NTL-LTER
North Temperate Lakes Long-Term Ecological Research

Research Protocols

Routine Sampling Description

Sampling generally occurs bi-weekly during the summer and monthly during the non-summer season.

  • Water temperature (every 1 m)
  • Dissolved oxygen (every 1 m)
  • Underwater PAR (vertical penetration compared to surface)
  • Secchi depth
  • Chlorophyll (discrete depths northern lakes, integrated southern lakes)
  • Zooplankton density
  • Phytoplankton biovolume (*ME/MO only, all other lakes have archived mounted slides)
  • Snow/ice thickness

Monthly and Quarterly Chemistry Sampling

  • Monthly – Total nitrogen and phosphorus (filtered/unfiltered), dissolved reactive silica, nitrate+nitrite, ammonium, total carbon (inorganic, organic), dissolved carbon (inorganic, organic), pH (all variables at multiple depths)
  • Quarterly – Major ions (Cl, SO4, Mg, Ca, Na, K, Fe, Mn), alkalinity, color
  • Quarterly – North only: specific conductance

Seasonal Sampling

  • Buoy deployment (TR, SP, ME)
  • Macrophyte sampling (TR, ME, MO, FI, WI)
  • Fish sampling
  • Benthic macroinvertebrates (northern only)
  • Crayfish (northern only)
  • Pelagic macroinvertebrates (northern only)
  • Groundwater wells (northern only)
  • Sediment deposition (TR, SP, CR)
  • Lake levels (northern only)
Annual sampling schedule for northern and southern lakes. Numbers represent the number of sampling events per month.

Sampling Locations

Northern Lakes
Allequash Lake (AL): 46.038317 -89.620617
Big Muskellunge Lake (BM): 46.021067 -89.611783
Crystal Bog (Bog 27-2) CB): 46.007583 -89.606183
Crystal Lake (CL): 46.00275 -89.612233
Sparkling Lake (SP): 46.007733 -89.701183
Trout Bog (Bog 12-15) (TB): 46.04125 -89.686283
Trout Lake (TR): 46.029267 -89.665017
Southern Lakes
Lake Mendota (ME): 43.09885 -89.40545
Lake Monona (MO): 43.06337 -89.36086
Lake Wingra (WI): 43.05258 -89.42499
Fish Lake (FI): 43.28733 -89.65173

Project Plan

NTL Core Program Project Plan: LTER Core Program Project Plan v1 – DRAFT

Protocols are actively being revised to a uniform, version controlled format and will be posted on this site as updated. All protocols will be updated by December 2023. Please email Grace Wilkinson if you need access to a protocol before that time. 

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Routine Lake Sampling Procedures

  • Northern Lakes Sampling (non-chem, plankton, monthly, and quarterly)
  • Southern Lakes Sampling (non-chem, plankton, monthly, and quarterly

Seasonal Sampling Procedures

  • Macrophytes – northern lakes
  • Macrophytes – southern lakes
  • Fish
  • Benthic Macroinvertebrates Sampling and Analysis
  • Pelagic Macroinvertebrates Sampling and Analysis
  • Groundwater Well Sampling
  • Sediment Trap Deployment and Analysis

Water Chemistry Analysis Procedures

Biological Sample Analysis Procedures

  • Chlorophyll Extraction and Analysis – Spectrophotometer
  • Chlorophyll Extraction and Analysis – Fluorometer
  • Zooplankton Analysis
  • Phytoplankton Analysis

Data Sheets, Bench Sheets, and Logs

  • Non-Chemistry Sampling Event Data Sheet
  • Monthly Chemistry Sampling Event Data Sheet
  • Quarterly Sampling Event Data Sheet
  • Sample Analysis Tracking Logs
  • Alkalinity Bench Sheet
  • Standard and Reagent Log Sheet
  • Chlorophyll Bench Sheets
  • Groundwater Well Sampling Data Sheet
  • Macrophyte Sampling Data Sheet – northern lakes
  • Macrophyte Sampling Data Sheet – southern lakes
  • Fish Sampling Data Sheet

Regional Lakes Sampling

  • Regional Lake Sampling
  • Regional Lake Sample Processing

Archived Research Protocols

PDFs of archived research protocols for various projects