Plum Island Ecosystems LTER Database

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:MON-PR-MBYSI2009.03
Dataset Title:Year 2009, 15 minute interval, water quality measurements of water column temperature, salinity, oxygen, and depth in the upper Parker River Estuary at Middle Road Bridge, Newbury, MA.
Investigator 1: 
First Name:Chuck
Last Name:Hopkinson
Address line 1:Georgia Sea Grant
Address line 2:University of Georgia
Address line 3:229 Marine Sciences
Zip Code:30602
Associate Investigators:Hap Garritt
Keywords:primary production, disturbance, temperature, oxygen, conductivity, salinity, depth, saturation, gases, Parker River, monitoring
Abstract:Year 2009, water quality sonde data.15 minute readings of water column temperature, salinity, oxygen and depth in the upper Parker River Estuary at Middle Rd Bridge, Newbury, MA
Contact: Plum Island Ecosystems LTER Information Manager
The Ecosystems Center
Marine Biological Lab
7 MBL St
Woods Hole, MA 02543
Phone (508) 289 7485
Online URL:
Data File URL
Data File Name MON-PR-MBYSI2009
Beginning Date 5/12/2009
End Date 11/23/2009
Number of Data Records 18703
Other Files to Reference
Availability Status Type 1
Quality Control Information
Maintenance Description
Log of Changes: Version 01: March 5, 2012, updated data and metadata. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 28/12 8:18 PM for QA/QC to EML 2.1.0
Version 02: May 29, 2014, updated data and metadata to comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 5/28/14 2:09 PM for QA/QC to EML 2.1.0
Version 03: May 30, 2014, metadata and data edit, data and metadata comply with importation to Drupal and LTER PASTA. Used MarcrosExportEML_HTML (working)pie_excel2007.xlsm 5/28/14 2:09 PM for QA/QC to EML 2.1.0
Geographic Description YSI water quality sonde at Middle Rd bridge on Parker River, Byfield, MA  
Location Bounding Box    
West Bounding Coordinate    
East Bounding Coordinate    
North Bounding Coordinate    
South Bounding Coordinate    
OR if single point location    
Latitude 42.758904  
Longitude -70.900941  
Taxonomic Protocols
Organisms studied
Methods:Measurements are made using a YSI 6600 water quality datalogging sonde. YSI Sonde sensors consist of 6150 optical dissolved oxygen probe , 6560 conductivity/temperature probe (thermistor) and non-vented** cable with level depth sensor (stainless steel strain gauge).

Missing data or blank values are caused by maintenance time periods or where sensor measurements are obviously wrong in the context of what would be expected. For example, the conductivity sensor has a relatively small opening and chamber for the conductivity electrodes, the estuary can have varying suspended sediment/detrital loads moving in the water column which enter the conductivity cell shorting out the electrodes making a faulty conductivity measurement (lower than expected). Oxygen measurements are dependent upon the conductivity measurements so the oxygen also becomes erroneous. Obvious measurements/data errors have been removed from the data set however the user of this data should also conduct their own data analysis to determine if the data are suitable for their particular situation.

Typical sensor/data problems are:
For oxygen: Poor/inaccurate conductivity measurements will affect the dissolved oxygen accuracy
For conductivity: Conductivity cell can have detrital material stuck in it, shorting out cell, resulting in lower than expected conductivity.
For depth: Depth strain gage pressure sensor may come out of the water at low tides resulting in many "zero" depth readings or sometimes negative values.

YSI Dissolved oxygen % saturation reporting can vary depending upon how the oxygen is calibrated.
For this data set two Oxygen percent saturation values are reported.
ODO%YSI variable name represents a YSI calibration in air, from Standard Methods, refers to calibration at a particular ATM pressure which allows DO% for calibration to fluctuate above/below 100% when ATM is above/below reference 760 or 1 ATM
ODO%Local variable name represents an oxygen calibration in air at a particular ATM pressure but it forces the DO% to be 100%, does not allow it to be under or above if ATM is above/below 760.
ODO%Local data should be used for metabolism studies when correcting for diffusion based on gradient deviations from 100% which by definition is the % saturation of oxygen in air.
ODO%YSI should not be used since it would require a known ATM pressure at each interval to calculate the ATM % saturation of oxygen to be use for that interval, probably a small correction anyway.
Concentration of DO remains the same for either calibration.

**Depth values needed corrections factors applied due to using a non-vented cable with the YSI. Pressure/depth readings needed a post deployment correction to account for changes in ambient atmospheric pressure. Marshview Farm (MFM) weather station 15 minute barometric pressure data was used to compute correction factors at the same time intervals as the 6600 sonde time intervals.
Ambient pressure changes correspond to the following water level changes, 1 mb = 0.0102 meters of water.

To correct our non-vented sonde depth readings for atmospheric pressure effects, we correct the sonde to 1 standard atmosphere (1013 millibars or 760 mm Hg) when we calibrate it, then apply an offset to the depth data (post collection) based on simultaneous measures of barometric pressure

2009 Depth Correction factor calculations for Middle Rd
Sonde is calibrated in air at ambient pressure and should be calibrated to the corresponding depth at pressures relative to 1 ATM (760torr or 1013.25 mBar. 1mB = 0.0102 meters of water, 1 Torr = 1.333224 mB.

If ambient air is 1014.58 mB pressure then sonde should be calibrated to 0.0136 m.
Example table is below.

Ambient ATM (Torr)
Ambient ATM (mB)
Offset meters















For 5/12/2009 the sonde depth was incorrectly calibrated to 0.000(m) instead of 0.0816(m). The error has been corrected/accounted for in the data file.

Table of Middle Road Bridge sonde depth calibrations by date for 2009
2009 Sonde Depth calib (m)

Offset (m)
Calib ATM (mB)

0.000, should have been (0.0816m)














Using the table above and measured depth data for the corresponding time intervals with pressure units in mB
Corrected depth (m) = (Measured depth + Offset) - ((Measured BAR- std ATM or 1013.25) x 0.0102)

Data Table

Variable Name Variable Description Units Measurement Scale Code Information Number Type DateTime Format Missing Value Code Missing Value Code Explanation
Date Date of sampling   datetime     DD-MON-YYYY NA NA = not available
Time Time of sampling (eastern standard time EST), 24 hr   datetime     hh:mm:ss NA NA = not available
Station Name of sampling station   nominal       NA NA = not available
Temp Temperature of water celsius interval   real   NA NA = not available
SpCond Specific conductivity of water millisiemenPerCentimeter ratio   real   NA NA = not available
Cond Conductivity of water millisiemenPerCentimeter ratio   real   NA NA = not available
Salinity Salinity of water partPerThousand interval   real   NA NA = not available
ODO%YSI Percent dissolved oxygen saturation of water percent ratio   real   NA NA = not available
ODO%Local Percent dissolved oxygen saturation of water percent ratio   real   NA NA = not available
ODO Conc Dissolved oxygen concentration of water milligramPerLiter ratio   real   NA NA = not available
Measured Depth Water column depth above non vented sonde pressure transducer meter ratio   real   NA NA = not available
Depth Offset Depth correction offset depending on calibration meter ratio   real   NA NA = not available
Measured BAR Barometric pressure from Marshview Farm (MFM) weather station (mbar) millibar ratio   real   NA NA = not available
Corrected Depth Water column depth above non vented sonde pressure transducer, correction factor applied for ambient atmospheric pressure changes meter ratio   real   NA NA = not available
Comments Comments about specific data   nominal       NA NA = not available