Marshwood High School, Eliot, Maine. Piscataqua River Site, 1996.
I. Data Set & Research Descriptors
1. Principal investigator & contact person
Joyce Tugel,
Chemistry Teacher
Marshwood High School
204 Dow Highway
Eliot, ME
03903
(207) 439-5600
email: jtugel@nh.ultranet.com
2. Entry verification
As tests are conducted by student
volunteers, the information is recorded on a data sheet provided by the Great
Bay Watch (NH) Water Quality Monitoring Program. Students then enter the data
into the "Alice" software database using a Power Mac 5200. Data files are
cross-checked by another student and the principal investigator prior to
submission to the Wells (ME) Reserve.
3. Experimental design
The Marshwood High School Water
Monitoring Program was founded four years ago as a part of the Great Bay Watch
Citizen's Water Quality Monitoring Program. Over 15 Great Bay Watch sites have
been established in the Great Bay Estuary, and samples are collected from April
through November. The objective of the Great Bay Watch is to establish a
long-term database that will provide information about the state of the estuary
and to increase knowledge and interest among its members and constituents about
the importance of conserving it. The Marshwood High site is located on the
Piscataqua River, and provides an opportunity for high school students to
volunteer in a program with "real science" applications.
4. Research methods
Water samples are collected from the
Piscataqua River site using a 5 gallon bucket with a clamped vinyl decanting
tube attached. The samples are analyzed for a) temperature; b) salinity; c) pH;
d) dissolved oxygen. Direct measurements of e) air temp; f) turbidity; and g)
water depth are also taken. A sample is also collected for h) fecal coliform
bacteria. All samples are collected and analyzed using procedures in compliance
with the Great Bay Watch QA/QC protocol. Detailed descriptions of the parameters
and procedures are avaliable in the Great Bay Watch training manual; a summary
of the procedures is included in this document. In addition to conducting the
appropriate calibrations on the day of sampling, all equipment is calibrated at
the beginning and midway through the sampling season by the Great Bay Watch
technical advisory team.
The directors of the Great Bay Watch volunteer monitoring program conducted a technical training session at Kingman Farm, the Sea Grant/Cooperative Extension laboratory facility, in March of 1996. The high school students and teachers participating in the project spent six hours performing the analyses, and all test results compared to samples of known concentration within the accepted QA/QC limits. The teachers attend two additional quality control sessions each year, and split samples are collected by the Great Bay Watch QA/QC team and analyzed at the Piscataqua River site twice each year. The teachers are present at every sampling session, and supervise the students' protocol.
a) Water temperature is measured in degrees Celsius with an
armored thermometer.
b) Salinity is determined with a hydrometer, which
measures the density of the water. This is converted to salinity by measuring
the temperature and using tables that relate the two measurements. The salinity
is extrapolated in units of parts per thousand.
c) pH is measured with a
pocket meter, which has first been calibrated with a pH 7.0 buffer solution. The
meter is rinsed twice with tap water before and after the buffer calibration and
once with sample water before the sample analysis.
d) Dissolved oxygen is
measured by Winkler titration. The protocol outlined in the Great Bay Watch
manual is similar to the methods used with a LaMotte DO kit, but the samples are
collected in 250 mL BOD glass bottles, and 100 mL subsamples are titrated with
manganese sulfate, iodide-azide, starch, sulfamic acid, and sodium thiosulfate.
A minimum of two titrations are conducted on each sample, agreeing within 0.5
mL.
e) Air temperature is measured in degrees Celsius with an air
thermometer.
f) Turbidity is measured with a Secchi disk, with lines marked
every 5 cm. The disk is lowered until it just goes out of sight, raised until it
just reappears, and the two measurements are averaged.
g) Water depth is
measured with the Secchi disk by lowering the disk until it touches bottom.
h) Water samples for fecal coliform bacteria counts are collected in sterile
Whirlpak bags. Tongs are used to lower the bags approximately 12 inches below
the surface, and samples are refrigerated until analyzed later that day. Trained
monitors conduct the membrane filtration process, with 100 mL water samples
filtered and incubated with Gelman MFC broth at 44.5 C for 24 hours. Negative
controls are run at the beginning and end of each filtration session.
5. Site location and character
The Great Bay Estuary is one
of two estuaries on the short coastline of New Hampshire. It is a complex
embayment composed of the Piscataqua River, Little Bay, and Great Bay. It drains
a watershed of 930 square miles, one-third of which is in Maine. Eight rivers
flow into the estuary, and one of them, the Piscataqua, is part of the boundary
between Maine and New Hampshire.
The Great Bay Estuary interacts with the Gulf of Maine at the mouth of the Piscataqua River which flows through the industrialized city of Portsmouth, New Hampshire. Approximately 14,500 years ago, the last glacier to cover the region retreated. Rising sea waters flowed into the basin that is now Great Bay proper, which was formed while the earth's crust was still compressed by the weight of the melting glacier. The waters drowned several river valleys and formed the Great Bay Estuary. Today, strong, tidally dominated and wind-driven currents control circulation. Sediments are resuspended and nutrients are widely distributed, thereby influencing primary productivity. Important habitats in the estuary include its waters, shellfish beds, subtidal eelgrass beds, mudflats, saltmarshes, channel bottoms and rocky intertidal areas.
The rapidly increasing population has heightened demands on the estuary in terms of shoreline development and recreational pursuits such as boating, fishing, hunting, and birdwatching.
Although it is known as one of the more pristine estuary systems on the Northeast coast, Great Bay has been identified as having potential problems with water quality. There are sewage treatment plants on most of the estuary's major rivers. Although most have been upgraded to secondary treatment levels, high bacterial counts occur in some parts of the estuary.
Today, 66% of the estuary's shellfish beds have been closed due to bacterial pollution. The US Department of Agriculture has identified the Great Bay as an estuary at risk. The Great Bay receives relatively low levels of both nitrogen and phosphorus compared to similar estuaries. However, more shoreline development carries with it the risk of increased nutrients entering the estuary.
Another source of potential degradation is related to petroleum
products. The Port of Portsmouth is an increasingly busy shipping port, with 91%
of its commercial shipping carrying petroleum products to and from the holding
tank farms on the New Hampshire shores of the Piscataqua River. A tanker spilled
nearly 1,000 gallons of oil into the Piscataqua River July 1, 1996 when the
moorings that attached the vessel to a dock at Schiller Station Separated. While
most of the oil was contained to the Piscataqua River, some seeped into other
areas of the Great Bay Estuary.
Additionally, several sites with potential
for toxic substance pollution exist on the shores of the estuary. They include
old tanning and bleach factories, the former Pease Air Force Base with its 14
Super Fund sites, and the Portsmouth Naval Shipyard.
The Marshwood High site is located in the Lower Piscataqua River near the Patten Yacht Yard, Inc., in South Eliot, ME (43 07' N Latitude, 70 47' W Longitude). This site is relatively close to the ocean, so its cool temperatures (low tide mean = 14.0 C, high tide mean = 12.5 C), high salinities (low tide mean = 27.6 ppt, high tide mean = 30.9 ppt), and relatively clear water (high tide mean secchi depth = 408 cm) are quite characteristic of its location. Dissolved oxygen levels are good at this site, with high and low tide saturation values averaging 96% and 95.4%, respectively. Fecal coliform levels tend to be low, with high and low tide geometric means of 3.2 and 4.9, respectively. (ref: The Great Bay Watch Five Year Report, 1990-1994; UNHMP-AR-SG-95-1)
6. Data collection period
Samples were collected from April
18, 1996 through November 6, 1996. The sampling occured approximately every
other week, and on each date, samples were taken at both low and high tides.
7. Associated researchers and projects
The Maine Partners in
Monitoring and New Hampshire Great Bay Watch Programs receive our data. In
return, we have access to all the PIM and GBW datasets from each of the sampling
years. We also submit our data to the Eliot and South Berwick Conservation
Commissions, who help support us financially.
II. Data Table Descriptors
1. The data appears in the following order (note that L = low tide, H = high tide): Date; water temp L (oC); water temp H (oC); dissolved oxygen L (ppm); dissolved oxygen H (ppm); salinity L (ppt); salinity H (ppt); saturation L (%); saturation H (%); pH L; pH H; fecal coliform L (cfu/100mL); fecal coliform H (cfu/100mL); transparency (turbidity) L (cm); transparency (turbidity) H (cm); depth L (cm); depth H (cm); air temp L (oC); air temp H (oC).
2. Remarks
April 18: Weather partly cloudy, boating
activities
May 6: Weather overcast, boating activities
May 20: Weather
foggy, boating activities
June 3: Weather overcast/shower, no boating
activities
June 17: Weather clear, boating activities
July 1: Weather
partly cloudy, boat maintenance, fish jumping
July 15: Weather overcast,
boaat maintenance
July 30: Weather partly cloudy, boating activities
Aug
14: Weather clear, boating activities
Aug 29: Weather overcast, tanks
unloading, boating activites
Sept 16: Weather overcast, boating
activites
Sept 30: Weather overcast, windy, no activities
Oct 15: Weather
clear, windy, boating
Oct 29: Weather partly cloudy, boating, boat
maintenance
Nov 6: Weather clear, boat repair, oil film
3. Explanations for missing data
Depth readings not possible
due to strong currents on 5/6/96 low tide and 7/1/96, 10/15/96, and 10/29/96
high tides. A period (.) was placed in the data table for the parameters that we
do not test for.