Estuarine Salinity Distribution and Classification Project

Brad Hubeny, Salem State University
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This is a field and lab activity in which students collect CTD data in a local estuary, contour the data, and analyze the results to classify the estuary based on standard classification schemes.

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I use this exercise in a sophomore/junior level course entitled "Estuaries and Pollution." This is mostly an elective course for Geological Sciences majors, but I also attract other students with environmental interests.

Skills and concepts that students must have mastered

Students should have a basic understanding of stratification of estuarine waters and how estuaries are classified based on salinity distributions (i.e. salt wedge, well-mixed, etc).

How the activity is situated in the course

The attached activity is the lab and analysis component of a field/lab investigation. Prior to this activity, students have spent a day in the field on collecting salinity and temperature values in the estuary using a YSI geochemical probe.


Content/concepts goals for this activity

Estuarine stratification

Higher order thinking skills goals for this activity

Contoured data in both map and cross section views
Used real data to classify the Danvers River Estuary
Used your problem solving skills to establish a procedure to answer the scientific question posed

Other skills goals for this activity

Corrected depth measurements for tidal stage
Calculated a profile's vertical exaggeration
Used Excel for basic computations and plotting

Description and Teaching Materials

A number of us collected water column data from the Danvers River Estuary with a YSI geochemical probe. We collected temperature and salinity readings at 1-meter depth intervals at nine total stations. These data are available in an Excel document. We will use these data to classify the estuary based on contoured plots and compare our classification to the calculation of river volume to tidal volume, as we discussed in class. For this exercise you will need to produce 1) and contoured map of surface salinity in the estuary, 2) a contoured fence-type profile diagram illustrating salinity variability with depth along the length of the estuary, and 3) water column plots of temperature, salinity, and σt for selected field locations along the transect.
Estuarine Classification Exercise (Microsoft Word 2007 (.docx) 158kB Jun9 14)
Spreadsheet of YSI data from Danvers River Estuary (MA) 23 September 2013 (Excel 2007 (.xlsx) 19kB Jun9 14)

Teaching Notes and Tips

If students are not comfortable with contouring, the mechanics of the exercise can be a bit overwhelming.


I correct this assignment based on the quality of their contouring, and the student's ability to synthesize and interpret the data to classify the estuary.

References and Resources