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The re-use of scientific data has the potential to greatly increase communication, collaboration and synthesis within and among disciplines, and thus is fostered, supported and encouraged. Permission to use this dataset is granted to the Data User free of charge subject to the following terms:

1) Acceptable use. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes. The Data User is permitted to produce and distribute derived works from this dataset provided that they are released under the same license terms as those accompanying this Data Set. Any other uses for the Data Set or its derived products will require explicit permission from the dataset owner.
2 ) Redistribution. The data are provided for use by the Data User. The metadata and this license must accompany all copies made and be available to all users of this Data Set. The Data User will not redistribute the original Data Set beyond this collaboration sphere.
3 ) Citation. It is considered a matter of professional ethics to acknowledge the work of other scientists. Thus, the Data User will properly cite the Data Set in any publications or in the metadata of any derived data products that were produced using the Data Set. Citation should take the following general form: Creator, Year of Data Publication, Title of Dataset, Publisher, Dataset identifier. For example:

Shaver, G. 1989. Above ground biomass in acidic tussock tundra experimental site, 1989, Arctic LTER, Toolik, Alaska. Arctic LTER, Marine Biological Lab, Woods Hole, Ma 02543. 1989gsttbm 

4 ) Acknowledgement. The Data User should acknowledge any institutional support or specific funding awards referenced in the metadata accompanying this dataset in any publications where the Data Set contributed significantly to its content. Acknowledgements should identify the supporting party, the party that received the support, and any identifying information such as grant numbers. For example:

Data sets were provided by the Arctic LTER. This material is based upon work supported by the National Science Foundation under Grants #DEB-981022, 9211775, 8702328; #OPP-9911278, 9911681, 9732281, 9615411, 9615563, 9615942, 9615949, 9400722, 9415411, 9318529; #BSR 9019055, 8806635, 8507493.

5 ) Notification. The Data User will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The Data User will provide the data contact with two reprints of any publications resulting from use of the Data Set and will provide copies, or on-line access to, any derived digital products. Notification will include an explanation of how the Data Set was used to produce the derived work.
6 ) Collaboration. The Data Set has been released in the spirit of open scientific collaboration. Data Users are thus strongly encouraged to consider consultation, collaboration and/or co-authorship with the Data Set Creator.

By accepting this Data Set, the Data User agrees to abide by the terms of this agreement. The Data Owner shall have the right to terminate this agreement immediately by written notice upon the Data User's breach of, or non-compliance with, any of its terms. The Data User may be held responsible for any misuse that is caused or encouraged by the Data User's failure to abide by the terms of this agreement.


While substantial efforts are made to ensure the accuracy of data and documentation contained in this Data Set, complete accuracy of data and metadata cannot be guaranteed. All data and metadata are made available "as is". The Data User holds all parties involved in the production or distribution of the Data Set harmless for damages resulting from its use or interpretation.

Dataset URLs:METADATA: HTML, Rich Text, XML(EML compliant)
DATA: Comma Delimited, Excel file with Metadata and data, Dataset via LTER Data Portal
Dataset ID:1990-2012_Oksrukuyik_Chl.04
Dataset Title:Epilithic and sestonic chlorophyll a for Oksrukuyik Creek during the summer from 1990 through 2012
Investigator 1: 
First Name:Breck
Last Name:Bowden
Organization:University of Vermont
Address line 2:303D Aiken Center
Address line 3:Rubenstein School of Environment and Natural Resources
Zip Code:05405
Investigator 2: 
First Name:Bruce
Last Name:Peterson
Organization:Marine Biological Laboratory
Address line 2:7 MBL St.
Address line 3:The Ecosystems Center
City:Woods Hole
Zip Code:02543
Investigator 3: 
First Name:Elissa
Last Name:Schuett
Organization:University of Vermont
Address line 2:3 College St.
Address line 3:RESL
Zip Code:05401
Associate Investigators:
Keywords:chlorophyll a, epilithic algae, Oksrukuyik Creek, primary productivity, streams, arctic streams
Abstract:Sestonic and epilithic chlorophyll a for the Oksrukuyik Creek during the summers of 1990 - current. Water was filtered for sestonic chlorophyll and rocks from designated locations on the Oksrukuyik Creek were scrubbed for epilithic algae approximately three times during summer, once in each June, July, and August. Phosphorus, in the form of phosphoric acid, and nitrogen, in the form of ammonium sulfate were added to the river 1991-1996 to raise SRP by 0.32 uM and N by 7.1 uM, respectively. Sampling stations were in the fertilized reach 1990-1996, in a recovery reach 1997-1999 and in the reference reach of the stream all years. Chlorophyll a was analyzed for the Oksrukuyik Creek since 1990.
For questions about the Metadata and data contact the Investigators.
For information about this web site contact:
Arctic LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7496
Online URL:
Data File URL
Data File Name 1990-2012_Oksrukuyik_Chl.csv
Beginning Date 8/7/1990
End Date 8/6/2012
Number of Data Records 2334
Other Files to Reference
Availability Status 1
Quality Control Information field replicates and lab replicates of samples as well as quality assurance of data
Maintenance Description ongoing data collection, updated annually
Log of Changes: 4/2013: JPB organized metadata and data into this file; 8/2013: EBS: updated data to include total chlorophyll, chlorophyll a, and phaeophytin
Version 2: Checked keywords against the LTER network preferred list and replaced non-preferred terms. Jim L 15Jan14
Version 3: 12/2013: JPB added 2011 and 2012 data.
Version 4: Changed Distrubution URL since the LTER network DAS system is being discontinued. JimL 9Apr2015
Location Name Oksrukuyik -0.1k Oksrukuyik -0.3k Oksrukuyik -0.7k Oksrukuyik 1.37k Wolf Creek  
Geographic Description Oksrukuyik Creek, North Slope of Alaska, reference reach, upstream of the formerly fertilized reach. Oksrukuyik Creek, North Slope of Alaska, reference reach, upstream of the formerly fertilized reach. Oksrukuyik Creek, North Slope of Alaska, reference reach, upstream of the formerly fertilized reach. Oksrukuyik Creek, North Slope of Alaska, recovery reach, formerly fertilized reach. Tributary of Oksrukuyik Creek, North Slope of Alaska.  
Location Bounding Box            
West Bounding Coordinate            
East Bounding Coordinate            
North Bounding Coordinate            
South Bounding Coordinate            
OR if single point location            
Latitude 68.671486222 68.671371694 68.67101801 68.679780992 68.6696714078003  
Longitude -149.1281271 -149.131155484 -149.137892686 -149.114206438 -149.127044677734  
Elevation 761.756 763.881 764.537 762.678 762  
Link to Google Map View on Google Map View on Google Map View on Google Map View on Google Map View on Google Map  
Organisms studied
Methods:Sestonic chlorophyll was sampled by filtering 500 mL stream water through a 47mm filter. The fitlers were returned to the lab and placed in 10ml of 90% buffered acetone and extracted for 24 hours. The samples were then read on a Turner 111 (1990-1991) and Turner 450 (1992-1997), TurnerDesigns 10AU (1998-present) Fluorometers. Beginning in 2004, phaeophytin was also measured, allowing for determination of chlorophyll a, in addition to total chlorophyll. To measure phaeophytin, acid was added to the sample after the initial reading, the sample sat for ~60 seconds, and read a second time on the fluorometer.
Epilithic chlorophyll was sampled using either a "2x2" or "whole rock" scrubbing method.
2x2 method: Epilithic chlorophyll was sampled three times on rocks from
riffles. Using a plastic 35mm slide mount to partition a known
area, the algae was scraped from the rock surface with a brass
brush. The brushed area of the rock, the brush and slide holder
were then rinsed and the slurry collected and brought up to a
volume of 56 ml. Five rocks were sampled from each riffle
Whole rock method: Whole rock samples were also collected from riffles.
The upper surface of rocks fitting into an area of 546cm^2 ( +/- 18cm) (363 cm2 ( +/- 18cm) in 1996) were scrubbed with a brass brush.
The slurry was brought to a volume of 1 L.The samples were returned to the lab
where they were filtered through a GF/C or GF/F glass fiber filter.
The filters were then placed in 10 ml of 90% buffered acetone and extracted in the dark for 24 hours. The samples
were then read on a Turner 111 (1990-1991) and Turner 450 (1992-1997), TurnerDesigns 10AU (1998-2012) Fluorometers.
Beginning in 2004, samples were analyzed for for chlorophyll a. After taking an initial fluorescence reading the sample was acidified with 100uL of 0.3N HCl and the sample was read again after waiting approximately 90 seconds. To calculate chlorophyll a concentration the second value is subtracted from the first value. The two different values represent total chlorophyll concentration and phaeophytin pigment concentration, by subtracting the phaeophytin from total chlorophyll, chlorophyll a is determined.

Reference Citations: R.G. Wetzel and G.E. Likens. 1979. Limnological Methods. Saunders. Philadelphia.
Notes: In 2004 several adjustments were made to the protocol from 2003. Extraction took place at approximately 4C using chilled acetone. A multipoint curve was analyzed using a chl a stock std. A Turner Designs solid standard could then be utilized as a check. GF/F 25mm filters were used. Additionally, chl a was corrected for pheophytin following EPA 445 and data is reported in corrected chl a. For more information please reference the chlorophyll protocol available on the Arctic LTER website.

Data Table

Variable Name Variable Description Data Type Units DateTime Format Code Information Missing Value Code
Site Code LTER Site code text        
River site of measurement (named) text        
Date Date datetime   dd-mmm-yy    
Station (km) Distance from N and P dripper, usually in kilometers Negative numbers indicate sites upstream from fertilization; positive numbers are downstream. text        
Reach Reference, recovery, or fertilized reach based on the location of the phosphorus and nitrogen addition. Additions occurred 1991-1996. text        
Type Type of sample (e.g. sestonic, whole rock epilithic, 2x2 epilithic) text        
Epilithic Total Chlorophyll (ug/cm^2) Total chlorophyll (ug/cm^2) for epilithic samples, whole rock scrubs or 2x2 number microgramPerCentimeterSquared     -1111=no data | -9999=below detection limit
Epilithic Chl a (ug/cm^2) Phaeophyton corrected Chl a (ug/cm^2) for epilithic samples, whole rock scrubs or 2x2 number microgramPerCentimeterSquared      
Epilithic Phaeopigment (ug/cm^2) Phaeopigment content (ug/cm^2) for epilithic samples, whole rock scrubs or 2x2 number microgramPerCentimeterSquared      
Sestonic Total Chlorophyll (ug/L) Total chlorophyll (ug/L) for sestonic samples number microgramPerLiter      
Sestonic Chl a (ug/L) Phaeophyton corrected Chl a (ug/L) for sestonic number microgramPerLiter      
Sestonic Phaeopigment (ug/L) Phaeopigment content (ug/L) for sestonic samlpes number microgramPerLiter      
Comments Notes about the data text        

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