Introductory Information:
Streams and rivers provide societies around the world with vital goods and services including drinking water, food, recreation, and aesthetic beauty. Additionally, streams and rivers harbor diverse organisms that are found nowhere else in the landscape. More than most other ecosystems, streams and rivers are adversely impacted by human activities which can compromise the ability of these systems to provide goods and services, and often result in a reduction of biodiversity. Identifying streams and rivers that are impacted by human activities is a key first step towards effective resource management (e.g., ecological restoration), and to do so ecologists have developed different types of assessment tools.
Impacts to streams are not always visible (e.g., adverse effects of many pollutants), and one common approach to evaluate the effects of human activities on streams is to examine biotic communities. Such 'biomonitoring' offers advantages over evaluating the stressor to the stream directly. For example, some stressors are present in the ecosystem infrequently (e.g., only during storm events) and impacts may be difficult to detect in the absence of very frequent sampling. However, impacts of these stressors, even those that are infrequent, may remain present and detectable in biotic communities for extended periods of time. Ecologists have learned to use a stream’s biotic community to evaluate the degree of these impacts.
Bioassessment in streams usually involves examination of fish and invertebrate communities, although other types of organisms (e.g., diatoms), are sometimes used. In this lab you will sample the benthic invertebrates of Galloway Creek which flows through the Biological Preserve on campus. With the data you gather you will compare a few community-level indices with another stream in the area that has contrasting land use. Additionally, you will learn how to calculate stream discharge (the volume of water flowing past a given point in a given amount of time), how to operate a hand-held water-quality meter that provides information on dissolved oxygen concentrations, conductivity and pH, and how to quantify how productive a body of water is by using light and dark bottles to indirectly measure photosynthesis and respiration.
In an aquatic setting, you can measure stream productivity by measuring the DO (dissolved oxygen) concentration of said body of water. There is a simple equation that can be used to find net primary production using known DO concentrations. NPP= GPP-R where NPP is net primary production, GPP is gross primary production, and R is respiration. There is also NEP (net ecosystem production)= GPP- R (respiration of everything). Primary production refers to plants, so we are concerned with how much oxygen they produce through photosynthesis. Another way to look at it is how much CO2 are they using up. We will be looking at how much oxygen is produced as a proxy for the amount of plant life that is present. Not everything in the water will be a plant though, there might be other organisms in the water too, things that use oxygen and release CO2. Even plants to some degree respire, however for simplicity sake will be finding NPP as opposed to NEP which means that we will assume that everything in our sample is either water or plant based. We will be using an initial stream DO concentration along with the concentrations that will you get from the water samples in your light and dark bottles (falcon tubes), to determine GPP, R, and NPP.
Objectives:
To introduce students to some common techniques used to sample a stream macroinvertebrate community, and how these communities can be used to indicate the overall ecological condition of a stream. To explore a way to test the productivity of a body of water, in this case a stream. To learn how to calculate stream discharge and test water quality.
Safety Issues:
This is two-week field-based lab. Please wear clothing that is appropriate for the weather as we will be in the field rain or shine!
Week 1: Macroinvertebrate Biomonitoring
Benthic-macroinvertebrate monitoring is the most common method of assessing the biological condition or 'health' of a stream. As stream conditions change, the benthic macroinvertebrate community responds. The number and diversity of organisms present in a stream are usually good indicators of stream condition. Benthic macroinvertebrates are easy to collect and each family can differ in their sensitivities to human impacts and pollution tolerance, making them useful organisms to assess a stream’s biological condition. Based on these differing sensitivities to pollution and/or habitat degradation, macroinvertebrate taxa can be classified into three broad categories:
Pollution Intolerant (high quality habitat) - Because of their inability to survive in the presence of pollution and/or habitat degradation, the presence of organisms in this group generally indicates a healthy stream with good water quality.
Somewhat Pollution Tolerant (middle quality habitat) - Organisms in this group can withstand some degree of pollution and/or habitat degradation but cannot survive very poor conditions.
Pollution Tolerant (low quality habitat) - Organisms in this group can survive in very poor conditions, with many of them having special adaptations that allow for their survival. Organisms such as mosquito larvae, pouch snails, and rat-tailed maggots, for example, can live in waters with little or no dissolved oxygen because they breathe oxygen from the air, not from the water.It is important to remember that these are general groupings of invertebrates. Finding a species from the pollution tolerant (low quality) group does not necessarily indicate an impacted stream. Pollution tolerant organisms have the ability to live in environments that are too harsh for many taxa, but can also live in high quality habitats. However, if these are the dominant types of organisms found, and few intolerant species are present, this usually indicates an impacted stream. During the pre-lab lecture, and later in the methods section, you will be shown how to sample macroinvertebrates and how to identify them for the purposes of this lab.
Week 2: Closed Chamber Respiration and Water Quality Assessment
We will be using a hand-held water-quality multimeter to determine the amount of dissolved oxygen and temperature of Galloway Creek and then using that same multimeter along with light and dark bottles (falcon tubes) to measure NPP, GPP, and R of Galloway Creek. We will also be calculating stream discharge for Galloway Creek.
Week 1: Benthic Macroinvertebrate Sampling and Identification
Macroinvertebrate Sampling Procedure:
The goal of benthic-macroinvertebrate sampling is to agitate the microhabitats sufficiently enough to dislodge the organisms and capture them in dip nets (D-nets). Sample at least three of the following habitats: logjams/fallen trees, leaf packs, riffles, slow-water areas, sand/muck and undercut banks.
Materials:
Lab worksheet and writing utensil
Aquatic invertebrate key
Sorting pan and forceps
1 Bottle filled with alcohol per group
1 D-net per groupBenthic-Macroinvertebrate Sampling Procedure:
Place the D-net opening facing upstream and in direct contact with the bottom.
While holding the net, have one group member gently kick benthic material into the opening.
Fill sorting trays with an inch of water and transfer benthic material into it.
Use forceps to collect benthic-macroinvertebrates and place them in the container filled with alcohol. These invertebrates will be taken back to the lab, where you will identify them.
*Note: Aquatic macroinvertebrates are commonly found on the surface of rocks and leaves.
In the lab:
Work with small groups to capture and identify aquatic invertebrates from your groups benthic samples to order. Your instructor will be available to help each group identify harder/problem invertebrates. You will then use the abundances of these invertebrates and answer questions 1-3.
Week 2: Water Quality and Macroinvertebrate Collection
1.) Water Chemistry Procedure:
The instructor or another volunteer from the Aquatic Ecology lab will be operating a multimeter. They will discuss what metrics they are recording and why it is important to know the chemistry of a stream. They will take recordings of dissolved oxygen, temperature, and pH in a rifle and in a pool. The groups will average the numbers for each microhabitat and record it on the designated table. 2) Closed Chamber Respiration (Light and Dark Bottles)
Materials:
A hand-held water-quality meter (multi-meter)
A dark bottle
A light bottle
Closed Chamber Respiration (Light and Dark Bottles) Procedure:
Each student will have a dark bottle and a light bottle, but will use class data for initial stream DO concentration.
We will use the class average of the stream’s dissolved oxygen concentration as the initial stream DO concentration for all students. Write that number into your table (question 7).
Each student will pick a spot along the creek and fill both the light and the dark tubes with stream water. Record on the data where the sample was taken from.
Rinse out each one three times using the stream water before finally filling them.
When you have your water sample, you will cap it underwater. This is to insure that no air gets in, if there is air in your tube tap the tube to get it out before capping it underwater.
Note the time that your sample was capped. Make sure to do steps 3-5 for both the light tube and the dark.
When both are filled with water, leave them for an hour (we will use this time to complete other portions of the lab).
After that time the multimeter will be used (by the instructor) to find the DO concentrations of both of your falcon tubes. Write those numbers in your table.
You will then finish the math to find NPP, GPP, and R.
3) Stream Discharge Procedure:
Stream discharge is defined as the volume of water flowing past a point in a given amount of time. Common units for expressing stream discharge include cubic feet per second, liters per second, cubic kilometers per year, and those used in the lab today, cubic meters per second. Discharge is most commonly measured in the field with a flow velocity meter, along with corresponding information on channel width and depth. We will be using the flow meter and testing another method to measure the velocity component of stream discharge (Q).
Using a measuring tape, two people will measure the width of the stream channel in meters.
Water velocity Water velocity will be measured first using the flow meter. Next it will be measured using an orange following the “float” protocol below.
Stream Discharge (Q) = Velocity * Depth* Width. Average discharge will be measured by taking the mean of the three measurements (only for “float” method).
The two values for Q will then be compared.
Flow meter:
Water velocity will be measured at five separate and equally spaced locations across the stream channel moving from the left to right banks. (Differentiating between right and left banks is done by looking in the downstream direction)
Using a meter stick measure the depth at each location and take the velocity at 40% of the depth. Record this data in the table located at the back of the lab.
Repeat until all 5 transects have been completed.
Stream Discharge (Q) = Velocity * Depth* Width of individual transects. Sum to find the total discharge of the stream section.
“Float” Protocol: (Based on procedure found here: https://www.inmtn.com/tools/float-method/)
Pick a stretch of the stream to be used at least 20 ft long and mark the beginning and end of the stretch.
Measure the width of the downstream transect of the stretch.
Take at least 10 depth measurements along the downstream transect.
Find the average depth measurement and multiply that with the width to get area.
Toss the orange upstream of the upstream transect of the chosen stretch and using a stopwatch (or phone timer) measure how long it takes the orange to make it from the upstream transect to the downstream transect. Repeat this three times.
Using the length of the stretch and the time it took the orange to traverse the transect calculate meters/second (m/s).
Multiply the m/s by the area to get the discharge. Repeat for each measurement then take the mean. This will give you the average stream discharge for your transect. Stream Ecology Lab - Write-Up (Print and turn in this sheet, written answers, the tables, and calculations)
Directions: Using the data you gathered at Galloway Creek, and that provided on invertebrate communities from a local reference stream, answer the following questions and turn in your data sheets relating to macroinvertebrates and stream discharge. Use L-THIA (https://engineering. purdue.edu/~lthia/) to answer questions related to the Galloway Creek Watershed and Coon Watersheds.
Questions:
1) What is the percent of tolerant, moderately intolerant, and intolerant invertebrate taxa in each of the two streams (Galloway and Coon Creek)? E.g., 15% tolerant in Galloway, etc.. (6 pts)
2) List the three most common orders of invertebrates you found and describe one characteristic you used to identify that order from others. (4 pts)
3) The formula for the Shannon-Wiener Diversity Index is: (6 pts) (show your work below)
H' = -Σ(pi ln(pi)) and pi =(Si/N)
"pi" is the relative abundance of each species, calculated as the proportion of individuals of a given species to the total number of individuals in the community, "Si" is the total number of individuals for one species, and "N" is the total number of individuals sampled (i.e. all species). Note that the equation has a -Σ at the beginning of it… this means that after you multiply out the (piln(pi)) for each species in the community (i.e. Galloway Creek macroinvertebrates or Coon Creek macroinvertebrates) you will need to sum the values that you calculated from those species in the same community together and multiply by -1.
What is the species (using the order) richness, and diversity (as H') of the invertebrate communities in Galloway Creek and Coon Creek (data provided below). Use the area to the right of the tables to show your work.
Coon Creek Invert
Taxa Number Collected N
Plecoptera 62 0.150851582 -0.285329556
Trichoptera 138 0.335766423 -0.36643517
Diptera 91 0.221411192 -0.333829118
Odonata 34 0.082725061 -0.206170101
Ephemeroptera 77 0.187347932 -0.313768029
Hemiptera 9 0.02189781 -0.083679605
Total 411
Richness
H’ 1.59
Galloway Creek
Invert Taxa Number Collected N
Oligochaeta 8 0.186046512 -0.312885316
Trichoptera 2 0.046511628 -0.142700137
Plecoptera 2 0.046511628 -0.142700137
Coleoptera 13 0.302325581 -0.361657206
Decapoda 2 0.046511628 -0.142700137
Planorbidae 1 0.023255814 -0.08746977
Diptera 5 0.11627907 -0.250204907
Hemiptera 2 0.046511628 -0.142700137
Odonata 6 0.139534884 -0.274805672
Ephemeroptera 2 0.046511628 -0.142700137
Total 43
Richness
H’ 2.0005
4) How do the values of richness and diversity compare? I.e., are the values consistently greater in one stream than the other? (4 pts)
5) Using model my watershed , calculate percent imperviousness for Coon Creek and Galloway Creek. From L-THIA homepage, click on ‘Great Lakes Watershed Management Project’, then click Michigan under ‘Quick State Selection’. Next, click on the LatLng (Latitude, Longitude) tab and enter the coordinates of the creek (For Galloway Creek, just zoom in on the map to Oakland University and follow Library Drive south to where it crosses over the creek on the preserve, use ‘Point’ instead of ‘LatLng’, click on Delineate and click on the stream). Click submit and wait for it to delineate. Next, click on the ‘Tools’ tab, and then the ‘Imperviousness’ tab and calculate the percent imperviousness from the values given.
Percent imperviousness = impervious area total / total landuse
(7.86+7.91+4.81)/36.29 x100=56.71%
What are some of the ways in which the two streams differ? E.g., with regards to their drainage areas, % imperviousness and land uses. How might this data explain the data you observed with regards to the invertebrate data? Do the differences in land use correspond to the differences you observed in invertebrate communities? Coon Creek latitude and longitude are as follows: 42.801164737515094,-82.89289377207297? (6 pts)
(0.67+0.05+0.00)/23.66 x100=3.04%
6) Calculate the stream discharge, compare the two methods and fill out the water chemistry table. (8 pts)
“Float” Stream Discharge Calculation
Depth Width of Transect (m) 5.7
Measurement # Water Depth (m) Area (Width*Depth) (m²)
1 0.16 Length of Stretch (m) 7.5
2 0.2 Time 1 (s) 15.57
3 0.22 Time 2 (s) 17.17
4 0.18 Time 3 (s)
5 0.14 Velocity (m/s) 1 0.0128
6 0.2 Velocity (m/s) 2 0.0128
7 0.18 Velocity (m/s) 3
8 0.16 Discharge (Q=AV) 1 (m³/s) 0.912
9 0.16 Discharge (Q=AV) 2 (m³/s) 1.14
10 0.2 Discharge (Q=AV) 3 (m³/s)
Average 0.18 Average Discharge (m³/s) 1.026
Stream Discharge Flow Meter
Location on measuring tape Water Depth (m) (same as above) Velocity at 40% depth (m/s) Discharge
1 0.16 0.08 0.0128
0.4 0.2 0.27 0.0216
0.4 0.22 0.3 0.0264
0.4 0.18 0.31 0.0223
0.4 0.14 0.24 0.0134
0.4 0.2 0.27 0.0216
0.5 0.18 0.28 0.0252
0.5 0.16 0.25 0.02
0.5 0.16 0.14 0.0112
0.5 0.2 0.05 0.005
total discharge (m3/s) 0.1795
How do the discharge values compare between the two methods?
Water Quality Table Riffle
Dissolve Oxygen 6.89 mg/L
Temperature 17.8 ºC
pH 7.2167
Water Quality Table Pool
Dissolve Oxygen 6.846 mg/L
Temperature 17.9 ºC
pH 7.21
7) Respiration table and math (6 pts)
Location of where sample was taken (riffle, pool, etc)
Initial stream DO concentration (mg/L) DO concentration dark bottle (mg/L) DO concentration for light bottle (mg/L)
8.2 8.25
Initial Stream DO for NPP calculations if you got your sample from slow moving water 6.84
Initial Stream DO for NPP calculations if you got your sample from fast moving water 6.89
Net primary production equation: Initial DO- Dark DO= R
NPP= GPP-R Light DO- Dark DO = GPP
Light DO- Initial DO = NPP
Use your numbers from the table above to find the following values for NPP (net primary production), GPP (gross primary production), and R (respiration). Then use those numbers that you found to fill in the net primary production equation. Show work below.
How do you think your values for NPP would change if the water came from a different part of the stream?
Sample Solution