Acceptance and utilization of LTER data requires that:
(1) The Principal Investigator be sent a notice stating reasons for acquiring any data and a description of the publication intentions.
(2) The Principal Investigator of the data set be sent a copy of the report or manuscript prior to submission and be adequately cited in any resultant publications.
(3) A copy of any resultant publications should be sent to:
Principal Investigator
Ecosystems Center
Marine Biological Laboratory
7 MBL St.
Woods Hole, MA 02543
| Dataset URLs: | METADATA: HTML, Rich Text, XML(EML compliant) DATA: Comma Delimited, Excel file with Metadata and data |
| Dataset ID: | WAT-VA-SigmaNutrients.01 |
| Dataset Title: | Nutrient samples collected by Sigma Autosampler between 2001 and 2007 in three headwater sites of contrasting land use, and at the Parker and Ipswich River Dams as they enter into the estuaries. |
| Investigator 1: | |
| First Name: | Charles |
| Last Name: | Hopkinson |
| Address line 1: | Ecosystems Center |
| Address line 2: | MBL |
| Address line 3: | 7 MBL St |
| City: | Woods Hole |
| State: | MA |
| Zip Code: | 02543 |
| Country: | USA |
| Investigator 2: | |
| First Name: | Wilfred |
| Last Name: | Wollheim |
| Address line 1: | Morse Hall |
| Address line 2: | UNH |
| Address line 3: | |
| City: | Durham |
| State: | NH |
| Zip Code: | 03824 |
| Country: | USA |
| Associate Investigators: | Corey Lawrence, Jeff Evans, Brian Pellerin, Hap Garrit, Emily Gaines, Joe Thouin, William Lee, Aaron Strong, Christina Maki |
| Keywords: | dissolved, nitrate, nitrogen, nutrient, phosphate, phosphorus, organic |
| Abstract: | Total organic nitrogen, total organic phosphorus, and nitrate concentrations collected frequently by Sigma autosampler (or volunteers in winter) from 5 sites. Sites include three headwater sites of contrasting land use (CC= Forest, SB = suburban, CS = wetland) and at the mouth of the Ipswich and Parker Rivers where the flow into the estuary. |
| Contact: | Plum Island Ecosystems LTER Information Manager The Ecosystems Center Marine Biological Lab 7 MBL St Woods Hole, MA 02543 Phone (508) 289 7485 Email: pie_im@mbl.edu Online URL: http://ecosystems.mbl.edu/PIE/ |
| DATA FILE INFORMATION: | |
| Data File URL | http://ecosystems.mbl.edu/PIE/data/WAT/data/WAT-VA-SigmaNutrients.dat |
| Data File Name | WAT-VA-SigmaNutrients |
| Beginning Date | 11/1/2001 |
| End Date | 5/24/2007 |
| Number of Data Records | 2708 |
| Other Files to Reference | All in the YSI series (for flow in the headwater sites). |
| Availability Status | Type 1 |
| Quality Control Information | All of our analyses go through an initial QA/QC at the time of analysis. This includes replicates, standard curves and percent digestion (TP) and nitrate-nitrite conversion (NO3), as well as regular standard checks. Despite this QA/QC there are several cases in which other questions might arise, including a small number of samples (6) for which reported NO3 values exceed TN values. See notes for additional issues regarding data quality. |
| Maintenance Description | Updated regularly to add dates or to enter data as analysis occurs. |
| Log of Changes: | 01) Sept, 2007. Updated to incorporate most recent data. |
| RESEARCH LOCATION: | Site 1 |
| Geographic Description | Watershed, CC (forest) |
| Location Bounding Box | |
| West Bounding Coordinate | |
| East Bounding Coordinate | |
| North Bounding Coordinate | |
| South Bounding Coordinate | |
| OR if single point location | |
| Latitude | 42.7692 |
| Longitude | -70.9165 |
| Methods: | Samples were collected with a Sigma auto-sampler on a daily, bi-daily, flow-weighted, or time weighted frequency from each site. Samples were preserved with sulfuric acid, except for those collected by volunteer in winter which were not acidified but frozen within 24 hours. Analysed for nitrate, TP, TN, and TOC. Sigma installation: Sigma autosampler is placed at a convenient location on the bank of each site. Sigma is visited every three weeks to replace/check bottles and batteries. Intake is fastened to reebar suspended above the sediments to prevent intake of particulates from the stream bottom. The bottles contain sulfuric acid to preserve nutrients in their ambient form. Bottles sit out for up to 6 weeks (but most often < 3 weeks) within the sampler before being filled and collected. Occasionally spiders or other bugs are found in the samples. See notes. Daily samples: Sigma pulls a 1L sample the same time each day (usually between 9am to 5pm). TwoDayComposite samples: Sigma pulls a 500ml sample and places it in the same bottle over two consecutive days. (usually grabbed between 9am and 5pm) Volunteer: A grab sample collected by a volunteer during winter period when sigma is not funcitonal. Composite-timeweighted_*hrs - The Sigma pulls a sample every * hours and places it into a single carboy. Usually the volume of the pull is 250ml. The number of hours varied when we first switched to this technique, but is now every 6hrs (4 time per day). Composite-flowweighted_*cms - The Sigma pulls a sample every * cubic meters per second pumped into a single carboy. The amount of cubic meters varies depending on the time of year. This technique relies on a depth sonde attached to the Sigma with associated rating curve. No longer used due to unreliablity of the depth sonde. Samples were processed at the Ecosystems Center in Woods Hole, MA. The processing procedure includes neutralization with sodium hydroxide and sodium bicarbonate, persulfate digestion, and nitrate and phosphate analysis using a Lachat auto-analyzer or spectrophotometer. As of 2004 TN and TOC are run together on a Shimadzu TN/TOC analyzer. Prior to 2004, TN was first digested and then run on a Lachat. TP is still digested and run on a spec. Where samples exist in archive TOCs will be run to complement TNs. NOTES AND COMMENTS: Some of the samples from this data set have yet to be run and/or need to be re-run. This file will be updated as samples are analyzed (re-analyzed) . |
| Variable Name | Variable Description | Units | Measurement Scale | Code Infomation | Number Type | DateTime Format | Missing Value Code | Missing Value Code Explanation |
| Site | Field Collection Site | nominal | CC = Cart Creek (forest) | CS = Cedar Swamp (wetland) | SB = Saw Mill Br (urban) | ID = Ipswich R. Dam, Ipswich | PD = Parker R. Dam, Byfield | blank cell | ||||
| Year | Year of collection | nominal | yyyy | blank cell | ||||
| Date 1 | Start date of sample collection | datetime | yyyy-mm-dd | blank cell | ||||
| Date 2 | End date of sample collection | datetime | yyyy-mm-dd | blank cell | ||||
| SampleType | A description of the type of sample routine used with the Sigma | nominal | Daily = one days sample per bottle collected by the autosampler | TwoDayComposite = two days sample per bottle collected by the autosampler | Volunteer = one days sample collected by volunteer | Composite-timeweighted_*hrs = samples are collected every * hours and pumped into a single carboy | Composite-flowweighted_*cms = samplers are collected after every * cubic meters has passed by the sigma. | |||||
| TN | Total Nitrogen as N. Digested to Nitrate + Nitrite and measured with a Lachat auto-analyzer or Shimadzu TN/TOC analyser. | microMolesPerLiter | ratio | real | blank cell | |||
| TP | Total Phosphorus as P. Digested to Phosphate-P measured with spectrophotometer or Lachat auto-analyzer | microMolesPerLiter | ratio | real | blank cell | |||
| NO3 | Nitrate + Nitrite-N as measured with a Lachat auto-analyzer | microMolesPerLiter | ratio | real | blank cell | |||
| TOC | Total organic carbon as C. Total organic carbon measured with Shimadzu TN/TOC analyzer. | microMolesPerLiter | ratio | real | blank cell | |||
| Notes | Comments relevant to quality of the data. | nominal | 5= Samples were run on Shimadzu and were corrected for poor machine performance so these values are as accurate as possible but are not perfect | 6 = Samples were run on Shimadzu (see Gaines 2/28/06 processed TN file) and were corrected for poor machine performance so these values are as accurate as possible but are not perfect | blank cell |