Physical and chemical data for various lakes near Toolik Research Station, Arctic LTER. Summer 2010 to 2014

Abstract: 

Decadal file describing the physical/chemical values recorded at various lakes near Toolik Research Station. 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: 

10582

EML revision ID: 

6

Short name: 

ARC_Lakes_Physchem_2010-2014

DOI: 

10.6073/pasta/c3dd8e3080965cd0
People

Keywords: 

Arctic LTER keywords: 

Dates

Date Range: 

Wednesday, July 13, 1983 to Saturday, August 26, 1989

Publication Date: 

Monday, December 12, 2011

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 Datsonde 4 (2000 to 2004) and Datasonde DS5 (2005-2009) 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 to present:
The following lakes have been used as experimental through 2014:

Nutrient enrichment: E5, E6, N2 Fert, N1
Food web manipulations: E1, S6, S11, I8
Reference lakes (no manipulations): Toolik, Fog 2, Fog 4, I6, Green Cabin Lake, S7, NE9B, I-Minus 1, N2 Ref

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. The site name "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. This lake is now being monitored. More information can be found at http://ecosystems.mbl.edu/ARC/lakes/lakedescriptions/n2.html
2. 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. More information can be found at http://ecosystems.mbl.edu/ARC/lakes/lakedescriptions/iseries.html and http://ecosystems.mbl.edu/ARC/lakes/lakedescriptions/i8.html
3. Fog 4 - has undergone no manipulation but serves as a reference lake for nutrient enrichment of lake E6
4. E5 - This is a deep lake that contains fish. In 2001 a nutrient enrichment began to mimic effects of increased nutrient availability. Lake Fog 2 serves a reference control for this lake. More information can be found at http://ecosystems.mbl.edu/ARC/lakes/lakedescriptions/e5.html
5. E6 - This is a shallow lake with no fish. In 2001 a nutrient enrichment began to mimic effects of increased nutrient availability. Lake Fog 4 serves as a reference lake for lake E6. A thermokarst was discovered on this lake however and so lake NE9B has been used in more recent years as a reference lake for E6. More information can be found at http://ecosystems.mbl.edu/ARC/lakes/lakedescriptions/e6.html
6. NE14 - has an active thermokarst

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: This field indicates which Hydrolab Datasonde instrument was used to take measurements
  • Type: Nominal
  • Missing values: None specified
Secchi_m
  • Label: Secchi_m
  • Definition: Measure of water transparency by depth a 22 cm Secchi Disk is visible to in meters (note where indicated "greater than" due to disk hitting the bottom before disappearing).
  • 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: This field indicates which Hydrolab Datasonde instrument was used to take measurements
  • Type: Nominal
  • Missing values: None specified
Secchi_m
  • Label: Secchi_m
  • Definition: Measure of water transparency by depth a 22 cm Secchi Disk is visible to in meters (note where indicated "greater than" due to disk hitting the bottom before disappearing).
  • 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