Attachment To:
Is The Water Safe for Aquatic Life?
Curriculum created by Sue Habeck, Tacoma Community College
Student Handout
IS THE WATER SAFE FOR AQUATIC LIFE?
Activity summary: You will measure some water quality factors and
observe and/or learn about the habitats around one or more bodies of
water. You will ponder factors that may contribute to poor water quality
and reflect on ways water quality may be improved for public safety and
the health of aquatic life.
Introduction to water quality issues:
Aquatic organisms depend upon “clean” water for their survival.
But what is “clean”? Different water bodies, such as streams, ponds,
estuaries, and oceans naturally vary in temperature, oxygen levels,
salinity, sediments, acidity, nutrients, etc. Different aquatic species are
adapted to different conditions. Some species have very narrow ranges of
tolerance while others can tolerate a wide range of conditions.
Water can be altered physically or chemically due to natural events
(e.g. volcanic eruption) or through human activities. Pollutants raining
down from the air or flowing from streets and pipes significantly affect
water quality, as do sediments, as well as heat from denuded landscapes
and climate change.
Nonnative, invasive species can also impart physical, chemical, and
ecological changes to a body of water (e.g. Spartina, a marsh grass).
When bodies of water are physically or chemically altered, the
effects are often complex. Some alterations can kill certain organisms
(e.g. low oxygen), while other alterations may affect reproduction and
development (e.g. feminization due to hormones and hormone mimics).
Other conditions may lead to long-term health problems such as cancer
and brain damage. Some pollutants can accumulate in the tissues of
organisms, magnifying in concentration at each step of the food chain
(e.g. mercury in fish). As different organisms respond to the changes, the
ecological balances are disrupted (e.g. red tides, which can cause
paralytic shellfish poisoning, are linked to fertilizer pollution).
Many people routinely check water quality factors and monitor the
health of aquatic organisms to help protect public health and to work
towards ecological restoration and protection.
Possible pre-lab activities:
You may first learn about water chemistry, habitats surrounding water
bodies, and/or how to use online maps and aerial photos. You may be
asked to complete a worksheet focusing on water chemistry and graphs.
Which bodies of water will be tested?
Your instructor will provide information about the specific bodies of water
that will be tested. You may be going on a class fieldtrip, or bringing
samples from home, or obtaining a test kit for use at home, or the
instructor may bring in water samples. For each water body, you will also
need to observe or learn about the surrounding habitats. Access to local
maps (paper or online) is also likely to be necessary.
** GEOGRAPHY of the water bodies
1.
a) What are the names of the water bodies?
b) What kind of water bodies are they? (e.g. pond? stream? Puget Sound?
etc.)
2. Using specific descriptive language, describe where the water bodies
are located. You may also be required to attach a map and/or aerial
photo of the location(s) you sampled. (Potential online sources: Google
Earth and NASA World Wind).
3. If several water bodies were tested, are they connected to one
another? How so?
4. Where does the water come from (e.g. underground springs? runoff
from…where?) If you don’t know, make some educated guesses.
** HABITATS around the water bodies
(You may be allowed to choose one of the water bodies if testing
several)
1. What kinds of land uses currently surround the body of water?
(e.g. houses with yards, apartments and stores, forests, industries,
etc.)
2. What kind of land uses are you aware of upstream? (also consider
ground water impacts)
3. Imagine this body of water and its habitat 300 years ago (before major
European influences). List some specific attributes.
4. Imagine all the changes that have occurred to this body of water in the
last 300 years. List as many specific kinds of disturbances you can
imagine and explain how these may affect water quality.
5. How you think this body of water has changed in the course of your
lifetime?
Explain why you think so.
Testing water quality factors
Depending on your test kits and the kinds of water bodies you are testing,
you will collect different kinds of measurements. Commonly collected
factors include temperature, salinity, pH, nitrates, oxygen, and CO 2..
Some schools and agencies have methods for testing heavy metals or
organic solvents but those tests are more expensive and difficult. It is
common to also test for sediments (turbidity) and fecal coliform (intestinal
bacteria from sewage or feces).
http://iodeweb5.vliz.be/oceanteacher/resources/
Obtain specific instructions from your instructor.
Common instructions include:
- read the instructions on the kits carefully (e.g. how many drops of
solution #1? Shake for how long? How do we recalibrate the digital
instrument? etc.)
- agree on the units you are recording (e.g. Celcius? ppt? etc)
- agree to take samples the same distance from shore at the same depth:
e.g. an arm’s reach from the bank, at the surface.
- wear gloves and goggles if instructed to;
- use good judgment about where to sample (e.g. don’t sample a goose
pellet);
- attempt to get as many samples as possible for each location;
- use clean test tubes and rinse between samples;
- try using different kinds of kits and tools;
- dump chemical fluids into a waste bin and dispose of properly at home or
in the lab;
** Record Data on a Data Sheet
- Record all factors that may influence your measurements such as date,
time, air temperature, tide level, and other factors (e.g. a recent snow
storm; recent fertilization nearby, etc.).
- Create a data sheet so that each factor is listed with appropriate units.
- Record all numbers in the appropriate locations on the data sheet.
- It is best to get as many replicate measurements as possible. Record all
values which are obtained. (You can compute summary statistics such as
averages later.)
** Follow up report about water quality factors
You may need to look some of these answers up in your text or elsewhere
if you did not catch the information in lecture or during the activity.
1. List at least two specific reasons why some of your measurements may
not be accurate.
2. List each factor that was test (e.g. pH) and one reason why its values
could potentially change throughout a year (seasonally or for other
reasons)
3. Choose one of the bodies of water you measured: _______________.
Pretend the following problems are detected in that body of water.
List at least two specific and realistic ways this may have happened for
your water body.
a) lower than normal oxygen levels at the surface:
b) higher than normal surface temperatures for this time of year:
** Follow up report about water quality factors
c) excessively high levels of nutrients like nitrates and phosphates:
d) significant increase in pH making it alkaline (basic):
e) increased levels of soluble lead (Pb):
4. Do you think that your water body would have different temperatures at
different depths? Why or why not?
5. What might happen to the chemistry at the surface of this water body if
the surface temperature remained warmer than usual all year? (hint:
“turnover”)
6. If you were to test Puget Sound, would you expect it to be more or less
saline than the Pacific Ocean and why? (The Pacific is about 3.5% or 35
ppt)
7. If saline water were to flow into a freshwater system, layers may
develop. Would the salty water be on the bottom or the top and why?
8. Name something specific which might happen to shelled organisms if
the pH of your body of water decreased significantly, like from extra
dissolved CO2.
9. When nutrient levels increase, “eutrophication” may occur. First, algae
and cyanobacteria populations increase. What next? Explain the steps, all
the way up to dead fish.
Displaying water quality data
1. Choose one of the factors we measured and draw a rough little BAR
graph with fully labeled axes (with units) and title.
2.
a) Describe a water quality situation where you could collect data and
describe it using a “connect-the-dots” graph rather than a bar graph. What
is your x-axis? (independent variable)
b) Describe another water quality situation where your x-axis is different
than for the two graphs above.
Designing scientific investigations
1. Choose any water quality factor you want to and write a scientific,
testable question .
2. Then describe how someone could test your idea.
Summary about one or more of the water bodies
you measured
1. Given what you have discovered about the habitat and the water quality
factors, what do you suspect are the top three “problems” that are
affecting the well-being of aquatic life in your water body?
2. List at two things that lawmakers and land managers could do to
improve the health of this water body for aquatic life.
3. List at least four ways YOU directly or indirectly contribute to water
quality problems near where you live and work.
4. List at least four things YOU could do to improve water quality
downstream from where you live.