Physical and chemical data for various lakes near Toolik Research Station, Arctic LTER. Summer 1990 to 1999

Abstract: 

Decadal file describing the physical/chemical values recorded at various lakes near Toolik Research Station during summers from 1990 to 1999. Sample site descriptors include site, date, time, depth. Depth profiles of physical measures collected in situ with Hydrolab Datasonde in the field include temperature, conductivity, pH, dissolved oxygen in both percent saturation and mg/l, SCUFA chlorophyll-a values in both volts and µg/l, and PAR.

Project Keywords: 

Data set ID: 

10584

EML revision ID: 

5

Short name: 

ARC_Lakes_Physchem_1990-1999

DOI: 

10.6073/pasta/1fd85582de93a281e5e5d3b80df97b52
People

Keywords: 

Arctic LTER keywords: 

Dates

Date Range: 

Tuesday, June 12, 1990 to Monday, August 9, 1999

Publication Date: 

Thursday, December 12, 1991

Methods: 

The physical characteristics and chemistry of lake waters of the Arctic LTER were sampled at various locations either weekly, monthly or once per field season depending on the site and the year.

Until 1992 (inclusive) Dissolved O2 and temperature were measured using a YSI 57 Oxygen Meter, water calibrated. Temperature and conductivity were ready by a YSI model 33 conductivity meter. Carbonate alkalinity was titrated against pH depending on expected alkalinity (Wetzel and Likens, 1979). pH was measured electrometrically with a corning portable expanded standard pH buffer and corrected for the temperature of the sample.

From 1993 to 2001 a Hydrolab SVR3-DL Surveyor 3 data logger and Hydrolab H2O-BT STd multiprobe were used to measure depth, temperature, pH, specific conductivity and dissolved oxygen. Alkalinity was measured by performing Gran titrations using DL12K Mettler autotitrator. Surface and underwater light transmission was measured using a Licor digital light meter until 1998. From 1998 onward Surface and underwater light transmission was measured using a Licor LI 1400 digital light meter with surface and underwater quantum sensors. The hydrolab was calibrated for O2 weekly using Winkler titrations. Conductivity, pH and depth were calibrated monthly.

From 2002 to present A Hydrolab Surveyor 4 data logger and Datasonde 4 and Datasonde DS5 Multiprobe were used to measure: depth, temperature, pH, specific conductivity, dissolved oxygen (mg/l), in-vivo fluorescence, and Photosynthetically active radiation (PAR) at half meter or meter intervals depending on the lake. Depth reading on sonde was calibrated in the field so that a depth of 0m was the water surface. The in vivo fluorescence measurements were taken using a Turner designs SCUFA(r) (Self-Contained Underwater Fluorescence Apparatus) attached to the Hydrolab Datasonde 4. The PAR measurements at both the surface and at each depth were taken using flat-faced, "cosine-corrected" Licor underwater quantum sensors attached to the Datasonde 4. The Hydrolab was calibrated weekly for oxygen, using the barometer in the Surveyor 4. Conductivity, and pH were also calibrated weekly using commercial standards. Because of the low conductivity of the waters around Toolik the potassium chloride (KCl) concentration in the reference electrode was changed weekly prior to calibration.

For all years Secchi disk depth was measured using a Secchi disk, a 22 cm black and white disk, that is lowered by hand into the water to the depth at which it vanishes from sight. This distance was then recorded. As there is only one depth for each site, the same Secchi depth is indicated for all depths measured at a particular site on a particular day. This measurement is generally made on the shady side of the boat and measured to the nearest 0.1 meters.
Reference Citations: Wetzel, R.G., G.E. Likens. 1979. Limnological Methods. Saunders. Philadelphia.

Site specific information for 1990's

The following lakes have been used as experimental to 1999:
Nutrient enrichment: N2 Fert, N1
Food Web manipulation: I8
Reference lakes (no manipulations): Toolik, N2 Ref, I6, E5*, E6**

1. Lake N2 was separated into two parts with a dividing curtain in 1985, with half being fertilized at a rate calculated to be approximately 5 times the normal loading of nitrogen and phosphorous. The fertilizers used were ammonium nitrate and phosphoric acid. Under site names "N2 Fert" indicates measurements from the fertilized side of the curtain (Measurements beginning July 5, 1985) and "N2 Ref" indicates the control (or reference) portion of the lake which was not fertilized. The curtain was removed in 2011. Prior to 1985 and after 2011 data from this lake was simply called Lake N2.
2. Lake N1 was fertilized at 4 times the annual loading of Toolik Lake for 5 summers from 1990-1994 with inorganic nitrogen and inorganic phosphorous. The recovery of N1 has been monitored since 1994.
3. I-Series lakes: These lakes are found in a series making up the largest tributary leading into Toolik Lake, where lake I1 is the furthest up-stream and lake I9 is the closest to Toolik lake inlet. Lake I8 has been part of a long term fish density manipulation since 1989. This manipulation involves removing low numbers of fish each summer to simulate fishing pressure on the system. Lake I6 serves as a reference lake for lake I8.

4. *E5 - Data from E5 1999 is baseline data for lake E5 which began a nutrient enrichment in 2001 to mimic effects of increased nutrient availability.

5. **E6 - Data from E6 contained in this file for 1999 is baseline data for Lake E6 which began a nutrient enrichment 2001.

Sites sampled.

Download a comma delimited (csv) or Excel file (includes metadata and data sheets).

Use of the data requires acceptance of the data use policy --> Arctic LTER Data Use Policy

To cite this data set see the citation example on the LTER Network Data Portal page for this data set.

Variables Details

(Variables names are in the first line/row of the CSV file and Excel data sheet.)
SortChem_#
  • Label: SortChem_#
  • Definition: Number used to identify samples - generally not used until later data but column remains with older data to enable comparison
  • Type: Nominal
  • Missing values: None specified
Site
  • Label: Site
  • Definition: Site Name: Name of the lake where measurements were taken. There are discrete sampling sites defined by water depth, generally they are at the point of maximum depth.
  • Type: Nominal
  • Missing values: None specified
Date
  • Label: Date
  • Definition: Date readings were taken on.
  • Type: Date/time
  • Date format: dd-mmm-yyyy
  • Missing values: None specified
Rounded Depth (m)
  • Label: Rounded Depth (m)
  • Definition: Depth of water measurement taken at starting from the surface as 0. This depth corresponds with data in other files (Nutrients, Chemistry)
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Hydrolab Depth
  • Label: Hydrolab Depth
  • Definition: Depth measured by hydrolab (where used), otherwise regular measured depth recorded
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Time_hr_dst
  • Label: Time_hr_dst
  • Definition: Exact time that each reading was recorded in Alaska Daylight Savings Time (1 hour ahead of Alaska Standard Time: if 13:00 DST than 12:00 AST)
  • Type: Nominal
  • Missing values: None specified
IBVSvr4a_V
  • Label: IBVSvr4a_V
  • Definition: Internal Battery Voltage of the Surveyor 4a Datalogger.
  • Type: Physical quantity
  • Unit: volt
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Temp_C
  • Label: Temp_C
  • Definition: Water temperature at depth.
  • Type: Physical quantity
  • Unit: celsius
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Cond_uS
  • Label: Cond_uS
  • Definition: Electrical conductivity of the water at depth.
  • Type: Physical quantity
  • Unit: microsiemenPerCentimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
pH
  • Label: pH
  • Definition: pH (opposite of the log of the hydrogen ion concentration).
  • Type: Physical quantity
  • Unit: dimensionless
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_Sat
  • Label: DO_Sat
  • Definition: The percent saturation of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_mg/l
  • Label: DO_mg/l
  • Definition: The concentration of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: milligramPerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_umoles/L
  • Label: DO_umoles/L
  • Definition: The concentration of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: micromolePerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Chl_V
  • Label: Chl_V
  • Definition: In Vivo measurement of chlorophyll-a concentration.
  • Type: Physical quantity
  • Unit: volt
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Chl_ug/l
  • Label: Chl_ug/l
  • Definition: In Vivo measurement of chlorophyll-a concentration.
  • Type: Physical quantity
  • Unit: microgramPerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
PAR_uEm2s
  • Label: PAR_uEm2s
  • Definition: PAR (photosynthetically active radiation) measured below the water surface.
  • Type: Physical quantity
  • Unit: microEinsteinPerMeterSquaredPerSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
refPAR_uEm2s
  • Label: refPAR_uEm2s
  • Definition: PAR (photosynthetically active radiation) measured with Deck unit to correct for changes in ambient light.
  • Type: Physical quantity
  • Unit: microEinsteinPerMeterSquaredPerSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Hydrolab
  • Label: Hydrolab
  • Definition: Measure of water transparency by depth a Secchi Disk is visible to.
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Secchi_m
  • Label: Secchi_m
  • Definition: This field indicates which Hydrolab Datasonde instrument was used to take measurements
  • Type: Nominal
  • Missing values: None specified
Notes
  • Label: Notes
  • Definition: Any additional information pertaining to measurements made for a particular depth, place and time.
  • Type: Nominal
  • Missing values: None specified
SortChem_#
  • Label: SortChem_#
  • Definition: Number used to identify samples - generally not used until later data but column remains with older data to enable comparison
  • Type: Nominal
  • Missing values: None specified
Site
  • Label: Site
  • Definition: Site Name: Name of the lake where measurements were taken. There are discrete sampling sites defined by water depth, generally they are at the point of maximum depth.
  • Type: Nominal
  • Missing values: None specified
Date
  • Label: Date
  • Definition: Date readings were taken on.
  • Type: Date/time
  • Date format: dd-mmm-yyyy
  • Missing values: None specified
Rounded Depth (m)
  • Label: Rounded Depth (m)
  • Definition: Depth of water measurement taken at starting from the surface as 0. This depth corresponds with data in other files (Nutrients, Chemistry)
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Hydrolab Depth
  • Label: Hydrolab Depth
  • Definition: Depth measured by hydrolab (where used), otherwise regular measured depth recorded
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Time_hr_dst
  • Label: Time_hr_dst
  • Definition: Exact time that each reading was recorded in Alaska Daylight Savings Time (1 hour ahead of Alaska Standard Time: if 13:00 DST than 12:00 AST)
  • Type: Nominal
  • Missing values: None specified
IBVSvr4a_V
  • Label: IBVSvr4a_V
  • Definition: Internal Battery Voltage of the Surveyor 4a Datalogger.
  • Type: Physical quantity
  • Unit: volt
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Temp_C
  • Label: Temp_C
  • Definition: Water temperature at depth.
  • Type: Physical quantity
  • Unit: celsius
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Cond_uS
  • Label: Cond_uS
  • Definition: Electrical conductivity of the water at depth.
  • Type: Physical quantity
  • Unit: microsiemenPerCentimeter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
pH
  • Label: pH
  • Definition: pH (opposite of the log of the hydrogen ion concentration).
  • Type: Physical quantity
  • Unit: dimensionless
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_Sat
  • Label: DO_Sat
  • Definition: The percent saturation of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: percent
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_mg/l
  • Label: DO_mg/l
  • Definition: The concentration of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: milligramPerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
DO_umoles/L
  • Label: DO_umoles/L
  • Definition: The concentration of dissolved oxygen at depth.
  • Type: Physical quantity
  • Unit: micromolePerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Chl_V
  • Label: Chl_V
  • Definition: In Vivo measurement of chlorophyll-a concentration.
  • Type: Physical quantity
  • Unit: volt
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Chl_ug/l
  • Label: Chl_ug/l
  • Definition: In Vivo measurement of chlorophyll-a concentration.
  • Type: Physical quantity
  • Unit: microgramPerLiter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
PAR_uEm2s
  • Label: PAR_uEm2s
  • Definition: PAR (photosynthetically active radiation) measured below the water surface.
  • Type: Physical quantity
  • Unit: microEinsteinPerMeterSquaredPerSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
refPAR_uEm2s
  • Label: refPAR_uEm2s
  • Definition: PAR (photosynthetically active radiation) measured with Deck unit to correct for changes in ambient light.
  • Type: Physical quantity
  • Unit: microEinsteinPerMeterSquaredPerSecond
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Hydrolab
  • Label: Hydrolab
  • Definition: Measure of water transparency by depth a Secchi Disk is visible to.
  • Type: Physical quantity
  • Unit: meter
  • Maximum: Not specified
  • Minimum: Not specified
  • Precision: Not specified
  • Missing values:
    • . = Missing or Not Measured
Secchi_m
  • Label: Secchi_m
  • Definition: This field indicates which Hydrolab Datasonde instrument was used to take measurements
  • Type: Nominal
  • Missing values: None specified
Notes
  • Label: Notes
  • Definition: Any additional information pertaining to measurements made for a particular depth, place and time.
  • Type: Nominal
  • Missing values: None specified