US Long-Term Ecological Research Network

 

Chemical Limnology:
 
Depth : NEAR BOTTOM indicates the sample was collected 2 meters above the bottom of the lake
Color440: Absorbance of filtered sample taken in a 10cm cell at 440 nm wavelength. Not corrected for path length or transformation. To convert it to the units used by Cuthbert and DelGiorgio (1992) and by most papers reporting color data, multiply by 23.03.
Color280: Absorbance of sample at 280 wavelength.
Color253: Absorbance of sample at 253 wavelength.
Cond: Conductivity was measured directly in the field using the YSI Sonde 500 DO/Temp/Conductivity meter. It was not temperature corrected.
TOTNUF: Total unfiltered nitrogen. Note that the sample quality on the total nitrogen is questionable as there was a relatively high (100-400 ppm) baseline contamination due to insufficient clearing of the HCl dispenser prior to dispensing.
TOTPUF: Total unfiltered phosphorus
DRSI: Total unfiltered Dissolved Reactive Silica
 
Anions:
This is the anions data (SO4 and CL). Anions samples were all collected at 1m and were filtered with a 0.44 micron filter. Samples were generally collected on a single date
 
Cations:
Date: Note that samples were monthly for lakes in 1998 and once in July or early August for lakes in 1999. 16 lakes were sampled in 1999 only. Collection frequency was reduced because of the very low temporal variability of the cations and to reduce the processing load on the analyzing lab.
Fe: Iron samples were ONLY analyzed in 1998. For approximately 16 of the lakes, no iron data was collected.
 
Chlorophyll:
 
This is all of the raw chlorophyll and phaeopigment data.
Notes on columns:
Top: Highest depth sample collected from
Bottom: Lowest depth sample collected from
Volfiltered: Volume (ml) of sample filtered
Chl: Total undegraded chlorophyll measured using protocol of (Lorenzen, 1967). Blank values indicate that sample was collected but not successfully analyzed.
Phaeo: Total degraded phaeopigment measurered using protocol of Lorenzen, 1967. Blank values indicate that sample was collected but not successfully analyzed.
Replicate #: To get a sense of variability between samples, 22 replicate samples were collected throughout the project. Replicate samples were collected in the field side by side but were not necessarily analysed in the same lab batch. Also 2 samples were collected in triplicate. 1 = first of replicate pair or single sample collected. 2 = second of pair of replicate samples. 3 = third of triplicate samples.
Chl + Phaeo: sum of Chl and Phaeo
 
VerticalProfile:
 
Unless otherwise indicated in notes, all parameters were collected using a YSI Sonde 500 Temperature/DO/Conductivity meter.
Temperature: degrees Celsius, as measured by YSI
DO: Dissolved oxygen (ppm) in water column as measured by YSI
Conductivity: Measured directly in water column using YSI
 
References:
 
Cuthbert, I. D. and P. d. Giorgio (1992). "Toward a standard method of measuring color in freshwater." Limnology and Oceanography 37(6): 1319-1326.
Lorenzen, C. J. (1967). "Determination of chlorophyll and pheo-pigments: spectrophotometric equations." Limnology and Oceanography 12: 343-346.
 
Lake Characteristics:
 
Project: Identifies what part of the project a lake was sampled for.
A core landscape position project lake = LPP
A core LTER lakes sampled for biology as part of the landscape positon project = LTER
One of the lakes sampled as part of Ben Greenfield MS thesis (2000) = Ben
A landscape position project lake sampled only for fish = Fish.
Lake_order: Lake order is a numerical surrogate for groundwater influx and hydrological position along a drainage network, with the highest number indicating the lake lowest in a watershed. We define lake order as follows: -3 indicates isolated seepage lakes, -2 indicates seepage lakes connected by intermittent streams, -1 indicates seepage lakes connected by a wetland, 0 indicates headwater drainage lakes, and 1 through 4 indicate drainage lakes, with the number indicating the order of the stream that exits the lake (Riera et al. 2000).
Area: lake area in acres. Using Arcview coverages, identified in Ben Greenfield MS thesis (2000) as described below
Direct_catchment: area of surrounding catchment feeding directly into lake (square meters). For drainage lakes, delineated starting from the outlet of the immediate upstream lake.
Total_catchment: area of surrounding catchment feeding into lake and all lakes upstream of given lake.
Max_depth (ft): Using agency published records, listed in Ben Greenfield MS thesis (2000) as described below
Perimeter (m): Lake perimeter. Using Arcview coverages, identified in Ben Greenfield MS thesis (2000)
Shoreline_devel: Shoreline development factor, defined in Cole's Limnology text
Wetlands_250m: Percent wetlands within catchment within buffer strip 250 meters distance from lake. Methods in Ben Greenfield MS thesis (2000
Wetlands_500m: Percent wetlands within catchment within buffer strip 500 meters distance from lake. Methods in Ben Greenfield MS thesis (2000
Mean_depth (ft): Mean depth, using WDNR data, when available.

Methods excerpted from Ben Greenfield's draft manuscript:
 
Chosen lakes included all regional hydrologic types (drainage lakes, headwater lakes, and seepage lakes). The study lakes also ranged widely in alkalinity and surrounding wetland abundance. Five of the lakes have been routinely sampled as part of the North Temperate Lakes Long Term Ecological Research site (NTL-LTER), and one lake has been sampled as part of the Cascading Trophic Interactions Project (Bade et al. 1998).
 
Chemical Data:

Lakes were monitored for pH, alkalinity, total phosphorus, chlorophyll a, and color during June, July, and August of 1997-1999 (all other parameters were also collected during these dates). Except as specified, all chemical data were collected and analyzed according to NTL-LTER protocols, which are available to the public for inspection at the NTL-LTER web site. Crampton Lake was sampled according to protocols outlined in Bade et al. (1998). Samples were collected monthly in each lake during the same season fish were collected with the exception that color data were collected in the year prior to fish collection for the NTL-LTER lakes and Crampton lake. Total phosphorus, chlorophyll a, and pH were averaged over June, July and August. Alkalinity and color were determined once, during midsummer. All parameters other than chlorophyll were collected 1 m below the lake surface, except in the five NTL-LTER lakes, where they were collected at the water surface. Color samples were filtered through 0.4 µm nucleopore filters and analyzed at 440 nm, which indicates overall humic content of surface waters (Cuthbert and del Giorgio 1992). Epilimnetic chlorophyll concentration was measured monthly to estimate primary productivity. Chlorophyll samples were collected on Fisher Type A/E glass fiber filters by raising and lowering sampling tubing at a constant rate while drawing water with a peristaltic pump. Samples were homogenized and stored in methanol for 24 hours prior to spectrophotometric determination of chlorophyll concentration (Lorenzen 1967). For the NTL-LTER lakes, chlorophyll data were taken from Sanderson (1998).
 
Lake Characteristics Data:

Spatial data included lake morphometry, watershed area, lake order, and surrounding wetland abundance. Maximum depth data were obtained from EPA Experimental Lake Survey records (Overton et al. 1986) and Wisconsin Department of Natural Resources surface water resources records (Black et al. 1963; Andrews and Threinen 1966; Steuck and Andrews 1977). Data on lake area, perimeter, and watershed area were obtained with ArcView using the methods of Gergel et al. (1999). We define watershed area as the direct drainage watershed. In drainage lakes, the watershed boundary extended up to the outlet of the immediate upstream lake. Total watershed area, terrestrial watershed area, and total watershed to lake area ratio were all examined. Lake order is a numerical surrogate for groundwater influx and hydrological position along a drainage network, with the highest number indicating the lake lowest in a watershed. We define lake order as follows: -3 indicates isolated seepage lakes, -2 indicates seepage lakes connected by intermittent streams, -1 indicates seepage lakes connected by a wetland, 0 indicates headwater drainage lakes, and 1 through 4 indicate drainage lakes, with the number indicating the order of the stream that exits the lake (Riera et al. 2000). Wetland proportion was determined for a zone 500 m distant from the lake shore that fell within the drainage area. Wetlands were defined using Wisconsin Wetlands Inventory Data (WDNR 1991) and included terrestrial wetlands, emergent macrophytes, and floating macrophytes. Wetland proportion data were arcsin(square root) transformed.
 
References cited:

Andrews, L. M. and C. W. Threinen (1966). Surface water resources of Oneida County. Madison, Wisconsin, Wisconsin Department of Natural Resources: 284.
Bade, D., J. Houser, et al., Eds. (1998). Methods of the Cascading Trophic Interactions Project. Madison, Wisconsin, USA, Center For Limnology, University of Wisconsin-Madison.
Black, J. J., L. M. Andrews, et al. (1963). Surface water resources of Vilas County. Madison, Wisconsin, Wisconsin Department of Natural Resources: 317.
Cuthbert, I. D. and P. del Giorgio (1992). "Toward a standard method of measuring color in freshwater." Limnology and Oceanography 37(6): 1319-1326.

Gergel, S. E., M. G. Turner, et al. (1999). "Dissolved organic carbon as an indicator of the scale of watershed influence on lakes and rivers." Ecological Applications 9(4): 1377-1390.
Lorenzen, C. J. (1967). "Determination of chlorophyll and pheo-pigments: spectrophotometric equations." Limnology and Oceanography 12: 343-346.

Overton, W. S., P. Kanciruk, et al. (1986). Characteristics of lakes in the Eastern United States. Volume II: Lakes sampled and descriptive statistics for physical and chemical variables. Washington, D. C., U. S. Environmental Protection Agency. 2: 374 pp.

Riera, J. L., J. J. Magnuson, et al. (2000). "A geomorphic template for the analysis of lake districts applied to the Northern Highland Lake District, Wisconsin, USA." Freshwater Biology 43(3): 301-318.

Sanderson, B. L. (1998). Factors regulating water clarity in Northern Wisconsin lakes. Zoology. Madison, Wisconsin, University of Wisconsin: 170.

Steuck, R. and L. M. Andrews (1977). Surface water resources of Forest County. Madison, Wisconsin, Wisconsin Department of Natural Resources: 198.

WDNR (1991). A user's guide to the Wisconsin Wetland Inventory, Wisconsin Department of Natural Resources.

Protocol Format
Process
Protocol ID
lpp_additional_metadata1
Protocol Type
field