
Pace, M.L., S.R. Carpenter, R.A. Johnson and J. T. Kurzweil. 2013. Zooplankton provide early warnings of a regime shift in a whole-lake manipulation. Limnology and Oceanography 58: 525-532.
For an explanation of our rationale and expected results see:
Carpenter, S. R., Brock, W. A., Cole, J. J., Kitchell, J. F., & Pace, M. L. 2008. Leading indicators of trophic cascades. Ecology Letters, 11(2), 128-138. doi:DOI 10.1111/j.1461-0248.2007.01131.x
Version Number
2

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

Abstract
Daily chlorophyll for surface water samples 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
Core Areas
Dataset ID
372
Date Range
-
Maintenance
completed
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.

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 Phosphorus, Chlorophyll, DOC, Color, and pH for Twenty UNDERC Lakes 1995 - 2003

Abstract
Data on total phosphorous, chlorophyll a, dissolved organic carbon, water color, and pH for a set of lakes located at the University of Notre Dame Environmental Research Center (UNDERC). Surface water samples were collected monthly from May through August either from shore with a telescoping pole or from a boat. Twenty lakes were sampled from 1995-2000. Fifteen of these lakes were sampled from 2001-2003.
Contact
Dataset ID
361
Date Range
-
Methods
Methods are described in Pace and Cole 2002 (https://doi.org/10.4319/lo.2002.47.2.0333). Surface water samples for the analysis of pH, dissolved organic carbon (DOC), chlorophyll a , total phosphorus color were collected by dipping a sample bottle. The total phosphorus (TP) samples were stored in a separate acid-washed bottle. Samples were collected monthly from May through August from a set of 20 lakes for the years 1995-2000. A subset of fifteen lakes were sampled in the same way from 2001-2003. Samples were stored in a cooler and returned the lab for processing within a few hours.
Version Number
3

Cascade Project at North Temperate Lakes LTER High Frequency Sonde Data from Food Web Resilience Experiment 2008 - 2011

Abstract
High-frequency sonde data collected from the surface waters of two lakes in Upper Peninsula of Michigan during the summers of 2008-2011. The food web of Peter Lake was slowly transformed by gradual additions of Largemouth bass (Micropterus salmoides) while Paul Lake was an unmanipulated reference. Sonde data were used to calculate resilience indicators to evaluate the stability of the food web and to calculate ecosystem metabolism.
Dataset ID
360
Date Range
-
Methods
Data were collected at 5 minute intervals using in-situ automated sensors (sondes). All measurements and samples were collected from a stationary raft over the deepest part of the lake.
Sondes were suspended from floats with probes at a depth of 0.75m below the surface. Sonde sensors were cleaned daily in the field and calibrated monthly following manufacturer guidelines. Peter and Paul lakes were each monitored with two YSI multiparameter sondes (model 6600 V2-4) fitted with optical DO (model 6150), pH (model 6561), optical Chl-a (model 6025), and conductivity-temperature (model 6560) probes. Sensor measurements were made at 0.75 m every 5 min and were calibrated weekly. PAR was measured and the UNDERC meteorology station maintained by the University of Notre Dame or by the North Temperate Lakes Weather Station at Woodruff Airport.
Outliers were replaced by NA. Occasional gaps in the record due to instrument cleaning are NA.
Version Number
1

Cascade Project at North Temperate Lakes LTER Core Data Zooplankton 1984 - 2016

Abstract
Zooplankton data from 1984-2016. Sampled approximately weekly with two net hauls through the water column (30 cm diameter net, 80 um mesh). There have been over eight zooplankton counters during this period, so species-level identifications (TAX, below) are not as consistent as those for some of the other datasets. Sampling Frequency: varies; Number of sites: 8
Core Areas
Dataset ID
355
Date Range
-
Maintenance
completed
Methods
Sampling:
Zooplankton were sampled approximately weekly with two net hauls through the water column (30 cm diameter net, 80 um mesh). Tows were taken at standard depths for almost all years. The standard depths are as follows: Peter, East Long, West Long, Crampton and Tuesday Lakes: 12m, Paul Lake: 8m, Ward Lake: 6m; exceptions are: for 2012 and beyond Tuesday Lake was sampled at 10m, Peter was sampled at 10m from 1984-1986, Paul was sampled at 7.5m in 1995. Samples were preserved with cold sugared formalin or Lugol's solution.
Version Number
16

Cascade Project at North Temperate Lakes LTER Core Data Process Data 1984 - 2016

Abstract
Data useful for calculating and evaluating primary production processes were collected from 6 lakes from 1984-2016. Chlorophyll a and pheophytin were measured by the same fluorometric method from 1984-2016. In some years chlorophyll and pheophytin were separated into size fractions (total, and a ‘small’ fraction that passed a 35 um mesh screen). Primary production was measured by the 14C method from 1984-1998. Dissolved inorganic carbon for primary production calculation was calculated from Gran alkalinity titration and air-equilibrated pH until 1987 when this method was replaced by gas chromatography. Until 1995 alkaline phosphatase activity was measured as an indicator of phosphorus deficiency.
Core Areas
Dataset ID
354
Date Range
-
Methods
General: Bade, D., J. Houser, and S. Scanga (editors). 1998. Methods of the Cascading Trophic Interactions Project. 5th edition. Center for Limnology, University of Wisconsin-Madison, and Cary Institute of Ecosystem Studies, Millbrook, NY.
Version Number
14

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 Core Data Physical and Chemical Limnology 1984 - 2016

Abstract
Physical and chemical variables are measured at one central station near the deepest point of each lake. In most cases these measurements are made in the morning (0800 to 0900). Vertical profiles are taken at varied depth intervals. Chemical measurements are sometimes made in a pooled mixed layer sample (PML); sometimes in the epilimnion, metalimnion, and hypolimnion; and sometimes in vertical profiles. In the latter case, depths for sampling usually correspond to the surface plus depths of 50percent, 25percent, 10percent, 5percent and 1percent of surface irradiance.
Dataset ID
352
Date Range
-
Methods
Methods for 1984-1990 were described by Carpenter and Kitchell (1993) and methods for 1991-1997 were described by Carpenter et al. (2001).
Version Number
14

Cascade Project at North Temperate Lakes LTER Core Data Nutrients 1991 - 2016

Abstract
Physical and chemical variables are measured at one central station near the deepest point of each lake. In most cases these measurements are made in the morning (0800 to 0900). Vertical profiles are taken at varied depth intervals. Chemical measurements are sometimes made in a pooled mixed layer sample (PML); sometimes in the epilimnion, metalimnion, and hypolimnion; and sometimes in vertical profiles. In the latter case, depths for sampling usually correspond to the surface plus depths of 50percent, 25percent, 10percent, 5percent and 1percent of surface irradiance. The 1991-1999 chemistry data was obtained from the Lachat auto-analyzer. Like the process data, there are up to seven samples per sampling date due to Van Dorn collections across a depth interval according to percent irradiance. Voichick and LeBouton (1994) describe the autoanalyzer procedures in detail. Nutrient samples were sent to the Cary Institute of Ecosystem Studies for analysis beginning in 2000. The Kjeldahl method for measuring nitrogen is not used at IES, and so measurements reported from 2000 onwards are Total Nitrogen.
Core Areas
Dataset ID
351
Date Range
-
Methods
Methods for 1984-1990 were described by Carpenter and Kitchell (1993) and methods for 1991-1997 were described by Carpenter et al. (2001).
Version Number
14
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