## Graphing Nutrient Trends from Stream Data

Watershed Map from the Miami Conservancy District

Please download Heidelberg University Great Miami nutrient, flow, & sediment data from multiple watersheds in Ohio. You will be graphing trends in their data from the Great Miami above Miamisburg. Read here for some general background on the Great Miami watershed.

Goals:

1) To examine the dataset organization; this may be of use to us as we compile our own data.

2) To create a hydrograph from the long-term flow data.

3) To plot long term nutrient trends through time.

4) To explore the relation of nutrient behavior with flow at distinct timescales (e.g.daily, seasonally, annually). * The Heidelberg dataset is unique because geochemistry was sampled every 8 hours.

5) To calculate R2 values to eventually determine if trends observed are significant.

Background

For our GSA poster we will be examining trends in silica and the nitrogen species nitrite (NO2) and nitrate (NO3). On the spreadsheet they are listed as silca (mg/L) and NO23 as N (mg/L). To understand how these elements behave together you will need to convert concentrations to moles. To do this you need the molar mass of silica (28.086 g/mol) and nitrogen (14.007 g/mol). If you divide the mass in mg/L by the molar mass in g/Mol your resulting answer will be in mM.

See this example on how to convert concentration. Practice this if it is unfamiliar to you.

Graphing Assignment (FOR GSA ABSTRACT)

Task 1: Graph Silica and NO2+NO3 as N vs. time. (10 pt)

1) Copy the spreadsheet into a new page (in the same file) and create columns for mM of silica and mM of NO23 as N.

2) Graph mM of silica and mM of NO23 as N vs. date

3) Run a best-fit linear trendline through each data set

4) Select options and display the R-squared value for each line

5) Write a caption for the figure that describes what is shown.

Task 2. Graph Silica vs. Cubic Meters of Flow (X) and NO2+NO3 in mMol of N vs. cubic meters of flow (10 pt)

1) Convert cfs into cubic meters (multiply by 0.028316847)

2) Run a best-fit linear trendline through each graph

3) Display R-squared value.

4) Write a caption for what is shown.

Task 3. Graph the molar ratio of Silica to NO2+NO3 as N vs.time. (10 pt)

1) Calculate ratio of Silica to NO23 as N (e.g. divide molar mass of silica by molar mass of NO23 as N)

2) Run a best-fit linear trendline through each graph

3) Display R-squared value.

4) Write a caption for what is shown.

Task 4. Calculate monthly averages of the Si:NO23 ratio for all available data & graph the average month trend (10 pt)

1) Copy spreadsheet and create a new spreadsheet, label this monthly averages.

2) Sort your data by month (see original spreadsheet, column OH).

3) Find the average concentration observed each month.

4) Create a graph with Si:NO23 molar ratios vs. month

5) Run a best-fit linear trendline through each graph

6) Display R-squared value.

7) Write a caption for what is shown. e.g. when are Si:NO3 ratios highest, lowest etc?

Task 5: Graph another timescale using the Si and/or NO32 molar data (e.g. hourly averages through time, daily averages through time, monthly averages through time). Create a caption that describes the graph. (10 pt)

Goals:

1) To examine the dataset organization; this may be of use to us as we compile our own data.

2) To create a hydrograph from the long-term flow data.

3) To plot long term nutrient trends through time.

4) To explore the relation of nutrient behavior with flow at distinct timescales (e.g.daily, seasonally, annually). * The Heidelberg dataset is unique because geochemistry was sampled every 8 hours.

5) To calculate R2 values to eventually determine if trends observed are significant.

Background

For our GSA poster we will be examining trends in silica and the nitrogen species nitrite (NO2) and nitrate (NO3). On the spreadsheet they are listed as silca (mg/L) and NO23 as N (mg/L). To understand how these elements behave together you will need to convert concentrations to moles. To do this you need the molar mass of silica (28.086 g/mol) and nitrogen (14.007 g/mol). If you divide the mass in mg/L by the molar mass in g/Mol your resulting answer will be in mM.

See this example on how to convert concentration. Practice this if it is unfamiliar to you.

Graphing Assignment (FOR GSA ABSTRACT)

Task 1: Graph Silica and NO2+NO3 as N vs. time. (10 pt)

1) Copy the spreadsheet into a new page (in the same file) and create columns for mM of silica and mM of NO23 as N.

2) Graph mM of silica and mM of NO23 as N vs. date

3) Run a best-fit linear trendline through each data set

4) Select options and display the R-squared value for each line

5) Write a caption for the figure that describes what is shown.

Task 2. Graph Silica vs. Cubic Meters of Flow (X) and NO2+NO3 in mMol of N vs. cubic meters of flow (10 pt)

1) Convert cfs into cubic meters (multiply by 0.028316847)

2) Run a best-fit linear trendline through each graph

3) Display R-squared value.

4) Write a caption for what is shown.

Task 3. Graph the molar ratio of Silica to NO2+NO3 as N vs.time. (10 pt)

1) Calculate ratio of Silica to NO23 as N (e.g. divide molar mass of silica by molar mass of NO23 as N)

2) Run a best-fit linear trendline through each graph

3) Display R-squared value.

4) Write a caption for what is shown.

Task 4. Calculate monthly averages of the Si:NO23 ratio for all available data & graph the average month trend (10 pt)

1) Copy spreadsheet and create a new spreadsheet, label this monthly averages.

2) Sort your data by month (see original spreadsheet, column OH).

3) Find the average concentration observed each month.

4) Create a graph with Si:NO23 molar ratios vs. month

5) Run a best-fit linear trendline through each graph

6) Display R-squared value.

7) Write a caption for what is shown. e.g. when are Si:NO3 ratios highest, lowest etc?

Task 5: Graph another timescale using the Si and/or NO32 molar data (e.g. hourly averages through time, daily averages through time, monthly averages through time). Create a caption that describes the graph. (10 pt)