Lab 8 Bioindicators

Lab 8 pre-lab.

You will be introduced to watersheds and bioindicators in this lab. You will create and use a dichotomous key to ID protist bioindicators from various water samples. In the next lab you will calculate biodiversity metrics from your data to evaluate the health of each stream from which the samples originated. The data collected in Lab 8 will be analyzed in Lab 9 and serve as the basis for your scientific manuscript.

Introduction
Do you know enough?
What we will do in lab?
LABridge

WHat is biodiversity? What can it tell us about a watershed?

Biodiversity is the variety of life in the world or in a particular habitat or ecosystem. It can be measured using two primary metrics:

richness- counting the number of unique species (e.g., 17 pollinator species in a meadow)
abundance- counting the total number of individuals of each species (e.g., 28 individual honey bees, 4 ruby-throated hummingbirds, 12 alfalfa butterflies, etc.)

We'll discuss more amount the ways to measure diversity in Lab 9. Biodiversity is vitally important because it is linked to the overall health of an ecosystem. This can be defined as ecosystem function, (the capacity of the system to provide goods and services that satisfy human needs), or ecosystem stability (showing little change from its natural state in the face of disturbance, like pollution).

A watershed is an area of land that drains or “sheds” water into a specific waterbody. Every body of water has a watershed. Watersheds drain rainfall and snowmelt into streams and rivers. These smaller bodies of water flow into larger ones, including lakes, bays, and oceans. Gravity helps to guide the path that water takes across the landscape (USGS, 2022). Streams are often key collection points across watersheds, which also then often run into small rivers, which flow into bigger ones. Bowling Green is part of the Green River Watershed in KY, which empties into the Mississippi/Missouri River Watershed basin, which flows into the Gulf of Mexico.

Key threats to the Green River and surrounding streams include forest loss, erosion, water demands, increasingly volatile cycles of flood and drought caused by a changing climate, agricultural runoff and pollution from resource extraction activities. Agricultural runoff is a particular concern. This is a type of non-point-source pollution (i.e., pollution transported by storm water collection) vs. point-source pollution (e.g., the direct dumping of toxins into a stream). The fertilizers, pesticides, and herbicides use in large scale commercial farming pose serous risks to aquatic life, fish-eating wildlife, and drinking water supplies. Streams located close to agriculture also often suffer from a reduce riparian zone. Riparian zones are tree and vegetative heavy buffer-areas that usually line the sides of healthy streams. The vegetation helps soak up pollutants in runoff and their root systems stabilize the banks. When these areas are clear-cut (for crops or livestock), increased pollutants enter the stream and stream-bank erosion leads to higher levels of sedimentation, causing further environmental and biodiversity issues.

It's possible to measure the biodiversity of a watershed to ascertain its overall health or function. Protists are a good bioindicator of overall stream health. Over the next two labs, we will compare water samples from two streams, located in two different sub-watersheds of the Green River Watershed. One is an example of a stream located close to large agricultural area, with little to no riparian zone (stream A) and the other is an example of a heavily-wooded stream, far-removed from agriculture or industry (stream B). This week we will be assessing the biodiversity of protists in our samples to assess the health of each stream

KY Watersheds (KY-EPA). Click for link to reporting page.

Green River Watershed Facts

9,230 square-mile watershed
Located in Central Kentucky
Vitally important for wildlife habitat, drinking water, irrigation, outdoor recreation.
Gives life to more species of plants and animals than any other Ohio River tributary.
From The Nature Conservancy (TNC)

Agricultural runoff flowing into a stream without a riparian zone (Lynn Betts).

Know the bold-faced terms introduced in this tab.

Review the watershed facts list and major threats.

DO you know enough about bioindicators?

Bioindicators are taxa (or communities) whose presence or absence can tell a great deal about the overall health of the ecosystem in question. They serve as "canaries in the coal mine" and can warn ecologist and conservationists that the ecosystem may be in decline before the appearance of other, larger, more troubling signs. By using the diversity of indicators as a warning, the intent is that restoration efforts can begin before lasting damage is done.

What makes some species good bioindicators? We know that organisms are highly adapted to both the biotic (living factors like competitors, prey, and predators) and abiotic factors (like light, temperature, pH, etc.) of their environment. Their niche represents the range of conditions they can tolerate while still maximizing growth and reproduction (i.e., fitness) within a specific range of environmental factors. Outside influences (like invasive species, pollution, and climate change) can alter the environment, changing both biotic and abiotic factors. This, in turn, can lead to decreased fitness for individuals in that environment and changes to population dynamics like abundance and richness. Good indicator species need to be common, so sampling and finding them is not problematic, but also sensitive to these types of environmental changes.

A classic bioindicator are the EPT taxa (Ephemeroptera (mayflies), Plecoptera (stoneflies) and Trichoptera (caddisflies). These genera represent benthic macroinvertebrates, and together are often used as bioindicators of stream health. Review the example in the sidebar.

In this lab, you will be using protists as bioindicators of watershed health and function. They are useful in this way for 6 primary reasons (Payne, 2013).

Environmentally sensitive
Important tropically (to the food web)
Broad distribution
Small & numerous (small samples yield big results)
Easy to identify
Resistant to decomposition

EPT taxa show a shift in community composition due to human-induced water withdrawals in the Umatilla River, Oregon. Disturbance-intolerant EPT taxa decline following an 85% reduction of stream flow. © 2010 Nature Education Modified from Miller et al. (2007). All rights reserved. Click the image for article.

What makes a taxa a good bioindicator? Be sure to read over the example graph.

Know the 6 specific reasons why protists are good bioindicators.

What will we do in lab & how will we do iT?

Lab 8 contains three exercises.

Hypothesis creation and introduction outline: You will generate a hypothesis for this project and outline your introduction section to prepare to write your manuscript.
Key creation: You will use your skills making a key and previous experience with protists to create a taxonomic key for protist identification.
Using your key, you will ID and record protists from two different stream samples, which vary greatly in their overall ecosystem health.

Think about protists, bioindicators, and watersheds. What topics might you include in your introduction?

What hypothesis might you construct concerning these streams and the species data you have collected?

Upper Green River. Photo courtesy of Green River Nature Conservancy.

If you feel confident with this material, click the bridge icon below and navigate to Blackboard to take the LABridge for this week. Be ready to be tested on this material before you go to the quiz, and make sure you have your Lab Notebook Guide ready to submit as well.

Click here to get to WKU's blackboard to take your LABridge for this week.

Lab 8 Protocol

Following this lab you should be able to...

Understand the importance of watershed health and its link to biodiversity
Discuss the importance of bioindicators and why protists are appropriate.
Create and use a taxonomic key.
Identify various species and taxonomic groups under the microscope.

Overview. In today's lab you create a taxonomic key to help ID protists. You will then ID protists from various water samples and use biodiversity metrics to evaluate watershed health.

Exercise I. Hypothesis creation and introduction outline.
Exercise II. You will review a slide show of common protists and make a quick taxonomic key. You will view prepare slides of each protist and test your key.
Exercise III. You will collected data of the type and quantity of each protist in two different water samples and prepare your data for analysis next week.

Exercise 1
Exercise II
Exercise III

Exercise i. research Prep & HYPOTHESIS GENERATION

We focused on the steps of the scientific method in our first unit on the scientific process. We will be putting that systematic approach towards this project and we'll begin with identifying our question, conducting background research, and constructing our hypothesis.

Procedure: Task A. Research Prep

See the figure and accordion box (in the sidebar) for a review on the scientific method.
Review the description of each stream from the Pre-Lab: Stream A is an example of a stream located close to large agricultural area, with little to no riparian zone, and stream B is an example of a heavily-wooded stream, far-removed from agriculture or industry.
Open your Lab Notebook Guide.
Review the content you were supplied in the Pre-Labs for Lab 8 and 9.
Discuss some key areas you will need to research for this project.
Complete Exercise 1 (part A) in your Lab Notebook Guide. You'll spend much more time researching the literature for your paper, but this will get you started.
There are additional resources in our library.

Procedure: Task B. Hypothesis Generation

Knowing what you now know about protists, bioindicators, and watersheds, what predictions might you make about these streams?
Your key research question is: Do these streams have the same level of protist biodiversity?
Discuss your potential hypotheses with your group.
Decide which variables you think are most important to use to answer this answer this research question. Be sure your hypotheses address each indicator you chose use in a specific way.
Complete Exercise 1 (part B) in your Lab Notebook Guide.

Ask a question

Questions can arise from observations in the field, in the lab, from the scientific literature (e.g., scientific posters, presentations or papers), or from pre-existing data. In this class, sometimes your question will be provided to you and other times you will get to decide what questions you want to investigate.

Conduct background research

This is a literature review process, in which researchers dig deep into what is already known about their topic of choice and what questions still remain. Often, the literature review helps to refine questions and direct hypothesis formation. Background research will be provided to you in our first few labs, but you will also do some research on your own in later lab activities.

Construct a hypothesis

A quality hypothesis must be testable, objectively measurable, specific, and falsifiable. It must include a prediction and potential mechanism(s) based in the literature or from previous work. You will do this often in BIOL 123.

Test with an experiment

There are various approaches to research design, based on your research question. These range from purely descriptive to experimental designs, which involve manipulation of a variable or variables. Regardless of the method selected, the design should have clearly identified variables by type, and should be both valid and reliable. You will have varying levels of input on the experiments we conduct in lab.

Analyze the data & draw conclusions

The methods used for analysis are largely based on the research design. In the biological sciences, analysis almost always involves the use of statistical tests and graphical representations of data. We will use several different types of statistics throughout this course.

Communicate your results

This last step is essential. For our understanding of the natural world to grow, new research must be shared so others can draw on what is known to expand our understanding. Results can be communicated through technical reports, presentations at conferences, scientific posters, and manuscripts which appear in scientific journals. You will create many of these products throughout BIOL 123

Exercise II. Learn to ID protists using a key

The photo gallery below depicts two images of each protist discussed in your lab manual and in the accompanying PowerPoint.
The first image on each slide is from a past BIOL 123 lab and was taken under the compound microscope. The second image is more idealized photo.

Procedure.

Open your Lab Notebook Guide for Lab 8.
Go through the images of the 7 listed protists and locate them in your slide tray.
Using the skills you developed earlier with keys and protist ID, create a dichotomous key for identifying them under the microscope.
Once your key is finished, test it using the prepared slides provided for each listed protist.
Remember! You will have to ID these on your final and you'll need to be good at this to complete Exercise II.

Protist List

Amoeba proteus
Plasmodium falciparum
Volvox sp.
Diatoms
Euglena gracilis
Paramecium caudatum
Spirogyra sp.

Exercise III. Identify live protists from different stream samples

Please view the videos below of protist movement. This will help get you prepared to identify living protists!

Materials.

Procedure. Identify the protists in each water sample

You will be investigating protists found in two different streams: stream A and stream B.
Investigate the videos below to see how some move, so you know what to expect.
There are two other common taxa, both animals, that you may also see. Planaria and daphnia are also pictured below.
Open your data table in Excel from the sidebar.
Images of the data tables are in the sidebar.
Stream samples are labeled on the back bench. Take your small beakers back by the samples (labeled as A or B). Aliquot 9mLs (3 droppers) of each stream sample into its corresponding beaker. Be sure you are also using the correctly labeled droppers. Watch out for contamination throughout this study.
Go to tab 1 in your spreadsheet.
Obtain your depression slides. You should have two in your slide tray.
To view a sample: Place two drops from stream A or B onto depression slide. Scan the entirety of the samples and fill out the correct column on your data table in tab one.
If you can see protists but they are moving too quickly, add 1 drop of proto-slow, located at your station.
View the videos at the bottom of this tab to help you with your species IDs.
Repeat this process (share tasks) until you have collected data on two different drop-samples from stream A and two different drop-samples from stream B.
Very Important! After you have recorded your IDs and abundance values, you need to order them alphabetically. Any species missing from any sample gets a zero. Your species list for each sample should contain exactly the same names in the same order.
Once you have reorganized your rows, calculate the sum and mean across samples for stream A and then for stream B. Directions for each are in the sidebar if needed.
Complete your Lab Notebook Guide.
Clean your stations and show your data tables to check out.

Slide diagrams and "search" directions. Click to enlarge.

Your data table in tab 1.

How to calculate SUM in Excel.

How to calculate the MEAN in Excel.

You might also see these small animals

Copepods are in the phylum Arthropoda.

Planaria are flatworms in the phylum Platyhelminthes.

Rotifers are in the phylum Rotifera.

Daphnia (water fleas) are in the phylum Arthropoda.

faculty spotlight: carl dick

Bats can also serve as valuable bioindicators for climate change, water quality, agricultural intensification, loss and fragmentation of forest habitats, and habitat pollution. Dr. Carl Dick is interested in bats and bat flies as part of his research which centers on the relationships of parasites and mammalian hosts. Bat flies are obligate, blood-feeding parasites of bats worldwide, and are found nowhere else. These flies have evolved numerous morphological, physiological, and behavioral adaptations to their parasitic life on the bat’s bodies. Because of their intimate relationships with bats, bat flies provide a model system for studies in evolution and ecology.
Contact: [email protected]
Tripartite associations between Afrotropical bats, eukaryotic parasites, and microbial symbionts... Bats, Bat Flies, and Fungi: Exploring Uncharted Waters...